physicsworld--2020-07-23--Weak electric currents track tiny magnetic skyrmions - Physics World

Magnetic skyrmions – quasiparticles with a vortex-like structure – show much promise as storage bits for next-generation computer memories and logic devices , but tracking their motion is no easy task .
Researchers at the RIKEN Center for Emergent Matter Science in Japan have now succeeded in tracing them using small pulses of electric current – a development that brings real-world devices based on skyrmions a step closer to reality .
Skyrmions can be thought of as 2D knots ( or “ spin textures ” ) in a material in which the magnetic moments rotate 360° within a plane .
@ @ @ @ @ @ @ magnetic thin films and multilayers , and are very small , measuring just tens of nanometres across .
Because skyrmions are much smaller than the magnetic domains used in modern disk drives , and also robust against external perturbations , they are considered ideal building blocks for future magnetic data storage technologies such as “ racetrack ” memories .
In these devices , spin currents ( which consist of electrons with opposite spins moving in opposite directions ) are used to “ push ” a magnetic domain past magnetic read/write heads .
A @ @ @ @ @ @ @ serve as a substitute information carrier ( a “ 1 ” in the binary system of 1s and 0s ) There is a drawback , however , in that it is difficult to measure skyrmions without using large electric currents .
This is because of their small size , which makes them crystallize in an energetically stable close-packed hexagonal lattice that is hard to budge .
In their experiments , a team of researchers led by Xiuzhen Yu studied thin films of iron germanide ( FeGe ) .
This material is magnetic , @ @ @ @ @ @ @ of having all the magnetic moments within each domain aligned in the same direction .
Instead , it is helimagnetic , meaning that the magnetic moments within its domains are arranged in spiral or helical patterns .
These unusual patterns make it easier to manipulate the skyrmions in the magnet , as the magnetic moments follow the spiral patterns .
Yu and colleagues began by etching a square notch in their FeGe film to generate localized spin current around the corner of the notch .
To create and then erase single skyrmions and @ @ @ @ @ @ @ researchers applied pulses of electric currents first in one direction relative to their notched films and then in the opposite direction .
By then recording the results using a technique called Lorentz transmission electron microscopy , they found a point in the material at which they could isolate individual skyrmions ( measuring just 80 nm in size ) and record how they moved based on known processes such as the topological Hall effect .
This effect occurs when a voltage is applied along a thin conducting sheet of material while a magnetic field @ @ @ @ @ @ @ The electric currents that the researchers applied to create and move the skyrmions in FeGe are very weak , around 109 A/m2 , which is a thousand times lower than that required for traditional magnetic domain wall hard drives .
“ Our result demonstrates that it is possible to manipulate and track individual skyrmions and skyrmion crystals ( which contain a number of vortices and are thus difficult to move ) using a relatively low electric current , ” Yu says .
“ Such detection is an important step towards real-world applications based @ @ @ @ @ @ @ to the reading procedure in a skyrmion-based logic device.
” Members of the team , who report their work in Science Advances , say they are now developing a bilayer system of FeGe films that could host combined skyrmions , which might be easier to detect .
“ We are also eager to track skyrmions in one-dimensional structures such as nanowires ( which would mimic a racetrack structure ) at room temperature , ” Yu tells Physics World .
“ The challenges here will be nanofabrication and device design .
”

Current-driven skyrmion motion. (Courtesy: XZ Yu)
Magnetic skyrmions – quasiparticles with a vortex-like structure – show much promise as storage bits for next-generation computer memories and logic devices, but tracking their motion is no easy task. Researchers at the RIKEN Center for Emergent Matter Science in Japan have now succeeded in tracing them using small pulses of electric current – a development that brings real-world devices based on skyrmions a step closer to reality.
Skyrmions can be thought of as 2D knots (or “spin textures”) in a material in which the magnetic moments rotate 360° within a plane. They exist in many structures, notably magnetic thin films and multilayers, and are very small, measuring just tens of nanometres across.
Because skyrmions are much smaller than the magnetic domains used in modern disk drives, and also robust against external perturbations, they are considered ideal building blocks for future magnetic data storage technologies such as “racetrack” memories. In these devices, spin currents (which consist of electrons with opposite spins moving in opposite directions) are used to “push” a magnetic domain past magnetic read/write heads. A skyrmion could replace a magnetic domain and serve as a substitute information carrier (a “1” in the binary system of 1s and 0s)
There is a drawback, however, in that it is difficult to measure skyrmions without using large electric currents. This is because of their small size, which makes them crystallize in an energetically stable close-packed hexagonal lattice that is hard to budge.
Making use of a helimagnet
In their experiments, a team of researchers led by Xiuzhen Yu studied thin films of iron germanide (FeGe). This material is magnetic, but not in the usual ferromagnetic sense of having all the magnetic moments within each domain aligned in the same direction. Instead, it is helimagnetic, meaning that the magnetic moments within its domains are arranged in spiral or helical patterns. These unusual patterns make it easier to manipulate the skyrmions in the magnet, as the magnetic moments follow the spiral patterns.
Yu and colleagues began by etching a square notch in their FeGe film to generate localized spin current around the corner of the notch. To create and then erase single skyrmions and skyrmion clusters in the film, the researchers applied pulses of electric currents first in one direction relative to their notched films and then in the opposite direction. By then recording the results using a technique called Lorentz transmission electron microscopy, they found a point in the material at which they could isolate individual skyrmions (measuring just 80 nm in size) and record how they moved based on known processes such as the topological Hall effect. This effect occurs when a voltage is applied along a thin conducting sheet of material while a magnetic field is applied perpendicular to its surface.
Relatively low electric current
The electric currents that the researchers applied to create and move the skyrmions in FeGe are very weak, around 109 A/m2, which is a thousand times lower than that required for traditional magnetic domain wall hard drives.
“Our result demonstrates that it is possible to manipulate and track individual skyrmions and skyrmion crystals (which contain a number of vortices and are thus difficult to move) using a relatively low electric current,” Yu says. “Such detection is an important step towards real-world applications based on these particles because it would correspond to the reading procedure in a skyrmion-based logic device.”
Members of the team, who report their work in Science Advances, say they are now developing a bilayer system of FeGe films that could host combined skyrmions, which might be easier to detect. “We are also eager to track skyrmions in one-dimensional structures such as nanowires (which would mimic a racetrack structure) at room temperature,” Yu tells Physics World. “The challenges here will be nanofabrication and device design.”


physicsworld--2020-07-22--Quantum-tunnelling time is measured using ultracold atoms - Physics World

The time it takes for an atom to quantum-mechanically tunnel through an energy barrier has been measured by Aephraim Steinberg of the University of Toronto and colleagues .
The team observed ultracold atoms tunnelling through a laser beam , and their experiment provides important clues in a long-standing mystery in quantum physics .
Quantum tunnelling involves a particle passing through an energy barrier despite lacking the energy required to overcome the barrier , as required by classical physics .
The phenomenon is not fully understood theoretically , yet it underpins practical technologies ranging from scanning tunnelling microscopy to flash memories @ @ @ @ @ @ @ about the length of time taken to cross the barrier – a process that can not be described as a classical trajectory .
This problem arises because quantum mechanics itself provides no prescription for it , explains Karen Hatsagortsyan of the Max Planck Institute for Nuclear Physics in Heidelberg , Germany .
“ Many definitions have been invented , but they describe the tunnelling process from different points of view ” , he says , “ and the relationship between them is not simple and straightforward.
” Hatsagortsyan was involved in one of @ @ @ @ @ @ @ escaping from atoms by light-induced ionization in a strong electric field – a process that involves the electrons tunnelling through a barrier as “ wave packets ” with a range of velocities .
These experiments use a phenomenon called angular streaking , which establishes a kind of “ clock ” that can measure tunnelling with a precision of attoseconds ( 10-18 s ) .
Because the peak of the wave packet is produced by interference effects , its behaviour does not follow our classical intuitions : it can seem to move from one @ @ @ @ @ @ @ faster than light , in defiance of special relativity .
This is because “ there is ‘ no law ’ connecting an incoming and an outgoing peak ” , says Steinberg .
“ Even if the peak appears at the output before the input even arrives , that doesn ’ t mean anything travelled faster than light.
” The method does not , however , really correspond to any previously defined picture of what the tunnelling time is , says Alexandra Landsman of the Max Planck Institute for the Physics of Complex Systems @ @ @ @ @ @ @ the other “ attoclock ” ionization studies of tunnelling .
Rather , it was a way to “ pick out a ‘ correct ’ physical definition of tunnelling time among a number of competing proposals ” , she says .
But these experiments seem to have created more controversy than consensus – partly because it is not clear how to define the time at which tunnelling “ starts ” .
Recently a team based mostly at Griffith University in Nathan , Australia , concluded from the same approach that particles might tunnel more @ @ @ @ @ @ @ be a question of definitions .
“ Sometimes ” , says Steinberg , “ there ’ s a quantity you can measure a number of different ways , and since they all give the same answer classically , we think these different measurements are probing the same thing.
” But they ’ re not necessarily – in which case “ two different measurements both of which we expected to reveal ‘ the tunnelling time ’ can have different results.
” But “ even if there isn ’ t one tunnelling time , neither @ @ @ @ @ @ @ ” , Steinberg adds .
“ There are maybe two or three timescales , and we need to work to understand what each one describes.
” Steinberg ’ s team approached the problem by measuring a definition of the tunnelling time determined by a kind of internal clock in the particles themselves .
For particles , they use a cloud of about five to ten thousand ultracold atoms of rubidium propelled gently towards a barrier induced by a light beam .
The atoms each have a spin that , when placed in a @ @ @ @ @ @ @ ) at a known frequency , which is the ticking clock .
The apparatus is arranged so that the particles will only experience an effective magnetic field inside the barrier itself .
By measuring how much the orientation of their spin has changed when atoms exit the barrier , they obtain a measure of how long the particles spent “ inside ” the barrier .
Proposed more than 50 years ago by two Russian physicists , Steinberg ’ s team created the experiment using atoms that adopt a collective state called a Bose-Einstein @ @ @ @ @ @ @ quantum mechanics .
The atoms have relatively long quantum wavelengths – a micron or so , which means they can penetrate relatively wide barriers , with long passage times of about a millisecond or so – which can be measured precisely .
“ We want particles with a well-controlled starting state and a very long wavelength ” , says Steinberg .
“ A BEC is an ideal way to produce this.
” “ Honestly , when we started these experiments ” , he adds , “ partly I just wanted to see with @ @ @ @ @ @ @ with 87 nucleons and 37 electrons [ that is , rubidium atoms ] could really tunnel all the way across a barrier 10,000 times larger than an atom itself ” .
To create the barrier and have the atoms impinge on it , the team used two laser beams .
“ We Bose-condense them inside an attractive ‘ laser tweezer ’ beam , which acts as an optical waveguide ” , says Steinberg .
Then they use a magnetic field to give the atoms a little push towards the barrier , moving at @ @ @ @ @ @ @ barrier is created by a blue laser beam , focused to be about a micron wide , with a frequency slightly greater than that of one of the resonances in the atoms .
Inside this laser ’ s intense electromagnetic field , the atoms will interact with it .
But “ the atoms can ’ t keep up , oscillate out of phase with the field , and end up in a higher-energy state ” , says Steinberg .
This means that the blue laser acts as a repulsive potential , about 1.3 @ @ @ @ @ @ @ few percent of the atoms can tunnel .
To reduce their random thermal motions , the researchers chill the system to a temperature of about 1 nK .
Deducing the tunnelling time is then a matter of measuring how the spin angles of the atoms in the trap have changed when they exit it .
In this way , says Steinberg , “ we are probing the dwell time of transmitted atoms in the barrier.
” They find that this is about 0.62 ms. “ This is a remarkable experiment , ” says @ @ @ @ @ @ @ because the quantity [ tunnelling time ] it measures is well defined ” , says Landsman .
“ The findings may have practical implications for tunnelling devices , since the measured time seems to correspond to the time the electron actually spends inside the barrier ” .
Steinberg adds that the technique could reveal something about the trajectory within the barrier itself .
“ We hope in the future to restrict our effective magnetic field to regions even smaller than the barrier ” , he says , “ so that when we look @ @ @ @ @ @ @ re measuring not how much time the atom spent somewhere ill-defined in the barrier , but in one particular region.
” According to one theoretical description , he says , it looks as though a particle “ appears on the far side without ever crossing the middle .
This is what we ’ d like to test.
” The research is described in Nature .

Quantum clock: rotating atomic spins have been used to measure the time it takes for quantum tunnelling to occur. (Courtesy: iStock/agsandrew)
The time it takes for an atom to quantum-mechanically tunnel through an energy barrier has been measured by Aephraim Steinberg of the University of Toronto and colleagues. The team observed ultracold atoms tunnelling through a laser beam, and their experiment provides important clues in a long-standing mystery in quantum physics.
Quantum tunnelling involves a particle passing through an energy barrier despite lacking the energy required to overcome the barrier, as required by classical physics. The phenomenon is not fully understood theoretically, yet it underpins practical technologies ranging from scanning tunnelling microscopy to flash memories.
There has been a long controversy about the length of time taken to cross the barrier – a process that cannot be described as a classical trajectory. This problem arises because quantum mechanics itself provides no prescription for it, explains Karen Hatsagortsyan of the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. “Many definitions have been invented, but they describe the tunnelling process from different points of view”, he says, “and the relationship between them is not simple and straightforward.”
Angular streaking
Hatsagortsyan was involved in one of several recent experiments that looked at electrons escaping from atoms by light-induced ionization in a strong electric field – a process that involves the electrons tunnelling through a barrier as “wave packets” with a range of velocities. These experiments use a phenomenon called angular streaking, which establishes a kind of “clock” that can measure tunnelling with a precision of attoseconds (10-18 s).
Because the peak of the wave packet is produced by interference effects, its behaviour does not follow our classical intuitions: it can seem to move from one side of the barrier to the other faster than light, in defiance of special relativity. This is because “there is ‘no law’ connecting an incoming and an outgoing peak”, says Steinberg. “Even if the peak appears at the output before the input even arrives, that doesn’t mean anything travelled faster than light.”
The method does not, however, really correspond to any previously defined picture of what the tunnelling time is, says Alexandra Landsman of the Max Planck Institute for the Physics of Complex Systems in Dresden, who led some of the other “attoclock” ionization studies of tunnelling. Rather, it was a way to “pick out a ‘correct’ physical definition of tunnelling time among a number of competing proposals”, she says.
More controversy than consensus
But these experiments seem to have created more controversy than consensus – partly because it is not clear how to define the time at which tunnelling “starts”. Recently a team based mostly at Griffith University in Nathan, Australia, concluded from the same approach that particles might tunnel more or less instantaneously.
It may all be a question of definitions. “Sometimes”, says Steinberg, “there’s a quantity you can measure a number of different ways, and since they all give the same answer classically, we think these different measurements are probing the same thing.” But they’re not necessarily – in which case “two different measurements both of which we expected to reveal ‘the tunnelling time’ can have different results.”
But “even if there isn’t one tunnelling time, neither is there an infinite number of options”, Steinberg adds. “There are maybe two or three timescales, and we need to work to understand what each one describes.”
Steinberg’s team approached the problem by measuring a definition of the tunnelling time determined by a kind of internal clock in the particles themselves. For particles, they use a cloud of about five to ten thousand ultracold atoms of rubidium propelled gently towards a barrier induced by a light beam.
Spinning clocks
The atoms each have a spin that, when placed in a magnetic field, will rotate (precess) at a known frequency, which is the ticking clock. The apparatus is arranged so that the particles will only experience an effective magnetic field inside the barrier itself. By measuring how much the orientation of their spin has changed when atoms exit the barrier, they obtain a measure of how long the particles spent “inside” the barrier.
Proposed more than 50 years ago by two Russian physicists, Steinberg’s team created the experiment using atoms that adopt a collective state called a Bose-Einstein condensate (BEC), described by quantum mechanics. The atoms have relatively long quantum wavelengths – a micron or so, which means they can penetrate relatively wide barriers, with long passage times of about a millisecond or so – which can be measured precisely. “We want particles with a well-controlled starting state and a very long wavelength”, says Steinberg. “A BEC is an ideal way to produce this.”
“Honestly, when we started these experiments”, he adds, “partly I just wanted to see with our own eyes that a composite particle with 87 nucleons and 37 electrons [that is, rubidium atoms] could really tunnel all the way across a barrier 10,000 times larger than an atom itself”.
Laser tweezer
To create the barrier and have the atoms impinge on it, the team used two laser beams. “We Bose-condense them inside an attractive ‘laser tweezer’ beam, which acts as an optical waveguide”, says Steinberg. Then they use a magnetic field to give the atoms a little push towards the barrier, moving at a few millimetres per second.
The barrier is created by a blue laser beam, focused to be about a micron wide, with a frequency slightly greater than that of one of the resonances in the atoms. Inside this laser’s intense electromagnetic field, the atoms will interact with it. But “the atoms can’t keep up, oscillate out of phase with the field, and end up in a higher-energy state”, says Steinberg. This means that the blue laser acts as a repulsive potential, about 1.3 micron wide, through which just a few percent of the atoms can tunnel. To reduce their random thermal motions, the researchers chill the system to a temperature of about 1 nK.
Deducing the tunnelling time is then a matter of measuring how the spin angles of the atoms in the trap have changed when they exit it. In this way, says Steinberg, “we are probing the dwell time of transmitted atoms in the barrier.” They find that this is about 0.62 ms.
“This is a remarkable experiment,” says Hatsagortsyan. It is “especially nice because the quantity [tunnelling time] it measures is well defined”, says Landsman. “The findings may have practical implications for tunnelling devices, since the measured time seems to correspond to the time the electron actually spends inside the barrier”.
Steinberg adds that the technique could reveal something about the trajectory within the barrier itself. “We hope in the future to restrict our effective magnetic field to regions even smaller than the barrier”, he says, “so that when we look at the final spin, we’re measuring not how much time the atom spent somewhere ill-defined in the barrier, but in one particular region.” According to one theoretical description, he says, it looks as though a particle “appears on the far side without ever crossing the middle. This is what we’d like to test.”
The research is described in Nature.


physicsworld--2020-07-22--Hubble trouble: a rapidly expanding cosmic debate - Physics World

The universe is expanding at an accelerating rate , but just how fast is that expansion ?
We thought we knew the answer to that question .
But recent findings have cast doubt on our understanding .
This story begins in the US in the 1920s .
Back then , most astronomers believed that our galaxy was all that existed – it was the entire universe .
But observations by the astronomer Edwin Hubble would transform our understanding of our place the cosmos .
During the previous decade , the American astronomer Henrietta Swan Leavitt had identified the relation between @ @ @ @ @ @ @ class of pulsing star known as Cepheid variables .
This key discovery enabled astronomers to accurately predict the distance to these stars , providing a sort of cosmic tape measure for measuring far larger distances than had been possible before .
While studying cepheid variables in the spiral nebulae , Hubble realised that these stars must be located far beyond our galaxy .
That led to the realisation that the Milky Way was just one galaxy among many .
Soon , Hubble discovered that almost all of these other galaxies are moving away @ @ @ @ @ @ @ cosmologist Georges Lemaître to conclude that the universe is expanding .
Hubble and Lemaître independently derived a mathematical relationship to describe this expansion .
The recession velocity ( v ) of a galaxy is equal to its distance ( D ) multiplied by the Hubble constant – a value which describes the rate of expansion at the current time .
Traditionally , the Hubble Constant is determined by measuring the distance and recession velocity of galaxies , by using astronomical objects of known brightness .
These so-called “ standard candles ” include type @ @ @ @ @ @ @ white-dwarf stars that have a certain critical mass .
By analysing maps of the Cosmic Microwave Background from the Planck mission , astronomers were able to calculate our most precise value yet of the Hubble constant : 67.4 kilometers per second per megaparsec .
In itself , it can be hard to get your head around what the Hubble Constant means .
But it matters because it dictates the age of the universe , and our understanding of how it evolved .
So it was a big shock in 2016 when a project @ @ @ @ @ @ @ arrived at a significantly higher value for the Hubble Constant : 73.2 kilometers per second per megaparsec .
That value would suggest the universe is younger than we thought .
Riess led the SH0ES Project , which involved measuring our old friends the Cepheid variables , the same type of star that had enabled Swann Leavitt ’ s and Hubble ’ s breakthroughs .
The SH0ES result appears to be backed up by another project with a quirky name , H0LiCOW .
That project , led by Sherry Suyu , calculates the Hubble @ @ @ @ @ @ @ gravitational lensing of light emitted from quasars .
These are luminous active galactic nuclei that exhibit brightness variations .
Looking ahead , if the discrepancy between the Planck measurement and the more local measurements of the Hubble constant becomes stronger , then we might be looking at new physics .
Another different measurement of the Hubble constant may come from the emerging field of gravitational-wave astronomy .
In theory , astronomers could get an accurate value of the Hubble Constant by observing the gravitational waves and light emitted by the merger of two @ @ @ @ @ @ @ incredibly energetic events , known as kilonovae , are proving to be few and far between .
Find out more about the Hubble constant mystery in the July 2020 issue of Physics World .

Video transcript
The universe is expanding at an accelerating rate, but just how fast is that expansion?
We thought we knew the answer to that question. But recent findings have cast doubt on our understanding.
This story begins in the US in the 1920s. Back then, most astronomers believed that our galaxy was all that existed – it was the entire universe.
But observations by the astronomer Edwin Hubble would transform our understanding of our place the cosmos.
During the previous decade, the American astronomer Henrietta Swan Leavitt had identified the relation between the luminosity and the period for a class of pulsing star known as Cepheid variables.
This key discovery enabled astronomers to accurately predict the distance to these stars, providing a sort of cosmic tape measure for measuring far larger distances than had been possible before.
While studying cepheid variables in the spiral nebulae, Hubble realised that these stars must be located far beyond our galaxy.
That led to the realisation that the Milky Way was just one galaxy among many.
Soon, Hubble discovered that almost all of these other galaxies are moving away from us. This led the Belgian cosmologist Georges Lemaître to conclude that the universe is expanding.
Hubble and Lemaître independently derived a mathematical relationship to describe this expansion. The recession velocity (v) of a galaxy is equal to its distance (D) multiplied by the Hubble constant – a value which describes the rate of expansion at the current time.
Traditionally, the Hubble Constant is determined by measuring the distance and recession velocity of galaxies, by using astronomical objects of known brightness. These so-called “standard candles” include type 1a supernovae – which are basically exploded white-dwarf stars that have a certain critical mass.
Now, let’s fast-forward to 2013.
By analysing maps of the Cosmic Microwave Background from the Planck mission, astronomers were able to calculate our most precise value yet of the Hubble constant: 67.4 kilometers per second per megaparsec.
In itself, it can be hard to get your head around what the Hubble Constant means. But it matters because it dictates the age of the universe, and our understanding of how it evolved.
So it was a big shock in 2016 when a project led by Nobel Prize winner Adam Riess arrived at a significantly higher value for the Hubble Constant: 73.2 kilometers per second per megaparsec. That value would suggest the universe is younger than we thought.
Riess led the SH0ES Project, which involved measuring our old friends the Cepheid variables, the same type of star that had enabled Swann Leavitt’s and Hubble’s breakthroughs.
The SH0ES result appears to be backed up by another project with a quirky name, H0LiCOW.
That project, led by Sherry Suyu, calculates the Hubble constant using another ingenuous method: the gravitational lensing of light emitted from quasars. These are luminous active galactic nuclei that exhibit brightness variations.
Looking ahead, if the discrepancy between the Planck measurement and the more local measurements of the Hubble constant becomes stronger, then we might be looking at new physics.
Another different measurement of the Hubble constant may come from the emerging field of gravitational-wave astronomy.
In theory, astronomers could get an accurate value of the Hubble Constant by observing the gravitational waves and light emitted by the merger of two neutron stars. But unfortunately, these incredibly energetic events, known as kilonovae, are proving to be few and far between.
Find out more about the Hubble constant mystery in the July 2020 issue of Physics World.


physicsworld--2020-07-22--From entangled earbuds to Star Wars: more examples of ‘transmogrified physics’ - Physics World

In January I revealed the discovery of “ transmogrified physics ” , a field of science consisting of surprising and hitherto unnoticed connections between the microscopic and the macroscopic worlds .
As an example I cited screwdriver oscillation , the phenomenon whereby you find only flathead screwdrivers in your toolbox when you urgently need one with a Phillips head , but when you need flatheads there are only Phillips heads .
Like neutrinos , it appears that screwdrivers can oscillate from one state to another .
I received enough responses to confirm my suspicion that this is an exciting and @ @ @ @ @ @ @ to send me reports of similar phenomena linking the micro- and macro-worlds , I received enough responses to confirm my suspicion that this is an exciting and fertile research territory .
Many readers reported , for instance , that their Allen wrenches obey the uncertainty principle ; when you aren ’ t looking , your tool chest is full of them , but when you need one there aren ’ t any – and if you need a specific one you only find the others in the set .
Other correspondents said their @ @ @ @ @ @ @ ’ t have enough data points to discover the law involved .
Fredy Zypman , head of physics at Yeshiva University in New York , came across several interesting phenomena including the following .
• Bragg planes Special aircraft used only in special occasions to show off .
• Centre of mass An attractor of churchgoers .
• Raman ( or Ramen ) scattering The phenomenon of spreading of noodles out of a tilted bowl .
• Change of phase What happens , and is quickly repressed , when one gets a good @ @ @ @ @ @ @ A desired ability of the dean to step in to avoid faculty conflagration .
Michael Hutchings of the Open University is another pioneer in the new field .
His discoveries include : • Hidden fault On starting up a well-used piece of apparatus there appears to be a serious fault .
On inspection one finds an obvious reason , such as one unit not having been switched on .
But when you switch it on , you find that a fault still exists .
• Entanglement When two or more lengths of connecting @ @ @ @ @ @ @ in a domestic environment and when roughly coiled , they will become hopelessly entangled .
Careful separation of them will inevitably end in a knot in at least one length .
I have seen macro-world entanglement myself in earbuds and Christmas-tree lights .
I put on earbuds , for instance , take them off , put them down – and then when I go to put them on again I have to unknot them .
What ’ s going on ?
I don ’ t take them off , do gymnastics , and @ @ @ @ @ @ @ more than classical physics is involved here .
Another example of transmogrified physics is science reliteracy , which is what happens when people try to give a retrospective , less than credible explanation of their gaffe .
An example occurs in the Star Wars movies .
In Episode IV ( 1977 ) , when we first meet the captain of the starship Millennium Falcon Han Solo , he brags , in what for the scriptwriters was clearly a throwaway line , that he “ made the Kessel Run in less than 12 parsecs @ @ @ @ @ @ @ any Star Wars enthusiast knows , is a treacherous hyperspace route that smugglers use to convey spices ( essentially the Star Wars euphemism for drugs ) from Kessel to wealthy customers .
But , as any half-scientifically literate person knows , a parsec is not a unit of time but of distance ; it ’ s an abbreviation of “ parallax arcsecond , ” or 3.26 light-years .
It was clearly an embarrassing slip-up in an otherwise meticulously detailed series of movies – no matter how much franchise spokespeople and diehard Star Wars @ @ @ @ @ @ @ or claim that they knew all along that parsec was a unit of distance .
So in the Star Wars spinoff Solo : a Star Wars Story ( 2018 ) , the explanation is provided that of course the Kessel Run is a unit of distance ; what Solo meant was that the run is normally 20 parsecs long but by taking shortcuts he managed to cut that distance down to under 12 parsecs .
Sure .
Whether or not you are gullible enough to really believe the later explanation , it amounts @ @ @ @ @ @ @ also call reverse explaneering .
I also received several examples from a US accelerator physicist who witnesses in political affairs the equivalent of “ beam-beam ” effects .
In a particle-collider context , this term refers to one beam breaking up , amplifying its own instabilities while exposing instabilities in the other .
Similarly when the US and China direct criticisms at each other , each ends up illuminating problems in the other ’ s situation while also magnifying its own .
My collider physicist contact has also found “ coherent instability ” @ @ @ @ @ @ @ don ’ t reduce but only reinforce it – throughout politics .
Take your pick from COVID-19 to America ’ s handling of international problems with almost any other nation .
Then there ’ s “ Landau damping ” , which in accelerator physics is what happens when you successfully counteract coherent instabilities by cleverly arranging elements internal to the beam to interact with it .
The same phenomenon can occur in politics when many factions , parties and agencies create a nearly insoluble problem , but then some of them suddenly do @ @ @ @ @ @ @ situation , thereby establishing a new peaceful norm .
Some readers of my January column accused me of irony and sarcasm , and lack of seriousness .
I disagree .
Further study of transmogrified physics is bound to reveal much about our surrounding world .
I ’ ll leave you with two of my favourites , both of which are also linked to politics .
There ’ s the screw , a politician who can make followers perform political work by spinning in circles .
Finally , I bring you the jerk , @ @ @ @ @ @ @ high rate of acceleration away from a troublesome issue .

Physics World, where it appeared under the headline "Transmogrified physics II". Members of the Institute of Physics can enjoy the full issue Taken from the July 2020 issue of, where it appeared under the headline "Transmogrified physics II". Members of the Institute of Physics can enjoy the full issue via the Physics World app
Robert P Crease reports on your latest work in the exciting new scientific field he discovered
Micro to macro Entanglement appears in the quantum world and in everyday life, for example, when a knot remains after you unpick tangled wires. (Courtesy: iStock/nortonrsx)
In January I revealed the discovery of “transmogrified physics”, a field of science consisting of surprising and hitherto unnoticed connections between the microscopic and the macroscopic worlds.
As an example I cited screwdriver oscillation, the phenomenon whereby you find only flathead screwdrivers in your toolbox when you urgently need one with a Phillips head, but when you need flatheads there are only Phillips heads. Like neutrinos, it appears that screwdrivers can oscillate from one state to another.
I received enough responses to confirm my suspicion that this is an exciting and fertile research territory.
After inviting readers to send me reports of similar phenomena linking the micro- and macro-worlds, I received enough responses to confirm my suspicion that this is an exciting and fertile research territory. Many readers reported, for instance, that their Allen wrenches obey the uncertainty principle; when you aren’t looking, your tool chest is full of them, but when you need one there aren’t any – and if you need a specific one you only find the others in the set. Other correspondents said their tools could dematerialize, though they didn’t have enough data points to discover the law involved.
Real examples
Fredy Zypman, head of physics at Yeshiva University in New York, came across several interesting phenomena including the following.
Bragg planes Special aircraft used only in special occasions to show off.
Special aircraft used only in special occasions to show off. Centre of mass An attractor of churchgoers.
An attractor of churchgoers. Raman (or Ramen) scattering The phenomenon of spreading of noodles out of a tilted bowl.
The phenomenon of spreading of noodles out of a tilted bowl. Change of phase What happens, and is quickly repressed, when one gets a good hand in poker.
What happens, and is quickly repressed, when one gets a good hand in poker. Resolving power A desired ability of the dean to step in to avoid faculty conflagration.
Michael Hutchings of the Open University is another pioneer in the new field. His discoveries include:
Hidden fault On starting up a well-used piece of apparatus there appears to be a serious fault. On inspection one finds an obvious reason, such as one unit not having been switched on. But when you switch it on, you find that a fault still exists.
On starting up a well-used piece of apparatus there appears to be a serious fault. On inspection one finds an obvious reason, such as one unit not having been switched on. But when you switch it on, you find that a fault still exists. Entanglement When two or more lengths of connecting wire are near each other, particularly in a domestic environment and when roughly coiled, they will become hopelessly entangled. Careful separation of them will inevitably end in a knot in at least one length.
I have seen macro-world entanglement myself in earbuds and Christmas-tree lights. I put on earbuds, for instance, take them off, put them down – and then when I go to put them on again I have to unknot them. What’s going on? I don’t take them off, do gymnastics, and then put them down. Clearly, more than classical physics is involved here.
Another example of transmogrified physics is science reliteracy, which is what happens when people try to give a retrospective, less than credible explanation of their gaffe.
Another example of transmogrified physics is science reliteracy, which is what happens when people try to give a retrospective, less than credible explanation of their gaffe. An example occurs in the Star Wars movies. In Episode IV (1977), when we first meet the captain of the starship Millennium Falcon Han Solo, he brags, in what for the scriptwriters was clearly a throwaway line, that he “made the Kessel Run in less than 12 parsecs”. The Kessel Run, as any Star Wars enthusiast knows, is a treacherous hyperspace route that smugglers use to convey spices (essentially the Star Wars euphemism for drugs) from Kessel to wealthy customers. But, as any half-scientifically literate person knows, a parsec is not a unit of time but of distance; it’s an abbreviation of “parallax arcsecond,” or 3.26 light-years.
It was clearly an embarrassing slip-up in an otherwise meticulously detailed series of movies – no matter how much franchise spokespeople and diehard Star Wars fans try to dance around this issue or claim that they knew all along that parsec was a unit of distance. So in the Star Wars spinoff Solo: a Star Wars Story (2018), the explanation is provided that of course the Kessel Run is a unit of distance; what Solo meant was that the run is normally 20 parsecs long but by taking shortcuts he managed to cut that distance down to under 12 parsecs. Sure.
Whether or not you are gullible enough to really believe the later explanation, it amounts to science reliteracy, which some textbooks also call reverse explaneering.
I also received several examples from a US accelerator physicist who witnesses in political affairs the equivalent of “beam-beam” effects. In a particle-collider context, this term refers to one beam breaking up, amplifying its own instabilities while exposing instabilities in the other. Similarly when the US and China direct criticisms at each other, each ends up illuminating problems in the other’s situation while also magnifying its own. My collider physicist contact has also found “coherent instability” – when attempts to control a disruption don’t reduce but only reinforce it – throughout politics. Take your pick from COVID-19 to America’s handling of international problems with almost any other nation.
Then there’s “Landau damping”, which in accelerator physics is what happens when you successfully counteract coherent instabilities by cleverly arranging elements internal to the beam to interact with it. The same phenomenon can occur in politics when many factions, parties and agencies create a nearly insoluble problem, but then some of them suddenly do something sensible and effective to stabilize the situation, thereby establishing a new peaceful norm.
The critical point
Some readers of my January column accused me of irony and sarcasm, and lack of seriousness. I disagree. Further study of transmogrified physics is bound to reveal much about our surrounding world. I’ll leave you with two of my favourites, both of which are also linked to politics. There’s the screw, a politician who can make followers perform political work by spinning in circles. Finally, I bring you the jerk, a politician who can move with a high rate of acceleration away from a troublesome issue.


physicsworld--2020-07-22--Best in physics: clinical prompt gamma measurements and FLASH dosimetry - Physics World

The “ Best-in-Physics ” poster session at the 2020 Joint AAPM|COMP Virtual Meeting highlights the top five abstracts in the imaging , therapy and multi-disciplinary science tracks .
Our first pick of this year ’ s top scoring studies examined multi-target tracking during radiotherapy and carotid plaque evaluation using quantitative ultrasound .
In our second look at the 2020 winning studies , we report on the first ever prompt gamma ray spectroscopy in a patient , plus an investigation into the use of ionizing radiation acoustic imaging for in vivo FLASH dosimetry .
Proton therapy offers dosimetric advantages over photon-based @ @ @ @ @ @ @ by factor of two or three , while delivering the same dose to the target .
It should also be possible to use the sharp distal edge of the Bragg peak to create a highly conformal high-dose area around the target .
“ However , in practise , we can ’ t do that yet as we don ’ t know exactly where the protons stop , ” explained Joost Verburg , from Massachusetts General Hospital and Harvard Medical School .
To address this problem , Verburg and colleagues are developing prompt gamma-ray @ @ @ @ @ @ @ range .
Prompt gamma rays are generated when the therapeutic proton beam interacts with atomic nuclei within the patient .
The idea is to measure the range of every proton pencil beam , during treatment delivery , by acquiring energy- and time-resolved prompt gamma-ray spectra .
These spectra are compared with a nuclear reaction model to determine the range deviation of the pencil-beam compared with the calculated treatment plan .
Verburg described his team ’ s prototype system and presented the first measurements of prompt gamma-ray spectra obtained during a patient treatment .
@ @ @ @ @ @ @ prototype prompt gamma-ray spectroscopy system , comprising a collimated array of fast scintillation detectors mounted on a 7-axis robotic positioning system for patient alignment .
Initial tests in phantoms revealed a typical measured range error of less than 1 mm .
“ This shows that in a situation where we actually know the materials and know where the protons end up , we are measuring exactly what we are supposed to , ” Verburg noted .
The first patient recruited in the team ’ s clinical study received proton therapy for a complex @ @ @ @ @ @ @ gamma spectra of one treatment field once per week for five weeks .
Results were consistent from week-to-week , with a systematic range deviation between the delivered proton range and the treatment plan .
The mean range error was just 1–2 mm , but Verburg noted that not all pencil beams stopped exactly where they were planned .
They observed a spread of around 3 mm sigma and a maximum range error of about 8 mm .
Compared with traditional range margins used for proton therapy ( 3.5 % + 1 mm , @ @ @ @ @ @ @ , these errors fit within traditional margins .
“ We successfully performed first ever prompt gamma ray spectroscopy in a patient , ” Verburg concluded .
“ The range errors that we measured were mostly consistent between fractions and within traditional range margins that are applied in proton therapy .
The test in phantoms also showed that our prompt gamma ray spectroscopy system is capable of aiming protons very precisely with a range position of around 1 mm .
This shows great potential – if we measure and fine tune the range of @ @ @ @ @ @ @ we can reduce the need for margins and design better proton treatments in future.
” FLASH radiotherapy is an emerging treatment modality that uses ultrahigh dose rates ( above 40 Gy/s ) to spare normal tissues and improve the therapeutic ratio compared with conventional radiotherapy .
The instantaneous delivery of higher dose rates , however , increases the need for reliable beam localization and dose monitoring tools , particularly when dealing with deep seated tumours , where current dosimeters can ’ t provide an adequate reading for safe delivery .
Noora Ba Sunbul @ @ @ @ @ @ @ the use of ionizing radiation acoustic imaging ( iRAI ) for in vivo FLASH dosimetry .
“ The main aim of this work is to fully develop a comprehensive simulation workflow to test the feasibility of iRAI as a reliable real-time dosimetry tool for FLASH radiotherapy , ” she explained .
When a pulsed beam of therapeutic radiation strikes tissue it causes localized dose deposition and thermal expansion , which generates acoustic waves .
iRAI works by detecting these waves with an ultrasound transducer and using them to construct dose-related images in real @ @ @ @ @ @ @ Ba Sunbul and colleagues used a modified linac to deliver a 6 MeV electron beam in FLASH mode to a gelatin phantom .
The field was collimated to 1×1 cm and an ideal transducer placed 10 cm from beam centre .
They also simulated the detection of induced acoustic waves following FLASH using Monte Carlo and k-Wave .
This involved simulating the full 3D dose distribution in the phantom , using this to define the initial pressure source , modelling the acoustic wave propagation and then reconstructing an image .
“ Comparing dose @ @ @ @ @ @ @ results showed acceptable agreement between measured and simulated results , with less than 6 % error at depths of less than 2 cm , ” said Ba Sunbul .
The team also used the instantaneous pressure signal to define the edges of the beam , determined by the change in this pressure signal between the phantom entrance and exit .
iRAI could identify the central beam edges within about 4 % of the film measurement .
The linac pulse duration and repetition rate , which define the dose rate , were seen to @ @ @ @ @ @ @ signal amplitude , as well as the dose .
Ba Sunbul explained that the pulse duration affects both the temporal and spatial resolution of the 2D reconstructed iRAI images , with longer pulses creating lower-resolution images .
She noted that this negatively affects the beam localization ability of iRAI .
“ We have developed a full simulation workflow for testing iRAI applicability in FLASH radiotherapy using ideal point-source ultrasound transducers , ” Ba Sunbul concluded .
The next step , she added , will be to simulate iRAI image reconstruction to mimic experimental @ @ @ @ @ @ @ ability to detect beam edges has already been verified experimentally using conventional radiotherapy in rabbit measurements and in a liver phantom .

Best in Physics presenter Joost Verburg (back row, next to the detector) and colleagues with the prototype prompt gamma detection system on its positioning robot. (Courtesy: Joost Verburg)
The “Best-in-Physics” poster session at the 2020 Joint AAPM|COMP Virtual Meeting highlights the top five abstracts in the imaging, therapy and multi-disciplinary science tracks. Our first pick of this year’s top scoring studies examined multi-target tracking during radiotherapy and carotid plaque evaluation using quantitative ultrasound. In our second look at the 2020 winning studies, we report on the first ever prompt gamma ray spectroscopy in a patient, plus an investigation into the use of ionizing radiation acoustic imaging for in vivo FLASH dosimetry.
First prompt gamma ray spectra measured during proton therapy
Proton therapy offers dosimetric advantages over photon-based radiotherapy, such as reducing integral dose by factor of two or three, while delivering the same dose to the target. It should also be possible to use the sharp distal edge of the Bragg peak to create a highly conformal high-dose area around the target. “However, in practise, we can’t do that yet as we don’t know exactly where the protons stop,” explained Joost Verburg, from Massachusetts General Hospital and Harvard Medical School.
To address this problem, Verburg and colleagues are developing prompt gamma-ray spectroscopy for in vivo verification of proton range. Prompt gamma rays are generated when the therapeutic proton beam interacts with atomic nuclei within the patient. The idea is to measure the range of every proton pencil beam, during treatment delivery, by acquiring energy- and time-resolved prompt gamma-ray spectra. These spectra are compared with a nuclear reaction model to determine the range deviation of the pencil-beam compared with the calculated treatment plan.
Verburg described his team’s prototype system and presented the first measurements of prompt gamma-ray spectra obtained during a patient treatment.
The MGH/Harvard team has created a full-scale prototype prompt gamma-ray spectroscopy system, comprising a collimated array of fast scintillation detectors mounted on a 7-axis robotic positioning system for patient alignment. Initial tests in phantoms revealed a typical measured range error of less than 1 mm. “This shows that in a situation where we actually know the materials and know where the protons end up, we are measuring exactly what we are supposed to,” Verburg noted.
The first patient recruited in the team’s clinical study received proton therapy for a complex base-of-skull meningioma. The researchers measured prompt gamma spectra of one treatment field once per week for five weeks. Results were consistent from week-to-week, with a systematic range deviation between the delivered proton range and the treatment plan.
The mean range error was just 1–2 mm, but Verburg noted that not all pencil beams stopped exactly where they were planned. They observed a spread of around 3 mm sigma and a maximum range error of about 8 mm. Compared with traditional range margins used for proton therapy (3.5% + 1 mm, or 6.6 mm for this case), these errors fit within traditional margins.
“We successfully performed first ever prompt gamma ray spectroscopy in a patient,” Verburg concluded. “The range errors that we measured were mostly consistent between fractions and within traditional range margins that are applied in proton therapy. The test in phantoms also showed that our prompt gamma ray spectroscopy system is capable of aiming protons very precisely with a range position of around 1 mm. This shows great potential – if we measure and fine tune the range of the proton beams in the patient, we can reduce the need for margins and design better proton treatments in future.”
Ionizing radiation acoustic imaging offers in vivo FLASH dosimetry
FLASH radiotherapy is an emerging treatment modality that uses ultrahigh dose rates (above 40 Gy/s) to spare normal tissues and improve the therapeutic ratio compared with conventional radiotherapy. The instantaneous delivery of higher dose rates, however, increases the need for reliable beam localization and dose monitoring tools, particularly when dealing with deep seated tumours, where current dosimeters can’t provide an adequate reading for safe delivery.
Noora Ba Sunbul from the University of Michigan is investigating the use of ionizing radiation acoustic imaging (iRAI) for in vivo FLASH dosimetry. “The main aim of this work is to fully develop a comprehensive simulation workflow to test the feasibility of iRAI as a reliable real-time dosimetry tool for FLASH radiotherapy,” she explained.
When a pulsed beam of therapeutic radiation strikes tissue it causes localized dose deposition and thermal expansion, which generates acoustic waves. iRAI works by detecting these waves with an ultrasound transducer and using them to construct dose-related images in real time.
To test their approach, Ba Sunbul and colleagues used a modified linac to deliver a 6 MeV electron beam in FLASH mode to a gelatin phantom. The field was collimated to 1×1 cm and an ideal transducer placed 10 cm from beam centre. They also simulated the detection of induced acoustic waves following FLASH using Monte Carlo and k-Wave. This involved simulating the full 3D dose distribution in the phantom, using this to define the initial pressure source, modelling the acoustic wave propagation and then reconstructing an image.
“Comparing dose profiles at different depths with our film-measured results showed acceptable agreement between measured and simulated results, with less than 6% error at depths of less than 2 cm,” said Ba Sunbul.
The team also used the instantaneous pressure signal to define the edges of the beam, determined by the change in this pressure signal between the phantom entrance and exit. iRAI could identify the central beam edges within about 4% of the film measurement.
The linac pulse duration and repetition rate, which define the dose rate, were seen to be inversely proportional to the instantaneous pressure signal amplitude, as well as the dose. Ba Sunbul explained that the pulse duration affects both the temporal and spatial resolution of the 2D reconstructed iRAI images, with longer pulses creating lower-resolution images. She noted that this negatively affects the beam localization ability of iRAI.
“We have developed a full simulation workflow for testing iRAI applicability in FLASH radiotherapy using ideal point-source ultrasound transducers,” Ba Sunbul concluded. The next step, she added, will be to simulate iRAI image reconstruction to mimic experimental set-ups, noting that iRAI’s ability to detect beam edges has already been verified experimentally using conventional radiotherapy in rabbit measurements and in a liver phantom.


physicsworld--2020-07-21--Therapeutics firms share inaugural prize for health physics - Physics World

Companies that use physics to unlock next-generation drugs for respiratory disorders and enable advanced cancer treatments are the first recipients of a new award for early-stage companies in healthcare and medicine .
Nebu~Flow , a University of Glasgow spin-out that is commercializing an acoustic nebulizer , and Cellular Highways , a Cambridge-based start-up that develops microfluidic devices for use in cell therapies , each received the inaugural Lee Lucas Award and £5000 in prize money as part of the annual Business Awards presented by the Institute of Physics ( IOP ) .
Speaking on 15 July at the first of @ @ @ @ @ @ @ Awards , IOP vice-president for business James McKenzie praised Cellular Highways , Nebu~Flow and 11 other award-winning companies for their work in bringing physics-based products to the market .
“ The awards recognize the significant contribution that physics makes to industry and business , and everyone here has done an incredibly good job of building a business off of physics , ” he told the online audience .
In accepting his company ’ s award , Nebu~Flow chief executive Elijah Nazarzadeh noted that , thanks to the COVID-19 pandemic , “ everyone is @ @ @ @ @ @ @ disorders ” .
Even before the coronavirus , though , conditions such as asthma and chronic obstructive pulmonary disease killed one person in the UK every five minutes on average , and Nazarzadeh pointed out that current drug treatments suffer from a significant flaw : the medication doesn ’ t always reach the right part of the patient ’ s lungs .
People with respiratory disorders , he explained , typically receive medication via nebulizers – machines that turn liquid drugs into aerosolized , inhalable droplets .
The problem is that many of @ @ @ @ @ @ @ small to reach the tiny air sacs in the lungs where carbon dioxide gets exchanged with life-sustaining oxygen .
Nebu~Flow ’ s award-winning device tackles this problem by using controlled acoustic waves to create a more uniform droplet size , and the strategy seems to be paying off .
In pre-clinical trials , the Nebu~Flow device increased the inhalable fraction of a common asthma drug , salbutamol , from 60 % to 90 % .
Like Nazarzadeh , Cellular Highways ’ chief executive Samson Rogers began his talk by focusing on patients .
@ @ @ @ @ @ @ tool in basic research , clinical applications such as cell therapies – in which cells are removed from the patient , assessed for their disease-fighting capabilities , and then selectively reintroduced into the body – require sorting speeds and volumes much higher than existing machines can deliver .
Cellular Highways ’ vortex-actuated cell sorting ( VACS ) technology works by generating a transient vortex within a microfluidic channel .
When this vortex flows downstream , Rogers explained , a cell is carried with it and gently deflected across the streamlines to be sorted @ @ @ @ @ @ @ time envelope of 23 microseconds , making VACS “ the fastest chip-based cell sorter yet invented ” , according to the award citation .
The Lee Lucas Award was made possible by a donation from a retired entrepreneurial physicist , Mike Lee , and his wife Ann ( née Lucas ) .
The pair were inspired to endow the award after reading a Physics World column in which McKenzie discussed the financial and reputational benefits that awards bring to early-stage companies .
In addition to the two Lee Lucas Award winners , four @ @ @ @ @ @ @ Hirst Magnetic Instruments , Promethean Particles and Thornton Tomasetti Defence – received IOP Business Innovation Awards for “ delivering significant economic and/or societal impact through the application of physics ” .
A further seven companies ( FeTu , Geoptic , ORCA Computing , Oxford HighQ , OxMet Technologies , Photon Force and QLM Technology ) received IOP Business Start-up Awards , which honour companies for physics-based inventions at an earlier stage of commercial development .
Additional information about all 13 award-winners is available on the IOP website .

Microfluidics maestro: Cellular Highways chief executive Samson Rogers poses with a prototype of the company's first commercial sell-sorting instrument. (Courtesy: Cellular Highways)
Companies that use physics to unlock next-generation drugs for respiratory disorders and enable advanced cancer treatments are the first recipients of a new award for early-stage companies in healthcare and medicine. Nebu~Flow, a University of Glasgow spin-out that is commercializing an acoustic nebulizer, and Cellular Highways, a Cambridge-based start-up that develops microfluidic devices for use in cell therapies, each received the inaugural Lee Lucas Award and £5000 in prize money as part of the annual Business Awards presented by the Institute of Physics (IOP).
Speaking on 15 July at the first of two webinars dedicated to the 2020 Business Awards, IOP vice-president for business James McKenzie praised Cellular Highways, Nebu~Flow and 11 other award-winning companies for their work in bringing physics-based products to the market. “The awards recognize the significant contribution that physics makes to industry and business, and everyone here has done an incredibly good job of building a business off of physics,” he told the online audience.
Better drug delivery, faster cell sorting
In accepting his company’s award, Nebu~Flow chief executive Elijah Nazarzadeh noted that, thanks to the COVID-19 pandemic, “everyone is now aware of the importance of respiratory disorders”. Even before the coronavirus, though, conditions such as asthma and chronic obstructive pulmonary disease killed one person in the UK every five minutes on average, and Nazarzadeh pointed out that current drug treatments suffer from a significant flaw: the medication doesn’t always reach the right part of the patient’s lungs.
Versatile device: Pre-clinical tests indicate that Nebu~Flow’s acoustic-wave-based aerosolization system could deliver new classes of biologic and surface-active drugs as well as traditional medications for respiratory illnesses. (Courtesy: Nebu~Flow)
People with respiratory disorders, he explained, typically receive medication via nebulizers – machines that turn liquid drugs into aerosolized, inhalable droplets. The problem is that many of these droplets are too big or too small to reach the tiny air sacs in the lungs where carbon dioxide gets exchanged with life-sustaining oxygen. Nebu~Flow’s award-winning device tackles this problem by using controlled acoustic waves to create a more uniform droplet size, and the strategy seems to be paying off. In pre-clinical trials, the Nebu~Flow device increased the inhalable fraction of a common asthma drug, salbutamol, from 60% to 90%.
Like Nazarzadeh, Cellular Highways’ chief executive Samson Rogers began his talk by focusing on patients. Although cell-sorting technology is already an important tool in basic research, clinical applications such as cell therapies – in which cells are removed from the patient, assessed for their disease-fighting capabilities, and then selectively reintroduced into the body – require sorting speeds and volumes much higher than existing machines can deliver. Cellular Highways’ vortex-actuated cell sorting (VACS) technology works by generating a transient vortex within a microfluidic channel. When this vortex flows downstream, Rogers explained, a cell is carried with it and gently deflected across the streamlines to be sorted. Each deflection takes place within a time envelope of 23 microseconds, making VACS “the fastest chip-based cell sorter yet invented”, according to the award citation.
Entrepreneurial inspiration
The Lee Lucas Award was made possible by a donation from a retired entrepreneurial physicist, Mike Lee, and his wife Ann (née Lucas). The pair were inspired to endow the award after reading a Physics World column in which McKenzie discussed the financial and reputational benefits that awards bring to early-stage companies.
In addition to the two Lee Lucas Award winners, four other firms – Advanced Hall Sensors, Hirst Magnetic Instruments, Promethean Particles and Thornton Tomasetti Defence – received IOP Business Innovation Awards for “delivering significant economic and/or societal impact through the application of physics”. A further seven companies (FeTu, Geoptic, ORCA Computing, Oxford HighQ, OxMet Technologies, Photon Force and QLM Technology) received IOP Business Start-up Awards, which honour companies for physics-based inventions at an earlier stage of commercial development.
Additional information about all 13 award-winners is available on the IOP website.


physicsworld--2020-07-21--Starspot study sheds light on why some red giants spin faster than others - Physics World

Some red-giant stars are rotating much faster than previously thought , according to a study led by Patrick Gaulme at Germany ’ s Max Planck Institute for Solar System Research .
Using NASA ’ s Kepler space telescope , the astronomers found that about 8 % of the red giants they observed are rotating fast enough to display starspots .
The team reckons that the elderly stars acquire their rapid rotation by following one of three distinct routes in their evolution .
In main sequence stars like the Sun , the complex interplay that occurs between stellar rotation and the @ @ @ @ @ @ @ fields .
When this magnetic activity is particularly strong , upwelling plumes of plasma in a star ’ s convective outer layers can be blocked , producing dark patches on its surface .
To an observer on Earth , these starspots cause a periodic variation in the star ’ s brightness as it rotates , bringing the spots in and out of our field of view .
Until recently , starspots were not thought to be present on red giant surfaces .
Since these older stars expand rapidly as they move out of @ @ @ @ @ @ @ angular momentum , previous theories had predicted that they must rotate more slowly than main sequence stars .
Slower rotation should reduce magnetic activity , preventing starspots from forming .
Gaulme ’ s team tested this idea by analysing a sample of around 4500 red giants , gathered by Kepler between 2009 and 2013 .
In contrast to previous theories , they found that 370 of the stars – around 8 % of them – displayed periodic brightness variations that could only be explained by starspots passing across their surfaces .
Some recent @ @ @ @ @ @ @ could appear in binary systems – in which a red giant can acquire angular momentum from its companion star until their rotations are synchronized .
This was indeed the case for some of the observed red giants , but this still only accounted for 15 % of the spotty stars analysed by the team .
By following the clues offered by their oscillations , Gaulme and colleagues concluded that the remainder of the red giants fell into two groups .
The first included stars with similar masses to the Sun , and the @ @ @ @ @ @ @ momentum as they engulfed orbiting planets and binary companions during their expansion .
In contrast , more massive stars in the second group displayed lower magnetic activity during their time as main sequence stars .
Their quieter environments prevented material from escaping , allowing the stars to retain angular momentum .
Therefore , despite slightly slowing down during their evolution , these stars still preserved enough magnetic activity to display spots after becoming red giants .
The team now hopes to improve their understanding further using ESA ’ s PLATO mission , which @ @ @ @ @ @ @ The study is described in Astronomy and Astrophysics .

Red-giant spotter: artist’s impression of the Kepler space telescope in Earth orbit. (Courtesy: NASA)
Some red-giant stars are rotating much faster than previously thought, according to a study led by Patrick Gaulme at Germany’s Max Planck Institute for Solar System Research. Using NASA’s Kepler space telescope, the astronomers found that about 8% of the red giants they observed are rotating fast enough to display starspots. The team reckons that the elderly stars acquire their rapid rotation by following one of three distinct routes in their evolution.
In main sequence stars like the Sun, the complex interplay that occurs between stellar rotation and the motions of plasma creates incredibly lively magnetic fields. When this magnetic activity is particularly strong, upwelling plumes of plasma in a star’s convective outer layers can be blocked, producing dark patches on its surface. To an observer on Earth, these starspots cause a periodic variation in the star’s brightness as it rotates, bringing the spots in and out of our field of view.
Until recently, starspots were not thought to be present on red giant surfaces. Since these older stars expand rapidly as they move out of the main sequence, while maintaining their angular momentum, previous theories had predicted that they must rotate more slowly than main sequence stars. Slower rotation should reduce magnetic activity, preventing starspots from forming.
Periodic brightness variations
Gaulme’s team tested this idea by analysing a sample of around 4500 red giants, gathered by Kepler between 2009 and 2013. In contrast to previous theories, they found that 370 of the stars – around 8% of them – displayed periodic brightness variations that could only be explained by starspots passing across their surfaces.
Some recent studies have suggested that red giant starspots could appear in binary systems – in which a red giant can acquire angular momentum from its companion star until their rotations are synchronized. This was indeed the case for some of the observed red giants, but this still only accounted for 15% of the spotty stars analysed by the team.
Engulfing planets
By following the clues offered by their oscillations, Gaulme and colleagues concluded that the remainder of the red giants fell into two groups. The first included stars with similar masses to the Sun, and the team believes these red giants acquired angular momentum as they engulfed orbiting planets and binary companions during their expansion.
In contrast, more massive stars in the second group displayed lower magnetic activity during their time as main sequence stars. Their quieter environments prevented material from escaping, allowing the stars to retain angular momentum. Therefore, despite slightly slowing down during their evolution, these stars still preserved enough magnetic activity to display spots after becoming red giants.
The team now hopes to improve their understanding further using ESA’s PLATO mission, which is scheduled to launch in 2026.
The study is described in Astronomy and Astrophysics.


physicsworld--2020-07-21--Growing the gravitational-wave network - Physics World

How has the COVID-19 pandemic affected work on the twin Laser Interferometer Gravitational-Wave Observatory ( LIGO ) ?
We were near the end of the our third observing run , which was planned to end on 30 April , when the pandemic hit .
COVID-19 forced us to shut down all operations at the LIGO observatories – located at Hanford , Washington and Livingston , Louisiana – on 27 March , about a month shy of the planned end date .
Still , the run was a great success , with 56 gravitational-wave candidates detected in 11 months – about @ @ @ @ @ @ @ now initiating a programme to install a series of detector upgrades , which we call Advanced LIGO Plus ( A+ ) , over the next 20 months that will result in gravitational-wave detections every one or two days .
Even working remotely , the LIGO team has made good progress on LIGO A+ in the past few months .
When do you expect to restart operations on LIGO ?
We tentatively resumed observatory work last month since it was safe to do so and we have established protocols to execute the upgrade programme @ @ @ @ @ @ @ .
LIGO consists of over 150 institutions and more than 1300 people from around the world .
Would the observatory be possible without such an international scope ?
I don ’ t think so , for many reasons .
The California Institute of Technology and the Massachusetts Institute of Technology are the institutions that built and operate LIGO .
However , to design and use LIGO effectively you need to look beyond the US .
So we looked to where the best science is being done .
And historically – 30 or 40 @ @ @ @ @ @ @ the best ideas for interferometry were emerging from Australia , Italy , Germany , the UK and other places .
Without these ideas and the people who developed and brought those ideas to maturation I don ’ t think we could have ever built LIGO , made it work and carried out its scientific programme .
How does the collaboration work with the European laser-interferometer gravitational-wave detector , situated near Pisa , Italy ?
Virgo is a different detector from LIGO , built by an independent set of people .
The LIGO scientific @ @ @ @ @ @ @ because of the realization that by combining our data , we could get much more information , particularly in the ability to locate gravitational events in the sky .
This international collaboration has greatly expanded our ability to detect gravitational waves and understand where they come from , and allows us to make strong astrophysical statements about what we see .
Japan recently opened the KAGRA gravitational-wave detector and there are plans for an observatory in India .
How will this enhance gravitational-wave science ?
Having three separate interferometers far away from each @ @ @ @ @ @ @ signals over a portion of the sky .
By putting a fourth detector in Japan and a fifth detector in India , we ’ ll be able to rapidly determine good sky localization for gravitational-wave events anywhere in the sky .
This is a wonderful thing , because one of our core goals is to tell astronomers that we saw an event in this portion of the sky and they should look at it quickly because they ’ ll see something very dramatic .
This is really what multimessenger astronomy is all about @ @ @ @ @ @ @ having multiple detectors ?
These detectors are exquisitely sensitive and easily perturbed by small things such as a malfunction in the detector or even somebody driving a truck nearby .
By having more detectors , even if you have one or two of them offline , you still get reasonable sky coverage .
Redundancy in the network makes a big difference .
Given the impact of COVID-19 , are you still keeping in touch with KAGRA and VIRGO ?
Yes .
Virgo concluded its third observation run at the same time as LIGO @ @ @ @ @ @ @ operations and resuming its Advanced Virgo Plus upgrade programme .
The KAGRA collaboration continues to commission its detector and successfully held its inaugural two-week long observing run in April .
KAGRA will join LIGO and Virgo in the fourth observation run that is scheduled to begin in early 2022 .
Equally important , the LIGO–Virgo collaboration is analysing the third observing run data set and continuing to find merging binary systems that are challenging our understanding of neutron star and black hole populations .
Stay tuned for new results coming out very soon @ @ @ @ @ @ @ merger in 2017 opened up the era of multimessenger astronomy .
What did it tell us about the universe ?
The binary neutron-star merger was spectacular in so many ways .
First and foremost , it fundamentally answered a lot of scientific questions such as that binary neutron-star mergers produce short-order gamma-ray bursts and that they also produce unique conditions in which heavy elements in the periodic table such as gold and platinum are forged .
It must have been incredibly exciting at the time ?
It became evident very quickly that this @ @ @ @ @ @ @ following days , weeks and months , the astronomical community kept looking at the data because , if you pardon the pun , it was such a scientific gold mine .
You see gamma rays that go away very quickly , then you see ultraviolet and optical and infrared .
Then there is a point when X-rays are emitted as the neutrons hit the interstellar medium .
The radio emissions going on for months and months .

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David Reitze, executive director of the Laser Interferometer Gravitational-Wave Observatory, talks to Richard Blaustein about how gravitational-wave observations are set for a multi-detector boost
Making waves David Reitze says that upgrades to gravitational-wave detectors could allow them to spot events almost every day. (Courtesy: Lance Hayashida/Caltech)
How has the COVID-19 pandemic affected work on the twin Laser Interferometer Gravitational-Wave Observatory (LIGO)?
We were near the end of the our third observing run, which was planned to end on 30 April, when the pandemic hit. COVID-19 forced us to shut down all operations at the LIGO observatories – located at Hanford, Washington and Livingston, Louisiana – on 27 March, about a month shy of the planned end date. Still, the run was a great success, with 56 gravitational-wave candidates detected in 11 months – about one each week. We’re now initiating a programme to install a series of detector upgrades, which we call Advanced LIGO Plus (A+), over the next 20 months that will result in gravitational-wave detections every one or two days. Even working remotely, the LIGO team has made good progress on LIGO A+ in the past few months.
When do you expect to restart operations on LIGO?
We tentatively resumed observatory work last month since it was safe to do so and we have established protocols to execute the upgrade programme in a safe and socially distant way.
LIGO consists of over 150 institutions and more than 1300 people from around the world. Would the observatory be possible without such an international scope?
I don’t think so, for many reasons. The California Institute of Technology and the Massachusetts Institute of Technology are the institutions that built and operate LIGO. However, to design and use LIGO effectively you need to look beyond the US. So we looked to where the best science is being done. And historically – 30 or 40 years ago – you find some of the best ideas for interferometry were emerging from Australia, Italy, Germany, the UK and other places. Without these ideas and the people who developed and brought those ideas to maturation I don’t think we could have ever built LIGO, made it work and carried out its scientific programme.
The binary neutron-star merger was spectacular in so many ways. It became evident very quickly that this was a first-of-its-kind event.
How does the collaboration work with the European laser-interferometer gravitational-wave detector, situated near Pisa, Italy?
Virgo is a different detector from LIGO, built by an independent set of people. The LIGO scientific collaboration joined forces with Virgo in 2007 because of the realization that by combining our data, we could get much more information, particularly in the ability to locate gravitational events in the sky. This international collaboration has greatly expanded our ability to detect gravitational waves and understand where they come from, and allows us to make strong astrophysical statements about what we see.
Japan recently opened the KAGRA gravitational-wave detector and there are plans for an observatory in India. How will this enhance gravitational-wave science?
Having three separate interferometers far away from each other provides a better ability to localize signals over a portion of the sky. By putting a fourth detector in Japan and a fifth detector in India, we’ll be able to rapidly determine good sky localization for gravitational-wave events anywhere in the sky. This is a wonderful thing, because one of our core goals is to tell astronomers that we saw an event in this portion of the sky and they should look at it quickly because they’ll see something very dramatic. This is really what multimessenger astronomy is all about.
What other benefits are there of having multiple detectors?
These detectors are exquisitely sensitive and easily perturbed by small things such as a malfunction in the detector or even somebody driving a truck nearby. By having more detectors, even if you have one or two of them offline, you still get reasonable sky coverage. Redundancy in the network makes a big difference.
Given the impact of COVID-19, are you still keeping in touch with KAGRA and VIRGO?
Yes. Virgo concluded its third observation run at the same time as LIGO. It is now back in limited operations and resuming its Advanced Virgo Plus upgrade programme. The KAGRA collaboration continues to commission its detector and successfully held its inaugural two-week long observing run in April. KAGRA will join LIGO and Virgo in the fourth observation run that is scheduled to begin in early 2022. Equally important, the LIGO–Virgo collaboration is analysing the third observing run data set and continuing to find merging binary systems that are challenging our understanding of neutron star and black hole populations. Stay tuned for new results coming out very soon. Read more LIGO–Virgo claims another neutron-star merger
The detection of the first neutron-star merger in 2017 opened up the era of multimessenger astronomy. What did it tell us about the universe?
The binary neutron-star merger was spectacular in so many ways. First and foremost, it fundamentally answered a lot of scientific questions such as that binary neutron-star mergers produce short-order gamma-ray bursts and that they also produce unique conditions in which heavy elements in the periodic table such as gold and platinum are forged.
It must have been incredibly exciting at the time?
It became evident very quickly that this was a first-of-its-kind event. Over the following days, weeks and months, the astronomical community kept looking at the data because, if you pardon the pun, it was such a scientific gold mine. You see gamma rays that go away very quickly, then you see ultraviolet and optical and infrared. Then there is a point when X-rays are emitted as the neutrons hit the interstellar medium. The radio emissions going on for months and months.