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Cambridge launches new Leverhulme Centre for Life in the Universe

Mon, 10/01/2022 - 15:11

The Leverhulme Centre for Life in the Universe will bring together an international team of scientists and philosophers, led by 2019 Nobel Laureate Professor Didier Queloz.

Thanks to simultaneous revolutions in exoplanet discoveries, prebiotic chemistry and solar system exploration, scientists can now investigate whether the Earth and the processes that made life possible are unique in the Universe.

The University has recently launched the Initiative for Planetary Science and Life in the Universe (IPLU) to enable cross-disciplinary research on planetology and life in the Universe.

Building on IPLU’s activities, the new Leverhulme Centre for Life in the Universe will support fundamental cross-disciplinary research over the next 10 years to tackle one of the great interdisciplinary challenges of our time: to understand how life emerged on Earth, whether the Universe is full of life, and ask what the nature of life is.

The Centre will include researchers from Cambridge’s Cavendish Laboratory, Department of Earth Sciences, Yusuf Hamied Department of Chemistry, Department of Applied Mathematics and Theoretical Physics, Institute of Astronomy, Department of Zoology, Department of History and Philosophy of Science, Faculty of Divinity, and the MRC Laboratory of Molecular Biology.

“The Centre will act as a catalyst for the development of our vision to understanding life in the Universe through a long-term research programme that will be the driving force for international coordination of research and education,” said Queloz, Jacksonian Professor of Natural Philosophy at the Cavendish Laboratory and Director of the Centre.

Research within the Centre will focus on four themes: identifying the chemical pathways to the origins of life; characterising the environments on Earth and other planets that could act as the cradle of prebiotic chemistry and life; discovering and characterising habitable exoplanets and signatures of geological and biological evolution; and refining our understanding of life through philosophical and mathematical concepts.

The Centre will collaborate with researchers at the University of Colorado Boulder, University College London, ETH Zurich, Harvard University and the Centre of Theological Inquiry in Princeton, New Jersey.

“Understanding the reactions that predisposed the first cells to form on Earth is the greatest unsolved mystery in science,” said programme collaborator Matthew Powner from University College London. “Critical challenges of increasing complexity must be addressed in this field, but these challenges represent one of the most exciting frontiers in science.”

Carol Cleland, Director of the Center for the Study of Origins and Professor of Philosophy at the University of Colorado Boulder, also collaborator on the programme said: “The new Centre is unique in the breadth of its interdisciplinarity, bringing together scientists and philosophers to address central questions about the nature and extent of life in the universe.

“Characteristics that scientists currently take as fundamental to life reflect our experience with a single example of life, familiar Earth life. These characteristics may represent little more than chemical and physical contingencies unique to the conditions under which life arose on Earth. If this is the case, our concepts for theorising about life will be misleading. Philosophers of science are especially well trained to help scientists 'think outside the box' by identifying and exploring the conceptual foundations of contemporary scientific theorising about life with an emphasis on developing strategies for searching for truly novel forms of life on other worlds.”

With a £10 million grant awarded by the Leverhulme Trust, the University of Cambridge is to establish a new research centre dedicated to exploring the nature and extent of life in the universe.

The Centre will act as a catalyst for the development of our vision to understanding life in the Universe through a long-term research programme that will be the driving force for international coordination of research and educationDidier QuelozESO/M. KornmesserArtists’s impression of the rocky super-Earth HD 85512 b


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Colour-changing magnifying glass gives clear view of infrared light

Thu, 02/12/2021 - 19:00

Detecting light beyond the visible red range of our eyes is hard to do, because infrared light carries so little energy compared to ambient heat at room temperature. This obscures infrared light unless specialised detectors are chilled to very low temperatures, which is both expensive and energy-intensive.

Now researchers led by the University of Cambridge have demonstrated a new concept in detecting infrared light, showing how to convert it into visible light, which is easily detected.

In collaboration with colleagues from the UK, Spain and Belgium, the team used a single layer of molecules to absorb the mid-infrared light inside their vibrating chemical bonds. These shaking molecules can donate their energy to visible light that they encounter, ‘upconverting’ it to emissions closer to the blue end of the spectrum, which can then be detected by modern visible-light cameras.

The results, reported in the journal Science, open up new low-cost ways to sense contaminants, track cancers, check gas mixtures, and remotely sense the outer universe.

The challenge faced by the researchers was to make sure the quaking molecules met the visible light quickly enough. “This meant we had to trap light really tightly around the molecules, by squeezing it into crevices surrounded by gold,” said first author Angelos Xomalis from Cambridge’s Cavendish Laboratory.

The researchers devised a way to sandwich single molecular layers between a mirror and tiny chunks of gold, only possible with ‘meta-materials’ that can twist and squeeze light into volumes a billion times smaller than a human hair.

“Trapping these different colours of light at the same time was hard, but we wanted to find a way that wouldn’t be expensive and could easily produce practical devices,” said co-author Dr Rohit Chikkaraddy from the Cavendish Laboratory, who devised the experiments based on his simulations of light in these building blocks.

“It’s like listening to slow-rippling earthquake waves by colliding them with a violin string to get a high whistle that’s easy to hear, and without breaking the violin,” said Professor Jeremy Baumberg of the NanoPhotonics Centre at Cambridge’s Cavendish Laboratory, who led the research.

The researchers emphasise that while it is early days, there are many ways to optimise the performance of these inexpensive molecular detectors, which then can access rich information in this window of the spectrum.

From astronomical observations of galactic structures to sensing human hormones or early signs of invasive cancers, many technologies can benefit from this new detector advance.

The research was conducted by a team from the University of Cambridge, KU Leuven, University College London (UCL), the Faraday Institution, and Universitat Politècnica de València.

The research is funded as part of a UK Engineering and Physical Sciences Research Council (EPSRC) investment in the Cambridge NanoPhotonics Centre, as well as the European Research Council (ERC), Trinity College Cambridge and KU Leuven.

Jeremy Baumberg is a Fellow of Jesus College, Cambridge. 

Reference:
Angelos Xomalis et al. ‘Detecting mid-infrared light by molecular frequency upconversion with dual-wavelength hybrid nanoantennas’, Science (2021). DOI: 10.1126/science.abk2593

By trapping light into tiny crevices of gold, researchers have coaxed molecules to convert invisible infrared into visible light, creating new low-cost detectors for sensing.

It’s like listening to slow-rippling earthquake waves by colliding them with a violin string to get a high whistle that’s easy to hear, and without breaking the violinJeremy BaumbergNanoPhotonics Cambridge/Ermanno Miele, Jeremy BaumbergNano-antennas convert invisible infrared into visible light


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Mystery of high-performing solar cell materials revealed in stunning clarity

Mon, 22/11/2021 - 15:38

The most commonly used material for producing solar panels is crystalline silicon, but achieving efficient energy conversion requires an energy-intensive and time-consuming production process to create a highly ordered wafer structure.

In the last decade, perovskite materials have emerged as promising alternatives to silicon.

The lead salts used to make perovskites are much more abundant and cheaper to produce than crystalline silicon, and they can be prepared in liquid ink that is simply printed to produce a film of the material. They also show great potential for other applications, such as energy-efficient light-emitting diodes (LEDs) and X-ray detectors.

The performance of perovskites is surprising. The typical model for an excellent semiconductor is a highly ordered structure, but the array of different chemical elements in perovskites creates a much ‘messier’ landscape.

This messiness causes defects in the material that lead to tiny ‘traps’, which typically reduce performance. But despite the presence of these defects, perovskite materials still show efficiency levels comparable to their silicon alternatives.   

In fact, earlier research by the same team behind the current work showed the disordered structure can actually increase the performance of perovskite optoelectronics, and their latest work seeks to explain why.  

Combining a series of new microscopy techniques, the group present a complete picture of the nanoscale chemical, structural and optoelectronic landscape of these materials, that reveals the complex interactions between these competing factors and ultimately, shows which comes out on top.

“What we see is that we have two forms of disorder happening in parallel,” said first author Kyle Frohna from Cambridge’s Department of Chemical Engineering and Biotechnology (CEB). “The electronic disorder associated with the defects that reduce performance, and then the spatial chemical disorder that seems to improve it.

“And what we’ve found is that the chemical disorder – the ‘good’ disorder in this case – mitigates the ‘bad’ disorder from the defects by funnelling the charge carriers away from these traps that they might otherwise get caught in.” 

In collaboration with researchers from the Cavendish Laboratory, the Diamond Light Source synchrotron facility in Didcot, and the Okinawa Institute of Science and Technology in Japan, the researchers used several different microscopic techniques to look at the same regions in the perovskite film. They could then compare the results from all these methods to present the full picture of what’s happening at a nanoscale level in these materials.

The findings will allow researchers to further refine how perovskite solar cells are made in order to maximise efficiency.

“We have visualised and given reasons why we can call these materials defect tolerant,” said co-author Miguel Anaya, also from CEB. “This methodology enables new routes to optimise them at the nanoscale to perform better for a targeted application. Now, we can look at other types of perovskites that are not only good for solar cells but also for LEDs or detectors and understand their working principles.”

“Through these visualisations, we now much better understand the nanoscale landscape in these fascinating semiconductors – the good, the bad and the ugly,” said Dr Sam Stranks from CEB, who led the research. “These results explain how the empirical optimisation of these materials by the field has driven these mixed composition perovskites to such high performances. But it has also revealed blueprints for design of new semiconductors that may have similar attributes – where disorder can be exploited to tailor performance.”

Reference:
Kyle Frohna et.al ‘Nanoscale chemical heterogeneity dominates the optoelectronic response of alloyed perovskite solar cells.’ Nature Nanotechnology (2021) DOI: 10.1038/s41565-021-01019-7

Researchers have visualised, for the first time, why perovskites – materials which could replace silicon in next-generation solar cells - are seemingly so tolerant of defects in their structure. The findings, led by researchers from the University of Cambridge, are published in the journal Nature Nanotechnology.

We now much better understand the nanoscale landscape in these fascinating semiconductors – the good, the bad and the uglySam StranksAlex T. at Ella Maru StudiosArtistic representation of electrons funneling into high quality areas of perovskite material


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No hint of theoretical particle sterile neutrino in new results

Fri, 29/10/2021 - 09:58

Results from a global science experiment have cast doubt on the existence of a theoretical particle beyond the Standard Model.

The results were gathered by an international team at the MicroBooNE experiment in the United States, with leadership from a UK team including researchers from the University of Cambridge.

The two most likely explanations for anomalies that were seen in two previous physics experiments: one which suggests a sterile neutrino, and one which points at limitations in those experiments, have been ruled out by MicroBooNE. 

The fourth neutrino

For more than two decades, this proposed fourth neutrino has remained a promising explanation for anomalies seen in earlier physics experiments. In these previous experiments, neutrinos were observed acting in a way not explained by the Standard Model of Physics – the leading theory to explain the building blocks of the universe and everything in it.

Neutrinos are the most abundant particle with mass in our universe, but they rarely interact with other matter, making them hard to study. But these elusive particles seem to hold answers to some of the biggest questions in physics – such as why the universe is made up of more matter than antimatter.

A 170-ton neutrino detector the size of a bus was created to study these particles – and became known as MicroBooNE. The international experiment has close to 200 collaborators from 36 institutions in five countries, and is supported by the Science and Technology Facilities Council (STFC) in the UK.

Standard Model holds up

The team used cutting-edge technology to record precise 3D images of neutrino events and examine particle interactions in detail. Four complementary analyses released by the international MicroBooNE collaboration, at the Fermi National Accelerator Laboratory (Fermilab), deal a blow to the fourth neutrino hypothesis.

All four analyses show no sign of the sterile neutrino, and instead the results align with the Standard Model. The data is consistent with what the Standard Model predicts: three kinds of neutrinos only. But the anomalies are real and still need to be explained. Crucially, MicroBooNE has also ruled out the most likely explanation to explain these anomalies without requiring new physics. 

These results mark a turning point in neutrino research. With the evidence for sterile neutrinos becoming weaker, scientists are investigating other possibilities for anomalies in perceived neutrino behaviour.

“This result is incredibly exciting as suggests something far more interesting than we expected is happening – it’s now our goal to find out what this could be,” said Dr Melissa Uchida, who leads the Neutrino Group at Cambridge’s Cavendish Laboratory.

“This heralds the start of a new era of precision for neutrino physics, in which we will deepen our understanding of how the neutrino interacts, how it impacted the evolution of the universe, and what it can reveal to us about physics beyond our current Standard Model of how the universe behaves at the most fundamental level,” said Professor Justin Evans from the University of Manchester, co-spokesperson of the experiment.

“Cambridge has played an integral part in this experiment both through the software — the reconstruction algorithms that allow us to distinguish particles and their interactions in MicroBooNE and through the analysis itself,” said Uchida. “With half the data still to analyse and more exotic avenues to pursue, there is an exciting journey ahead.”

The UK at MicroBooNE

The UK has taken a leading role in MicroBooNE, leading the development of state-of-the-art pattern recognition algorithms, making world-leading contributions to the understanding of neutrino interactions in the argon, and bringing a broad range of expertise to these searches for the elusive sterile neutrinos.

UK universities involved in MicroBooNE are Manchester, Edinburgh, Cambridge, Lancaster, Warwick and Oxford.

Mission to understand neutrinos

With our understanding of neutrinos still incomplete, the UK through STFC has invested in a science programme to address these key science questions, as well as invest in new technologies.

The UK government has already invested £79 million in the Deep Underground Neutrino Experiment, Long-Baseline Neutrino Facility (LBNF), and the new PIP-II accelerator, all hosted by Fermilab.

This investment has given UK scientists and engineers the chance to take leading roles in the management and development of the DUNE far detector, the LBNF neutrino beam targetry and PIP-II accelerator.

Professor Mark Thomson, Executive Chair of STFC and one of the first UK physicists to join MicroBooNE, said: “This much-awaited result is a significant step our understanding of neutrinos. This extremely challenging measurement is also important in that the MicroBooNE experiment used a new technology to record detailed images of individual neutrino interactions.

“The successful use the liquid argon imaging technology is a major stepping stone towards DUNE.

“Once complete by the end of this decade, DUNE will use several detectors each of the size of an extra-deep Olympic swimming pool, but with liquid argon replacing the water, to measure the movements and behaviours of neutrinos.”

Adapted from an STFC press release

New results from the MicroBooNE experiment deal a significant blow to a theoretical particle known as the sterile neutrino.

Cindy Arnold, FermilabTeams prepare to move the MicroBooNE cryostat from DZero to the Liquid Argon Test Facility (LArTF).


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Cambridge physicists announce results that boost evidence for new fundamental physics

Tue, 19/10/2021 - 13:44

In March 2020, the same experiment released evidence of particles breaking one of the core principles of the Standard Model – our best theory of particles and forces – suggesting the possible existence of new fundamental particles and forces.

Now, further measurements by physicists at Cambridge’s Cavendish Laboratory have found similar effects, boosting the case for new physics.

The Standard Model describes all the known particles that make up the universe and the forces that they interact through. It has passed every experimental test to date, and yet physicists know it must be incomplete. It does not include the force of gravity, nor can it account for how matter was produced during the Big Bang, and contains no particle that could explain the mysterious dark matter that astronomy tells us is five times more abundant than the stuff that makes up the visible world around us.

As a result, physicists have long been hunting for signs of physics beyond the Standard Model that might help us to address some of these mysteries.

One of the best ways to search for new particles and forces is to study particles known as beauty quarks. These are exotic cousins of the up and down quarks that make up the nucleus of every atom.

Beauty quarks don’t exist in large numbers in the world around as they are incredibly short-lived – surviving on average for just a trillionth of a second before transforming or decaying into other particles. However, billions of beauty quarks are produced every year by CERN’s giant particle accelerator, the Large Hadron Collider, which are recorded by a purpose-built detector called LHCb.

The way beauty quarks decay can be influenced by the existence of undiscovered forces or particles. In March, a team of physicists at LHCb released results showing evidence that beauty quarks were decaying into particles called muons less often than to their lighter cousins, electrons. This is impossible to explain in the Standard Model, which treats electrons and muons identically, apart from the fact that electrons are around 200 times lighter than muons. As a result, beauty quarks ought to decay into muons and electrons at equal rates. Instead, the physicists at LHCb found that the muon decay was only happening around 85% as often as the electron decay.

The difference between the LHCb result and the Standard Model was about three units of experimental error, or ‘3 sigma’ as it is known in particle physics. This means there is only around a one in a thousand chance of the result being caused by a statistical fluke.

Assuming the result is correct, the most likely explanation is that a new force that pulls on electrons and muons with different strengths is interfering with how these beauty quarks decay. However, to be sure if the effect is real more data is needed to reduce the experimental error. Only when a result reaches the ‘5 sigma’ threshold, when there is less than a one in a million chance of it being due to random chance, will particle physicists start to consider it a genuine discovery.

“The fact that we’ve seen the same effect as our colleagues did in March certainly boosts the chances that we might genuinely be on the brink of discovering something new,” said Dr Harry Cliff from the Cavendish Laboratory. “It’s great to shed a little more light on the puzzle.”

Today’s result examined two new beauty quark decays from the same family of decays as used in the March result. The team found the same effect – the muon decays were only happening around 70% as often as the electron decays. This time the error is larger, meaning that the deviation is around ‘2 sigma’, meaning there is just over a 2% chance of it being due to a statistical quirk of the data. While the result isn’t conclusive on its own, it does add further support to a growing pile of evidence that there are new fundamental forces waiting to be discovered.

“The excitement at the Large Hadron Collider is growing just as the upgraded LHCb detector is about to be switched on and further data collected that will provide the necessary statistics to either claim or refute a major discovery,” said Professor Val Gibson, also from the Cavendish Laboratory.

Results announced by the LHCb experiment at CERN have revealed further hints for phenomena that cannot be explained by our current theory of fundamental physics.

The fact that we’ve seen the same effect as our colleagues did in March certainly boosts the chances that we might genuinely be on the brink of discovering something newHarry CliffCERNView of the LHCb detector


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