Quantum effects could help make twisted bilayer graphene a superconductor

09 Mar 2023 Isabelle Dumé

Measuring tBLG devices: the cryostat insert used in the experiments. (Courtesy: J Lau)

Quantum geometry plays a key role in allowing a material known as twisted bilayer graphene (tBLG) to become a superconductor, according to new experiments by physicists at The Ohio State University, The University of Texas at Dallas, and the National Institute for Materials Science in Japan. The finding implies that the widely employed Bardeen–Cooper–Schrieffer (BCS) equations for superconductors need to be modified for materials like tBLG that have very slow-moving charges. It may also help provide new guiding principles in the search for new superconductors that operate at higher temperatures, say the researchers.

 

Sound mimics gravity in experiment that simulates convection in stars and planets

28 Feb 2023

Radial force: image of the rotating, gas-filled bulb with superimposed lines and arrows showing the convection cells. (Courtesy: J Koulakis et al/Physical Review LettersI/i>)

Sound waves have been used in the lab to mimic the role that gravity plays in driving convection in huge rotating bodies such as stars and planets. The new experiment was created by Seth Putterman and colleagues at the University of California Los Angeles and it allowed the researchers to create gravity-driven circulation patterns.

 

Evidence for ‘near-ambient’ superconductivity found in lutetium hydride

08 Mar 2023 Michael Banks

Hot topic: Ranga Dias and colleagues at the Univeristy of Rochester have announced the discovery of a new room-temperature superconductor (Courtesy: Adam Fenster/Univeristy of Rochester)

Superconductivity has been observed at 20 °C (294 K) in a nitrogen-doped lutetium hydride under a pressure of 1 GPa (10 kbar). The material was made and studied by Ranga Dias and colleagues at the University of Rochester in the US, who claim that the finding raises hopes that a material that superconducts at ambient conditions may soon be found.

 

Debris ejected from the DART impact helped give asteroid Dimorphos an extra push

06 Mar 2023

Impact zone: snapshots of the impact taken by Hubble show the evolution of the ejecta streams in the hours and days after DART impacted Dimorphos. (Courtesy: NASA, ESA, STScI, Jian-Yang Li (PSI), Joseph DePasquale (STScI)).

The impact of a spacecraft into the asteroid Dimorphos last year changed the asteroid’s orbital period around its companion asteroid, Didymos, by 33 minutes, with much of the momentum change coming from the ejecta liberated by the impact. That is one of the findings from a quintet of new papers that has now verified the amount by which the impact knocked the 177 m-wide Dimorphos from its orbit.

 

Machine learning joins the search for extra-terrestrial intelligence

02 Mar 2023 Hamish Johnston

In this episode of the Physics World Weekly podcast we meet three scientists who are trying to answer a question that humanity has long pondered: does intelligent life exist elsewhere in the universe?

Peter Ma and Leandro Rizk of the University of Toronto and Cherry Ng of the French National Centre for Scientific Research in Orleans are part of a team that has used machine learning to identify eight potential “technosignatures” in data from the Robert C Byrd Green Bank Telescope. The trio explain how they look for signs of intelligent life in radio-telescope data and how machine learning gives a helping hand.

 

Researchers grow electronics directly inside living tissue

06 Mar 2023 Tami Freeman

A complex cocktail The injectable gel being tested on a microfabricated circuit. (Courtesy: Thor Balkhed)

Interfacing neural tissue with electronics provides a way to investigate the complex electrical signalling characteristics of the nervous system. Implanted electronic devices can also be used to modulate neural circuitry to prevent or treat various diseases. Unfortunately, there’s a fundamental mismatch between rigid electronic substrates and soft tissues that risks damage to delicate living systems.

Researchers in Sweden have come up with a way around this mismatch, by generating electrodes within the body. The team – from Linköping University, Lund University and the University of Gothenburg – has developed a method of creating soft, substrate-free conducting materials directly inside living tissue, using the body’s molecules as triggers.

 

Advanced electron microscopy: new paradigms for studying nanomaterials

23 Feb 2023 Sponsored by IUVSTA

Join the audience for a live webinar at 1 p.m. GMT on 22 March 2023 exploring the progress achieved by electron microscopy instruments and methods to aid the study of nanomaterials

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In this webinar, you will learn about the remarkable progress achieved by electron microscopy instrument to answer applied and basic questions raised by the constantly growing field of nanotechnology.

We will present a series of studies of nano objects (such as molecules, nanoparticles, nanotubes, nanowires) to provide examples on the need to change our views of experiment design, execution and analysis. Previously, it was common to think that electron microscopy as a very useful but qualitative atom resolution imaging tool for materials science. At present, researchers must use these advanced tools in association with physicochemical simulations, machine learning, big data, etc. to target the generation of reliable and quantitatively verified physical models from the measurements.