Skip to main content

Reset your password

Please enter the e-mail address you used to register to reset your password

Note: The verification e-mail to change your password should arrive immediately. However, in some cases it takes longer. Don't forget to check your spam folder.

If you haven't received the e-mail in 24 hours, please contact customerservices@ioppublishing.org

Registration complete

Thank you for registering with Physics World
If you'd like to change your details at any time, please visit My account

Close
Home » Page 1471

Gongs away

When Andre Geim received a phone call from Sweden’s Nobel-prize committee last month, his first response was “Oh, shit”. Not that he was unhappy about sharing the Nobel Prize for Physics with his fellow graphene pioneer (and University of Manchester colleague) Konstantin Novoselov. Far from it. It was just that winning a Nobel prize is “a life-changing exercise”, as Geim told Swedish journalists shortly after the announcement was made.

But how much does winning a Nobel prize really affect a physicist’s career? In the case of Geim and Novoselov, the effect may indeed reach “oh, shit” proportions, for two reasons. One is that the Nobel is unquestionably the most prestigious prize in physics. In the words of Carlo Rubbia, who shared the prize in 1984 for discovering the W and Z bosons, winning it is “certainly not a small perturbation”. The other reason is that at the ages of 52 and 36, respectively, Geim and Novoselov probably have more career left ahead of them than most newly minted laureates; during the 2000s, the median age of physics laureates upon receiving the prize was just shy of 70, having crept upwards since the 1970s.

Of course, few physicists will ever find themselves packing their bags for Stockholm, or even come within a sniff of the prestigious Nobels. However, there are plenty of other prizes on offer, and thousands of physicists receive gongs of one kind or another every year. These range from named awards that carry significant amounts of prestige and cash to humble “best poster” certificates that come with warm congratulations and a textbook for a prize. For many, receiving these small awards will be a highlight of their careers.

Other fish in the sea

The Nobel prize is at the apex of the gong pyramid, but there is nevertheless a clutch of other international awards that can – and frequently do – claim runner-up status. Of these, the best established are the $100,000 Wolf prizes, which the privately run Wolf Foundation has awarded in most years since 1978. A well-regarded award in its own right, the Wolf Prize in Physics has gained some additional prestige in recent years thanks to its tendency to anticipate the Nobel: no less than 14 Wolf-prize winners have gone on to pick up Nobel medals in physics, five of them just one year later.

Other awards in the nearly Nobel camp include the Japan prize, which covers a broader range of subjects than either the Nobel or the Wolf prizes and is worth $450,000. The Japan prize counts Web pioneer Tim Berners-Lee and laser inventor Theodore Maiman among its awardees, and is sometimes called the “Nobel of the East”. However, it is now being challenged for that title by the $1m Shaw prizes, which were established in 2004 by the Hong Kong businessman and philanthropist Run Run Shaw to honour achievements in astronomy, life sciences and mathematics.

Indeed, the past decade has seen a boom in big-ticket science prizes, with the $0.5m Gruber Prize in Cosmology (first awarded in 2000), the $1m Kavli prizes (2005) and, most recently, the €0.4m BBVA Foundation awards (2009) weighing in alongside the Shaw and older honours. Unlike winners of big research grants, recipients of these awards are not required to spend the money on academic pursuits. Some, however, do so anyway. For example, Jerry Nelson, the California Institute of Technology astronomer who won the Kavli Prize for Astrophysics earlier this year, told Physics World that he had “basically distributed it to noteworthy colleagues and institutions”, after he had paid for several friends and family members to attend the prize ceremony in Oslo, Norway.

Financially, the many awards granted by learned societies (including the Institute of Physics, which publishes Physics World) will never rival those with links to deep-pocketed philanthropists. What they lack in monetary value, however, they often make up for in history and prestige. The Royal Society’s Copley Medal, for example, dates back to 1731 and counts luminaries such as William Herschel, Michael Faraday and J J Thomson among its recipients. Nelson, who won the American Astronomical Society’s Dannie Heineman prize in 1995, says that such awards were important to him because they “act as a reminder that what one is doing is of some interest and importance to others”, even if they are “financially minor” in comparison to a Kavli prize.

Early birds

Most awards given in the physics community are designed to recognize past achievements, not to facilitate future ones. The exceptions are the “early career” prizes. These are awarded to scientists at the beginning of their careers, and evidence suggests that they can have a tremendous impact on the individual concerned. “Probably the most important prize I got, in terms of getting me started, was fourth prize in the US Science Talent Search, which I won when I was in high school,” says Frank Wilczek of the Massachusetts Institute of Technology, who shared the 2004 Nobel Prize for Physics for his theoretical work on the strong interaction. “It showed me more of the big world and enhanced my self-confidence.”

Many early-career awards provide more tangible assistance as well. The MacArthur Fellowships in the US, for example, come with $0.5m in research funding over five years, and are designed to support talented researchers early in their careers. Other early-career awards, such as the UK’s Royal Society University Research Fellowships, make it easier for the recipient to find a permanent position by paying part of their salary for a few years, as well as providing start-up money for new projects.

The bottom line is that with or without a financial sweetener, early-career awards can be an important way of distinguishing a researcher from his or her peers. Faced with stiff competition for funding and permanent academic positions, those with a gong or two on their CVs are frequently at an advantage. “My previous awards and prizes helped a lot in terms of getting national and international recognition, and in promoting my career towards a chaired professorship,” agrees Jürgen Eckert, who last year was handed Germany’s highest research award, the 72.5m Leibniz prize, and is now director of the Leibniz Institute for Solid State and Materials Research in Dresden.

The cloudy lining

There is, of course, a down side to winning a prize. One common complaint among winners of major awards is that finding time to do research becomes much more difficult, since they are expected to give interviews and speeches, and are frequently asked to serve on committees as well. But there are also more subtle effects, as Rubbia points out. “Having the [Nobel] prize forces you to always do things that are right,” notes the former CERN director-general. “The capability of making a mistake, which is the driving force for scientific innovation – in the sense that you will only make progress if you make mistakes – is reduced.”

A separate concern, Rubbia continues, is that having a Nobel prize “is a responsibility, in that you have to take positions and have opinions on a much wider range of topics”. This can cause difficulties, he says, because “we have to realize that we are not experts on everything. The problem for most of my colleagues – and presumably me – is a tendency to become experts in areas that aren’t part of our expertise. So you have to exercise some modesty.”

The reverse problem of being pigeonholed as an expert in just one area is also a concern for some winners. Both Novoselov and Geim say they were already trying to “escape” research on graphene even before they won their Nobel for isolating it. That will almost certainly be more difficult now, although it is not without precedent. Only John Bardeen has ever won more than one Nobel Prize for Physics, but a number of laureates have made significant impacts in other fields. The best recent example is atomic physicist Steven Chu, who shared the prize in 1997 and is currently secretary of the US Department of Energy.

A more general issue with prize-giving is sometimes known as the “Matthew effect”, after a biblical quotation from the Gospel of Matthew that runs “For to all those who have, more will be given…but from those who have nothing, even what they have will be taken away.” It is certainly true that some physicists receive an enormous number of awards. The medals and certificates won by the late Abdus Salam, for example, fill an entire wall and part of a small room in the library of the institute he founded, the International Centre for Theoretical Physics. As a passionate advocate for science in the developing world as well as a prominent theorist, Salam was a special case, but it is hard to argue with the notion that some physicists get more gongs than they deserve. And, inevitably, the law of diminishing returns applies. “Recognition for the same work that got me the Nobel prize means less to me personally, at a psychological level, since in some sense it’s icing on the cake – not that there’s anything wrong with icing,” says Wilczek. However, he adds that he is “as gratified as ever” to see other parts of his work, or his body of work as a whole, properly appreciated.

But ultimately, Wilczek says, the most important thing that winners of any award can do is to keep a sense of perspective on what prizes are really about. “All prizes are nice to get, but most of them are, or should be, corollaries of achievements,” he says. “It’s the achievements themselves that are the core sources of pride and standing in the community.” Something to bear in mind next year, perhaps, when – yet again – a phone call from Sweden fails to interrupt your work or slumber.

Bosons bossed into Bose–Einstein condensate

Many physicists believed it could not be done, but now a team in Germany has created a Bose–Einstein condensate (BEC) from photons. BECs are formed when identical bosons – particles with integer spin – are cooled until all particles are in the same quantum state. This means that a BEC comprising tens of thousands of particles behaves as a single quantum particle.

The first BEC was made in 1995 by cooling a cloud of rubidium atoms to near absolute zero and today such condensates are routinely used to study a variety of quantum phenomena. However, few physicists had contemplated making a BEC from the most common boson in the universe – the photon. This is because photons are easily created or destroyed when they interact with other matter, which makes it very difficult to cool a fixed number of photons such that they form a condensate.

But now Martin Weitz and colleagues at the University of Bonn in Germany have devised a way of isolating and cooling photons. Although they cannot capture a fixed number of photons, the number fluctuates around a mean value, allowing the ensemble to be characterized using conventional BEC theory.

Trapped between two mirrors

The team trapped its photons between two concave mirrors that are separated by a maximum of 1.5 µm. This distance (to within an integer number) defines the maximum wavelength – or minimum energy – of a photon that is confined longitudinally within the cavity between the mirrors. The cavity is filled with a dye that is held at room temperature – and, crucially, the thermal energy of the dye is about 1% of the photon energy.

This large energy difference means that it is highly unlikely that additional photons will emerge from the dye, or that the dye will completely absorb a photon. Instead, the photons collide with the dye molecules, giving up or receiving small amounts of energy. These interactions cool the photons to room temperature – which is cold enough to create a photon BEC – while preserving the number of photons.

The team created the BEC by firing a laser into the cavity to fill it with photons. The laser was then kept on throughout the experiment to make up for photons that were lost at the mirrors and imperfections in the cavity. Some of the photons pass through one of the mirrors to a spectrometer, which measures the distribution of photon energies in the cavity. At low laser intensities the cavity contains a broad range of photon energies with a sharp cut-off at the cavity’s minimum energy.

Critical number of photons

When the laser intensity is increased, the number of photons in the cavity rises and the broad distribution endures until the photon number reaches about 60,000. Above this critical value, according to Weitz, the photon gas is dense enough for a BEC to form – much like a liquid drop condensing in a gas.

The team knows that the BEC has formed because a large peak in the photon energy spectrum emerges just above the cut-off energy. This peak corresponds to a large number of photons piling into the lowest energy state of the cavity. As the laser intensity is increased further, the number of photons in the BEC reaches millions.

To convince themselves that the peak is related to a BEC, rather than the cavity behaving like a laser, the researchers repeated the experiment at several different separation distances. They found that the peak always emerged at the same photon density – something that would not be seen in a laser, according to Weitz.

Small effective mass

The cavity has a planar design, which means that the photons are confined to two dimensions. As a result of the longitudinal confinement, they behave as if they are particles with an “effective mass” corresponding to the cut-off energy. This mass is still extremely small, which is why photons will form a BEC at room temperature and don’t need to be cooled to micro-Kelvin temperatures like atoms.

Interactions between the photons are much weaker than those between atoms and this means that photons can form a true 2D BEC. Atoms, on the other hand can only form a 3D BEC.

According to Weitz, creating thermalized light doesn’t necessarily require a laser and devices could be “pumped” by other light sources – including the Sun. As a result, he believes they could be used to shrink the size of solar cells by concentrating light within devices. He also believes BEC could be used to build sources of coherent light that don’t involve a laser.

The research is described in Nature 468 545 and, writing in the same issue of the journal, James Anglin of the Technical University of Kaiserslautern calls it “a landmark achievement”. He also points out that the experiment shows how “physics is the art of interchangeable” because in addition to showing the wave-like properties of atoms, BECs have now been used to show particle-like properties of light.

Robot geckos and flying snakes

GECKO.jpg


By Hamish Johnston

For millennia humans have dreamt of flight – inspired no doubt by nature’s denizens of the sky. Although people now fly routinely, even the most advanced flying machine seems clunky and amateurish compared to the elegance of a dragonfly or swallow.

Indeed, scientists and engineers are desperate to learn from nature and you can read about some of the results in a special issue of the journal Bioinspiration & Biomimetics that is devoted to flight.

The issue includes nine papers that investigate how flying snakes glide through the air, how hummingbirds hover and even how a gecko uses its tail to right itself while falling.

You can see the robotic gecko above.

The issue’s guest editors, David Lentink and Andrew Biewener, have written a nice overview entitled “Nature-inspired flight: beyond the leap”.

Neutrinos could detect secret fission reactors

Oil tankers fitted with neutrino detectors, hundreds of thousands of tonnes in mass, could be floated offshore to check for undeclared nuclear fission reactors. That’s the idea of physicists in France, who have proposed the Secret Neutrino Interactions Finder (SNIF) as a way of enforcing the nuclear non-proliferation treaty – although some experts doubt its feasibility.

Currently, fission reactors over the world are monitored by the United Nations’ International Atomic Energy Agency (IAEA), based in Vienna. The IAEA uses several “near-field” tools to make sure reactors are running legally, from CCTV-type cameras to metallic or fibre-optic networks that can detect when fuel is being loaded. In some cases, the agency installs thermal monitors to check that reactors are not being operated for too long, as might be required for the production of bomb-making plutonium.

Another, perhaps more fail-safe way to monitor reactors would be to detect the nearby levels of anti-neutrinos – light particles that are emitted copiously in nuclear-fission reactions. Because the flux of anti-neutrinos arriving at a certain area is proportional to the power of a reactor and its proximity, the anti-neutrino level at any point should be an indicator of what fission reactions are taking place nearby.

Neutrino oscillations

But, as researchers discovered almost a decade ago, the science is more complicated. Neutrinos have a small, finite mass – not zero, as was previously thought – and are able to oscillate from one type to another. This means that a detector looking for one type of anti-neutrino would always detect fewer than expected, because some of them oscillate into different types before arrival.

Thierry Lasserre at the French Alternative Energies and Atomic Energy Commission says that improvements in the understanding of neutrino oscillation have enabled his group to explore the use of anti-neutrino detectors for “far-field” reactor monitoring. Lasserre and his colleagues have calculated how anti-neutrino fluxes fall with distance from a reactor, taking into account oscillations. They have then analysed all the other sources of anti-neutrinos – 200 nuclear power stations over the globe – to produce a map of background anti-neutrino levels.

In a final calculation, Lasserre’s group showed that a neutrino detector would need to be sunk just 500 m or more underwater to prevent catching any cosmic rays, which would confuse the signal. The researchers think that, for monitoring fission reactions in a radius of 100–500 km, a detector would need a scintillator mass of 1034 free protons – in the order of a hundred thousand tonnes.

Friendly and clandestine activities

John Learned, a physicist at the University of Hawaii, US, who first suggested using neutrino detectors for global fission-reactor monitoring, believes the group has performed some “excellent” calculations, but notes that the SNIF idea is not totally new. He adds, however, “With a network of monitors one can record the activity of a group of reactors, perhaps some friendly ones, and some clandestine reactors. With various methods under development we can do a better job, even than indicated in this paper.”

Others are not so sure. Andrew Monteith of the IAEA’s Novel Technologies Unit says that the IAEA is at present only interested in neutrino detectors for near-field detection, because only that is within its current remit. “The far-field approach that’s discussed in the paper has never really been an official part of our thinking,” Monteith explains. “We’re taking it on a stage-by-stage basis, and the near-field one is certainly more realistic for us, in terms of cost and deployment.”

Expensive solution?

Julian Whichello, head of the Novel Technologies Unit, believes Lasserre’s SNIF detector could cost in the region of $100 million – almost the same as the IAEA’s entire budget for global verification of fission reactors. “This is something that’s well and truly outside of the current budget of the agency,” he says.

Still, Lasserre explains that his group’s goal was to explore the scientific possibilities rather than have political influence. “This is very futuristic,” he says. “It’s huge, it will cost a lot of money and it’s a difficult effort. Technically it would be possible in the next 30 years, but I’m not aware of any programme in the world to build such devices.”

The research is available at arXiv:1011.3850.

Europe extends key space missions

The European Space Agency (ESA) has announced it is to extend the lifetimes of seven key missions until 2014. The ESA-led probes, including the Planck microwave observatory and the Mars Express orbiter, will now take measurements for a further two years beyond 2012 – the previous end date for the missions.

The decision to operate the missions until 2014 was taken by ESA’s Science Programme Committee (SPC) at a meeting in Paris last week. Five other ESA-led missions will be extended, including the Cluster probe studying the Earth’s magnetosphere, the International Gamma-Ray Astrophysics Laboratory, the Venus Express orbiter, the X-ray observatory XMM-Newton and the Proba-2 satellite, which tests new types of space technology.

Waiting for the Sun

ESA’s contribution to four international projects, including the Cassini–Huygens mission to Saturn and the Hubble Space Telescope, will also continue until at least 2014. The other missions are Hinode, which was launched in 2006 by the Japanese Space Agency (JAXA), and NASA’s SOHO mission. The extension will allow the two probes to study the Sun during its next peak of magnetic activity, which is expected in 2013.

“It is a good day for European space science,” says David Southwood, ESA’s director of science and robotic exploration. “It is not an easy time to make such commitments but we should not doubt the wisdom of the SPC in squeezing even more return from the big investments of the past.”

Mapping the cosmos

ESA’s Planck probe, which was launched in April 2009, will map the cosmic microwave background (CMB) – a remnant of the Big Bang – in the finest detail yet. Planck carries two instruments: the high-frequency instrument (HFI) and the low-frequency instrument (LFI). The HFI will not operate beyond 2011, when it will run out of the liquid coolant needed to cool the instrument to a temperature of about 0.1 K.

However, the two-year extension will allow Planck to make further use of the LFI, which operates at about 20 K and measures the microwave sky with high sensitivity between 27 and 77 GHz. This will enable it to make better measurements of the CMB polarization. Nazzareno Mandolesi, principal investigator for the LFI told physicsworld.com that “This [extension] will improve the sensitivity of the LFI greatly, giving us the possibility to choose a region of the sky that we can more deeply observe.”

However, some researchers warn of the need to maintain a balance between keeping operational satellites going and spending the money to build new ones instead.”It is very difficult to argue against extending their operation to keep up the flow of excellent scientific data,” says Matt Griffin of the University of Wales, Cardiff, and principal investigator of the Spire instrument on ESA’s Herschel probe that was launched together with Planck. “Eventually though, some of them are going to have to be retired to make financial room for the next generation of missions.”

Flat pack LHC

ikea.jpg

By Hamish Johnston

If you need cheering up on a dreary Monday, this cartoon has been making the rounds on the blogs…

Coming to an Ikea near you, it’s the HÄDRÖNN CJÖLIDDER.

No, it’s not a hair metal band from the 80s, it’s a flat pack version of the Large Hadron Collider.

The cartoon is in the form of assembly instructions from the Swedish giant and includes the pitfalls of poor assembly (involving a black hole) and the reward for getting it right.

The panel on the right deals with the injection of protons!

You can see the entire cartoon here.

Plasmonic sensor detects viruses

The first biosensor made from plasmonic nanohole arrays has been unveiled by researchers in the US. The device, which exploits “extraordinary optical transmission”, can detect live viruses in a biological solution.

Recent years have seen a number of viral disease outbreaks, raising fears that such viruses could rapidly spread and turn into a pandemic. Controlling future epidemics will require rapid and sensitive diagnostic techniques capable of detecting low concentrations of viruses in biological solutions.

Plasmonics to the rescue

Plasmonics is a new branch of photonics that employs surface plasmon polaritons (SPPs), which arise from the interaction of light with collective oscillations of electrons at a metal’s surface.

The new sensor was made by Hatice Altug and colleagues at Boston University and exploits SPP resonances that occur in plasmonic nanohole arrays. These are arrays of tiny holes just 200–350 nm across and spaced 500–800 nm apart on very thin noble metal films, such as those made of gold.

At certain wavelengths, the nanohole arrays can transmit light much more strongly than expected for such a collection of apertures. This phenomenon is called extraordinary optical transmission (EOT) and it occurs thanks to SPP resonances.

Measuring red-shifts

The resonance wavelength of the EOT depends on the dielectric constant of the medium surrounding the plasmon sensor. As pathogens bind to the sensor surface, the refractive index of the medium increases, increasing the wavelength of the plasmonic resonance, explains Altug. This shift can then be measured to identify the presence of virus paricles.

Different viruses can be detected by attaching highly specific antiviral immunoglobulins to the sensor surface. Different immunoglobulins can capture different viruses from a sample solution (see figure).

The researchers have already used their device to detect pseudo viruses that look like highly lethal viruses, such as Ebola and smallpox. “Our platform could be easily adapted for point-of-care diagnostics that can detect a broad range of viral pathogens in resource-limited clinical settings, in defence and homeland security applications as well as in civilian settings such as airports,” said team leader Hatice Altug.

Simpler and better

Team member John Connor added that the technique has many advantages over conventional virus detection methods such as polymerase chain reaction (PCR) and cell culturing. Cell culturing is a highly specialized labour-intensive process and PCR, while robust and accurate, cannot detect new or highly divergent strains of viruses – unlike the new sensor.

And that’s not all. “The detection platform is also compatible with physiological solutions (such as blood or serum) and is not sensitive to changes in the ionic strengths of these solutions. It can reliably detect viruses at medically relevant concentrations,” added team member Ahmet Yanik.

Next on the list for the researchers, who are working with the United States Army Medical Research Institute for Infectious Diseases (USAMRIID), is to make a portable version of their platform using micofluidics.

The current work was published in Nano Letters.

Beetle beauty captured in silicon

Researchers in Canada have created a new material that mimics the brilliant iridescent colours seen in beetle shells. As the eye-catching effect can be switched off with the simple addition of water, the researchers believe their new material could lead to applications including “smart windows”.

Structural colours, such as those on beetle shells and butterfly wings, differ from traditional pigments because the colour results from the interaction of light with periodic structures on the surface of the material. In certain biological materials, including the shells of scarab beetles, these exoskeletons take on a twisted or “chiral” structure, which causes reflected light to emerge circularly polarized.

Kevin Shopsowitz, working with colleagues at the University of British Columbia and FPInnovations, has now succeeded in mimicking this effect in a silica film. The breakthrough occurred with a certain degree of serendipity as the researchers were working with their industrial partner to develop forms of porous silica that could be used to store gases such as hydrogen. They were using nanocrystalline cellulose (NCC) as a template in silicon, which was then burned away to leave gaps within the silica.

Twist and shout

But when Shopsowitz had forged the material, he discovered that is appeared to be iridescent. Analyzing the material with polarized optical microscopy (POM) revealed that the surface of the silica film had taken on a fingerprint-like texture during evaporation, with its associated spiralling pattern. Further analysis using transmission electron microscopy (TEM) confirmed that the individual nanocrystalline cellulose rods had organised into a “chiral nematic” structure.

“The eureka moment occurred when Kevin [Shopsowitz] discovered that the materials were iridescent,” Mark MacLachlan, one of the researchers at the University of Columbia, told physicsworld.com. “Although NCC by itself forms iridescent films, we never thought it could be retained in the silica material.”

Photo of coloured silica films
Coloured silica films

Silica is usually a colourless material but modifying the surface in this way caused these films to reflect light at specific wavelengths. The researchers demonstrated that by changing the conditions of the synthesis, they could control how tightly wound the helix is (the pitch) and hence the wavelength of light that is reflected. In this way, they produced films that were a range of different colours.

Smart windows

What is more, Shopsowitz’s team show that the iridescence can be turned off by the simple addition of water, before returning again when the material is dried out. They claim that this ability to switch between iridescent and colourless films, combined with the ability to control the pitch of the spirals, could be used to develop smart windows that respond to environmental conditions.

“It’s fascinating research inspired by bio-mimetics,” says Nicholas Roberts, a biologist at the University of Bristol, who specializes in neurobiology and sensory systems in nature. Roberts notes that liquid crystal chiral structures have been known for over 100 years and the similarities between cholesteric liquid crystals and beetle cuticles where noticed in the 1920s. “However, cholesteric liquid crystals are ordered fluids and the innovation here is to get the same self assembled structure be locked into something solid,” he says.

The evolutionary significance of this ability of beetles is still not fully established. Writing in an article for the print edition of Physics World in August, zoologist David Pye of the University of London, UK, believes that – in the case of scarab beetles – it could be a tactic for improving communication within the species. It is widely accepted that these beetles take on bright colours to camouflage themselves within their forest environment: green for leaft backgrounds and metallic colours to imitate dappled sunlight. But if the eyes of these beetles have evolved to see polarized light, this would provide a system for these creatures to break the camouflage while remaining hidden.

This latest research is described in a paper in this week’s Nature.

Penrose claims to have glimpsed universe before Big Bang

Circular patterns within the cosmic microwave background suggest that space and time did not come into being at the Big Bang but that our universe in fact continually cycles through a series of “aeons”. That is the sensational claim being made by University of Oxford theoretical physicist Roger Penrose, who says that data collected by NASA’s WMAP satellite support his idea of “conformal cyclic cosmology”. This claim is bound to prove controversial, however, because it opposes the widely accepted inflationary model of cosmology.

According to inflationary theory, the universe started from a point of infinite density known as the Big Bang about 13.7 billion years ago, expanded extremely rapidly for a fraction of a second and has continued to expand much more slowly ever since, during which time stars, planets and ultimately humans have emerged. That expansion is now believed to be accelerating and is expected to result in a cold, uniform, featureless universe.

Penrose, however, takes issue with the inflationary picture and in particular believes it cannot account for the very low entropy state in which the universe was believed to have been born – an extremely high degree of order that made complex matter possible. He does not believe that space and time came into existence at the moment of the Big Bang but that the Big Bang was in fact just one in a series of many, with each big bang marking the start of a new “aeon” in the history of the universe.

Big Bang all over again

Central to Penrose’s theory is the idea that in the very distant future the universe will in one sense become very similar to how it was at the Big Bang. He says that at these points the shape, or geometry, of the universe was and will be very smooth, in contrast to its current very jagged form. This continuity of shape, he maintains, will allow a transition from the end of the current aeon, when the universe will have expanded to become infinitely large, to the start of the next, when it once again becomes infinitesimally small and explodes outwards from the next big bang. Crucially, he says, the entropy at this transition stage will be extremely low, because black holes, which destroy all information that they suck in, evaporate as the universe expands and in so doing remove entropy from the universe.

Penrose now claims to have found evidence for this theory in the cosmic microwave background, the all-pervasive microwave radiation that was believed to have been created when the universe was just 300,000 years old and which tells us what conditions were like at that time. The evidence was obtained by Vahe Gurzadyan of the Yerevan Physics Institute in Armenia, who analysed seven years’ worth of microwave data from WMAP, as well as data from the BOOMERanG balloon experiment in Antarctica. Penrose and Gurzadyan say they have clearly identified concentric circles within the data – regions in the microwave sky in which the range of the radiation’s temperature is markedly smaller than elsewhere.

Seeing through the Big Bang

According to Penrose and Gurzadyan, these circles allow us to “see through” the Big Bang into the aeon that would have existed beforehand. The circles, they say, are the marks left in our aeon by the spherical ripples of gravitational waves that were generated when black holes collided in the previous aeon. And they say that these circles pose a problem for inflationary theory because this theory says that the distribution of temperature variations across the sky should be Gaussian, or random, rather than having discernable structures within it.

Julian Barbour, a visiting professor of physics at the University of Oxford, says that these circles would be “remarkable if real and sensational if they confirm Penrose’s theory”. They would, he says, “overthrow the standard inflationary picture”, which, he adds, has become widely accepted as scientific fact by many cosmologists. But he believes that the result will be “very controversial” and that other researchers will look at the data very critically. He says there are many disputable aspects to the theory, including the abrupt shift of scale between aeons and the assumption, central to the theory, that all particles will become massless in the very distant future. He points out, for example, that there is no evidence that electrons decay.

The research is described at arXiv: 1011.3706.

Information converted to energy

Physicists in Japan have shown experimentally that a particle can be made to do work simply by receiving information, rather than energy. They say that their demonstration, which uses a feedback system to control the electric potential of tiny polystyrene beads, does not violate the second law of thermodynamics and could in future lead to new types of microscopic devices.

The experiment, carried out by Shoichi Toyabe of Chuo University in Tokyo and colleagues, is essentially the practical realization of a thought experiment proposed by James Clerk Maxwell in 1871. Maxwell envisaged a gas initially at uniform temperature contained in a box separated into two compartments, with a tiny intelligent being, later called “Maxwell’s demon”, controlling a shutter between the two compartments. By knowing the velocity of every molecule in the box, the demon can in principle time the opening and closing of the shutter to allow the build-up of faster molecules in one compartment and slower ones in the other. In this way, the demon can decrease the entropy inside the box without transferring energy directly to the particles, in apparent contradiction of the second law of thermodynamics.

Among the many responses to this conundrum was that of Leó Szilárd in 1929, who argued that the demon must consume energy in the act of measuring the particle speeds and that this consumption will lead to a net increase in the system’s entropy. In fact, Szilárd formulated an equivalence between energy and information, calculating that kTln2 (or about 0.69 kT) is both the minimum amount of work needed to store one bit of binary information and the maximum that is liberated when this bit is erased, where k is Boltzmann’s constant and T is the temperature of the storage medium.

Spiral staircase

Toyabe and colleagues have observed this energy-information equivalence by varying an electric field so that it represents a kind of spiral staircase. The difference in electrical potential between successive steps on the staircase is kT, meaning that a thermally fluctuating particle placed in the field will occasionally jump up a step but more often than not it will take a step downwards. What the researchers did was to intervene so that whenever the particle does move upwards they place the equivalent of a barrier behind it, preventing the particle from falling beyond this point. Repeating the process allows it to gradually climb the staircase.

The experiment consisted of a 0.3 µm-diameter particle made up of two polystyrene beads that was pinned to a single point on the underside of the top of a glass box containing an aqueous solution. The shape of an applied electric field forced the particle to rotate in one direction or, in other words, to fall down the potential-energy staircase. Buffered by the molecules in the solution, however, the particle every so often rotated slightly in the opposite direction, allowing it to take a step upwards.

By tracking the particle’s motion using a video camera and then using image-analysis software to identify when the particle had rotated against the field, the researchers were able to raise the metaphorical barrier behind it by inverting the field’s phase. In this way they could gradually raise the potential of the particle even though they had not imparted any energy to it directly.

Quantifiable breakthrough

In recent years other groups have shown that collections of particles can be rearranged so as to reduce their entropy without providing them with energy directly. The breakthrough in the latest work is to have quantified the conversion of information to energy. By measuring the particle’s degree of rotation against the field, Toyabe and colleagues found that they could convert the equivalent of one bit information to 0.28 kTln2 of energy or, in other words, that they could exploit more than a quarter of the information’s energy content.

Processes taking place on the nanoscale are completely different to those we are familiar with, and information is part of that picture Christian Van den Broeck, University of Hasselt

The research is described in Nature Physics, and in an accompanying article Christian Van den Broeck of the University of Hasselt in Belgium describes the result as “a direct verification of information-to-energy conversion” but points out that the conversion factor is an idealized figure. As he explains, it regards just the physics taking place on the microscopic scale and ignores the far larger amount of energy consumed by the macroscopic devices, among them the computers and human operators involved. He likens the energy gain to that obtained in an experimental fusion facility, which is dwarfed by the energy needed to run the experiment. “They are cheating a little bit,” joked Van den Broeck over the telephone. “This is not something you can put on the shelf and sell at this point.”

However, Van den Broeck does believe that the work could lead to practical applications within perhaps the next 30 or 40 years. He points out that as devices get ever more miniature the energy content of the information used to control them – kT at room temperature being equivalent to about 4 × 10–21 J – will approach that required to operate them. “Nobody thinks of using bits to boil water,” he says, “but that would in principle be possible at nanometre scales.” And he speculates that molecular processes occurring in nature might already be converting information to energy in some way. “The message is that processes taking place on the nanoscale are completely different from those we are familiar with, and that information is part of that picture.”

Copyright © 2026 by IOP Publishing Ltd and individual contributors