scientificamerican--2020-09-03--Physicists Create City-Sized Ultrasecure Quantum Network

Quantum cryptography promises a future in which computers communicate with one another over ultrasecure links using the razzle-dazzle of quantum physics .
But scaling up the breakthroughs in research labs to networks with a large number of nodes has proved difficult .
Now an international team of researchers has built a scalable city-wide quantum network to share keys for encrypting messages .
The network can grow in size without incurring an unreasonable escalation in the costs of expensive quantum hardware .
Also this system does not require any node to be trustworthy , thus removing any security-sapping weak links .
@ @ @ @ @ @ @ the laboratory and in deployed fibers across the city of Bristol ” in England , says Siddarth Koduru Joshi of the University of Bristol .
He and his colleagues demonstrated their ideas using a quantum network with eight nodes in which the most distant nodes were 17 kilometers apart , as measured by the length of the optical fiber connecting them .
The team ’ s findings appeared in Science Advances on September 2 .
Quantum cryptography involves using the laws of quantum physics to create a private key for encoding and decoding @ @ @ @ @ @ @ distribution , or QKD .
In the most often used protocol for QKD , one party , Alice , prepares and sends a quantum bit , or qubit , to another , Bob .
The qubit is a particle in a quantum superposition of two states .
Bob chooses , at random , one of a set of measurements of the particle .
If Bob chooses the correct type of measurement , he will know the value Alice encoded in the qubit .
After a sequence of measurements of such qubits , Alice @ @ @ @ @ @ @ to use the results of a certain subset of Bob ’ s measurements ( both know the value of each qubit for this subset ) .
They discard the other measurements .
Crucially , the results are not public , and Alice and Bob use them to create a private key to encrypt and decrypt messages sent over a public link .
But this method is hard to scale up .
Imagine you want to add another user , Charlie , to the network .
One option is for Bob and Charlie to @ @ @ @ @ @ @ can send a message to Charlie via Bob , but she has to trust Bob .
“ That ’ s not very attractive , ” says team member Sebastian Neumann of the Institute for Quantum Optics and Quantum Information–Vienna .
“ The whole point of quantum cryptography is unconditional security.
” To avoid having to trust Bob , Charlie can connect directly to both Alice and Bob .
Now those two will need extra hardware to communicate with Charlie because a new node can not be added without disrupting the existingnodes .
And @ @ @ @ @ @ @ one extra node .
The requirements mushroom in cost and complexity as new nodes are added .
For example , a two-node network has one link , a three-node network has three of them , an eight-node network has 28 , and a 100-node network needs 4,950 .
Joshi and his colleagues used another QKD protocol that involves sharing entangled particles between any two nodes to design a new kind of network that overcomes many of these problems .
In this protocol , Alice and Bob use pairs of entangled photons to create @ @ @ @ @ @ @ from such a pair , Alice randomly performs one of a certain set of measurements .
Bob does the same with his particle .
Because the photons are entangled , Alice and Bob will get the same result if they make the same measurement .
The two publicly share their sequence of measurements of the paired particles .
They then choose the subset that would have given them the same results and discard the others .
These results , which are never publicly disclosed , form the basis for a private key .
@ @ @ @ @ @ @ each of the eight nodes is physically connected to all the other nodes , the researchers created one with a central source that sends entangled photons to the eight nodes , named Alice , Bob , Chloe , Dave , Feng , Gopi , Heidi and Ivan .
Each node is only connected via a single optical fiber link to the source , making a total of eight links—far less than the 28 that would be required for traditional QKD with no trusted nodes .
So even though the nodes are not physically @ @ @ @ @ @ @ establishes a virtual link between each pair of them via the magic of quantum entanglement such that each pair can create a private key .
The central source has a so-called nonlinear crystal that spits out a pair of photons that are entangled in their polarization .
These photons have a wavelength centered on roughly about 1,550 nanometers , plus or minus a few tens of nanometers .
If one were to look for and find one of the photons at , say , 1,560 nanometers , the the law of conservation of @ @ @ @ @ @ @ have a wavelength of 1,540 nanometers .
One such narrow wavelength is a channel .
The central source splits up the wavelength of the initial entangled pair into 16 channels , eight on either side of , and equidistant from , 1,550 nanometers .
Doing so effectively creates eight pairs of channels , numbered 1 to 8 on one side and –1 to –8 on the other .
Upon measurement , the photons will , of course , be found in only a single pair of channels upon measurement , and not in @ @ @ @ @ @ @ combined , or multiplexed , in the same optical fiber and sent to each node .
Each node gets a different combination of channels .
For example , Alice received channels 2 , 6 , 7 and 8 ; Dave receives –6 , –4 , –3 and 1 ; and Gopi receives –8 , 5 , 4 and –2 .
The wavelengths are chosen such that any two nodes always share at least one pair of channels that could have entangled photons in them .
In the above scheme , Alice and Dave @ @ @ @ @ @ @ and Gopi share channels 2 and –2 and 8 and –8 ; and Dave and Gopi share –4 and 4 .
Each node monitors all of its channels to measure the polarization state of a potential photon if it appears in one of them .
So if a photon detector were to click for Alice , she effectively has made a measurement to see whether the photon is polarized in one direction ( horizontal or vertical ) or another ( diagonal or antidiagonal ) .
As it happens , only one of the @ @ @ @ @ @ @ entangled photon at exactly the same time .
After a series of such measurements with a large number of pairs of entangled photons , the nodes broadcast their photon counts and the corresponding time stamps of when the photons were detected .
This information allows the nodes to figure out which pairs of photons were measured by which pair of nodes .
For example , Alice and Dave realize that they have a strong correlation in the number of detections for a certain time stamp .
This correlation represents their share of entangled @ @ @ @ @ @ @ use the results of these measurements to establish a key between the two of them .
Adding a new node is simple : just connect it to the central source , which only has to modify its channel-splitting-and-multiplexing scheme .
But none of the existing nodes need worry .
“ Alice does not have to change anything as the network changes , ” Joshi says .
Also , the additional hardware required scales linearly with the increase in nodes—a major improvement , compared with earlier techniques .
Crucially , none of the nodes @ @ @ @ @ @ @ pair of them can establish a secure link to create an unbreakable quantum key , which can be used to encode and decode messages .
Future large-scale quantum networks will have to solve at least two major problems : One is that they must interconnect an arbitrarily large number of users .
Secondly , such networks have to span vast intracontinental and intercontinental distances—something that requires using either quantum repeaters to extend the range over which one can distribute quantum states or satellites to beam down qubits or entangled particles to nodes on @ @ @ @ @ @ @ University of Technology in the Netherlands , who was not involved in the new work , acknowledges that it extends QKD to “ reach many more users within the limited range of QKD without repeaters.
” Joshi ’ s team admits that its work has not yet tackled the issue of distances larger than the span of a small city .
To increase the range , the researchers are thinking of using satellites to carry their central source of entangled photons .
“ We are working toward making such a source space compatible @ @ @ @ @ @ @ have to make it robust enough .
”

Quantum cryptography promises a future in which computers communicate with one another over ultrasecure links using the razzle-dazzle of quantum physics. But scaling up the breakthroughs in research labs to networks with a large number of nodes has proved difficult. Now an international team of researchers has built a scalable city-wide quantum network to share keys for encrypting messages.
The network can grow in size without incurring an unreasonable escalation in the costs of expensive quantum hardware. Also, this system does not require any node to be trustworthy, thus removing any security-sapping weak links.
“We have tested it both in the laboratory and in deployed fibers across the city of Bristol” in England, says Siddarth Koduru Joshi of the University of Bristol. He and his colleagues demonstrated their ideas using a quantum network with eight nodes in which the most distant nodes were 17 kilometers apart, as measured by the length of the optical fiber connecting them. The team’s findings appeared in Science Advances on September 2.
Two’s Company, Three’s a Crowd
Quantum cryptography involves using the laws of quantum physics to create a private key for encoding and decoding messages, a process called quantum key distribution, or QKD.
In the most often used protocol for QKD, one party, Alice, prepares and sends a quantum bit, or qubit, to another, Bob. The qubit is a particle in a quantum superposition of two states. Bob chooses, at random, one of a set of measurements of the particle. If Bob chooses the correct type of measurement, he will know the value Alice encoded in the qubit. After a sequence of measurements of such qubits, Alice and Bob publicly exchange notes and agree to use the results of a certain subset of Bob’s measurements (both know the value of each qubit for this subset). They discard the other measurements. Crucially, the results are not public, and Alice and Bob use them to create a private key to encrypt and decrypt messages sent over a public link.
But this method is hard to scale up. Imagine you want to add another user, Charlie, to the network. One option is for Bob and Charlie to establish a secure link. Then Alice can send a message to Charlie via Bob, but she has to trust Bob.
“That’s not very attractive,” says team member Sebastian Neumann of the Institute for Quantum Optics and Quantum Information–Vienna. “The whole point of quantum cryptography is unconditional security.”
To avoid having to trust Bob, Charlie can connect directly to both Alice and Bob. Now those two will need extra hardware to communicate with Charlie because a new node cannot be added without disrupting the existingnodes. And this issue arises when you add just one extra node. The requirements mushroom in cost and complexity as new nodes are added. For example, a two-node network has one link, a three-node network has three of them, an eight-node network has 28, and a 100-node network needs 4,950.
Joshi and his colleagues used another QKD protocol that involves sharing entangled particles between any two nodes to design a new kind of network that overcomes many of these problems.
A Metropolitan Multiplex
In this protocol, Alice and Bob use pairs of entangled photons to create a private key. Given one photon from such a pair, Alice randomly performs one of a certain set of measurements. Bob does the same with his particle. Because the photons are entangled, Alice and Bob will get the same result if they make the same measurement. The two publicly share their sequence of measurements of the paired particles. They then choose the subset that would have given them the same results and discard the others. These results, which are never publicly disclosed, form the basis for a private key.
Instead of building a network in which each of the eight nodes is physically connected to all the other nodes, the researchers created one with a central source that sends entangled photons to the eight nodes, named Alice, Bob, Chloe, Dave, Feng, Gopi, Heidi and Ivan. Each node is only connected via a single optical fiber link to the source, making a total of eight links—far less than the 28 that would be required for traditional QKD with no trusted nodes.
So even though the nodes are not physically connected, the protocol the researchers developed establishes a virtual link between each pair of them via the magic of quantum entanglement such that each pair can create a private key.
The central source has a so-called nonlinear crystal that spits out a pair of photons that are entangled in their polarization. These photons have a wavelength centered on roughly about 1,550 nanometers, plus or minus a few tens of nanometers. If one were to look for and find one of the photons at, say, 1,560 nanometers, the the law of conservation of energy dictates that its entangled partner would have a wavelength of 1,540 nanometers. One such narrow wavelength is a channel. The central source splits up the wavelength of the initial entangled pair into 16 channels, eight on either side of, and equidistant from, 1,550 nanometers. Doing so effectively creates eight pairs of channels, numbered 1 to 8 on one side and –1 to –8 on the other. Upon measurement, the photons will, of course, be found in only a single pair of channels and not in the others.
These channels are then combined, or multiplexed, in the same optical fiber and sent to each node. Each node gets a different combination of channels. For example, Alice received channels 2, 6, 7 and 8; Dave receives –6, –4, –3 and 1; and Gopi receives –8, 5, 4 and –2. The wavelengths are chosen such that any two nodes always share at least one pair of channels that could have entangled photons in them. In the above scheme, Alice and Dave share channels 6 and –6; Alice and Gopi share channels 2 and –2 and 8 and –8; and Dave and Gopi share –4 and 4.
Each node monitors all of its channels to measure the polarization state of a potential photon if it appears in one of them. So if a photon detector were to click for Alice, she effectively has made a measurement to see whether the photon is polarized in one direction (horizontal or vertical) or another (diagonal or antidiagonal). As it happens, only one of the other nodes would have detected the corresponding entangled photon at exactly the same time.
After a series of such measurements with a large number of pairs of entangled photons, the nodes broadcast their photon counts and the corresponding time stamps of when the photons were detected. This information allows the nodes to figure out which pairs of photons were measured by which pair of nodes. For example, Alice and Dave realize that they have a strong correlation in the number of detections for a certain time stamp. This correlation represents their share of entangled photons. Alice and Dave can now use the results of these measurements to establish a key between the two of them.
Scaling Up Securely
Adding a new node is simple: just connect it to the central source, which only has to modify its channel-splitting-and-multiplexing scheme. But none of the existing nodes need worry. “Alice does not have to change anything as the network changes,” Joshi says.
Also, the additional hardware required scales linearly with the increase in nodes—a major improvement, compared with earlier techniques. Crucially, none of the nodes have to be trusted, yet any pair of them can establish a secure link to create an unbreakable quantum key, which can be used to encode and decode messages.
Future large-scale quantum networks will have to solve at least two major problems: One is that they must interconnect an arbitrarily large number of users. Secondly, such networks have to span vast intracontinental and intercontinental distances—something that requires using either quantum repeaters to extend the range over which one can distribute quantum states or satellites to beam down qubits or entangled particles to nodes on the ground.
Ronald Hanson of Delft University of Technology in the Netherlands, who was not involved in the new work, acknowledges that it extends QKD to “reach many more users within the limited range of QKD without repeaters.”
Joshi’s team admits that its work has not yet tackled the issue of distances larger than the span of a small city. To increase the range, the researchers are thinking of using satellites to carry their central source of entangled photons. “We are working toward making such a source space compatible,” Joshi says. “We have to make it robust enough.”


scientificamerican--2020-09-03--Star Systems Can Be Born Topsy Turvy

Star Systems Can Be Born Topsy Turvy

Our solar system is far from the only way to put together stars and their planets .
`` If you look at all the stars in our galaxy , in the Milky Way , more than half of the stars are formed in multiples .
Meaning there 's more than one star in the system . ''
Astrophysicist Jaehan Bae of the Carnegie Institution for Science .
He has studied one of those systems — with THREE stars .
It 's called `` GW Orionis '' — and it 's freshly formed .
Only a million years old .
`` @ @ @ @ @ @ @ .
It 's a baby . ''
Bae says if you translate that million-year lifespan to that of a HUMAN , it 's the equivalent of a week-old baby .
And how many week-old babies do you bump into ?
`` So if you just walk around your neighborhood there 's little chance you meet a baby who 's one week old .
So first of all , it 's hard to find these systems — they 're pretty rare . ''
Bae and his colleagues got lucky spotting this one .
Using @ @ @ @ @ @ @ image the star system .
And they say it differs from our own solar system in more than just star count .
In our solar system , for example , all eight planets orbit the Sun more or less in a single plane .
Think of the Sun as the center of a vinyl record -- with the planets strung out along the grooves .
In contrast , Bae 's team discovered that the stars in this triple-star system are ringed by clouds of dust in MULTIPLE warped and misaligned planes — picture @ @ @ @ @ @ @ two-dimensional vinyl record .
The observations are in the journal Science .
[ Stefan Kraus et al , A triple-star system with a misaligned and warped circumstellar disk shaped by disk tearing ] Those rings of dust will presumably go on to form planets , as the star system matures .
And Bae says astronomers have indeed observed other , more mature star systems — with planets , orbiting in these misaligned planes .
`` And we wanted to understand if that happens when the planets are born , or whether it 's @ @ @ @ @ @ @ you know , a billion years . ''
The finding suggests that weirdly aligned planetary systems are BORN that way — and that stars and their embryonic planets can be all topsy turvy… even in their infancy .
[ The above text is a transcript of this podcast . ]

Full Transcript
Our solar system is far from the only way to put together stars and their planets.
“If you look at all the stars in our galaxy, in the Milky Way, more than half of the stars are formed in multiples—meaning there’s more than one star in the system.”
Astrophysicist Jaehan Bae of the Carnegie Institution for Science. He has studied one of those systems—with three stars. It’s called GW Orionis. And it’s freshly formed—only a million years old.
“Yeah, it’s really, really young. It’s a baby.”
Bae says if you translate that million-year life span to that of a human, it’s the equivalent of a week-old baby. And how many week-old babies do you bump into?
“So if you just walk around your neighborhood, there’s little chance you meet a baby who’s one week old. So, first of all, it’s hard to find these systems—they’re pretty rare.”
Bae and his colleagues got lucky spotting this one. Using radio telescopes, they were able to image the star system. And they say it differs from our own solar system in more than just star count.
In our solar system, for example, all eight planets orbit the sun more or less in a single plane. Think of the sun as the center of a vinyl record—with the planets strung out along the grooves.
In contrast, Bae’s team discovered that the stars in this triple-star system are ringed by clouds of dust in multiple warped and misaligned planes—picture a three-dimensional gyroscope rather than a two-dimensional vinyl record. The observations are in the journal Science. [Stefan Kraus et al., A triple-star system with a misaligned and warped circumstellar disk shaped by disk tearing]
Those rings of dust will presumably go on to form planets as the star system matures. And Bae says astronomers have indeed observed other, more mature star systems—with planets orbiting in these misaligned planes.
“And we wanted to understand if that happens when the planets are born or whether it’s some evolutionary thing that happens over, you know, a billion years.”
The finding suggests that weirdly aligned planetary systems are born that way—and that stars and their embryonic planets can be all topsy-turvy—even in their infancy.
—Christopher Intagliata
[The above text is a transcript of this podcast.]


scientificamerican--2020-09-03--How to Decide Who Should Get a COVID-19 Vaccine First

If and when a safe and effective COVID-19 vaccine is available , what is the fairest way to distribute it ?
In a policy report published on Thursday in Science , 19 public health experts laid out an ethical framework called the Fair Priority Model .
It is geared toward three principles : benefiting people and limiting harm , prioritizing countries already disadvantaged by poverty or low life expectancy , and avoiding discrimination .
The report is critical of previously suggested vaccine allocation plans , including two proposed by the World Health Organization : one of them would distribute vaccines @ @ @ @ @ @ @ size , and the other would prioritize health care workers and adults who are above age 65 or have underlying health conditions .
Some national distribution proposals , such as a draft of a preliminary framework released on Tuesday by the National Academies of Sciences , Engineering , and Medicine , similarly prioritize health care workers and adults with other illnesses for initial vaccine allotment .
Other plans , including one published in May in the Hastings Center Report , argue the U.S. should consider racial and socioeconomic disparities when deciding who to @ @ @ @ @ @ @ vaccine distribution program could be stymied , however , if another country decides to hoard more vaccines than it needs .
The framework described in Science aims to prevent such selfish nationalist impulses .
Its authors acknowledge countries ’ proclivity to place their own interests before those of others but argue that cross-border responsibilities in a global health emergency should supersede such urges .
The framework addresses both the pandemic ’ s immediate impacts—illness and death—as well as its long-term repercussions for education and economies .
The Fair Priority Model includes three phases @ @ @ @ @ @ @ premature death .
To guide distribution decisions during this phase , the authors propose using a health metric called standard expected years of life lost ( SEYLL ) , which calculates years of life lost because of the pandemic in each country by comparing premature deaths with global life expectancies .
The second phase brings in other metrics to quantify and minimize the economic and social consequences of the COVID-19 .
And the third prioritizes countries with higher virus transmission rates while also ensuring all countries eventually receive enough vaccine doses to halt @ @ @ @ @ @ @ vice provost for global initiatives and chair of medical ethics and health policy at the University of Pennsylvania ’ s Perelman School of Medicine , led the development of the Fair Priority Model .
Scientific American spoke to Emanuel about the model and how it could be implemented .
[ And edited transcript of the interview follows . ]
Why is it important to have an ethical framework for vaccine distribution that supersedes nationalism ?
We expect national partiality , and there ’ s even some good moral reasons for some national partiality @ @ @ @ @ @ @ there ’ s not a good reason for absolute partiality , where a country covers every one of its citizens before giving any vaccine internationally .
There ’ s a good ethical reason not to have absolute vaccine nationalism .
And many governments are arguing for fair and equitable distribution of vaccines .
The vaccine manufacturers themselves argue for global distribution , and we also have international organizations , such as COVAX [ a collaboration co-led by Gavi , the Vaccine Alliance , the Coalition for Epidemic Preparedness Innovations and the WHO ] @ @ @ @ @ @ @ and equitable distribution .
[ Editor ’ s Note : The Trump administration has said it will not participate in the COVAX effort , because it does not want to work with the WHO .
This decision could limit U.S. access to a COVID-19 vaccine if it is developed by another country . ]
The problem is : there ’ s almost no definition of what “ fair and equitable ” means , specifically in terms of distribution .
Being ethicists , public health people and political scientists , we thought that we @ @ @ @ @ @ @ such a definition .
Will vaccine manufacturers take fair allocation into account ?
They ’ re going to face a challenge in how to distribute the vaccine .
Do they just sell it to the highest bidder ?
There are some manufacturers that seem to be inclined toward that .
Do they contribute some of it to international groups such as COVAX ?
We think that at least some manufacturers recognize the importance of having it distributed around the world and very accessible .
Again , a number of pharmaceutical company CEOs have @ @ @ @ @ @ @ .
They don ’ t always seem to have the world ’ s interests at top of mind , but I think , in this case , many of the leading companies do think it ’ s important to address the pandemic worldwide , not just in the countries in which they ’ re based .
Why , in your opinion , are the WHO ’ s distribution proposals flawed ?
One proposal is to give the vaccine to all countries based on a percentage of their population—first to 3 percent of every @ @ @ @ @ @ @ 20 percent .
That seems to fulfill the ethical principle of equal moral concern—treating people similarly and not discriminating based on race or sex or religion .
The problem that is immediately obvious is that different areas of the world are suffering at different rates .
Typically , when you ’ re giving international assistance , you give it to the people who are suffering most .
Then there ’ s the view that we should distribute it based on people who are most at risk , and that ’ s typically defined @ @ @ @ @ @ @ over 65 .
First of all , it ’ s clear that health care workers aren ’ t equally high-risk , especially in developed countries , where proper PPE [ personal protective equipment ] has driven their risk down significantly .
But more importantly , the approach is biased toward rich , well-developed countries because those countries have more health care workers per capita and also have more elderly people .
How did you choose the three ethical underpinnings you used to develop the Fair Priority Model ?
Well , we didn ’ @ @ @ @ @ @ @ ethical values that go back to Socrates .
You can see them in almost every country in the world .
They ’ re what are often called overlapping or common principles .
Everyone thinks you should limit harm and benefit people , and that ’ s a moral obligation .
It ’ s been well articulated that we should help the disadvantaged .
And we all have a sense that people want to be treated equally ; we shouldn ’ t discriminate against people .
We were looking for principles that are commonly @ @ @ @ @ @ @ ethical view [ is ] .
How does the SEYLL metric fit into those values ?
When you have a set of ethical values , what are the distribution conclusions you can draw from them ?
We argue that these values suggest three phases of vaccine distribution , based on things such as how severe the harm is , if it ’ s reversible or whether you can compensate people in other ways if you don ’ t distribute vaccines to them .
In that analysis , death is devastating—you can ’ t @ @ @ @ @ @ @ ’ s clearly irreversible .
Our top priority in phase 1 should be minimizing the number of deaths , both directly from COVID-19 and indirectly because of the health care system being overwhelmed .
In phase 2 , we also want to minimize economic and social dislocations , which can be serious and devastating ; they can last a long time and be irreversible .
But they can be compensated in other ways , so they ought to be addressed .
We asked what metrics best embody those phases , and that ’ @ @ @ @ @ @ @ because it takes into account how many years you live , compared with the world average , and it ’ s a uniform measure across countries .
What future lessons for other global crises can be informed by this framework ?
I think this framework has wide applicability to other pandemics , in the sense that it clearly defines what the core ethical values are , how we should think about harms that come out of a public health crisis and what goals we should try to realize .
We have to be @ @ @ @ @ @ @ is not ethics divorced from empirical data .
Theory and practice work hand in hand , and the epidemiology is going to determine hotspots and where you distribute the vaccine first .
These ethical values are broad , and we need to include them as we think about common problems such as climate change .
One of the important things this framework shares with climate change is it ’ s forward-looking .
We need to work to ameliorate problems that are coming , not try to say who ’ s to blame and @ @ @ @ @ @ @ it .
It ’ s a very important orientation : let ’ s look to the future and solve the problem going forward .
Read more about the coronavirus outbreak from Scientific American here .
And read coverage from our international network of magazines here .

If and when a safe and effective COVID-19 vaccine is available, what is the fairest way to distribute it? In a policy report published on Thursday in Science, 19 public health experts laid out an ethical framework called the Fair Priority Model. It is geared toward three principles: benefiting people and limiting harm, prioritizing countries already disadvantaged by poverty or low life expectancy, and avoiding discrimination.
The report is critical of previously suggested vaccine allocation plans, including two proposed by the World Health Organization: one of them would distribute vaccines to each country according to its population size, and the other would prioritize health care workers and adults who are above age 65 or have underlying health conditions. Some national distribution proposals, such as a draft of a preliminary framework released on Tuesday by the National Academies of Sciences, Engineering, and Medicine, similarly prioritize health care workers and adults with other illnesses for initial vaccine allotment. Other plans, including one published in May in the Hastings Center Report, argue the U.S. should consider racial and socioeconomic disparities when deciding who to prioritize for a vaccine.
Any national vaccine distribution program could be stymied, however, if another country decides to hoard more vaccines than it needs. The framework described in Science aims to prevent such selfish nationalist impulses. Its authors acknowledge countries’ proclivity to place their own interests before those of others but argue that cross-border responsibilities in a global health emergency should supersede such urges. The framework addresses both the pandemic’s immediate impacts—illness and death—as well as its long-term repercussions for education and economies.
The Fair Priority Model includes three phases. The first is designed to reduce premature death. To guide distribution decisions during this phase, the authors propose using a health metric called standard expected years of life lost (SEYLL), which calculates years of life lost because of the pandemic in each country by comparing premature deaths with global life expectancies. The second phase brings in other metrics to quantify and minimize the economic and social consequences of the COVID-19. And the third prioritizes countries with higher virus transmission rates while also ensuring all countries eventually receive enough vaccine doses to halt community transmission.
Ezekiel J. Emanuel, vice provost for global initiatives and chair of medical ethics and health policy at the University of Pennsylvania’s Perelman School of Medicine, led the development of the Fair Priority Model. Scientific American spoke to Emanuel about the model and how it could be implemented.
[And edited transcript of the interview follows.]
Why is it important to have an ethical framework for vaccine distribution that supersedes nationalism?
We expect national partiality, and there’s even some good moral reasons for some national partiality. But from an ethical standpoint, there’s not a good reason for absolute partiality, where a country covers every one of its citizens before giving any vaccine internationally. There’s a good ethical reason not to have absolute vaccine nationalism. And many governments are arguing for fair and equitable distribution of vaccines. The vaccine manufacturers themselves argue for global distribution, and we also have international organizations, such as COVAX [a collaboration co-led by Gavi, the Vaccine Alliance, the Coalition for Epidemic Preparedness Innovations and the WHO], that have said they want fair and equitable distribution. [Editor’s Note: The Trump administration has said it will not participate in the COVAX effort, because it does not want to work with the WHO. This decision could limit U.S. access to a COVID-19 vaccine if it is developed by another country.] The problem is: there’s almost no definition of what “fair and equitable” means, specifically in terms of distribution. Being ethicists, public health people and political scientists, we thought that we were best suited to try to design such a definition.
Will vaccine manufacturers take fair allocation into account?
They’re going to face a challenge in how to distribute the vaccine. Do they just sell it to the highest bidder? There are some manufacturers that seem to be inclined toward that. Do they contribute some of it to international groups such as COVAX? We think that at least some manufacturers recognize the importance of having it distributed around the world and very accessible. Again, a number of pharmaceutical company CEOs have come out in favor of this strategy. They don’t always seem to have the world’s interests at top of mind, but I think, in this case, many of the leading companies do think it’s important to address the pandemic worldwide, not just in the countries in which they’re based.
Why, in your opinion, are the WHO’s distribution proposals flawed?
One proposal is to give the vaccine to all countries based on a percentage of their population—first to 3 percent of every country’s population, then to 20 percent. That seems to fulfill the ethical principle of equal moral concern—treating people similarly and not discriminating based on race or sex or religion. The problem that is immediately obvious is that different areas of the world are suffering at different rates. Typically, when you’re giving international assistance, you give it to the people who are suffering most.
Then there’s the view that we should distribute it based on people who are most at risk, and that’s typically defined as frontline health care workers and people over 65. First of all, it’s clear that health care workers aren’t equally high-risk, especially in developed countries, where proper PPE [personal protective equipment] has driven their risk down significantly. But more importantly, the approach is biased toward rich, well-developed countries because those countries have more health care workers per capita and also have more elderly people.
How did you choose the three ethical underpinnings you used to develop the Fair Priority Model?
Well, we didn’t choose them. These are fundamental ethical values that go back to Socrates. You can see them in almost every country in the world. They’re what are often called overlapping or common principles. Everyone thinks you should limit harm and benefit people, and that’s a moral obligation. It’s been well articulated that we should help the disadvantaged. And we all have a sense that people want to be treated equally; we shouldn’t discriminate against people. We were looking for principles that are commonly accepted, no matter what your particular ethical view [is].
How does the SEYLL metric fit into those values?
When you have a set of ethical values, what are the distribution conclusions you can draw from them? We argue that these values suggest three phases of vaccine distribution, based on things such as how severe the harm is, if it’s reversible or whether you can compensate people in other ways if you don’t distribute vaccines to them. In that analysis, death is devastating—you can’t compensate someone after they die. It’s clearly irreversible.
Our top priority in phase 1 should be minimizing the number of deaths, both directly from COVID-19 and indirectly because of the health care system being overwhelmed. In phase 2, we also want to minimize economic and social dislocations, which can be serious and devastating; they can last a long time and be irreversible. But they can be compensated in other ways, so they ought to be addressed.
We asked what metrics best embody those phases, and that’s how we got to SEYLL, because it takes into account how many years you live, compared with the world average, and it’s a uniform measure across countries.
What future lessons for other global crises can be informed by this framework?
I think this framework has wide applicability to other pandemics, in the sense that it clearly defines what the core ethical values are, how we should think about harms that come out of a public health crisis and what goals we should try to realize. We have to be tied to the facts of a pandemic—this is not ethics divorced from empirical data. Theory and practice work hand in hand, and the epidemiology is going to determine hotspots and where you distribute the vaccine first.
These ethical values are broad, and we need to include them as we think about common problems such as climate change. One of the important things this framework shares with climate change is it’s forward-looking. We need to work to ameliorate problems that are coming, not try to say who’s to blame and put the onus on them to fix it. It’s a very important orientation: let’s look to the future and solve the problem going forward.
Read more about the coronavirus outbreak from Scientific American here. And read coverage from our international network of magazines here.


scientificamerican--2020-09-02--Death by Lightning Is Common for Tropical Trees

The chance that a human being like you will be struck by lightning is minuscule .
But what if you ’ re a tall tree in the tropics ?
“ Lightning happens in milliseconds .
We can ’ t predict where it ’ s going to be , and we generally can ’ t find it after it ’ s happened , so what a hard thing to study.
” Evan Gora , an ecologist at the University of Louisville .
Now , for the first time , Gora and his colleagues were able to quantify the effects of lightning @ @ @ @ @ @ @ to satellite data and a network of ground sensors .
“ We saw that forests that have more lightning strikes hitting per hectare per year have fewer large trees per hectare , presumably because they ’ re killed by lightning .
More biomass turns over every year , so basically , the lightning seems to be affecting the forests and causing trees to die .
And then they have less total biomass.
” In a ground survey in Panama , the researchers found that a single lightning strike typically damages more than 20 @ @ @ @ @ @ @ five or six of them die .
The scientists combined this figure with their satellite data from around the world to estimate how many trees in tropical forests die each year due to lightning .
“ We think around 830 million trees are struck by lightning , and about a quarter of those , around 200 million , are killed .
So that ’ s a lot .
And as I mentioned before , we know that it ’ s not just a random tree in the forest : typically , it ’ @ @ @ @ @ @ @ is in the journal Global Change Biology .
[ Evan M. Gora et al.
, Pantropical geography of lightning-caused disturbance and its implications for tropical forests ] Gora says the findings reveal that that lightning is one of the most important natural factors killing trees in the tropics .
How climate change will affect lightning patterns is not well-understood .
But some models predict more frequent lightning as the planet continues to warm—which could mean even more carbon-storing trees would disappear .
“ Tropical forests basically function as our planet ’ s , @ @ @ @ @ @ @ .
So if we ’ re decreasing the carbon stored in them , that ’ s going to have a big effect on their ability to continue , you know , conditioning our planet and taking up all that carbon that we ’ re producing.
” Gora ’ s work is just the beginning of this research .
He hopes that future technological advances and fieldwork will help scientists better understand lightning ’ s role in ecosystems across the planet .
The findings should be illuminating .
[ The above text is a @ @ @ @ @ @

Full Transcript
[CLIP: Thunder sound]
The chance that a human being like you will be struck by lightning is minuscule. But what if you’re a tall tree in the tropics?
“Lightning happens in milliseconds. We can’t predict where it’s going to be, and we generally can’t find it after it’s happened, so what a hard thing to study.”
Evan Gora, an ecologist at the University of Louisville. Now, for the first time, Gora and his colleagues were able to quantify the effects of lightning strikes in tropical forests around the world—thanks to satellite data and a network of ground sensors.
“We saw that forests that have more lightning strikes hitting per hectare per year have fewer large trees per hectare, presumably because they’re killed by lightning. More biomass turns over every year, so basically, the lightning seems to be affecting the forests and causing trees to die. And then they have less total biomass.”
In a ground survey in Panama, the researchers found that a single lightning strike typically damages more than 20 trees. And within a year, five or six of them die. The scientists combined this figure with their satellite data from around the world to estimate how many trees in tropical forests die each year due to lightning.
“We think around 830 million trees are struck by lightning, and about a quarter of those, around 200 million, are killed. So that’s a lot. And as I mentioned before, we know that it’s not just a random tree in the forest: typically, it’s the largest trees.”
The study is in the journal Global Change Biology. [Evan M. Gora et al., Pantropical geography of lightning-caused disturbance and its implications for tropical forests]
Gora says the findings reveal that that lightning is one of the most important natural factors killing trees in the tropics. How climate change will affect lightning patterns is not well-understood. But some models predict more frequent lightning as the planet continues to warm—which could mean even more carbon-storing trees would disappear.
“Tropical forests basically function as our planet’s, you know, main terrestrial air conditioner. So if we’re decreasing the carbon stored in them, that’s going to have a big effect on their ability to continue, you know, conditioning our planet and taking up all that carbon that we’re producing.”
Gora’s work is just the beginning of this research. He hopes that future technological advances and fieldwork will help scientists better understand lightning’s role in ecosystems across the planet. The findings should be illuminating.
—Scott Hershberger
[The above text is a transcript of this podcast.]


scientificamerican--2020-09-04--We Can't Fight COVID-19 on a Country by Country Basis

Recently , one of my patients borrowed money from a loan shark just to get a private taxi to the hospital .
When we had a problem locating her test results , she broke down , justifiably furious .
She probably wouldn ’ t be able to find the money to come in again .
Another patient , an elderly woman , was so scared off by COVID-19 that she had avoided the hospital for days .
She died within hours of finally arriving—of a treatable urinary tract infection that had entered her blood .
As a doctor in a @ @ @ @ @ @ @ , I ’ ve seen the myriad of ways COVID-19 has upended life and medical care , leading to tragic outcomes , even if indirectly .
South Africa is quickly becoming a COVID-19 hot zone , with over 470,000 confirmed cases , the fifth highest in the world .
Confirmed are now over 11,000 in a country of just 58 million people .
According to a report by the South African Medical Research Council , there were 17,000 excess deaths from May 6 to July 14 as compared to data from the past @ @ @ @ @ @ @ see every day : deaths are rising , and some are from COVID-19 , but many more result from people unable to afford transportation to the hospital as a result of worsening economic conditions , or delaying treatment until it ’ s too late .
That includes people with minor problems—like my patient with a simple urinary tract infection who was afraid to come to the hospital—and those seeking treatment for serious diseases like HIV/AIDS and tuberculosis ( TB ) .
In South Africa , there are nearly eight million people living with @ @ @ @ @ @ @ over a decade ago the disease killed more than 800 people every day , it is terrifying to see a situation unfold where people can no longer access lifesaving treatment .
And according to a recent report , people with HIV or TB have twice the risk of dying from COVID-19 .
I was a small child during the height of the AIDS epidemic here , but I still remember when an HIV diagnosis was a guaranteed death sentence .
Now , HIV is a chronic disease that can be successfully managed with @ @ @ @ @ @ @ completely transformed—from emaciated and listless to healthy and thriving—after just a few months of taking antiretroviral medication .
It ’ s been astounding to me , even as a doctor .
Unless we find a way to get the pandemic under control , this transformative progress could be threatened .
The stakes could not be higher .
What can be done ?
I ’ m just one doctor trying to do my best for patients , but there is only so much that one doctor or one small hospital can do .
We @ @ @ @ @ @ @ doesn ’ t care about where you ’ re from or where you live .
Squelching it one place means nothing if it ’ s raging somewhere else .
And we need to squelch it completely .
We ’ ve seen what can happen when the world comes together to solve big problems , like it did during the height of the AIDS epidemic .
Strong leadership from the United States in creating and investing in the Global Fund to Fight AIDS , Tuberculosis and Malaria and in the President 's Emergency Plan @ @ @ @ @ @ @ AIDS related deaths and new infections by half globally .
Now , the Global Fund has a new to fight COVID-19 and also make sure that all the progress we ’ ve made against epidemics like AIDS , TB and malaria isn ’ t lost .
But it needs support .
The U.S. Congress has a chance to provide a boost of funding for the Global Fund in its final round of COVID relief , being negotiated now .
This money will go towards much needed PPE for health workers like me , @ @ @ @ @ @ @ and resources to protect long standing AIDS , TB and malaria programs .
Every day I do the best I can for my patients .
Every day I try to breathe through the anxiety and fear of possibly failing them and becoming sick myself .
I will keep going .
But now we need systems and countries to step up .
If the world could come together once to fight a deadly epidemic , and if the U.S. could be a leader in that fight , surely it can happen again , right @ @ @ @ @ @ @ ?

Editor’s Note (12/21/21): This article is being showcased in a special collection about equity in health care that was made possible by the support of Takeda Pharmaceuticals. The article was published independently and without sponsorship.
Recently, one of my patients borrowed money from a loan shark just to get a private taxi to the hospital. When we had a problem locating her test results, she broke down, justifiably furious. She probably wouldn’t be able to find the money to come in again. Another patient, an elderly woman, was so scared off by COVID-19 that she had avoided the hospital for days. She died within hours of finally arriving—of a treatable urinary tract infection that had entered her blood.
As a doctor in a small rural hospital here in South Africa, I’ve seen the myriad of ways COVID-19 has upended life and medical care, leading to tragic outcomes, even if indirectly.
South Africa is quickly becoming a COVID-19 hot zone, with over 470,000 confirmed cases, the fifth highest in the world. Confirmed are now over 11,000 in a country of just 58 million people.
According to a report by the South African Medical Research Council, there were 17,000 excess deaths from May 6 to July 14 as compared to data from the past two years. This reflects what I see every day: deaths are rising, and some are from COVID-19, but many more result from people unable to afford transportation to the hospital as a result of worsening economic conditions, or delaying treatment until it’s too late. That includes people with minor problems—like my patient with a simple urinary tract infection who was afraid to come to the hospital—and those seeking treatment for serious diseases like HIV/AIDS and tuberculosis (TB).
In South Africa, there are nearly eight million people living with HIV. In a country where just over a decade ago the disease killed more than 800 people every day, it is terrifying to see a situation unfold where people can no longer access lifesaving treatment. And according to a recent report, people with HIV or TB have twice the risk of dying from COVID-19.
I was a small child during the height of the AIDS epidemic here, but I still remember when an HIV diagnosis was a guaranteed death sentence. Now, HIV is a chronic disease that can be successfully managed with treatment. I’ve seen patients completely transformed—from emaciated and listless to healthy and thriving—after just a few months of taking antiretroviral medication. It’s been astounding to me, even as a doctor. Unless we find a way to get the pandemic under control, this transformative progress could be threatened. The stakes could not be higher.
What can be done?
I’m just one doctor trying to do my best for patients, but there is only so much that one doctor or one small hospital can do. We need a global plan. This pandemic doesn’t care about where you’re from or where you live. Squelching it one place means nothing if it’s raging somewhere else. And we need to squelch it completely.
We’ve seen what can happen when the world comes together to solve big problems, like it did during the height of the AIDS epidemic. Strong leadership from the United States in creating and investing in the Global Fund to Fight AIDS, Tuberculosis and Malaria and in the President's Emergency Plan For AIDS Relief made an astonishing difference , cutting AIDS related deaths and new infections by half globally.
Now, the Global Fund has a new plan to fight COVID-19 and also make sure that all the progress we’ve made against epidemics like AIDS, TB and malaria isn’t lost. But it needs support. The U.S. Congress has a chance to provide a boost of funding for the Global Fund in its final round of COVID relief, being negotiated now. This money will go towards much needed PPE for health workers like me, new diagnostics to aggressively test for COVID-19 and resources to protect long standing AIDS, TB and malaria programs.
Every day I do the best I can for my patients. Every day I try to breathe through the anxiety and fear of possibly failing them and becoming sick myself. I will keep going. But now we need systems and countries to step up. If the world could come together once to fight a deadly epidemic, and if the U.S. could be a leader in that fight, surely it can happen again, right? The question is, will it?


scientificamerican--2020-09-04--Google's Quantum Computer Achieves Chemistry Milestone

When researchers at Google announced last fall that they had achieved “ quantum superiority ” —a point at which a quantum computer can perform a task beyond the reach of regular computers—some people wondered what the big deal was .
The program , which checked the output of a random number generator , was of limited practical value and did not prove that the company ’ s machine could do anything useful , critics said .
Now , however , Google ’ s quantum computer has achieved something that could have real-world applications : successfully simulating a simple chemical reaction @ @ @ @ @ @ @ quantum chemistry , which could expand scientists ’ understanding of molecular reactions and lead to useful discoveries , such as better batteries , new ways to make fertilizer and improved methods of removing carbon dioxide from the air .
Last year ’ s quantum superiority experiment was run on a chip dubbed Sycamore , which contained 53 superconducting quantum bits , or qubits .
Chilled to near absolute zero , the qubits take on quantum-mechanical properties , allowing scientists to manipulate them in more complicated and useful ways than the simple “ on/off @ @ @ @ @ @ @ the bits of classical computers .
The hope is that one day , quantum computers will become powerful enough to quickly perform calculations that would take the lifetime of the universe for a classical computer to complete .
This quantum-chemistry experiment , which was described in the August 28 issue of the journal Science , relied on the same basic Sycamore design , though it only used 12 qubits .
But it demonstrates the system ’ s versatility , says Ryan Babbush , the researcher in charge of developing algorithms for the Google @ @ @ @ @ @ @ in fact , this device is a completely programmable digital quantum computer that can be used for really any task you might attempt , ” he says .
The team first simulated a simplified version of the energy state of a molecule consisting of 12 hydrogen atoms , with each of the 12 qubits representing one atom ’ s single electron .
They then modeled a chemical reaction in a molecule containing hydrogen and nitrogen atoms and including how that molecule ’ s electronic structure would change when its hydrogen atoms shifted from @ @ @ @ @ @ @ the energy of electrons dictates how fast a reaction occurs at a given temperature or concentration of different molecules , such simulations could help chemists understand exactly how that reaction works—and how it would change if they altered the temperature or the chemical cocktail .
The simulation the researchers ran , known as the Hartree-Fock procedure , can also be performed on a classical computer , so it did not , by itself , demonstrate the superiority of a quantum computer .
And it was run with help from a classical computer , @ @ @ @ @ @ @ calculation and then refine new rounds of quantum simulation .
But the feat validates the project ’ s underlying methods , which will be integral to future quantum-chemistry simulations , says Nicholas Rubin , a research scientist on the Google quantum team .
And it was twice as large as the previous record-holding chemistry calculation made on a quantum computer .
In 2017 IBM performed a quantum-chemistry simulation using six qubits .
Rubin says that result described a molecular system with a level of complexity that scientists in the 1920s could calculate by @ @ @ @ @ @ @ 12 qubits , Google ’ s project tackled a system that could be calculated with a 1940s-era computer .
“ If we double it again , we ’ ll probably go to something like 1980 , ” Babbush adds .
“ And if we double it again , then we ’ ll probably be beyond what you could do classically today.
” So far , no quantum computer has achieved what a classical computer could not , says Xiao Yuan , a postdoctoral research fellow at Stanford University ’ s Institute for Theoretical @ @ @ @ @ @ @ Google ’ s paper in Science .
Even the company ’ s achievement of quantum superiority in 2019 was called into question by IBM researchers , who showed a way to achieve the same results on a supercomputer in two and a half days , although Google ’ s version took just more than three minutes .
But , Yuan says , the quantum-chemistry experiment is an important step toward a major goal .
“ If we can use a quantum computer to solve a classically hard and meaningful question , that would @ @ @ @ @ @ @ ” he adds .
There is no theoretical reason scientists could not achieve that goal , Yuan says , but the technical challenge of moving from a few qubits to several hundred—and eventually many more—will require a lot of complicated engineering .
A general-purpose quantum computer with millions of qubits will require the development of error-correction protocols , a particularly arduous problem that may take a decade or more to solve .
But so-called noisy intermediate-scale quantum computers , which do not have full error correction , might still prove useful in the @ @ @ @ @ @ @ quantum computing , because a chemical reaction is inherently quantum , says Alán Aspuru-Guzik , a pioneer of quantum chemistry at the University of Toronto .
To fully model such a reaction , one must know the quantum states of all the electrons involved .
And what better way is there to model a quantum system than to use another quantum system ?
Long before engineers develop a generally programmable quantum computer , devices with a handful of qubits should be able to outperform classical computers on a subset of interesting problems in @ @ @ @ @ @ @ this is a big deal , but it ’ s not the end of the story , ” he adds .
For instance , Aspuru-Guzik is seeking better battery materials to store energy produced by wind turbines and solar cells .
Such materials have properties that can be in conflict : they need to be reactive enough to charge and discharge quickly but still stable enough to avoid exploding or catching fire .
Computer models of the reactions could help identify ideal materials for that tricky task .
Such models could also be @ @ @ @ @ @ @ so , quantum computers may not be the only revolutionary new way to model chemical reactions , Aspuru-Guzik says .
It is possible that artificial intelligence could develop algorithms efficient enough to run usable simulations on classical computers .
To hedge its bets , his lab works on both possibilities : it is developing new algorithms to run on midrange quantum computers and creating AI-driven robots to discover new types of materials .
But Google ’ s work makes Aspuru-Guzik optimistic that quantum computing can solve interesting problems in the not too distant @ @ @ @ @ @ @ that a quantum computer can do today , ” he says .
“ But there is a lot of work , both in the hardware and the software , to get there .
”

When researchers at Google announced last fall that they had achieved “quantum superiority”—a point at which a quantum computer can perform a task beyond the reach of regular computers—some people wondered what the big deal was. The program, which checked the output of a random number generator, was of limited practical value and did not prove that the company’s machine could do anything useful, critics said.
Now, however, Google’s quantum computer has achieved something that could have real-world applications: successfully simulating a simple chemical reaction. The feat points the way toward quantum chemistry, which could expand scientists’ understanding of molecular reactions and lead to useful discoveries, such as better batteries, new ways to make fertilizer and improved methods of removing carbon dioxide from the air.
Last year’s quantum superiority experiment was run on a chip dubbed Sycamore, which contained 53 superconducting quantum bits, or qubits. Chilled to near absolute zero, the qubits take on quantum-mechanical properties, allowing scientists to manipulate them in more complicated and useful ways than the simple “on/off” flows of current that make up the bits of classical computers. The hope is that one day, quantum computers will become powerful enough to quickly perform calculations that would take the lifetime of the universe for a classical computer to complete.
This quantum-chemistry experiment, which was described in the August 28 issue of the journal Science, relied on the same basic Sycamore design, though it only used 12 qubits. But it demonstrates the system’s versatility, says Ryan Babbush, the researcher in charge of developing algorithms for the Google project. “It shows that, in fact, this device is a completely programmable digital quantum computer that can be used for really any task you might attempt,” he says.
The team first simulated a simplified version of the energy state of a molecule consisting of 12 hydrogen atoms, with each of the 12 qubits representing one atom’s single electron. They then modeled a chemical reaction in a molecule containing hydrogen and nitrogen atoms, including how that molecule’s electronic structure would change when its hydrogen atoms shifted from one side to the other. Because the energy of electrons dictates how fast a reaction occurs at a given temperature or concentration of different molecules, such simulations could help chemists understand exactly how that reaction works—and how it would change if they altered the temperature or the chemical cocktail.
The simulation the researchers ran, known as the Hartree-Fock procedure, can also be performed on a classical computer, so it did not, by itself, demonstrate the superiority of a quantum computer. And it was run with help from a classical computer, which used machine learning to evaluate each calculation and then refine new rounds of quantum simulation. But the feat validates the project’s underlying methods, which will be integral to future quantum-chemistry simulations, says Nicholas Rubin, a research scientist on the Google quantum team. And it was twice as large as the previous record-holding chemistry calculation made on a quantum computer.
In 2017 IBM performed a quantum-chemistry simulation using six qubits. Rubin says that result described a molecular system with a level of complexity that scientists in the 1920s could calculate by hand. In doubling that figure to 12 qubits, Google’s project tackled a system that could be calculated with a 1940s-era computer. “If we double it again, we’ll probably go to something like 1980,” Babbush adds. “And if we double it again, then we’ll probably be beyond what you could do classically today.”
So far, no quantum computer has achieved what a classical computer could not, says Xiao Yuan, a postdoctoral research fellow at Stanford University’s Institute for Theoretical Physics, who wrote a commentary accompanying Google’s paper in Science. Even the company’s achievement of quantum superiority in 2019 was called into question by IBM researchers, who showed a way to achieve the same results on a supercomputer in two and a half days, although Google’s version took just more than three minutes. But, Yuan says, the quantum-chemistry experiment is an important step toward a major goal. “If we can use a quantum computer to solve a classically hard and meaningful question, that would be really the most exciting news,” he adds.
There is no theoretical reason scientists could not achieve that goal, Yuan says, but the technical challenge of moving from a few qubits to several hundred—and eventually many more—will require a lot of complicated engineering. A general-purpose quantum computer with millions of qubits will require the development of error-correction protocols, a particularly arduous problem that may take a decade or more to solve. But so-called noisy intermediate-scale quantum computers, which do not have full error correction, might still prove useful in the meantime.
Chemistry is well matched with quantum computing, because a chemical reaction is inherently quantum, says Alán Aspuru-Guzik, a pioneer of quantum chemistry at the University of Toronto. To fully model such a reaction, one must know the quantum states of all the electrons involved. And what better way is there to model a quantum system than to use another quantum system? Long before engineers develop a generally programmable quantum computer, devices with a handful of qubits should be able to outperform classical computers on a subset of interesting problems in chemistry, Aspuru-Guzik says. “So this is a big deal, but it’s not the end of the story,” he adds.
For instance, Aspuru-Guzik is seeking better battery materials to store energy produced by wind turbines and solar cells. Such materials have properties that can be in conflict: they need to be reactive enough to charge and discharge quickly but still stable enough to avoid exploding or catching fire. Computer models of the reactions could help identify ideal materials for that tricky task. Such models could also be important in developing new drugs.
Even so, quantum computers may not be the only revolutionary new way to model chemical reactions, Aspuru-Guzik says. It is possible that artificial intelligence could develop algorithms efficient enough to run usable simulations on classical computers. To hedge its bets, his lab works on both possibilities: it is developing new algorithms to run on midrange quantum computers and creating AI-driven robots to discover new types of materials.
But Google’s work makes Aspuru-Guzik optimistic that quantum computing can solve interesting problems in the not too distant future. “This is the best that a quantum computer can do today,” he says. “But there is a lot of work, both in the hardware and the software, to get there.”


scientificamerican--2020-09-04--Coronavirus News Roundup, August 29-September 4

The items below are highlights from the free newsletter , “ Smart , useful , science stuff about COVID-19.
” To receive newsletter issues daily in your inbox , sign up here .
Please consider a monthly contribution to support this newsletter .
Several media outlets this week have covered hints and speculation that two SARS-CoV-2 vaccines—probably ones being tested by Moderna and by Pfizer in thousands of people—could be approved on an emergency basis in October or November by the U.S. federal government .
Groups reported to be prioritized to receive these vaccines include health care workers , essential @ @ @ @ @ @ @ over 65 , Native Americans , prisoners , and people in some other racial and ethnic categories .
It ’ s probably wise to pay attention to recently reported statements by Dr. Anthony Fauci , the top infectious disease official in the U.S. , on this topic .
In a 9/1/20 story by Liz Szabo at Kaiser Health News , Fauci says that indeed a vaccine could be available “ earlier than expected if ongoing clinical trials produce overwhelmingly positive results.
” An independent board called the Data and Safety Monitoring Board has @ @ @ @ @ @ @ short if strong results come in , Szabo reports .
Fauci says he trusts this board to eschew political influence , the story states .
And people also should trust the vaccine approval process because the experimental data behind any recommendations or decisions will be made public , Fauci is described as saying .
Others quoted in the story raise concerns about stopping these large-scale efficacy and safety studies early .
A string of new research and an editorial all published in the medical journal JAMA suggest that inexpensive , widely available anti-inflammatory @ @ @ @ @ @ @ and methylprednisolone—reduce deaths among people with severe COVID-19 , reports Roni Caryn Rabin at The New York Times ( 9/2/20 ) .
These anti-inflammatory compounds are often just called “ steroids , ” but they are not the same as the anabolic steroids that can be misused by athletes .
The new findings prompted the World Health Organization to update its COVID-19 treatment advice and strongly recommend the corticosteroids for `` severely and critically ill patients , but not to those with mild disease , ” Rabin writes .
JAMA ’ s editor @ @ @ @ @ @ @ as saying , “ Clearly , now steroids are the standard of care [ for severe and critical COVID-19 ] .
” COVID-19 patients often die of the body ’ s extreme immune response to the virus , which leads to inflammation , the story states : https : //www.nytimes.com/2020/09/02/health/coronavirus-steroids.html .
My ears perked up a month or so ago when a children ’ s hospital infectious-diseases pediatrician told me she treated the first reported case in her state of the rare multi-system inflammatory syndrome affecting some children exposed to the new coronavirus @ @ @ @ @ @ @ is known as MIS-C ; it ’ s called PIMS in the UK and some other places .
The pediatrician said it 's difficult to determine how to treat children with MIS-C because there are no senior colleagues to draw on who have in-depth experience with the syndrome—COVID-19 is only 8 or so months old and doctors only described MIS-C in late April .
I grew curious about how doctors solve that problem with this dangerous condition , which it turns out is more life-threatening and potentially harmful to kids than COVID-19 is @ @ @ @ @ @ @ children ’ s hearts .
So , I reported and wrote a story for Scientific American about what is known so far about diagnosing and treating MIS-C ( 9/1/20 ) .
Corticosteroids are among the treatments that some doctors have prescribed , but their true effectiveness is unclear because there are no randomly assigned , controlled experiments under way yet to test this treatment and others for MIS-C.
It ’ s well-known by now that COVID-19 also damages the hearts of many of its adult victims .
In a 8/31/20 essay for Scientific @ @ @ @ @ @ @ Barber describes a related phenomenon—new findings of potentially fatal heart damage in people of all ages , including some previously healthy college and professional athletes , weeks or even months after a symptom-free infection with the new coronavirus .
These patients come to suffer from myocarditis , or inflammation of the heart , which often manifests with shortness of breath , a racing heartbeat , chest pain , fever , or fatigue , Barber writes .
The long-term impact could be significant , according to a cardiologist at the DZHK Centre for Cardiovascular @ @ @ @ @ @ @ from an email ) in the piece .
He writes : “ My personal take is that COVID will increase the incidents of heart failure over the next decades.
” Some cases resolve on their own , the story states , but the best defense for now is not getting the virus .
Testing for SARS-CoV-2 and then isolating people who test positive have proven key to gaining control over the pandemic in many countries .
In an excellent , in-depth piece in The New Yorker ( 9/2/20 ) , surgeon , writer @ @ @ @ @ @ @ lays out the morass of issues that make it difficult to obtain such a test in the U.S. As part of the solution , he proposes a “ national grid , ” as we have for the nation ’ s electricity , `` for the generation , transmission , or distribution of our testing supply.
” Currently , he notes , “ the vast majority of infected Americans , including those with symptoms , never get tested . ''
To be effective for controlling outbreaks , tests should be repeated at least weekly @ @ @ @ @ @ @ The problem is not a lack of technology for testing , he states .
It ’ s that there has been no coordinated implementation to effectively deploy all this technology .
Better logistics to manage billing systems , the flow of people at test sites , and of swab , reagent , and test tube supplies will be key to fixing coronavirus testing in the U.S. , he writes .
And better logistics also could improve the logjams that occur with the four companies that process most test samples in the U.S. , @ @ @ @ @ @ @ pick up the slack , but currently go largely unused , he reports .
The piece concludes with a forecast for “ one of the worst falls and winters in American history , ” but Gawande also notes some collaborative advances and communities that are doing things right , recognizing that public health is part of health care .
You might enjoy “ Updated guidelines for what not to wear after Labor Day , ” by Caroline Doyle and Ginny Hogan , for McSweeney ’ s ( 9/2/20 ) .

The items below are highlights from the free newsletter, “Smart, useful, science stuff about COVID-19.” To receive newsletter issues daily in your inbox, sign up here. Please consider a monthly contribution to support this newsletter.
Several media outlets this week have covered hints and speculation that two SARS-CoV-2 vaccines—probably ones being tested by Moderna and by Pfizer in thousands of people—could be approved on an emergency basis in October or November by the U.S. federal government. Groups reported to be prioritized to receive these vaccines include health care workers, essential workers, national security employees, people over 65, Native Americans, prisoners, and people in some other racial and ethnic categories. It’s probably wise to pay attention to recently reported statements by Dr. Anthony Fauci, the top infectious disease official in the U.S., on this topic. In a 9/1/20 story by Liz Szabo at Kaiser Health News, Fauci says that indeed a vaccine could be available “earlier than expected if ongoing clinical trials produce overwhelmingly positive results.” An independent board called the Data and Safety Monitoring Board has the authority to recommend cutting vaccine experiments short if strong results come in, Szabo reports. Fauci says he trusts this board to eschew political influence, the story states. And people also should trust the vaccine approval process because the experimental data behind any recommendations or decisions will be made public, Fauci is described as saying. Others quoted in the story raise concerns about stopping these large-scale efficacy and safety studies early.
A string of new research and an editorial all published in the medical journal JAMA suggest that inexpensive, widely available anti-inflammatory drugs called corticosteroids—specifically dexamethasone, hydrocortisone, and methylprednisolone—reduce deaths among people with severe COVID-19, reports Roni Caryn Rabin at The New York Times (9/2/20). These anti-inflammatory compounds are often just called “steroids,” but they are not the same as the anabolic steroids that can be misused by athletes. The new findings prompted the World Health Organization to update its COVID-19 treatment advice and strongly recommend the corticosteroids for "severely and critically ill patients, but not to those with mild disease,” Rabin writes. JAMA’s editor in chief is quoted in the story as saying, “Clearly, now steroids are the standard of care [for severe and critical COVID-19].” COVID-19 patients often die of the body’s extreme immune response to the virus, which leads to inflammation, the story states: https://www.nytimes.com/2020/09/02/health/coronavirus-steroids.html.
My ears perked up a month or so ago when a children’s hospital infectious-diseases pediatrician told me she treated the first reported case in her state of the rare multi-system inflammatory syndrome affecting some children exposed to the new coronavirus. In the U.S., the syndrome is known as MIS-C; it’s called PIMS in the UK and some other places. The pediatrician said it's difficult to determine how to treat children with MIS-C because there are no senior colleagues to draw on who have in-depth experience with the syndrome—COVID-19 is only 8 or so months old and doctors only described MIS-C in late April. I grew curious about how doctors solve that problem with this dangerous condition, which it turns out is more life-threatening and potentially harmful to kids than COVID-19 is. MIS-C can cause long-term damage to children’s hearts. So, I reported and wrote a story for Scientific American about what is known so far about diagnosing and treating MIS-C (9/1/20). Corticosteroids are among the treatments that some doctors have prescribed, but their true effectiveness is unclear because there are no randomly assigned, controlled experiments under way yet to test this treatment and others for MIS-C.
It’s well-known by now that COVID-19 also damages the hearts of many of its adult victims. In a 8/31/20 essay for Scientific American, emergency department physician Dr. Carolyn Barber describes a related phenomenon—new findings of potentially fatal heart damage in people of all ages, including some previously healthy college and professional athletes, weeks or even months after a symptom-free infection with the new coronavirus. These patients come to suffer from myocarditis, or inflammation of the heart, which often manifests with shortness of breath, a racing heartbeat, chest pain, fever, or fatigue, Barber writes. The long-term impact could be significant, according to a cardiologist at the DZHK Centre for Cardiovascular Imaging in Germany who is quoted (from an email) in the piece. He writes: “My personal take is that COVID will increase the incidents of heart failure over the next decades.” Some cases resolve on their own, the story states, but the best defense for now is not getting the virus.
Testing for SARS-CoV-2 and then isolating people who test positive have proven key to gaining control over the pandemic in many countries. In an excellent, in-depth piece in The New Yorker (9/2/20), surgeon, writer, and public health researcher Atul Gawande lays out the morass of issues that make it difficult to obtain such a test in the U.S. As part of the solution, he proposes a “national grid,” as we have for the nation’s electricity, "for the generation, transmission, or distribution of our testing supply.” Currently, he notes, “the vast majority of infected Americans, including those with symptoms, never get tested." To be effective for controlling outbreaks, tests should be repeated at least weekly and possibly daily, he reports. The problem is not a lack of technology for testing, he states. It’s that there has been no coordinated implementation to effectively deploy all this technology. Better logistics to manage billing systems, the flow of people at test sites, and of swab, reagent, and test tube supplies will be key to fixing coronavirus testing in the U.S., he writes. And better logistics also could improve the logjams that occur with the four companies that process most test samples in the U.S., Gawande writes. Some U.S. labs could pick up the slack, but currently go largely unused, he reports. The piece concludes with a forecast for “one of the worst falls and winters in American history,” but Gawande also notes some collaborative advances and communities that are doing things right, recognizing that public health is part of health care.
You might enjoy “Updated guidelines for what not to wear after Labor Day,” by Caroline Doyle and Ginny Hogan, for McSweeney’s (9/2/20).


scientificamerican--2020-09-04--We Can't Fight COVID-19 on a Country-by-Country Basis


scientificamerican--2020-09-03--Star Systems Can Be Born Topsy-Turvy

Star Systems Can Be Born Topsy-Turvy

Our solar system is far from the only way to put together stars and their planets .
“ If you look at all the stars in our galaxy , in the Milky Way , more than half of the stars are formed in multiples—meaning there ’ s more than one star in the system.
” Astrophysicist Jaehan Bae of the Carnegie Institution for Science .
He has studied one of those systems—with three stars .
It ’ s called GW Orionis .
And it ’ s freshly formed—only a million years old .
Bae says if you translate that million-year @ @ @ @ @ @ @ , it ’ s the equivalent of a week-old baby .
And how many week-old babies do you bump into ?
“ So if you just walk around your neighborhood , there ’ s little chance you meet a baby who ’ s one week old .
So , first of all , it ’ s hard to find these systems—they ’ re pretty rare.
” Bae and his colleagues got lucky spotting this one .
Using radio telescopes , they were able to image the star system .
And they say it @ @ @ @ @ @ @ more than just star count .
In our solar system , for example , all eight planets orbit the sun more or less in a single plane .
Think of the sun as the center of a vinyl record—with the planets strung out along the grooves .
In contrast , Bae ’ s team discovered that the stars in this triple-star system are ringed by clouds of dust in multiple warped and misaligned planes—picture a three-dimensional gyroscope rather than a two-dimensional vinyl record .
The observations are in the journal Science .
[ @ @ @ @ @ @ @ system with a misaligned and warped circumstellar disk shaped by disk tearing ] Those rings of dust will presumably go on to form planets as the star system matures .
And Bae says astronomers have indeed observed other , more mature star systems—with planets orbiting in these misaligned planes .
“ And we wanted to understand if that happens when the planets are born or whether it ’ s some evolutionary thing that happens over , you know , a billion years.
” The finding suggests that weirdly aligned planetary systems are born @ @ @ @ @ @ @ planets can be all topsy-turvy—even in their infancy .
[ The above text is a transcript of this podcast . ]


scientificamerican--2020-09-05--Poem: Bring Back the Leaf

Poem: Bring Back the Leaf

They sent out a dove : it wobbled home , wings slicked in a rainbow of oil , a sprig of tinsel snagged in its beak , a yard of fishing-line binding its feet .
They sent out an arctic fox : it plodded the bays of the northern fringe in muddy socks and a nylon cape .
Bring back , bring back the leaf .
Bring back the reed and the reef , set the ice sheet back on its frozen plinth , tuck the restless watercourse into its bed , sit the glacier down on its highland throne @ @ @ @ @ @ @ the mountain peak .
Let the northern lights be the northern lights not the alien glow over Glasgow or Leeds .
A camel capsized in a tropical flood .
Caimans dozed in Antarctic lakes .
Polymers rolled in the sturgeon 's blood .
Hippos wandered the housing estates .
Bring back , bring back the leaf .
Bring back the tusk and the horn unshorn .
Bring back the fern , the fish , the frond and the fowl , the golden toad and the pygmy owl , revisit the scene where swallowtails @ @ @ @ @ @ @ They sent out a boat .
Go little breaker , splinter the pack-ice and floes , nose through the rafts and pads of wrappers and bottles and nurdles and cans , the bergs and atolls and islands and states of plastic bags and micro-beads and the forests of smoke .
Bring back , bring back the leaf , bring back the river and sea .

Edited by Dava Sobel
They sent out a dove: it wobbled home,
wings slicked in a rainbow of oil,
a sprig of tinsel snagged in its beak,
a yard of fishing-line binding its feet.
Bring back, bring back the leaf.
They sent out an arctic fox:
it plodded the bays
of the northern fringe
in muddy socks
and a nylon cape.
Bring back, bring back the leaf.
Bring back the reed and the reef,
set the ice sheet back on its frozen plinth,
tuck the restless watercourse into its bed,
sit the glacier down on its highland throne,
put the snow cap back on the mountain peak.
Let the northern lights be the northern lights
not the alien glow over Glasgow or Leeds.
A camel capsized in a tropical flood.
Caimans dozed in Antarctic lakes.
Polymers rolled in the sturgeon's blood.
Hippos wandered the housing estates.
Bring back, bring back the leaf.
Bring back the tusk and the horn
unshorn.
Bring back the fern, the fish, the frond and the fowl,
the golden toad and the pygmy owl,
revisit the scene
where swallowtails fly
through acres of unexhausted sky.
They sent out a boat.
Go little breaker,
splinter the pack-ice and floes, nose
through the rafts and pads
of wrappers and bottles and nurdles and cans,
the bergs and atolls and islands and states
of plastic bags and micro-beads
and the forests of smoke.
Bring back, bring back the leaf,
bring back the river and sea.