Nobel Prize in Physics

Nobel Prize in Physics won by scientists using lasers to solve the universe’s smallest mysteries

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Winners Arthur Ashkin, Gérard Mourou and Donna Strickland helped develop technology dreamed up in science fiction that led to breakthroughs such as eye surgery.

The 2018 Nobel Prize in Physics has been given to scientists who used lasers to solve some of the universe’s smallest mysteries.

The award was given to Arthur Ashkin and the other half jointly to Gérard Mourou and Donna Strickland.

Ashkin was given the prize for “optical tweezers and their application to biological systems”, the committee wrote. Those optical tweezers use lasers to grab particles, atoms, viruses and other living cells.

That in turn allowed for something from science fiction’s dreams: using light to move physical objects around. He found that he could push small particles towards the centre of the beam and hold them there.

As well as being a stunning breakthrough in itself, the discovery led to further work as scientists could use the tweezers to investigate the tiny processes that power the universe. They can grab bacteria without harming them, for instance, allowing Ashkin and other scientists to investigate what the committee called the “machinery of life”.

Mourou and Strickland allowed mankind to create the shortest and most intense laser pulses ever seen. With a technique called chirped pulse amplification, or CPA, they allowed for high-intensity lasers, of the kind that are used today millions of times to carry out corrective eye surgeries.

Their discoveries also laid the foundation for the work done by Ashkin. And the full implications of their work have still not yet been found.

“The innumerable areas of application have not yet been completely explored,” the committee wrote. “However, even now these celebrated inventions allow us to rummage around in the microworld in the best spirit of Alfred Nobel – for the greatest benefit to humankind.”

Strickland is the first woman to be named a Nobel laureate since 2015. She is also only the third to have won the physics prize, with the first being Marie Curie in 1903.

Nobel Prize Awarded for Quantum Topology

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Topology is used to study the properties of objects such as this trefoil knot.

 

Topology is used to study the properties of objects such as this trefoil knot.

Three physicists were awarded the Nobel Prize in Physics today for rewriting our understanding of exotic quantum states on the surfaces of materials. Their work explains the behavior of superconductors and superfluids by connecting these systems to topology, the mathematical study of spatial properties including surfaces.

Half of the prize goes to David J. Thouless, a physicist at the University of Washington in Seattle, while the other half will be split between J. Michael Kosterlitz, a physicist at Brown University, and F. Duncan M. Haldane, a physicist at Princeton University. All three were born in the United Kingdom and later moved to the United States.

Superconductors are materials that can carry a current without any electrical resistance. Scientists first described them in the early 20th century; by the middle of the century they had developed a quantum-based theory of how many superconductors behave. But puzzles remained.

For example, in 1980 the experimental physicist Klaus von Klitzingdiscovered the quantum Hall effect, a strange phenomenon whereby the conductance of a flat sheet of material, when cooled close to absolute zero and placed in a strong magnetic field, changes in a step-wise fashion. As the magnetic field changes, the material’s conductance jumps from value to value. The behavior couldn’t be explained by physicists at the time.

A few years later, Thouless described the quantum Hall effect by combining quantum theory with concepts borrowed from topology. This field of mathematics studies the properties of objects that remain constant even if the object is twisted or deformed, but not torn apart. For example, a doughnut and a picture frame appear different but are topologically the same, as each has one hole in the center. Importantly, objects can only have integer numbers of holes — zero, one or two, for example, but never a hole and a half. In the same way, Thouless realized that the electrons inside the conducting material couldn’t be viewed as individual entities; instead they had to be approached as a single collection that could only take on integer values of conductance — zero, one or two, but never one and a half. Thouless, Haldane and Kosterlitz pioneered the mathematical description of quantum materials in thin films and in one-dimensional objects (such as a chain of atoms) by borrowing concepts such as this one from topology.

This work has since been applied to disparate systems from magnetic tape to quantum computers. “The breakthroughs of these three scientists allowed massive progress to be made in understanding and calculating the properties of many material systems. In my own case it opened up 25 years of research into magnetic thin films — which is what computer hard drives store information on,” said Steve Bramwell, a physicist at University College London, in an interview with the Guardian. Haldane alluded to some of these applications this morning. “I was, as everyone else is, very surprised. And very gratified,” he said. “A lot of tremendous new discoveries that are based on this original work are now happening.”

What can a graphene sandwich reveal about proteins?

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Stronger than steel, but only one atom thick – latest research using the 2D miracle material graphene could be the key to unlocking the mysteries around the structure and behaviour of proteins in the very near future.

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Scientists at The University of Manchester and the SuperSTEM facility, which is located at STFC’s Daresbury Laboratory and funded by the Engineering and Physical Sciences Research Council (EPSRC), have discovered that the most fragile, microscopic materials can be protected from the harmful effects of radiation when under the microscope if they are ‘sandwiched’ between two sheets of . The technique could soon be the key to enabling the direct study of every single individual atom in a , something yet to be achieved, and revolutionise our understanding of cell structure, how the immune system reacts to viruses and aid in the design of new antiviral drugs.

Observing the structure of some the tiniest of objects, such as proteins and other sensitive 2D materials, at the atomic scale requires a powerful electron microscope. This is exceptionally difficult because the radiation from the can destroy the highly fragile object being imaged before any useful data can be accurately recorded. However, by protecting fragile objects between two sheets of graphene it means they can be imaged for longer without damage under the electron beam, making it possible to quantitatively identify every single atom within the structure. This technique has proven very successful on the test case of a fragile in-organic 2D crystal and the results published in the journal ACS Nano.

During this research, the team of scientists, which included Sir Kostya Novoselov, who shared a Nobel Prize in Physics in 2010 for exploiting the remarkable properties of graphene, were able to observe the effects of encapsulating a microscopic crystal of another highly fragile 2D material, molybdenum di-sulfide, between two sheets of graphene. They found that they were able to apply a high electron beam to directly image, identify and obtain complete chemical analysis of each and every atom within the molybdenum di-sulfide sheet, without causing any defects to the material through radiation.

The University of Manchester’s Dr Recep Zan, who led the research team, said: “Graphene is a million times thinner than paper, yet stronger than steel, with fantastic potential in areas from electronics to energy. But this research shows its potential in biochemistry could also be just as significant, and could eventually open up all sorts of applications in the biotechnology arena.”

Professor Quentin Ramasse, Scientific Director at SuperSTEM added: “What this research demonstrates is not so much about graphene itself, but how it can impact the detail and accuracy at which we can directly study other inorganic 2D materials or highly fragile molecules. Until now this has mostly been possible through less direct and often complicated methods such as protein crystallography which do not provide a direct visualisation of the object in question. This new capability is particularly exciting because it could pave the way to being able to image every single atom in a protein chain for example, something which could significantly impact our development of treatments for conditions such as cancer, Alzheimer’s and HIV.”

Grossly warped ‘nanographene’.

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Chemists at Boston College and Nagoya University in Japan have synthesized the first example of a new form of carbon, the team reports in the most recent online edition of the journal Nature Chemistry.

nanographene

The new material consists of multiple identical pieces of grossly warped graphene, each containing exactly 80 carbon atoms joined together in a network of 26 rings, with 30 hydrogen atoms decorating the rim. Because they measure slightly more than a nanometer across, these individual molecules are referred to generically as “nanocarbons,” or more specifically in this case as “grossly warped nanographenes.”

Until recently, scientists had identified only two forms of pure carbon: diamond and graphite. Then in 1985, chemists were stunned by the discovery that carbon atoms could also join together to form hollow balls, known as fullerenes. Since then, scientists have also learned how to make long, ultra-thin, hollow tubes of carbon atoms, known as carbon nanotubes, and large flat single sheets of carbon atoms, known as graphene. The discovery of fullerenes was awarded the Nobel Prize in Chemistry in 1996, and the preparation of graphene was awarded the Nobel Prize in Physics in 2010.

Graphene sheets prefer planar, 2-dimensional geometries as a consequence of the hexagonal, chicken wire-like, arrangements of trigonal carbon atoms comprising their two-dimensional networks. The new form of carbon just reported in Nature Chemistry, however, is wildly distorted from planarity as a consequence of the presence of five 7-membered rings and one 5-membered ring embedded in the hexagonal lattice of carbon atoms.

Odd-membered-ring defects such as these not only distort the sheets of atoms away from planarity, they also alter the physical, optical, and electronic properties of the material, according to one of the principle authors, Lawrence T. Scott, the Jim and Louise Vanderslice and Family Professor of Chemistry at Boston College.

“Our new grossly warped nanographene is dramatically more soluble than a planar nanographene of comparable size,” said Scott, “and the two differ significantly in color, as well. Electrochemical measurements revealed that the planar and the warped nanographenes are equally easily oxidized, but the warped nanographene is more difficult to reduce.”

Graphene has been highly touted as a revolutionary material for nanoscale electronics. By introducing multiple odd-membered ring defects into the graphene lattice, Scott and his collaborators have experimentally demonstrated that the electronic properties of graphene can be modified in a predictable manner through precisely controlled chemical synthesis.

Source: http://machineslikeus.com