scientificamerican--2020-08-17--This Twist on Schrödinger's Cat Paradox Has Major Implications for Quantum Theory

What does it feel like to be both alive and dead ?
That question irked and inspired Hungarian-American physicist Eugene Wigner in the 1960s .
He was frustrated by the paradoxes arising from the vagaries of quantum mechanics—the theory governing the microscopic realm that suggests , among many other counterintuitive things , that until a quantum system is observed , it does not necessarily have definite properties .
Take his fellow physicist Erwin Schrödinger ’ s famous thought experiment in which a cat is trapped in a box with poison that will be released if a radioactive atom decays .
@ @ @ @ @ @ @ before the box is opened , the story goes , the atom has both decayed and not decayed , leaving the unfortunate cat in limbo—a so-called superposition between life and death .
But does the cat experience being in superposition ?
Wigner sharpened the paradox by imagining a ( human ) friend of his shut in a lab , measuring a quantum system .
He argued it was absurd to say his friend exists in a superposition of having seen and not seen a decay unless and until Wigner opens the lab door @ @ @ @ @ @ @ friend ’ thought experiment shows that things can become very weird if the observer is also observed , ” says Nora Tischler , a quantum physicist at Griffith University in Brisbane , Australia .
Now Tischler and her colleagues have carried out a version of the Wigner ’ s friend test .
By combining the classic thought experiment with another quantum head-scratcher called entanglement—a phenomenon that links particles across vast distances—they have also derived a new theorem , which they claim puts the strongest constraints yet on the fundamental nature of reality .
@ @ @ @ @ @ @ Physics on August 17 , has implications for the role that consciousness might play in quantum physics—and even whether quantum theory must be replaced .
The new work is an “ important step forward in the field of experimental metaphysics , ” says quantum physicist Aephraim Steinberg of the University of Toronto , who was not involved in the study .
“ It ’ s the beginning of what I expect will be a huge program of research.
” Until quantum physics came along in the 1920s , physicists expected their theories to @ @ @ @ @ @ @ outcome of experiments with certainty .
But quantum theory appears to be inherently probabilistic .
The textbook version—sometimes called the Copenhagen interpretation—says that until a system ’ s properties are measured , they can encompass myriad values .
This superposition only collapses into a single state when the system is observed , and physicists can never precisely predict what that state will be .
Wigner held the then popular view that consciousness somehow triggers a superposition to collapse .
Thus , his hypothetical friend would discern a definite outcome when she or he @ @ @ @ @ @ @ her or him in superposition .
This view has since fallen out of favor .
“ People in the foundations of quantum mechanics rapidly dismiss Wigner ’ s view as spooky and ill-defined because it makes observers special , ” says David Chalmers , a philosopher and cognitive scientist at New York University .
Today most physicists concur that inanimate objects can knock quantum systems out of superposition through a process known as decoherence .
Certainly , researchers attempting to manipulate complex quantum superpositions in the lab can find their hard work destroyed @ @ @ @ @ @ @ systems .
So they carry out their tests at ultracold temperatures and try to isolate their apparatuses from vibrations .
Several competing quantum interpretations have sprung up over the decades that employ less mystical mechanisms , such as decoherence , to explain how superpositions break down without invoking consciousness .
Other interpretations hold the even more radical position that there is no collapse at all .
Each has its own weird and wonderful take on Wigner ’ s test .
The most exotic is the “ many worlds ” view , which says @ @ @ @ @ @ @ , reality fractures , creating parallel universes to accommodate every possible outcome .
Thus , Wigner ’ s friend would split into two copies and , “ with good enough supertechnology , ” he could indeed measure that person to be in superposition from outside the lab , says quantum physicist and many-worlds fan Lev Vaidman of Tel Aviv University .
The alternative “ Bohmian ” theory ( named for physicist David Bohm ) says that at the fundamental level , quantum systems do have definite properties ; we just do not know @ @ @ @ @ @ @ their behavior .
In that case , the friend has a single experience , but Wigner may still measure that individual to be in a superposition because of his own ignorance .
In contrast , a relative newcomer on the block called the QBism interpretation embraces the probabilistic element of quantum theory wholeheartedly ( QBism , pronounced “ cubism , ” is actually short for quantum Bayesianism , a reference to 18th-century mathematician Thomas Bayes ’ s work on probability . )
QBists argue that a person can only use quantum mechanics to @ @ @ @ @ @ @ beliefs about what he or she will measure in an experiment .
“ Measurement outcomes must be regarded as personal to the agent who makes the measurement , ” says Ruediger Schack of Royal Holloway , University of London , who is one of QBism ’ s founders .
According to QBism ’ s tenets , quantum theory can not tell you anything about the underlying state of reality , nor can Wigner use it to speculate on his friend ’ s experiences .
Another intriguing interpretation , called retrocausality , allows events @ @ @ @ @ @ @ .
“ In a retrocausal account , Wigner ’ s friend absolutely does experience something , ” says Ken Wharton , a physicist at San Jose State University , who is an advocate for this time-twisting view .
But that “ something ” the friend experiences at the point of measurement can depend upon Wigner ’ s choice of how to observe that person later .
The trouble is that each interpretation is equally good—or bad—at predicting the outcome of quantum tests , so choosing between them comes down to taste .
“ @ @ @ @ @ @ @ , ” Steinberg says .
“ We don ’ t even know if the list of potential solutions we have is exhaustive.
” Other models , called collapse theories , do make testable predictions .
These models tack on a mechanism that forces a quantum system to collapse when it gets too big—explaining why cats , people and other macroscopic objects can not be in superposition .
Experiments are underway to hunt for signatures of such collapses , but as yet they have not found anything .
Quantum physicists are also placing ever @ @ @ @ @ @ @ a team in Vienna reported doing so with a 2,000-atom molecule .
Most quantum interpretations say there is no reason why these efforts to supersize superpositions should not continue upward forever , presuming researchers can devise the right experiments in pristine lab conditions so that decoherence can be avoided .
Collapse theories , however , posit that a limit will one day be reached , regardless of how carefully experiments are prepared .
“ If you try and manipulate a classical observer—a human , say—and treat it as a quantum system , it @ @ @ @ @ @ @ Bassi , a quantum physicist and proponent of collapse theories at the University of Trieste in Italy .
Tischler and her colleagues believed that analyzing and performing a Wigner ’ s friend experiment could shed light on the limits of quantum theory .
They were inspired by a new wave of theoretical and experimental papers that have investigated the role of the observer in quantum theory by bringing entanglement into Wigner ’ s classic setup .
Say you take two particles of light , or photons , that are polarized so that they @ @ @ @ @ @ @ photons can also be placed in a superposition of vibrating both horizontally and vertically at the same time , just as Schrödinger ’ s paradoxical cat can be both alive and dead before it is observed .
Such pairs of photons can be prepared together—entangled—so that their polarizations are always found to be in the opposite direction when observed .
That may not seem strange—unless you remember that these properties are not fixed until they are measured .
Even if one photon is given to a physicist called Alice in Australia , while @ @ @ @ @ @ @ Bob in a lab in Vienna , entanglement ensures that as soon as Alice observes her photon and , for instance , finds its polarization to be horizontal , the polarization of Bob ’ s photon instantly syncs to vibrating vertically .
Because the two photons appear to communicate faster than the speed of light—something prohibited by his theories of relativity—this phenomenon deeply troubled Albert Einstein , who dubbed it “ spooky action at a distance.
” These concerns remained theoretical until the 1960s , when physicist John Bell devised a way to @ @ @ @ @ @ @ there could be a more mundane explanation behind the correlations between entangled partners .
Bell imagined a commonsense theory that was local—that is , one in which influences could not travel between particles instantly .
It was also deterministic rather than inherently probabilistic , so experimental results could , in principle , be predicted with certainty , if only physicists understood more about the system ’ s hidden properties .
And it was realistic , which , to a quantum theorist , means that systems would have these definite properties even if nobody @ @ @ @ @ @ @ the maximum level of correlations between a series of entangled particles that such a local , deterministic and realistic theory could support .
If that threshold was violated in an experiment , then one of the assumptions behind the theory must be false .
Such “ Bell tests ” have since been carried out , with a series of watertight versions performed in 2015 , and they have confirmed reality ’ s spookiness .
“ Quantum foundations is a field that was really started experimentally by Bell ’ s [ theorem ] —now @ @ @ @ @ @ @ ’ ve spent a lot of time reimplementing those experiments and discussing what they mean , ” Steinberg says .
“ It ’ s very rare that people are able to come up with a new test that moves beyond Bell.
” The Brisbane team ’ s aim was to derive and test a new theorem that would do just that , providing even stricter constraints— “ local friendliness ” bounds—on the nature of reality .
Like Bell ’ s theory , the researchers ’ imaginary one is local .
They also explicitly @ @ @ @ @ @ @ they insist that experimenters are free to choose what to measure without being influenced by events in the future or the distant past .
( Bell implicitly assumed that experimenters can make free choices , too . )
Finally , the team prescribes that when an observer makes a measurement , the outcome is a real , single event in the world—it is not relative to anyone or anything .
Testing local friendliness requires a cunning setup involving two “ superobservers , ” Alice and Bob ( who play the role of Wigner @ @ @ @ @ @ @ Debbie .
Alice and Bob each have their own interferometer—an apparatus used to manipulate beams of photons .
Before being measured , the photons ’ polarizations are in a superposition of being both horizontal and vertical .
Pairs of entangled photons are prepared such that if the polarization of one is measured to be horizontal , the polarization of its partner should immediately flip to be vertical .
One photon from each entangled pair is sent into Alice ’ s interferometer , and its partner is sent to Bob ’ s .
Charlie @ @ @ @ @ @ @ in this test .
Rather , they are beam displacers at the front of each interferometer .
When Alice ’ s photon hits the displacer , its polarization is effectively measured , and it swerves either left or right , depending on the direction of the polarization it snaps into .
This action plays the role of Alice ’ s friend Charlie “ measuring ” the polarization .
( Debbie similarly resides in Bob ’ s interferometer . )
Alice then has to make a choice : She can measure the photon ’ @ @ @ @ @ @ @ would be the equivalent of opening the lab door and asking Charlie what he saw .
Or she can allow the photon to continue on its journey , passing through a second beam displacer that recombines the left and right paths—the equivalent of keeping the lab door closed .
Alice can then directly measure her photon ’ s polarization as it exits the interferometer .
Throughout the experiment , Alice and Bob independently choose which measurement choices to make and then compare notes to calculate the correlations seen across a series of entangled @ @ @ @ @ @ @ out 90,000 runs of the experiment .
As expected , the correlations violated Bell ’ s original bounds—and crucially , they also violated the new local-friendliness threshold .
The team could also modify the setup to tune down the degree of entanglement between the photons by sending one of the pair on a detour before it entered its interferometer , gently perturbing the perfect harmony between the partners .
When the researchers ran the experiment with this slightly lower level of entanglement , they found a point where the correlations still violated Bell @ @ @ @ @ @ @ .
This result proved that the two sets of bounds are not equivalent and that the new local-friendliness constraints are stronger , Tischler says .
“ If you violate them , you learn more about reality , ” she adds .
Namely , if your theory says that “ friends ” can be treated as quantum systems , then you must either give up locality , accept that measurements do not have a single result that observers must agree on or allow superdeterminism .
Each of these options has profound—and , to some @ @ @ @ @ @ @ paper is an important philosophical study , ” says Michele Reilly , co-founder of Turing , a quantum-computing company based in New York City , who was not involved in the work .
She notes that physicists studying quantum foundations have often struggled to come up with a feasible test to back up their big ideas .
“ I am thrilled to see an experiment behind philosophical studies , ” Reilly says .
Steinberg calls the experiment “ extremely elegant ” and praises the team for tackling the mystery of the observer ’ @ @ @ @ @ @ @ it is no surprise that quantum mechanics forces us to give up a commonsense assumption—physicists knew that from Bell— “ the advance here is that we are a narrowing in on which of those assumptions it is , ” says Wharton , who was also not part of the study .
Still , he notes , proponents of most quantum interpretations will not lose any sleep .
Fans of retrocausality , such as himself , have already made peace with superdeterminism : in their view , it is not shocking that future measurements @ @ @ @ @ @ @ many-worlds adherents long ago threw out the requirement that quantum mechanics prescribes a single outcome that every observer must agree on .
And both Bohmian mechanics and spontaneous collapse models already happily ditched locality in response to Bell .
Furthermore , collapse models say that a real macroscopic friend can not be manipulated as a quantum system in the first place .
Vaidman , who was also not involved in the new work , is less enthused by it , however , and criticizes the identification of Wigner ’ s friend with a @ @ @ @ @ @ @ paper “ are ridiculous ; the friend has to be macroscopic , ” he says .
Philosopher of physics Tim Maudlin of New York University , who was not part of the study , agrees .
“ Nobody thinks a photon is an observer , unless you are a panpsychic , ” he says .
Because no physicist questions whether a photon can be put into superposition , Maudlin feels the experiment lacks bite .
“ It rules something out—just something that nobody ever proposed , ” he says .
Tischler accepts the @ @ @ @ @ @ @ want to overclaim what we have done , ” she says .
The key for future experiments will be scaling up the size of the “ friend , ” adds team member Howard Wiseman , a physicist at Griffith University .
The most dramatic result , he says , would involve using an artificial intelligence , embodied on a quantum computer , as the friend .
Some philosophers have mused that such a machine could have humanlike experiences , a position known as the strong AI hypothesis , Wiseman notes , though nobody @ @ @ @ @ @ @ out to be true .
But if the hypothesis holds , this quantum-based artificial general intelligence ( AGI ) would be microscopic .
So from the point of view of spontaneous collapse models , it would not trigger collapse because of its size .
If such a test was run , and the local-friendliness bound was not violated , that result would imply that an AGI ’ s consciousness can not be put into superposition .
In turn , that conclusion would suggest that Wigner was right that consciousness causes collapse .
“ @ @ @ @ @ @ @ live to see an experiment like this , ” Wiseman says .
“ But that would be revolutionary.
” Reilly , however , warns that physicists hoping that future AGI will help them home in on the fundamental description of reality are putting the cart before the horse .
“ It ’ s not inconceivable to me that quantum computers will be the paradigm shift to get to us into AGI , ” she says .
“ Ultimately , we need a theory of everything in order to build an AGI on a @ @ @ @ @ @ @ ” That requirement may rule out more grandiose plans .
But the team also suggests more modest intermediate tests involving machine-learning systems as friends , which appeals to Steinberg .
That approach is “ interesting and provocative , ” he says .
“ It ’ s becoming conceivable that larger- and larger-scale computational devices could , in fact , be measured in a quantum way.
” Renato Renner , a quantum physicist at the Swiss Federal Institute of Technology Zurich ( ETH Zurich ) , makes an even stronger claim : regardless of @ @ @ @ @ @ @ , he says , the new theorem tells us that quantum mechanics needs to be replaced .
In 2018 Renner and his colleague Daniela Frauchiger , then at ETH Zurich , published a thought experiment based on Wigner ’ s friend and used it to derive a new paradox .
Their setup differs from that of the Brisbane team but also involves four observers whose measurements can become entangled .
Renner and Frauchiger calculated that if the observers apply quantum laws to one another , they can end up inferring different results in @ @ @ @ @ @ @ paper is another confirmation that we have a problem with current quantum theory , ” says Renner , who was not involved in the work .
He argues that none of today ’ s quantum interpretations can worm their way out of the so-called Frauchiger-Renner paradox without proponents admitting they do not care whether quantum theory gives consistent results .
QBists offer the most palatable means of escape , because from the outset , they say that quantum theory can not be used to infer what other observers will measure , Renner says @ @ @ @ @ @ @ though : If everything is just personal to me , how can I say anything relevant to you ?
” he adds .
Renner is now working on a new theory that provides a set of mathematical rules that would allow one observer to work out what another should see in a quantum experiment .
Still , those who strongly believe their favorite interpretation is right see little value in Tischler ’ s study .
“ If you think quantum mechanics is unhealthy , and it needs replacing , then this is useful @ @ @ @ @ @ @ ” Vaidman says .
“ But I don ’ t agree that this is the case—many worlds explains everything.
” For now , physicists will have to continue to agree to disagree about which interpretation is best or if an entirely new theory is needed .
“ That ’ s where we left off in the early 20th century—we ’ re genuinely confused about this , ” Reilly says .
“ But these studies are exactly the right thing to do to think through it.
” Disclaimer : The author frequently writes for @ @ @ @ @ @ @ research in physics and cosmology and partially funded the Brisbane team ’ s study .

What does it feel like to be both alive and dead?
That question irked and inspired Hungarian-American physicist Eugene Wigner in the 1960s. He was frustrated by the paradoxes arising from the vagaries of quantum mechanics—the theory governing the microscopic realm that suggests, among many other counterintuitive things, that until a quantum system is observed, it does not necessarily have definite properties. Take his fellow physicist Erwin Schrödinger’s famous thought experiment in which a cat is trapped in a box with poison that will be released if a radioactive atom decays. Radioactivity is a quantum process, so before the box is opened, the story goes, the atom has both decayed and not decayed, leaving the unfortunate cat in limbo—a so-called superposition between life and death. But does the cat experience being in superposition?
Wigner sharpened the paradox by imagining a (human) friend of his shut in a lab, measuring a quantum system. He argued it was absurd to say his friend exists in a superposition of having seen and not seen a decay unless and until Wigner opens the lab door. “The ‘Wigner’s friend’ thought experiment shows that things can become very weird if the observer is also observed,” says Nora Tischler, a quantum physicist at Griffith University in Brisbane, Australia.
Now Tischler and her colleagues have carried out a version of the Wigner’s friend test. By combining the classic thought experiment with another quantum head-scratcher called entanglement—a phenomenon that links particles across vast distances—they have also derived a new theorem, which they claim puts the strongest constraints yet on the fundamental nature of reality. Their study, which appeared in Nature Physics on August 17, has implications for the role that consciousness might play in quantum physics—and even whether quantum theory must be replaced.
The new work is an “important step forward in the field of experimental metaphysics,” says quantum physicist Aephraim Steinberg of the University of Toronto, who was not involved in the study. “It’s the beginning of what I expect will be a huge program of research.”
A Matter of Taste
Until quantum physics came along in the 1920s, physicists expected their theories to be deterministic, generating predictions for the outcome of experiments with certainty. But quantum theory appears to be inherently probabilistic. The textbook version—sometimes called the Copenhagen interpretation—says that until a system’s properties are measured, they can encompass myriad values. This superposition only collapses into a single state when the system is observed, and physicists can never precisely predict what that state will be. Wigner held the then popular view that consciousness somehow triggers a superposition to collapse. Thus, his hypothetical friend would discern a definite outcome when she or he made a measurement—and Wigner would never see her or him in superposition.
This view has since fallen out of favor. “People in the foundations of quantum mechanics rapidly dismiss Wigner’s view as spooky and ill-defined because it makes observers special,” says David Chalmers, a philosopher and cognitive scientist at New York University. Today most physicists concur that inanimate objects can knock quantum systems out of superposition through a process known as decoherence. Certainly, researchers attempting to manipulate complex quantum superpositions in the lab can find their hard work destroyed by speedy air particles colliding with their systems. So they carry out their tests at ultracold temperatures and try to isolate their apparatuses from vibrations.
Several competing quantum interpretations have sprung up over the decades that employ less mystical mechanisms, such as decoherence, to explain how superpositions break down without invoking consciousness. Other interpretations hold the even more radical position that there is no collapse at all. Each has its own weird and wonderful take on Wigner’s test. The most exotic is the “many worlds” view, which says that whenever you make a quantum measurement, reality fractures, creating parallel universes to accommodate every possible outcome. Thus, Wigner’s friend would split into two copies and, “with good enough supertechnology,” he could indeed measure that person to be in superposition from outside the lab, says quantum physicist and many-worlds fan Lev Vaidman of Tel Aviv University.
The alternative “Bohmian” theory (named for physicist David Bohm) says that at the fundamental level, quantum systems do have definite properties; we just do not know enough about those systems to precisely predict their behavior. In that case, the friend has a single experience, but Wigner may still measure that individual to be in a superposition because of his own ignorance. In contrast, a relative newcomer on the block called the QBism interpretation embraces the probabilistic element of quantum theory wholeheartedly (QBism, pronounced “cubism,” is actually short for quantum Bayesianism, a reference to 18th-century mathematician Thomas Bayes’s work on probability.) QBists argue that a person can only use quantum mechanics to calculate how to calibrate his or her beliefs about what he or she will measure in an experiment. “Measurement outcomes must be regarded as personal to the agent who makes the measurement,” says Ruediger Schack of Royal Holloway, University of London, who is one of QBism’s founders. According to QBism’s tenets, quantum theory cannot tell you anything about the underlying state of reality, nor can Wigner use it to speculate on his friend’s experiences.
Another intriguing interpretation, called retrocausality, allows events in the future to influence the past. “In a retrocausal account, Wigner’s friend absolutely does experience something,” says Ken Wharton, a physicist at San Jose State University, who is an advocate for this time-twisting view. But that “something” the friend experiences at the point of measurement can depend upon Wigner’s choice of how to observe that person later.
The trouble is that each interpretation is equally good—or bad—at predicting the outcome of quantum tests, so choosing between them comes down to taste. “No one knows what the solution is,” Steinberg says. “We don’t even know if the list of potential solutions we have is exhaustive.”
Other models, called collapse theories, do make testable predictions. These models tack on a mechanism that forces a quantum system to collapse when it gets too big—explaining why cats, people and other macroscopic objects cannot be in superposition. Experiments are underway to hunt for signatures of such collapses, but as yet they have not found anything. Quantum physicists are also placing ever larger objects into superposition: last year a team in Vienna reported doing so with a 2,000-atom molecule. Most quantum interpretations say there is no reason why these efforts to supersize superpositions should not continue upward forever, presuming researchers can devise the right experiments in pristine lab conditions so that decoherence can be avoided. Collapse theories, however, posit that a limit will one day be reached, regardless of how carefully experiments are prepared. “If you try and manipulate a classical observer—a human, say—and treat it as a quantum system, it would immediately collapse,” says Angelo Bassi, a quantum physicist and proponent of collapse theories at the University of Trieste in Italy.
A Way to Watch Wigner’s Friend
Tischler and her colleagues believed that analyzing and performing a Wigner’s friend experiment could shed light on the limits of quantum theory. They were inspired by a new wave of theoretical and experimental papers that have investigated the role of the observer in quantum theory by bringing entanglement into Wigner’s classic setup. Say you take two particles of light, or photons, that are polarized so that they can vibrate horizontally or vertically. The photons can also be placed in a superposition of vibrating both horizontally and vertically at the same time, just as Schrödinger’s paradoxical cat can be both alive and dead before it is observed.
Such pairs of photons can be prepared together—entangled—so that their polarizations are always found to be in the opposite direction when observed. That may not seem strange—unless you remember that these properties are not fixed until they are measured. Even if one photon is given to a physicist called Alice in Australia, while the other is transported to her colleague Bob in a lab in Vienna, entanglement ensures that as soon as Alice observes her photon and, for instance, finds its polarization to be horizontal, the polarization of Bob’s photon instantly syncs to vibrating vertically. Because the two photons appear to communicate faster than the speed of light—something prohibited by his theories of relativity—this phenomenon deeply troubled Albert Einstein, who dubbed it “spooky action at a distance.”
These concerns remained theoretical until the 1960s, when physicist John Bell devised a way to test if reality is truly spooky—or if there could be a more mundane explanation behind the correlations between entangled partners. Bell imagined a commonsense theory that was local—that is, one in which influences could not travel between particles instantly. It was also deterministic rather than inherently probabilistic, so experimental results could, in principle, be predicted with certainty, if only physicists understood more about the system’s hidden properties. And it was realistic, which, to a quantum theorist, means that systems would have these definite properties even if nobody looked at them. Then Bell calculated the maximum level of correlations between a series of entangled particles that such a local, deterministic and realistic theory could support. If that threshold was violated in an experiment, then one of the assumptions behind the theory must be false.
Such “Bell tests” have since been carried out, with a series of watertight versions performed in 2015, and they have confirmed reality’s spookiness. “Quantum foundations is a field that was really started experimentally by Bell’s [theorem]—now over 50 years old. And we’ve spent a lot of time reimplementing those experiments and discussing what they mean,” Steinberg says. “It’s very rare that people are able to come up with a new test that moves beyond Bell.”
The Brisbane team’s aim was to derive and test a new theorem that would do just that, providing even stricter constraints—“local friendliness” bounds—on the nature of reality. Like Bell’s theory, the researchers’ imaginary one is local. They also explicitly ban “superdeterminism”—that is, they insist that experimenters are free to choose what to measure without being influenced by events in the future or the distant past. (Bell implicitly assumed that experimenters can make free choices, too.) Finally, the team prescribes that when an observer makes a measurement, the outcome is a real, single event in the world—it is not relative to anyone or anything.
Testing local friendliness requires a cunning setup involving two “superobservers,” Alice and Bob (who play the role of Wigner), watching their friends Charlie and Debbie. Alice and Bob each have their own interferometer—an apparatus used to manipulate beams of photons. Before being measured, the photons’ polarizations are in a superposition of being both horizontal and vertical. Pairs of entangled photons are prepared such that if the polarization of one is measured to be horizontal, the polarization of its partner should immediately flip to be vertical. One photon from each entangled pair is sent into Alice’s interferometer, and its partner is sent to Bob’s. Charlie and Debbie are not actually human friends in this test. Rather, they are beam displacers at the front of each interferometer. When Alice’s photon hits the displacer, its polarization is effectively measured, and it swerves either left or right, depending on the direction of the polarization it snaps into. This action plays the role of Alice’s friend Charlie “measuring” the polarization. (Debbie similarly resides in Bob’s interferometer.)
Alice then has to make a choice: She can measure the photon’s new deviated path immediately, which would be the equivalent of opening the lab door and asking Charlie what he saw. Or she can allow the photon to continue on its journey, passing through a second beam displacer that recombines the left and right paths—the equivalent of keeping the lab door closed. Alice can then directly measure her photon’s polarization as it exits the interferometer. Throughout the experiment, Alice and Bob independently choose which measurement choices to make and then compare notes to calculate the correlations seen across a series of entangled pairs.
Tischler and her colleagues carried out 90,000 runs of the experiment. As expected, the correlations violated Bell’s original bounds—and crucially, they also violated the new local-friendliness threshold. The team could also modify the setup to tune down the degree of entanglement between the photons by sending one of the pair on a detour before it entered its interferometer, gently perturbing the perfect harmony between the partners. When the researchers ran the experiment with this slightly lower level of entanglement, they found a point where the correlations still violated Bell’s bound but not local friendliness. This result proved that the two sets of bounds are not equivalent and that the new local-friendliness constraints are stronger, Tischler says. “If you violate them, you learn more about reality,” she adds. Namely, if your theory says that “friends” can be treated as quantum systems, then you must either give up locality, accept that measurements do not have a single result that observers must agree on or allow superdeterminism. Each of these options has profound—and, to some physicists, distinctly distasteful—implications.
Reconsidering Reality
“The paper is an important philosophical study,” says Michele Reilly, co-founder of Turing, a quantum-computing company based in New York City, who was not involved in the work. She notes that physicists studying quantum foundations have often struggled to come up with a feasible test to back up their big ideas. “I am thrilled to see an experiment behind philosophical studies,” Reilly says. Steinberg calls the experiment “extremely elegant” and praises the team for tackling the mystery of the observer’s role in measurement head-on.
Although it is no surprise that quantum mechanics forces us to give up a commonsense assumption—physicists knew that from Bell—“the advance here is that we are a narrowing in on which of those assumptions it is,” says Wharton, who was also not part of the study. Still, he notes, proponents of most quantum interpretations will not lose any sleep. Fans of retrocausality, such as himself, have already made peace with superdeterminism: in their view, it is not shocking that future measurements affect past results. Meanwhile QBists and many-worlds adherents long ago threw out the requirement that quantum mechanics prescribes a single outcome that every observer must agree on.
And both Bohmian mechanics and spontaneous collapse models already happily ditched locality in response to Bell. Furthermore, collapse models say that a real macroscopic friend cannot be manipulated as a quantum system in the first place.
Vaidman, who was also not involved in the new work, is less enthused by it, however, and criticizes the identification of Wigner’s friend with a photon. The methods used in the paper “are ridiculous; the friend has to be macroscopic,” he says. Philosopher of physics Tim Maudlin of New York University, who was not part of the study, agrees. “Nobody thinks a photon is an observer, unless you are a panpsychic,” he says. Because no physicist questions whether a photon can be put into superposition, Maudlin feels the experiment lacks bite. “It rules something out—just something that nobody ever proposed,” he says.
Tischler accepts the criticism. “We don’t want to overclaim what we have done,” she says. The key for future experiments will be scaling up the size of the “friend,” adds team member Howard Wiseman, a physicist at Griffith University. The most dramatic result, he says, would involve using an artificial intelligence, embodied on a quantum computer, as the friend. Some philosophers have mused that such a machine could have humanlike experiences, a position known as the strong AI hypothesis, Wiseman notes, though nobody yet knows whether that idea will turn out to be true. But if the hypothesis holds, this quantum-based artificial general intelligence (AGI) would be microscopic. So from the point of view of spontaneous collapse models, it would not trigger collapse because of its size. If such a test was run, and the local-friendliness bound was not violated, that result would imply that an AGI’s consciousness cannot be put into superposition. In turn, that conclusion would suggest that Wigner was right that consciousness causes collapse. “I don’t think I will live to see an experiment like this,” Wiseman says. “But that would be revolutionary.”
Reilly, however, warns that physicists hoping that future AGI will help them home in on the fundamental description of reality are putting the cart before the horse. “It’s not inconceivable to me that quantum computers will be the paradigm shift to get to us into AGI,” she says. “Ultimately, we need a theory of everything in order to build an AGI on a quantum computer, period, full stop.”
That requirement may rule out more grandiose plans. But the team also suggests more modest intermediate tests involving machine-learning systems as friends, which appeals to Steinberg. That approach is “interesting and provocative,” he says. “It’s becoming conceivable that larger- and larger-scale computational devices could, in fact, be measured in a quantum way.”
Renato Renner, a quantum physicist at the Swiss Federal Institute of Technology Zurich (ETH Zurich), makes an even stronger claim: regardless of whether future experiments can be carried out, he says, the new theorem tells us that quantum mechanics needs to be replaced. In 2018 Renner and his colleague Daniela Frauchiger, then at ETH Zurich, published a thought experiment based on Wigner’s friend and used it to derive a new paradox. Their setup differs from that of the Brisbane team but also involves four observers whose measurements can become entangled. Renner and Frauchiger calculated that if the observers apply quantum laws to one another, they can end up inferring different results in the same experiment.
“The new paper is another confirmation that we have a problem with current quantum theory,” says Renner, who was not involved in the work. He argues that none of today’s quantum interpretations can worm their way out of the so-called Frauchiger-Renner paradox without proponents admitting they do not care whether quantum theory gives consistent results. QBists offer the most palatable means of escape, because from the outset, they say that quantum theory cannot be used to infer what other observers will measure, Renner says. “It still worries me, though: If everything is just personal to me, how can I say anything relevant to you?” he adds. Renner is now working on a new theory that provides a set of mathematical rules that would allow one observer to work out what another should see in a quantum experiment.
Still, those who strongly believe their favorite interpretation is right see little value in Tischler’s study. “If you think quantum mechanics is unhealthy, and it needs replacing, then this is useful because it tells you new constraints,” Vaidman says. “But I don’t agree that this is the case—many worlds explains everything.”
For now, physicists will have to continue to agree to disagree about which interpretation is best or if an entirely new theory is needed. “That’s where we left off in the early 20th century—we’re genuinely confused about this,” Reilly says. “But these studies are exactly the right thing to do to think through it.”
Disclaimer: The author frequently writes for the Foundational Questions Institute, which sponsors research in physics and cosmology and partially funded the Brisbane team’s study.


scientificamerican--2020-08-14--Coronavirus News Roundup: August 8-August 14

In the U , .S.
, “ …community outbreaks of the coronavirus this summer have centered on restaurants and bars , often the largest settings to infect Americans , ” writes Jennifer Steinhauer at The New York Times ( 8/12/20 ) .
Data show that about a quarter of Louisiana ’ s coronavirus cases since March , other than those in nursing homes , prisons , and the like , trace back to bars and restaurants , the story reports .
In Maryland , “ 12 percent of new cases last month were traced to restaurants…and in Colorado , 9 @ @ @ @ @ @ @ to bars and restaurants , ” Steinhauer reports .
Indoor dining is banned in New York City and many other places , the story states .
Many food-service workers have felt pressured to return to their jobs when restaurants re-opened .
These jobs are often low-paying , may not offer health insurance , and are disproportionately held by Hispanic people , the story states .
A study published 8/7/20 that assessed a laser-beam approach to measuring the effectiveness of face masks received some misleading and incorrect media coverage this week .
This 8/12/20 @ @ @ @ @ @ @ clears up many of the misconceptions .
First , this was not a study of the effectiveness of face masks for blocking droplets released during speech that potentially contain SARS-CoV-2 .
It was a study of a method for measuring mask effectiveness .
And the sample sizes were too low to serve as a test of effectiveness for cutting transmission risk ( which again , the study was not meant to do ) .
Also , talking is just one of the ways we might release droplets containing the virus .
Singing , @ @ @ @ @ @ @ them .
So , don ’ t throw out your unjustly maligned neck-gaiter , the story states .
Most evidence shows that cloth masks , including “ properly worn neck gaiters , filter out the majority of [ SARS-CoV-2 and other ] viral particles and provide some protection for an individual , ” says an infectious diseases researcher at the University of California , San Francisco , who is quoted in the piece .
In an 8/7/20 essay in The New York Times , a prominent epidemiologist and a banker call for a @ @ @ @ @ @ @ for up to six weeks to “ crush the spread of the virus to less than one new case per 100,000 people per day.
” Currently , the U.S. reports 17 new cases per 100,000 people daily and a total of at least 50,000 new cases daily , write Michael Osterholm , director of the Center for Infectious Disease Research and Policy at the University of Minnesota , and Neel Kashkari , president of the Federal Reserve Bank of Minneapolis .
The essay states that prematurely relaxed lockdowns caused the failure of U.S. @ @ @ @ @ @ @ mandates and “ soft ” social distancing policies “ are not enough to control this pandemic , ” the authors write .
A renewed lockdown should “ mandate sheltering in place for everyone but the truly essential workers , ” they add .
Under such a policy , the nation ’ s testing and contact tracing capacity could “ support reopening the economy.
” The authors conclude : “ There is no trade-off between health and the economy .
Both require aggressively getting control of the virus.
” And here ’ s an @ @ @ @ @ @ @ than 150 U.S. medical professionals , that calls for the U.S. to “ shut down , start over , do it right ” in order to prevent further COVID-19 deaths ( updated 8/13/20 ) .
Researchers now are studying more than 165 vaccine candidates to protect against SARS-CoV-2 , according to The New York Times ’ vaccine tracker , last updated 8/12/20 .
A total of eight now are in phase 3 , that is , being studied in thousands of people for effectiveness and for any rare , unsafe side effects .
@ @ @ @ @ @ @ CanSinoBIO vaccine approved by the military in China as a “ specially needed drug ” for soldiers and the Russia Ministry of Health ’ s vaccine that recently made news and reportedly might be produced by the end of this year .
Neither of these two vaccines underwent a phase 3 study , which concerns many biomedical researchers , public-health experts , and others .
By Jonathan Corum , Denise Grady , Sui-Lee Wee , and Carl Zimmer .
This piece by Eric Bender for Knowable ( 7/30/30 ) features a few angles @ @ @ @ @ @ @ that I haven ’ t seen elsewhere .
For instance , Bender explains how research teams and regulators have sped up this work ( e.g .
individual teams are testing one or two candidates rather than 20 ; reduced paperwork requirements from regulators ; parallel animal and early human safety experiments ; and round-the-clock work ) .
The piece also describes the safety commitments among developers of vaccines previously approved for other conditions .
The story also clarifies what the endpoint and bar for success are for a phase 3 study ( effectiveness @ @ @ @ @ @ @ ) of a vaccine candidate : “ The trials [ experiments ] all need to run until tests show that a certain number of participants have been exposed to the virus in their normal lives , ” Bender writes .
Moderna ’ s Phase 3 study is set to enroll about 30,000 healthy people in the U.S. , and the University of Oxford/AstraZeneca Phase 3 study is set to test its candidate in about 50,000 people in the UK and other countries , the story states .
The piece also provides some reassuring @ @ @ @ @ @ @ side effects are seen as acceptable while others are not .
This useful interactive , “ Could my symptoms be Covid-19 ?
” is available in English and in Spanish and showcases the work of developers and artists at The New York Times .
Written by Tara Parker-Pope and Mika Grondahl , the 8/5/20 piece makes clear how widely symptoms can vary among people with the disease .
The piece states that four symptoms are very common among people diagnosed with COVID-19 — fever , loss of taste or smell , dry cough @ @ @ @ @ @ @ notes several other less common symptoms .
It also describes the most common symptoms in children .
“ If you have a symptom that might be Covid-19 , ” the story states , “ doctors say you should isolate until you can be tested .
Most patients will recover on their own within a few weeks…Seek medical care at any time if you experience trouble breathing , any concerning symptom or take a turn for the worse.
” Sobering reporting by Adam Rogers at Wired makes a strong case that a lack of @ @ @ @ @ @ @ , leaders , and policy-makers has significantly hobbled efforts to launch strong studies ( randomized studies on large numbers of people who , along with researchers , are “ blinded ” to whether they receive a treatment or a placebo ) and slowed scientific progress toward finding effective drug treatments for COVID-19 ( 8/10/20 ) .
“ In the U.S. , a lack of central planning , methodological obstacles , and professional pressures meant that since the pandemic began , everyone raced off at top speed , but in different directions , producing @ @ @ @ @ @ @ they got results at all , ” Rogers writes .
The piece ends with a solution for the next pandemic — “ a whole network of centers ready to mount clinical trials at a moment ’ s notice.
” You might enjoy “ Your school district ’ s reopening survey , ” by Kara Baskin for McSweeney ’ s ( 8/5/20 ) .

In the U,.S., “…community outbreaks of the coronavirus this summer have centered on restaurants and bars, often the largest settings to infect Americans,” writes Jennifer Steinhauer at The New York Times (8/12/20). Data show that about a quarter of Louisiana’s coronavirus cases since March, other than those in nursing homes, prisons, and the like, trace back to bars and restaurants, the story reports. In Maryland, “12 percent of new cases last month were traced to restaurants…and in Colorado, 9 percent of outbreaks overall have been traced to bars and restaurants,” Steinhauer reports. Indoor dining is banned in New York City and many other places, the story states. Many food-service workers have felt pressured to return to their jobs when restaurants re-opened. These jobs are often low-paying, may not offer health insurance, and are disproportionately held by Hispanic people, the story states.
A study published 8/7/20 that assessed a laser-beam approach to measuring the effectiveness of face masks received some misleading and incorrect media coverage this week. This 8/12/20 story by Jonathan Lambert at Science News clears up many of the misconceptions. First, this was not a study of the effectiveness of face masks for blocking droplets released during speech that potentially contain SARS-CoV-2. It was a study of a method for measuring mask effectiveness. And the sample sizes were too low to serve as a test of effectiveness for cutting transmission risk (which again, the study was not meant to do). Also, talking is just one of the ways we might release droplets containing the virus. Singing, coughing, and sneezing also can release them. So, don’t throw out your unjustly maligned neck-gaiter, the story states. Most evidence shows that cloth masks, including “properly worn neck gaiters, filter out the majority of [SARS-CoV-2 and other] viral particles and provide some protection for an individual,” says an infectious diseases researcher at the University of California, San Francisco, who is quoted in the piece.
In an 8/7/20 essay in The New York Times, a prominent epidemiologist and a banker call for a renewed and stricter lockdown in the U.S. for up to six weeks to “crush the spread of the virus to less than one new case per 100,000 people per day.” Currently, the U.S. reports 17 new cases per 100,000 people daily and a total of at least 50,000 new cases daily, write Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, and Neel Kashkari, president of the Federal Reserve Bank of Minneapolis. The essay states that prematurely relaxed lockdowns caused the failure of U.S. efforts to contain SARS-CoV-2. Public mask mandates and “soft” social distancing policies “are not enough to control this pandemic,” the authors write. A renewed lockdown should “mandate sheltering in place for everyone but the truly essential workers,” they add. Under such a policy, the nation’s testing and contact tracing capacity could “support reopening the economy.” The authors conclude: “There is no trade-off between health and the economy. Both require aggressively getting control of the virus.”
And here’s an open letter, reportedly signed by more than 150 U.S. medical professionals, that calls for the U.S. to “shut down, start over, do it right” in order to prevent further COVID-19 deaths (updated 8/13/20).
Researchers now are studying more than 165 vaccine candidates to protect against SARS-CoV-2, according to The New York Times’ vaccine tracker, last updated 8/12/20. A total of eight now are in phase 3, that is, being studied in thousands of people for effectiveness and for any rare, unsafe side effects. And two have been approved: the CanSinoBIO vaccine approved by the military in China as a “specially needed drug” for soldiers and the Russia Ministry of Health’s vaccine that recently made news and reportedly might be produced by the end of this year. Neither of these two vaccines underwent a phase 3 study, which concerns many biomedical researchers, public-health experts, and others. By Jonathan Corum, Denise Grady, Sui-Lee Wee, and Carl Zimmer.
This piece by Eric Bender for Knowable (7/30/30) features a few angles and nuggets on SARS-CoV-2 vaccine development efforts that I haven’t seen elsewhere. For instance, Bender explains how research teams and regulators have sped up this work (e.g. individual teams are testing one or two candidates rather than 20; reduced paperwork requirements from regulators; parallel animal and early human safety experiments; and round-the-clock work). The piece also describes the safety commitments among developers of vaccines previously approved for other conditions. The story also clarifies what the endpoint and bar for success are for a phase 3 study (effectiveness and safety study among thousands of people) of a vaccine candidate: “The trials [experiments] all need to run until tests show that a certain number of participants have been exposed to the virus in their normal lives,” Bender writes. Moderna’s Phase 3 study is set to enroll about 30,000 healthy people in the U.S., and the University of Oxford/AstraZeneca Phase 3 study is set to test its candidate in about 50,000 people in the UK and other countries, the story states. The piece also provides some reassuring information about the context in which certain side effects are seen as acceptable while others are not.
This useful interactive, “Could my symptoms be Covid-19?” is available in English and in Spanish and showcases the work of developers and artists at The New York Times. Written by Tara Parker-Pope and Mika Grondahl, the 8/5/20 piece makes clear how widely symptoms can vary among people with the disease. The piece states that four symptoms are very common among people diagnosed with COVID-19 — fever, loss of taste or smell, dry cough, and fatigue. The piece also notes several other less common symptoms. It also describes the most common symptoms in children. “If you have a symptom that might be Covid-19,” the story states, “doctors say you should isolate until you can be tested. Most patients will recover on their own within a few weeks…Seek medical care at any time if you experience trouble breathing, any concerning symptom or take a turn for the worse.”
Sobering reporting by Adam Rogers at Wired makes a strong case that a lack of coordination among U.S. medical centers, researchers, leaders, and policy-makers has significantly hobbled efforts to launch strong studies (randomized studies on large numbers of people who, along with researchers, are “blinded” to whether they receive a treatment or a placebo) and slowed scientific progress toward finding effective drug treatments for COVID-19 (8/10/20). “In the U.S., a lack of central planning, methodological obstacles, and professional pressures meant that since the pandemic began, everyone raced off at top speed, but in different directions, producing incompatible, unusable, or incoherent results—if they got results at all,” Rogers writes. The piece ends with a solution for the next pandemic — “a whole network of centers ready to mount clinical trials at a moment’s notice.”
You might enjoy “Your school district’s reopening survey,” by Kara Baskin for McSweeney’s (8/5/20).


scientificamerican--2020-08-18--How to Turn 175 Years of Words in Scientific American into an Image

Summarizing the history of a 175-year-old magazine—that 's 5,107 editions with 199,694 pages containing 110,292,327 words !
—into a series of graphics was a daunting assignment .
When the hard drive with 64 gigabytes of .pdf files arrived at my home in Germany , I was curious to dig in but also a bit scared : as a data-visualization consultant with a background in cognitive science , I am well aware that the nuance of language and its semantic contents can only be approximated with computational methods .
I like to start by brainstorming concept ideas and data-discovery questions and @ @ @ @ @ @ @ To get inspired , I read samples of the magazine across the decades , marveling at the old illustrations and typefaces .
I set up a data-preprocessing pipeline early on to extract the text from the .pdf files and run the first analyses .
I used Jupyter Notebooks ( a flexible programming environment for data exploration ) with the spaCy Python library ( which uses computational linguistics to turn mere character sequences into a structured representation of language ) as well as the pandas package ( a tool kit for processing large amounts @ @ @ @ @ @ @ .
A central question in any data-science project is how wide a net one casts on the data set .
If the net is too coarse , all the interesting little fish might escape .
Yet if it is too fine , one can end up with a lot of debris , and too much detail can obscure the big picture .
Can we find a simple but interesting and truthful way to distill a wealth of data into a digestible form ?
The editors and I explored many concept ideas : looking @ @ @ @ @ @ @ of specific words , changes in interpunctuation styles ( would there be a rise of question marks ? )
, and mentions of persons and places .
Would any of these approaches be supported by the available data ?
It soon became apparent that any texts from the predigital era of Scientific American ( before 1993 ) are to some degree affected by optical character-recognition ( OCR ) errors .
Reconstructing the original text from images is an inherently noisy process where letters can be mixed up ( for instance , “ substantially @ @ @ @ @ @ @ ” ) , words might be combined or split at the wrong places , or multicolumn layouts might be read in the wrong order .
Accordingly , zooming out on the data-analysis lens to a yearly perspective ( rather than working on the level of individual editions ) and analyzing the count of single words ( rather than looking for compound terms or doing sentence-level analyses ) became our sweet spot in the trade-off space between accuracy and robustness against noise .
My first intuition was to focus on “ what ” has @ @ @ @ @ @ @ the data , I became especially intrigued by looking at the “ how ” : the evolution of verbs , adjectives and adverbs .
These word types can tell so much about how the tone and attitude of the original magazine have changed from the engineering-driven , mechanistic language to the multifaceted science magazine we know today .
Another key insight was learning that there is actually very little variety in the vocabulary used in the English language .
Given that the frequency of words in a language ( and in the corpus @ @ @ @ @ @ @ is so skewed , rather than comparing raw numbers of how often words occur , it became far more compelling to look at how the proportion of text a word occupies each year ( its relative frequency ) evolves over time .
Based on this central idea , we explored many different visual forms—word clouds , stack area graphs , line charts , animations , spatial maps of semantic spaces—before settling on the layered stacked area chart for the opening spread as the overview visualization .
This high-level view of the major shifts @ @ @ @ @ @ @ layers , ” is complemented by the individual miniature line charts showing the evolution of each top peaking word per year .
Making dense chart arrangements effortlessly scannable requires conscious visual design choices .
Reinforcing the shape of the line chart with a continuous color scale may seem like a redundant decoration , but it is perceptually quite effective because it allows us to quickly see if a word is “ old ” or “ new ” without studying the line shape in detail .
In addition , the color associations ( gray/brown @ @ @ @ @ @ @ compared to a fresh , modern purple for the present ) help to tie data semantics and visual form together .
Doing data science means having to live with imperfections .
No model can be a 1:1 reproduction of reality , and some of the data still remains mysterious to me .
For instance : Why does the use of “ substantially ” drop so substantially after 1868 ?
( I suspect some OCR errors in connection with new typefaces . )
Others are launching points for investigation : Why did “ tomato @ @ @ @ @ @ @ Each new discovery instigates curiosity , and I encourage others to view this data set not as an objective and final measurement but as inspiration for new questions .
Explore the data yourself at www.scientificamerican.com/interactive/science-words

Summarizing the history of a 175-year-old magazine—that's 5,107 editions with 199,694 pages containing 110,292,327 words!—into a series of graphics was a daunting assignment. When the hard drive with 64 gigabytes of .pdf files arrived at my home in Germany, I was curious to dig in but also a bit scared: as a data-visualization consultant with a background in cognitive science, I am well aware that the nuance of language and its semantic contents can only be approximated with computational methods.
I like to start by brainstorming concept ideas and data-discovery questions and immersing myself in the available materials. To get inspired, I read samples of the magazine across the decades, marveling at the old illustrations and typefaces. I set up a data-preprocessing pipeline early on to extract the text from the .pdf files and run the first analyses. I used Jupyter Notebooks (a flexible programming environment for data exploration) with the spaCy Python library (which uses computational linguistics to turn mere character sequences into a structured representation of language) as well as the pandas package (a tool kit for processing large amounts of numeric data easily and quickly).
A central question in any data-science project is how wide a net one casts on the data set. If the net is too coarse, all the interesting little fish might escape. Yet if it is too fine, one can end up with a lot of debris, and too much detail can obscure the big picture. Can we find a simple but interesting and truthful way to distill a wealth of data into a digestible form? The editors and I explored many concept ideas: looking at sentence lengths, the first occurrences of specific words, changes in interpunctuation styles (would there be a rise of question marks?), and mentions of persons and places. Would any of these approaches be supported by the available data?
It soon became apparent that any texts from the predigital era of Scientific American (before 1993) are to some degree affected by optical character-recognition (OCR) errors. Reconstructing the original text from images is an inherently noisy process where letters can be mixed up (for instance, “substantially” was often parsed as “snbstantlally”), words might be combined or split at the wrong places, or multicolumn layouts might be read in the wrong order. Accordingly, zooming out on the data-analysis lens to a yearly perspective (rather than working on the level of individual editions) and analyzing the count of single words (rather than looking for compound terms or doing sentence-level analyses) became our sweet spot in the trade-off space between accuracy and robustness against noise.
My first intuition was to focus on “what” has been written about, but working with the data, I became especially intrigued by looking at the “how”: the evolution of verbs, adjectives and adverbs. These word types can tell so much about how the tone and attitude of the original magazine have changed from the engineering-driven, mechanistic language to the multifaceted science magazine we know today.
Another key insight was learning that there is actually very little variety in the vocabulary used in the English language. Given that the frequency of words in a language (and in the corpus of Scientific American's text archives) is so skewed, rather than comparing raw numbers of how often words occur, it became far more compelling to look at how the proportion of text a word occupies each year (its relative frequency) evolves over time.
Based on this central idea, we explored many different visual forms—word clouds, stack area graphs, line charts, animations, spatial maps of semantic spaces—before settling on the layered stacked area chart for the opening spread as the overview visualization. This high-level view of the major shifts in vocabulary, shown as “sediment layers,” is complemented by the individual miniature line charts showing the evolution of each top peaking word per year.
Making dense chart arrangements effortlessly scannable requires conscious visual design choices. Reinforcing the shape of the line chart with a continuous color scale may seem like a redundant decoration, but it is perceptually quite effective because it allows us to quickly see if a word is “old” or “new” without studying the line shape in detail. In addition, the color associations (gray/brown representing the mechanistic, vintage past, compared to a fresh, modern purple for the present) help to tie data semantics and visual form together.
Doing data science means having to live with imperfections. No model can be a 1:1 reproduction of reality, and some of the data still remains mysterious to me. For instance: Why does the use of “substantially” drop so substantially after 1868? (I suspect some OCR errors in connection with new typefaces.) Others are launching points for investigation: Why did “tomato” peak so heavily in 1978? Each new discovery instigates curiosity, and I encourage others to view this data set not as an objective and final measurement but as inspiration for new questions.
Explore the data yourself at www.scientificamerican.com/interactive/science-words


scientificamerican--2020-08-18--Explore 175 Years of Words in Scientific American

We invite you to dive in and explore a database of words that appeared prominently in the print history of Scientific American .
Below , each year of that history is represented by a single word , which was selected through a text-analysis project that started with all 5,107 issues of the magazine .
Words whose relative frequency peaked in each individual year were identified .
Among those top contenders , the single noun , verb , adjective or adverb that was used most often was deemed the winner .
The line charts , which reflect the frequency of each @ @ @ @ @ @ @ left ) to 2020 ( far right ) , are scaled to the maximum value .
To learn more about how the data were collected , analyzed and visualized , see “ How to Turn 175 Years of Words in Scientific American into an Image.
” As science historian Lorraine Daston wrote in an essay for our special 175th anniversary issue : “ Science has never been speechless .
Scientific journals began in the 17th century , and since then , science has been all about communication—first and foremost between scientists and other @ @ @ @ @ @ @ public fascinated by the latest discoveries , inventions and speculations about fossils , electricity , atoms , computers , genes and galaxies ... .
It is entirely in keeping with the visual spirit of scientific communication that the very words used in all 5,107 issues of Scientific American since 1845 should be turned into an image .
[ In this project , you ’ ll see ] word frequencies undulate , soaring and plunging as a function of time to track the way science talked about itself to itself.
” To read more @ @ @ @ @ @ @ of popular words paired with key moments in the history of the magazine—see “ Visualizing 175 Years of Words in Scientific American.
” Have you found fun patterns or interesting word juxtapositions ?
Share your screenshots and thoughts on social media using the hashtags # SciAm175 and # ScienceWords .

We invite you to dive in and explore a database of words that appeared prominently in the print history of Scientific American. Below, each year of that history is represented by a single word, which was selected through a text-analysis project that started with all 5,107 issues of the magazine. Words whose relative frequency peaked in each individual year were identified. Among those top contenders, the single noun, verb, adjective or adverb that was used most often was deemed the winner. The line charts, which reflect the frequency of each word over time from 1845 (far left) to 2020 (far right), are scaled to the maximum value. To learn more about how the data were collected, analyzed and visualized, see “How to Turn 175 Years of Words in Scientific American into an Image.”
As science historian Lorraine Daston wrote in an essay for our special 175th anniversary issue: “Science has never been speechless. Scientific journals began in the 17th century, and since then, science has been all about communication—first and foremost between scientists and other scientists, but also with a broader public fascinated by the latest discoveries, inventions and speculations about fossils, electricity, atoms, computers, genes and galaxies.... It is entirely in keeping with the visual spirit of scientific communication that the very words used in all 5,107 issues of Scientific American since 1845 should be turned into an image. [In this project, you’ll see] word frequencies undulate, soaring and plunging as a function of time to track the way science talked about itself to itself.”
To read more from Daston—and for a guided graphical tour of popular words paired with key moments in the history of the magazine—see “Visualizing 175 Years of Words in Scientific American.”
Have you found fun patterns or interesting word juxtapositions? Share your screenshots and thoughts on social media using the hashtags #SciAm175 and #ScienceWords.


scientificamerican--2020-08-18--The Language of Science

The Language of Science

Since at least the 17th century , science has struggled with words .
Francis Bacon , visionary of a new , experimental natural philosophy , called language an “ idol of the marketplace ” : a counterfeit currency we trade in so habitually that we no longer notice the gap between words and the world .
True to its Baconian ideology , the Royal Society of London , one of the world 's oldest scientific societies , made nullius in verba ( roughly , “ on no one 's word ” ) its motto soon after it was established in @ @ @ @ @ @ @ Royal Society 's suspicion of language in Gulliver 's Travels , published in 1726 : instead of conversing , some members of the Academy of Lagado carry around a sack of things that they exchange instead of words .
Science aspired to show , not tell .
Yet science has never been speechless .
Scientific journals also began in the 17th century , and since then , science has been all about communication—first and foremost between scientists and other scientists , but also with a broader public fascinated by the latest discoveries , @ @ @ @ @ @ @ , atoms , computers , genes and galaxies .
How to communicate about the world in words ?
Into the crack between words and things sprang images : woodcuts , engravings , lithographs , photographs , diagrams , graphics of all kinds .
Modern science is ingeniously , intrinsically and extravagantly visual .
No wonder “ see ” is a word whose popularity spans all 175 years of writing about science and technology in Scientific American .
It is entirely in keeping with the visual spirit of scientific communication that the very words @ @ @ @ @ @ @ American since 1845 should be turned into an image .
Like the patterns in marbled paper , the word frequencies undulate , soaring and plunging as a function of time to track the way science talked about itself to itself .
Epistemic virtues ( which are to knowledge what moral virtues are to goodness ) such as “ certainty , ” flanked by its boon companions “ universal , ” “ rational ” and “ truth , ” spiked in the middle decades of the 19th century , whereas clusters such as “ @ @ @ @ @ @ @ “ conjecture ” and “ interpret ” peaked suggestively between the 1950s and the 1970s .
After World War II , when the most prominent scientists of the day—Albert Einstein , J. Robert Oppenheimer , Linus Pauling—reflected on the wider significance of their science for a nonspecialist audience , values and assumptions taken for granted in research journals came out into the open in the pages of Scientific American .
Just as revealing as the jagged peaks and troughs are the trajectories of words that have persisted over time : “ average , @ @ @ @ @ @ @ , ” “ experiment , ” “ observation , ” “ standard , ” “ skill ” and , yes , “ see.
” Instead of the Alps , these word landscapes resemble gently rolling hills : they have their ups and downs , but for the most part they are as steady as the horizon .
They represent the enduring practices of science that survive revolutions in theories and even shifts in epistemic virtues .
Scientific images are multipurpose tools : they represent things , relationships , even arguments .
But just @ @ @ @ @ @ @ territory it represents , words do not mirror the world in every detail .
Although the relative frequencies of words used are highly suggestive , they can not convey the texture of the magazine issue by issue .
A reader nowadays might wonder : Where are the women ?
Why are some fields of research missing ?
Who paid for science back then ?
No image can tell the whole story , if only because the story that interests us changes over time .
When images do succeed , they enlist sight in @ @ @ @ @ @ @ a rippling physiognomy of 175 years of science for the curious public .
—L.D .
To learn more about how the data were collected , analyzed and visualized , see “ How to Turn 175 Years of Words in Scientific American into an Image.
” To search for your own favorite words and to explore other juxtapositions , visit “ Explore 175 Years of Words in Scientific American .
”

Credit: Moritz Stefaner and Christian Lässer
Since at least the 17th century, science has struggled with words. Francis Bacon, visionary of a new, experimental natural philosophy, called language an “idol of the marketplace”: a counterfeit currency we trade in so habitually that we no longer notice the gap between words and the world. True to its Baconian ideology, the Royal Society of London, one of the world's oldest scientific societies, made nullius in verba (roughly, “on no one's word”) its motto soon after it was established in 1660. Satirist Jonathan Swift parodied the Royal Society's suspicion of language in Gulliver's Travels, published in 1726: instead of conversing, some members of the Academy of Lagado carry around a sack of things that they exchange instead of words. Science aspired to show, not tell.
Yet science has never been speechless. Scientific journals also began in the 17th century, and since then, science has been all about communication—first and foremost between scientists and other scientists, but also with a broader public fascinated by the latest discoveries, inventions and speculations about fossils, electricity, atoms, computers, genes and galaxies. How to communicate about the world in words? Into the crack between words and things sprang images: woodcuts, engravings, lithographs, photographs, diagrams, graphics of all kinds. Modern science is ingeniously, intrinsically and extravagantly visual. No wonder “see” is a word whose popularity spans all 175 years of writing about science and technology in Scientific American.
It is entirely in keeping with the visual spirit of scientific communication that the very words used in all 5,107 issues of Scientific American since 1845 should be turned into an image. Like the patterns in marbled paper, the word frequencies undulate, soaring and plunging as a function of time to track the way science talked about itself to itself. Epistemic virtues (which are to knowledge what moral virtues are to goodness) such as “certainty,” flanked by its boon companions “universal,” “rational” and “truth,” spiked in the middle decades of the 19th century, whereas clusters such as “imagination,” “intuition,” “conjecture” and “interpret” peaked suggestively between the 1950s and the 1970s. After World War II, when the most prominent scientists of the day—Albert Einstein, J. Robert Oppenheimer, Linus Pauling—reflected on the wider significance of their science for a nonspecialist audience, values and assumptions taken for granted in research journals came out into the open in the pages of Scientific American.
Just as revealing as the jagged peaks and troughs are the trajectories of words that have persisted over time: “average,” “exception,” “cause,” “experiment,” “observation,” “standard,” “skill” and, yes, “see.” Instead of the Alps, these word landscapes resemble gently rolling hills: they have their ups and downs, but for the most part they are as steady as the horizon. They represent the enduring practices of science that survive revolutions in theories and even shifts in epistemic virtues.
Scientific images are multipurpose tools: they represent things, relationships, even arguments. But just as a map does not duplicate the territory it represents, words do not mirror the world in every detail. Although the relative frequencies of words used are highly suggestive, they cannot convey the texture of the magazine issue by issue. A reader nowadays might wonder: Where are the women? Why are some fields of research missing? Who paid for science back then? No image can tell the whole story, if only because the story that interests us changes over time. When images do succeed, they enlist sight in the cause of insight—in this case, a rippling physiognomy of 175 years of science for the curious public. —L.D.
Credit: Moritz Stefaner and Christian Lässer
Credit: Moritz Stefaner and Christian Lässer
To learn more about how the data were collected, analyzed and visualized, see “How to Turn 175 Years of Words in Scientific American into an Image.” To search for your own favorite words and to explore other juxtapositions, visit “Explore 175 Years of Words in Scientific American.”


scientificamerican--2020-08-18--Celebrating Scientific American's 175th Anniversary

Welcome to Scientific American 's 175th anniversary issue !
We 've had a blast putting it together and hope you enjoy it .
Scientific American is the oldest continuously published magazine in the U.S. For our demisemiseptcentennial ( also known as , no kidding , a quartoseptcentennial ) , we are presenting a mix of surprising history stories ( featuring Harry Houdini , M. C. Escher and federal censors burning copies of our magazine ) and deeper looks at some of the most transformative , thrilling , dizzying discoveries of the past 175 years .
When the magazine began , @ @ @ @ @ @ @ as it is today .
Astronomers thought our Milky Way galaxy was the extent of the universe .
Now we know we inhabit just one of over 100 billion galaxies .
The universe is n't just mind-bendingly big , it 's getting bigger , and—as if that were n't enough—the rate of expansion is faster all the time .
Astrophysicist Martin Rees shows what we 've learned and what the biggest questions are for the next 175 years .
One of the most disturbing discoveries of the past 175 years is that , @ @ @ @ @ @ @ of the species on Earth have abruptly died off .
The mass extinctions were triggered by massive volcanic activity or an asteroid impact , causing a cascade of catastrophe that disrupted the atmosphere and wiped out plants and animals that had ruled the planet for hundreds of millions of years .
Now we are in danger of causing a sixth mass extinction .
Author Peter Brannen guides us through the absolute worst times on Earth and shows what was lost .
Charles Darwin published On the Origin of Species 14 years after Scientific @ @ @ @ @ @ @ of life on Earth and of our own history as a species .
Senior editor Kate Wong introduces our evolutionary ancestors from the past seven million years and reveals that our family tree is impressively tangled .
In the midst of a global pandemic , it 's startling to read about how confident we once were that medicine could conquer infectious disease , as journalist Maryn McKenna recounts .
Our best long-term hope for conquering the new coronavirus is research into vaccines and antivirals , but in the meantime , public health measures @ @ @ @ @ @ @ 175 years are the best way to stay safe .
That , and staying informed by trustworthy sources of scientific information .
The most visible differences between life in 1845 and 2020 are technological .
Historians Naomi Oreskes and Erik M. Conway explore how science and technology have developed in parallel , each boosting the other , and how advances in information sharing are some of the main drivers of innovation .
To understand the information Scientific American has presented over the years , senior graphics editor Jen Christiansen and data designer Moritz @ @ @ @ @ @ @ for each year of our existence .
The visualization project begins here and continues throughout the issue with a time line and pairs of words that peaked in different years , showing ways the language of science has evolved .
The most shameful episodes in our history are when we used scientific language to promote bigotry .
Senior editor Jen Schwartz and senior copy editor Dan Schlenoff reckon with the sexism and racism in our archives and show how science can be twisted to make bias seem like objectivity .
We are committed @ @ @ @ @ @ @ inclusive and just .
Join us online at ScientificAmerican.com for more anniversary highlights , including an interactive featuring some of the greatest hits of science history .
Search our database of most often used words to find your own patterns .
Science has shaped our rich past , and we look forward to covering how it shapes the future .
”

Welcome to Scientific American's 175th anniversary issue! We've had a blast putting it together and hope you enjoy it. Scientific American is the oldest continuously published magazine in the U.S. For our demisemiseptcentennial (also known as, no kidding, a quartoseptcentennial), we are presenting a mix of surprising history stories (featuring Harry Houdini, M. C. Escher and federal censors burning copies of our magazine) and deeper looks at some of the most transformative, thrilling, dizzying discoveries of the past 175 years.
When the magazine began, the universe didn't seem as big as it is today. Astronomers thought our Milky Way galaxy was the extent of the universe. Now we know we inhabit just one of over 100 billion galaxies. The universe isn't just mind-bendingly big, it's getting bigger, and—as if that weren't enough—the rate of expansion is faster all the time. Astrophysicist Martin Rees shows what we've learned and what the biggest questions are for the next 175 years.
One of the most disturbing discoveries of the past 175 years is that, on at least five occasions, most of the species on Earth have abruptly died off. The mass extinctions were triggered by massive volcanic activity or an asteroid impact, causing a cascade of catastrophe that disrupted the atmosphere and wiped out plants and animals that had ruled the planet for hundreds of millions of years. Now we are in danger of causing a sixth mass extinction. Author Peter Brannen guides us through the absolute worst times on Earth and shows what was lost.
Charles Darwin published On the Origin of Species 14 years after Scientific American was established, transforming our understanding of life on Earth and of our own history as a species. Senior editor Kate Wong introduces our evolutionary ancestors from the past seven million years and reveals that our family tree is impressively tangled.
In the midst of a global pandemic, it's startling to read about how confident we once were that medicine could conquer infectious disease, as journalist Maryn McKenna recounts. Our best long-term hope for conquering the new coronavirus is research into vaccines and antivirals, but in the meantime, public health measures that have been used for more than 175 years are the best way to stay safe. That, and staying informed by trustworthy sources of scientific information.
The most visible differences between life in 1845 and 2020 are technological. Historians Naomi Oreskes and Erik M. Conway explore how science and technology have developed in parallel, each boosting the other, and how advances in information sharing are some of the main drivers of innovation.
To understand the information Scientific American has presented over the years, senior graphics editor Jen Christiansen and data designer Moritz Stefaner visualized the most commonly used words for each year of our existence. The visualization project begins here and continues throughout the issue with a time line and pairs of words that peaked in different years, showing ways the language of science has evolved.
The most shameful episodes in our history are when we used scientific language to promote bigotry. Senior editor Jen Schwartz and senior copy editor Dan Schlenoff reckon with the sexism and racism in our archives and show how science can be twisted to make bias seem like objectivity. We are committed to making Scientific American's future more inclusive and just.
Join us online at ScientificAmerican.com for more anniversary highlights, including an interactive featuring some of the greatest hits of science history. Search our database of most often used words to find your own patterns. Science has shaped our rich past, and we look forward to covering how it shapes the future.”


scientificamerican--2020-08-18--175 Years of Discovery

175 Years of Discovery

The essay by this nuclear physicist contained so many details on the hydrogen bomb ( which were all public anyway @ @ @ @ @ by the Atomic Energy Commission .
It was one of the first of numerous articles @ @ @ @ @ warfare .

April 1950
“The Hydrogen
Bomb: II”
by Hans A. Bethe
The essay by this nuclear physicist contained so many details on the hydrogen bomb (which were all public anyway) that it was censored by the Atomic Energy Commission. It was one of the first of numerous articles on nuclear weapons and nuclear warfare.
Credit: Getty Images


scientificamerican--2020-08-18--New Pen-and-Ink Method Draws Health Sensors Directly on Skin

A handful of stencils and three pens sound like materials for a child ’ s art project .
But researchers have now used these tools to draw functional heart monitors directly on human skin .
Wearable sensor technology , which helps doctors check a variety of health indicators , has in recent years advanced from bulky devices to flexible patches that stick to people like temporary tattoos .
These prefabricated sensors can be expensive , however .
They also tend to follow skin contours imperfectly , making them sensitive to the wearer ’ s motion .
Researchers say a new @ @ @ @ @ @ @ Communications in July , offers a solution to both problems .
A team led by biomedical engineer Faheem Ershad of the University of Houston first developed a conductive ink using silver flakes in a polymer solution that is compatible with human skin .
The researchers loaded the ink into modified ballpoint pens , then placed a stencil made of tape on a volunteer and traced within it to draw the requisite circuitry .
“ It ’ s like a kindergartener learning how to draw shapes , ” Ershad says .
“ It ’ @ @ @ @ @ @ @ minutes , the ink dried to create a working sensor .
A standard electrical lead was taped on to provide power and transmit data to a computer .
Using this ink alone , the researchers measured skin hydration and the electrical activity of heart and skeletal muscles .
Because it conformed perfectly to the skin , wearers could walk around without jarring the sensor and thus reducing data quality .
The ink resisted sweat and rubbing but was easily removed with a wet paper towel and soap .
“ It ’ s robust @ @ @ @ @ @ @ part , ” says Dmitry Kireev , who researches wearable bioelectronics at the University of Texas at Austin and was not involved in the study .
“ It ’ s a very elegant solution.
” For more complex devices , Ershad ’ s team used two additional inks : one served as a semiconductor , and the other acted as a dielectric ( a type of insulator ) .
Drawing different layers with each ink , the researchers crafted temperature and strain sensors on a sheet of skinlike silicone .
“ The authors @ @ @ @ @ @ @ ” says Zheng Yan , a biomedical engineer at the University of Missouri , who was not involved in the new research .
Yan and his colleagues have developed similar technology using pencils and paper , but their method is limited to passive conductors that can not introduce energy into a circuit .
By drawing active electronics such as transistors , which can function as switches or amplifiers , Ershad hopes to create sophisticated sensors to detect health indicators ranging from compounds in sweat to the brain ’ s electrical activity .
The @ @ @ @ @ @ @ truly wireless by incorporating more advanced ink-based circuits .
After that achievement , they say , people could use affordable kits of stencils and pens to monitor their own health at home .

A handful of stencils and three pens sound like materials for a child's art project. But researchers have now used these tools to draw functional health monitors directly on human skin.
Wearable sensor technology, which helps doctors check a variety of health indicators, has in recent years advanced from bulky devices to flexible patches that stick to people like temporary tattoos. These prefabricated sensors can be expensive, however. They also tend to follow skin contours imperfectly, making them sensitive to the wearer's motion. Researchers say that a new drawn-on-skin electronics system, described in Nature Communications, could offer a solution to both problems.
A team led by biomedical engineer Faheem Ershad of the University of Houston first developed a conductive ink using silver flakes in a polymer solution that is safe to use on human skin. The researchers loaded the ink into modified ballpoint pens, then placed a stencil made of tape and film on a volunteer and traced within it to draw the requisite circuitry. “It's like a kindergartener learning how to draw shapes,” Ershad says. “It's really that simple.” Within five minutes the ink dried to create a working sensor. The researchers then taped on a standard electrical lead to provide power and transmit data to a computer.
Using just this type of ink, the team measured skin hydration and the electrical activity of heart and skeletal muscles. Because the sensor conformed perfectly to the skin, wearers could walk around without jarring it and thereby reducing data quality. The ink resisted sweat and rubbing but was easily removed with a wet paper towel and soap. “It's robust and very easily applied on any body part,” says Dmitry Kireev, who researches wearable bioelectronics at the University of Texas at Austin and was not involved in the study. “It's a very elegant solution.”
For more complex devices, Ershad's team used two additional inks: one served as a semiconductor, and the other acted as a dielectric (a type of insulator). Drawing different layers with each ink, the researchers crafted temperature and strain sensors on a sheet of skinlike silicone. “The authors already demonstrated many very attractive applications,” says Zheng Yan, a biomedical engineer at the University of Missouri, who was not involved in the new research. Yan and his colleagues have developed similar technology using pencils and paper, but their method is limited to passive conductors that cannot introduce energy into a circuit. By drawing active electronics such as transistors, which can function as switches or amplifiers, Ershad says that he hopes to create sophisticated sensors to detect health indicators ranging from compounds in sweat to the brain's electrical activity.
The researchers plan to eventually make their sensors truly wireless by incorporating more advanced ink-based circuits. After that achievement, they say, people could use affordable kits of stencils and pens to monitor their own health at home.