The cities of Richland and Ozersk were on opposing sides during the Cold War, but they have a lot in common. Richland, in eastern Washington state, was built as a “company town” for the Hanford nuclear reactor, America’s main plutonium-production facility. Ozersk, in the southern Ural Mountains, is its Russian counterpart – a “closed city” where, even today, most residents are connected in some way to the nearby Maiak plutonium plant.
Because these plants were vital to the US and Soviet nuclear-weapons programmes, workers at Hanford and Maiak got paid extremely well, and they and their families enjoyed a wide range of benefits. But as Kate Brown reveals in her book Plutopia, these privileges came at a terrible cost. Between the 1940s and the 1980s, the Hanford and Maiak reactors each released at least 200 million curies of radioactivity into the environment – twice as much as caused by the explosion at the Chernobyl nuclear reactor. The areas nearby are now some of the most polluted places on Earth.
In this podcast, you will hear Brown – an historian at the University of Maryland, Baltimore County – talking to Physics World reviews editor Margaret Harris about her research on these two “atomic cities” and what she hopes physicists will learn from their stories.
The big story this week is that astronomers working on the BICEP2 telescope may have spotted the first direct evidence for cosmic inflation. This is very good news for the physicist Andrei Linde, who along with Alan Guth and others did much of the early work on inflation. In the above YouTube video Linde, who is certainly in the running for a Nobel prize, receives a surprise visit from BICEP2 team member Chao-Lin Kuo. Kuo is the first to tell Linde and his wife, the physicist Renata Kallosh, the news that the theory that Linde developed more than 30 years earlier had finally been backed up by direct observational evidence. Not surprisingly, champagne glasses are clinking!
Here at physicsworld.com we have tried to tell both sides of the story: the thrill of seeing the first hints of cosmic inflation, tempered with calls for caution that more data are needed before inflation is victorious over other theories describing the early universe.
Nanoparticles could increase the amount of solar energy captured by plants by as much as 30%. That is the conclusion of researchers at the Massachusetts Institute of Technology (MIT), who have shown that plants with semiconducting carbon nanotubes in their leaves can better convert energy from sunlight into electrical current.
The team believes that the discovery could be exploited in a new field dubbed plant “nanobionics”, whereby nanoparticles could enhance natural functions in ordinary plants and also be used to create artificial plant-like systems that grow and repair themselves using sunlight and water. Potential applications include biochemical detectors for monitoring pollutants in the environment and perhaps even new technologies that would help increase crop yields.
“Plants provide us with food and fuel, and even the oxygen we breathe, but they have been little used in technology applications until now,” says team member Juan Pablo Giraldo. “We are talking about a new field at the interface between nanotechnology and plant biology, which we have called plant nanobionics.”
Measuring electron flow
Led by Michael Strano, the team used two techniques to measure electron flow in plant leaves and chloroplasts in the lab. The first relied on measuring the changes in colour of a dye that intercepts electrons between the photosystems in chloroplasts extracted from plants. The second is based on monitoring changes in chlorophyll fluorescence in extracted chloroplasts and leaves. Chloroplasts are organelles inside a plant cell that use chlorophyll to capture and store the energy from solar radiation.
According to the MIT team, the nanotubes appear to enhance the amount of light absorbed by chlorophyll at wavelengths that are normally only weakly captured by plants. This includes green light as well as the ultraviolet and near-infrared parts of the electromagnetic spectrum. The result is that the nanoparticle-treated plant leaves can produce as much as 30% more photocurrent than non-treated plants.
The researchers also found that nanotubes combined with polymer nanoparticles containing ceria (a rare-earth metal oxide) act as “antioxidants”, and dramatically reduce the number of damaging oxygen radicals in extracted chloroplasts – something that could also help increase photosynthetic activity.
Self-repairing artificial plant-like systems
“Being able to enhance chloroplast photosynthesis with nanoparticles could allow us to develop artificial plant-like systems that would be powered by solar energy and be able to repair themselves like real plants,” says Giraldo. “Both these and the nanoparticle-augmented ordinary plants, might, for example, be used as biochemical detectors for monitoring pollutants, such as nitric oxide, in the environment. They might even be able to detect dangerous chemicals and gases, depending on the type of nanoparticle incorporated.”
The team says that it would now like to better understand how carbon nanotubes capture and transfer light energy to the photosynthetic machinery in plant chloroplasts. “The ultimate goal is to find out whether assembling chloroplasts with nanoparticles such as carbon nanotubes can help increase the amount of chemical fuels (such as glucose) that plants produce,” Giraldo explains. “Such studies will take our technology to a new level of applications, such as increasing crop yields or algae biofuel production.
“Ideally, we need remote-detection instruments that allow us to image in real time the near-infrared fluorescence changes of carbon nanotubes in plants under real-life conditions,” he adds.
This week has seen physics news hit the mainstream in a way not seen since the Higgs boson was discovered at the CERN particle-physics lab in 2012.
On Monday, researchers working on the Background Imaging of Cosmic Extragalactic Polarization (BICEP2) telescope at the South Pole revealed that they have detected the first evidence for the primordial B-mode polarization of the cosmic microwave background (CMB). You can read our news stories about the finding here and here.
Yet could scientists in the UK have got there first if a telescope they had been planning to build – dubbed Clover – hadn’t been axed in 2009?
In 2007 UK physicists and astronomers were hit by a massive funding crisis that engulfed one of the country’s main funding agencies: the Science and Technology Facilities Council (STFC). The £80m black hole in the STFC’s budget forced the council to stop supporting research into the International Linear Collider, withdraw from the Gemini telescopes in Hawaii and Chile, as well as slashing grants for researchers in particle physics and astronomy.
The fallout from the crisis was felt for a number of years afterwards (some would say it still is today) and was followed by a host of “programmatic reviews”, which ranked projects against each other and sometimes resulted in the cancellation of lower-priority facilities.
Although Clover was actually deemed to be of “high importance” by the STFC in a 2008 review, it didn’t escape the chop, which happened in March 2009. The reason given by the STFC was because construction costs had risen by 60% to some £7.5m.
A collaboration between Cambridge, Cardiff, Manchester and Oxford universities, the UK-led telescope, which would have been located in the in the Atacama Desert in Chile, was designed to search for exactly what BICEP2 discovered this week.
Michael Jones, an experimental cosmologist at Oxford who was an instrument scientist for Clover, told physicsworld.com that while the BICEP2 results are “very exciting” but need to be confirmed by other telescopes, he bemoans the fact that Clover could have been one of those experiments now at the forefront of B-mode research.
“It was very clear back when Clover was cancelled that this day was going to arrive – everyone in the field recognizes the importance of the B-mode measurement, and everyone knew that when or if it was discovered, then it was going to be front-page news,” says Jones. “The fact that it seems to have been measured at such a high level means that Clover would definitely have been able to detect it. Of course, we can’t say whether or not Clover would have been first, but even if Clover hadn’t been first, it would have been part of what is now a highly important field.”
Of course, UK researchers are still involved in BICEP2, with Cardiff University a collaborating member of the telescope, and other experiments now in the hunt for B-modes such as Polarbear and the European Space Agency’s Planck mission.
But that seems scant consolation given the possibility that the UK might have got there first. “It is certainly worth pointing out that the STFC made the decision to pull the UK out of a field of unquestioned scientific importance, in which we had a leading position, to save what in retrospect seems to be quite a small amount of money,” adds Jones.
Many of you reading this will have experienced (or at least known somebody else who has experienced) a medical scan of some type. Even if you have a background in physics, these procedures can seem mysterious and even slightly menacing, not helped by the clinical designs of the equipment and some of the sounds they make. A new series of online courses offered by an academic collaboration in Scotland has been designed to demystify the world of medical-imaging techniques by presenting the science and technology in non-technical ways.
The courses include introductions to ultrasound, magnetic resonance imaging (MRI), positron emission tomography (PET), and computerized tomography (CT). “The material was designed for non-specialists with an interest in science who might want to understand a bit more about medical imaging: school teachers, pupils, patients, relatives of patients,” says Dave Wyper, director of the Scottish Imaging Network: A Platform for Scientific Excellence (SINAPSE).
SINAPSE is a consortium of six Scottish universities: Aberdeen, Dundee, Edinburgh, Glasgow, St Andrews and Stirling. The group specializes in medical imaging, and about 50% of its members are medical physicists. To develop these courses, SINAPSE teamed up with eCom Scotland, a specialist in online learning. In an e-mail exchange with Wyper, I learned that the courses – which can be accessed worldwide – present medical imaging in simple terms with the aid of basic graphics. Currently, each course costs just under £10 though the pricing is under review and courses may become free of charge in the future.
These medical-imaging courses are an interesting example of a recent development in education known as massive open online courses, or MOOCs for short. Despite their slightly silly name, MOOCs have the potential to transform online learning by widening global access to education. These are usually short courses mixing online teaching with assignments such as problem sets and extended projects. While the concept of online private study has been around for as long as the Web, the novelty with MOOCs is that these courses are freely available and the providers take full advantage of the latest Web technology, such as online video and interactive virtual labs.
You can learn more in a feature I wrote about the rise of MOOCs that appears in the March issue of Physics World, which is a special issue on education and is available as a free PDF download. I also produced this short film about a new initiative at the Massachusetts Institute of Technology in which MOOCs technologies are being incorporated into the traditional undergraduate physics programme. Take a look at that to discover what the students make of this new form of blended learning.
A way of modulating the waveforms of individual, coherent high-energy photons at room temperature has been demonstrated by researchers in the US and Russia. The advance opens the way for new quantum-optics technologies capable of extremely high-precision measurements, as well as the possibility of quantum-information systems based on nuclear processes. The new approach could also be useful for those doing fundamental research in a variety of areas, ranging from the role of quantum phenomena in biological processes to fundamental questions in quantum optics itself.
The technique was developed by Olga Kocharovskaya, Farit Vagizov and colleagues at Texas A&M University and the Kazan Federal University. Their set-up bears some similarity to a Mössbauer spectroscopy experiment. A sample of radioactive cobalt-57 decays to an excited state of iron-57, which then decays by emitting a 14.4 keV “soft” gamma-ray photon. This photon can then be absorbed and re-emitted by a nearby stainless-steel foil containing iron-57. Because of the Mössbauer effect, no energy is lost in the recoil of the stainless-steel lattice and the photon is emitted at 14.4 keV with very little spectral blurring.
As the foil absorbs and re-emits the photons, it is vibrated at megahertz frequencies. By making clever use of the Doppler effect, the team is able to shape a single photon into a double pulse and even a train of ultrashort pulses. This makes it possible to use the gamma-ray photons to encode quantum information in a “time-bin qubit” – quantum bits in which information is encoded in terms of the relative arrival time of pulses.
Easier to detect
The new method offers advantages over schemes for encoding quantum information in lower-energy optical or microwave photons. Photons in the 10–100 keV energy range – soft gamma rays from nuclear transitions and “hard” X-rays from atomic transitions – penetrate deeper into materials and can be detected with greater efficiency. And in the case of the Mössbauer photons, the recoil-less nature of the effect means that the re-emitted photons retain their quantum coherence at room temperature.
Recent developments towards the generation of entangled gamma-photon pairs, combined with the team’s new method, could lead to quantum-computing applications that use nuclei as qubits. “Entangled nuclear ensembles may be produced via resonant interactions with the entangled photons, using quantum-memory protocols,” explains Kocharovskaya.
The new technique gives physicists a more versatile way of controlling gamma rays than current methods of manipulating high-energy photons. “In our approach, we have more parameters to manipulate,” Kocharovskaya says. Indeed, the team can alter the amplitude, frequency and phase of the radiation and change the nature and temporal profile of the modulating wave. Arbitrary waveforms can be created “on demand” by changing the absorber depth and frequency of resonance. “Besides, our method allows one to manipulate single gamma-photons, which is impossible with the existing nonlinear techniques,” she says. Kocharovskaya and colleagues are now working to improve their technique as well as pursuing a number of potential applications.
Deterministic pulse shaping
“This study opens for the first time possibilities for deterministic pulse shaping in the X-ray regime,” says X-ray optics expert Ralf Röhlsberger of DESY in Hamburg, Germany. “Unfortunately, the positive aspects come with some drawbacks.” He points out that photons in this energy range are difficult to manipulate using conventional optical devices and that photon loss through absorption and scattering will limit performance. “These technologies, however, have nevertheless the potential to boost our understanding of fundamental aspects of the light–matter interactions,” he says.
Christoph Keitel of the Max Planck Institute for Nuclear Physics in Heidelberg, Germany, agrees that the work of Kocharovskaya and colleagues is a significant accomplishment. He points out that “this is a demanding field with numerous serious challenges: the radiation sources are weak and often relatively dirty, and the couplings to the nuclei are generally small. This renders this absolutely clean and innovative way of coherently adapting gamma waves so impressive.”
The technique is described in Nature and a preprint is available on arXiv.
Optical “nanotweezers” that can grasp and move objects just a few tens of nanometres in size have been created by researchers in Spain and Australia. The new tool is gentle enough to grasp tiny objects such as viruses without destroying them, and works in biologically-friendly media such as water. The nanotweezers could find a range of uses, from helping us to understand the biological mechanisms underlying diseases to assembling tiny machines.
Controlling the placement of individual molecules is critical in medicine, for example, where investigating the origin of diseases often requires manipulating viruses or large proteins. The accurate placement of tiny objects such as carbon nanotubes is also expected to play an important role in the development of nanotechnologies such as molecular motors and other tiny devices.
Beating the diffraction limit
While nanometre-sized objects can be moved around using conventional optical tweezers, the precision to which this can be done is subject to the diffraction limit – about 300 nm for visible light. However, this limit does not apply to near-field light waves. These exist near light-emitting regions and drop rapidly in intensity across distances that are much smaller than the diffraction limit.
In the 1990s some researchers suggested that a near-field scanning optical microscope could be capable of trapping and manipulating objects as small as a few nanometres. This type of microscope captures near-field light by scanning a tiny aperture – usually tens of nanometres in diameter – just a few nanometres above the object of interest.
Too hot to handle?
Turning such a microscope into optical tweezers involves firing laser light through the aperture, thus focusing it to a tiny spot of near-field light. As in current optical tweezers, the intensity gradient of the light across the spot draws tiny dielectric objects to the spot’s centre, where the electric field is strongest. In principle, this could allow tiny objects to be held and manipulated with nanometre precision. However, experimental tests of this technique were never done because of the concern that the concentrated light at the tip of the microscope would be so intense that it would damage heat-sensitive objects or even the microscope tip itself.
Now, Romain Quidant at the Institute of Photonic Sciences in Barcelona and colleagues have shown that tiny objects can be successfully trapped and manipulated using light of much lower intensity than had been contemplated in earlier designs. The team’s set-up involves a 1-μm-diameter optical fibre with an 85-nm-wide bow-tie-shaped aperture milled into its end (see image above).
A firm handshake
Quidant and colleagues reduced the intensity using a new technique called self-induced back action (SIBA) trapping that relies on adjusting the local field intensity in real time, based on the behaviour of the specimen. “The trapped object plays an active role in the trapping mechanism,” says Quidant. He explains that the trapping process is like a firm handshake that neither crushes nor releases the object. This method reduces the intensity of light needed to hold the object by several orders of magnitude, which removes the possibility of damage to the tip or object.
Quidant and colleagues used a near-infrared laser the power of which could be modulated between 2–5 mW. The researchers showed that polystyrene beads 50 nm in diameter – about the size of the virus that causes yellow fever – suspended in water could be successfully trapped and held for longer than 30 min. As well as firing the laser down the fibre so that light emerged from the aperture, the team also looked at an alternative set-up in which the laser was shone through an external lens that focused it onto the aperture. However, the researchers concluded that this external illumination configuration was inferior because the position of the aperture had to be fixed, which limited the mobility of the sample.
“We foresee this technique could become a universal tool in nanoscience, in any research where the non-invasive manipulation of nano-objects would be required,” says Quidant.
Yesterday, researchers from the Background Imaging of Cosmic Extragalactic Polarization (BICEP2) telescope at the South Pole revealed that they have detected the first evidence for the primordial B-mode polarization of the cosmic microwave background (CMB). The astronomers claimed that the primordial B-mode polarization signal – which is related to primordial gravitational waves that flowed through the early universe – is the first direct evidence for cosmic inflation and has been measured to a statistical certainty of 3σ. Now, cosmologist and Perimeter Institute director Neil Turok, who worked on an inflationary model of his own with Stephen Hawking in the 1990s, urges caution and says that extensive experimental confirmation is necessary before BICEP2’s results can be considered as evidence for inflation.
Ugly tweaks
“If…and it’s a big if…this is true, it would be spectacular evidence for what happened at the Big Bang,” Turok told physicsworld.com. While he agreed that at first glance, the BICEP2 observations are in keeping with inflation “as suggested over 30 years ago, wherein space–time would resonate with the aftershocks of inflation and would ring like a bell”, a closer look at the discrepancy between the new results and previous data from the Planck and WMAP telescopes is what worries Turok.
I believe that if both Planck and the new results agree, then together they would give substantial evidence against inflation!
Neil Turok
Perimeter Institute director Neil Turok. (Courtesy: Gabriela Secara)
Indeed, the tensor-to-scalar ratio of 0.20 that BICEP2 measured is considered to be significantly larger than that expected from previous analyses of data. But the BICEP2 researchers said in their press conference yesterday that they believe certain tweaks could be made to an extension of the ΛCDM cosmological model that could make the two results agree.
“But these tweaks would be tremendously ugly….and in fact, I believe that if both Planck and the new results agree, then together they would give substantial evidence against inflation!” exclaims Turok, further explaining that “[we] must be careful before we treat them as true”.
Inflationary recipes
Astrophysicist Peter Coles, who is based at the University of Sussex in the UK, is also cautious about the BICEP2 data interpretations. He told physicsworld.com, “It seems to me though that there’s a significant possibility of some of the polarization signal in E and B [modes] not being cosmological. This is a very interesting result, but I’d prefer to reserve judgement until it is confirmed by other experiments. If it is genuine, then the spectrum is a bit strange and may indicate something added to the normal inflationary recipe.” He also cautions that if true, the results would constitute an important consistency check on a certain class of inflationary theories, but would not be direct evidence. “In order to be direct, we would have to be able to state categorically that it couldn’t be generated in any other way. I don’t think we can say that.” Indeed, Coles has set up a general “straw poll” on his blog, asking people to vote on the results. At the time of writing, his results show that most people believe that it is too soon to decide.
If it is genuine, then the spectrum is a bit strange and may indicate something added to the normal inflationary recipe
Peter Coles
Turok says that the BICEP2 experiment “is absolutely heroic”, but also that possible contamination could have occurred during data taking. Although the telescope is based in the South Pole – one of the clearest places on Earth for observational astronomy – there could be noise thanks to the Earth’s atmosphere. He also says that the signal could be contaminated thanks to signals from dust in the galaxy (known as synchrotron radiation), as well as due to lensing, because the observations are made through galactic clusters. The BICEP2 team says in its paper that it has ruled out contamination from synchrotron radiation and dust at a statistical significance of about 2.3σ. But Turok is unimpressed with those values, and points out that the final 5σ discovery that the team claimed needs to be better explained.
Extraordinary proof?
While he extends his “kudos” to the team for going after a really fascinating question, Turok currently remains a sceptic. “I will quote Carl Sagan and say ‘extraordinary claims require extraordinary evidence’, and they don’t have extraordinary evidence just yet.” He reiterates that the BICEP2 and Planck/WMAP discrepancies need to be resolved, and that result will be essential because “something has got to give”. He urges other experiments to confirm the results and suggests that the combined observational results should then fit a simple yet detailed cosmological model before the BICEP2 observations can be thought of as proof of primordial gravitational waves or indeed inflation.
“I am a humble theorist,” says Turok with a laugh, “now the real task is for the experimental community to scan and replicate results…it might take months or years and there is still everything to play for but we should have an answer relatively soon.”
Unfortunately, there’s no getting away from the fact that many concepts in physics are hard and that cutting-edge experiments are incredible feats of technical endeavour. We can, though, all take solace from the fact that physicists at the frontiers of research have often spent decades living and breathing their subjects, which means they know the basics of their own field far better than anyone else.
All of which underlines the importance for any good physicist of a decent physics education – in fact, if you haven’t already, you might want to download our free PDF of the March issue of Physics World magazine. It includes tips, tricks and techniques for helping you to teach and learn physics from those in the know.
You can see Ireland’s Feynman doodle here, but we also invited you to send in doodles of your own. Our favourite so far is by 51-year-old reader Tracey, who is currently preparing for a GCSE in mathematics in Oxfordshire, UK. Her partner is a physicist who subscribes to Physics World and it was while flicking through the March issue of the magazine that she noticed Ireland’s doodle. Tracey also enjoys art and her doodle, pictured above, is painted in watercolours.
Before this she worked as a volunteer in classes run by Oxfordshire County Council to help adults pick up basic maths skills and also served as a learning support assistant in maths and English classes at a local college. “The mathematician I used to help is brilliant and he inspired me to study GCSE maths, which he is currently teaching me,” says Tracey. “Maths is not a natural subject for me, although I enjoy the challenge of it and I can understand how a lot of students fear the subject!”
If you’ve got a doodle of your own up your sleeve, do link to it below or e-mail us at pwld@iop.org.
And if you don’t get Physics World each month, simply join the Institute of Physics to get access via our apps or desktop version via this link for just £15/€20/$25 for 12 issues a year.
The first evidence for the primordial B-mode polarization of the cosmic microwave background (CMB) has been detected by astronomers working on the Background Imaging of Cosmic Extragalactic Polarization (BICEP2) telescope at the South Pole. The polarization signal is the first direct evidence for cosmic inflation and has been measured to a statistical certainty of 3σ. The primordial B-mode polarization is related to primordial gravitational waves that are thought to have abounded in the early universe.
Cosmologists believe that when the universe was very young – a mere 10–35 s after the Big Bang – it underwent a period of extremely rapid expansion, known as “inflation”, when its volume increased by a factor of up to 1080 in a tiny fraction of a second. About 380,000 years after the Big Bang, the CMB – the thermal remnant of the Big Bang – came into being. Over the years, the CMB has been measured with great accuracy, but these observations brought some problems: the CMB showed that the entire observable universe seemed to be homogeneous, flat and isotropic, while the physics of the Big Bang suggests that it should be highly curved and heterogeneous.
Inflation was first proposed in 1980 by the physicist Alan Guth, and is currently the best way to resolve these conundrums. It suggests that the entire observable universe originated in a small causally connected region that expanded at an exponential rate so that the horizon became much larger and space could be flat. Inflation also serves the purpose of ironing out any anisotropies or curvature of space, putting the universe into a rather simple state that is only mildly pertubated by quantum fluctuations. Such fluctuations are thought to have occurred in a “microscopic inflationary region” that eventually magnified to cosmic size, becoming the seeds for the growth of structure in the universe – everything from stars to galaxies. There are also variations in temperature of about 100 µK in the CMB (which is normally at an even temperature of 3 K), which reveal density fluctuations in the early universe.
Extreme gravitational conditions
Scientists also believe that rather extreme gravitational conditions prevailed during the universe’s infancy. Gargantuan primordial gravitational waves are thought to have propagated through the universe during the first moments of inflation and this would have produced a so-called cosmic gravitational-wave background (CGB). This gravitational-wave background would, in turn, have left its own imprint on the polarization of the CMB – a sort of “curl” component or rotation that is known as the primordial B-mode polarization.
The BICEP2 telescope (the white dish at the top right of the blue building) has made an important discovery. (The dish on the left is the South Pole Telescope.) (Courtesy: National Science Foundation)
This is why researchers the world over have been keen to detect the primordial B-mode polarization – it would be evidence of primordial gravitational waves and so inflation. And it is this B-mode polarization that the BICEP2 collaboration has detected for the first time. There is also another similar component known as non-primordial B-mode polarization, which is caused by gravitational lensing, and this was detected last year by the South Pole Telescope (SPT). There are also other polarization variations, known as E-mode or gradient variations, that describe how the magnitude of polarization changes over the CMB.
Scientists cannot distinguish between the polarization caused by gravitational waves, which has a tensor component, and that caused by density waves, which have a scalar component, simply by looking at the temperature variations of the CMB. Also, the primordial B-mode polarization is thought to be much weaker than the E-mode, making it even more difficult to detect. However, certain measurements on the polarization angles that can be detected at each point on the sky provide extra information and allow scientists to differentiate between the tensor and scalar components, providing a “tensor-to-scalar” ratio. This ratio has been measured by BICEP2 to be 0.20 with a statistical significance of about 3σ. The possibility that the ratio is zero is ruled out with a statistical certainty of 7σ.
A value of 0.20 is considered to be significantly larger than that expected from previous analyses of data from the Planck and WMAP telescopes. “This has been like looking for a needle in a haystack, but instead we found a crowbar,” says BICEP2 co-leader Clem Pryke of the University of Minnesota. Craig Hogan, director of the Fermilab Center for Particle Astrophysics, told physicsworld.com that “If it’s confirmed, it is truly profound – the first direct evidence not only for inflation, but of a quantum behaviour of space and time. The image of polarization is a relic imprint of roughly a single quanta of graviton action.”
According to the BICEP2 collaboration, its results suggest that “the long search for tensor B-modes is apparently over, and a new era of B-mode cosmology has begun”.
In this video Andrew Jaffe of Imperial College London explains why cosmologists believe that the universe underwent a period of vast and raid growth when it was just fractions of a second old.
