Proton–boron fusion passes scientific milestone

09 Mar 2023

Team work: researchers in the control room of the Large Helical Device at Japan’s National Institute for Fusion Science in Toki. (Courtesy: TAE Technologies)

Physicists in the US and Japan have observed nuclear fusion between protons and boron-11 atoms in a magnetically confined plasma for the first time. They say that the result demonstrates the potential of proton–boron fusion as a plentiful, economical source of energy. But others caution that the scientific basis for such an energy source remains largely unproven and that huge technical hurdles stand in the way of commercial power plants.

 

Cosmic-ray muons used to create cryptography system

16 Jan 2023

Cosmic rain: Simulation of a particle shower created by a 1 TeV proton hitting the atmosphere 20 km above the Earth. (Courtesy: Dinoj/CC BY 2.5)

The random arrival times of cosmic-ray muons at the Earth’s surface can be used to encode and decode confidential messages – according to Hiroyuki Tanaka at the University of Tokyo. He claims that the new scheme is more secure than other cryptographic systems because it does not require the sender and receiver of a message to exchange a secret key. Having confirmed important aspects of the technology in the lab, he reckons it will be commercially competitive for use over short distances in offices, data centres and private homes.

 

Synthetic skin removes the need for human volunteers in mosquito bite trials

20 Feb 2023 Tami Freeman

Investigating mosquito behaviour Rice University bioengineering graduate student Kevin Janson is developing a hydrogel-based platform that eliminates the need for human volunteers and speeds data analysis in studies of mosquito feeding patterns. (Courtesy: Brandon Martin/Rice University)

Mosquitoes are often considered the world’s most dangerous animal. While feeding on blood through the skin they transmit pathogens that cause deadly diseases such as malaria, dengue, Zika and yellow fever. According to the World Health Organization, mosquito-borne diseases are responsible for more than 700,000 deaths each year.

 

Flashing droplets could shed light on atomic physics and quantum tunnelling

15 Mar 2023

Atomic analogue: when a beam of light is shone into a water droplet, the light is trapped inside. (Courtesy: Javier Tello Marmolejo)

Light waves confined in an evaporating water droplet provide a useful model of the quantum behaviour of atoms, researchers in Sweden and Mexico have discovered. Through a simple experiment, a team led by Javier Marmolejo at the University of Gothenburg has shown how the resonance of light inside droplets of specific sizes can provide robust analogies to atomic energy levels and quantum tunnelling.

 

Interactions between ultracold molecules controlled by physicists

14 Feb 2023

Controlled reaction: artists impression of two identical molecules colliding (left) to create an intermediate complex (centre). The complex sets off an interaction that changes the final state of the molecules (right). (Courtesy: Juliana Park)

A way of colliding ultracold molecules while controlling the rate at which they react has been developed by physicists at the Massachusetts Institute of Technology (MIT) in the US. Researchers at Germany’s Max Planck Institute for Quantum Optics have made a similar discovery using an different experimental technique. Their research opens new pathways for enhanced control of chemical reactions.

 

Coherent correlation imaging tracks fluctuations on the nanoscale

07 Feb 2023

Borderlands: this image shows boundaries between magnetic domains, which shift back and forth in time. The image shows a region that is 700 nm in width. (Courtesy: Christopher Klose / MBI)

Using a new image reconstruction technique, physicists in Germany and the US have made clear and detailed movies of nanoscale fluctuations in a magnetic material. To capture these features, a team led by Christopher Klose at the Max Born Institute, Berlin, used an advanced algorithm to identify correlations in the spatial patterns in multiple X-ray images.

 

Aerogel insulation could provide habitable regions on Mars

18 Jul 2019 Isabelle Dumé

The silica aerogel used in the experiment. Courtesy: Robin Wordsworth/Harvard University

Regions of Mars could be made habitable within decades using current technology. So say researchers at Harvard University, the California Institute of Technology (Caltech) and the University of Edinburgh who suggest warming just certain areas of the planet – using greenhouse-like shields made from silica aerogels – rather than terraforming it entirely.

 

Novel imaging platform reveals the neuronal basis of a drifting mind

22 Mar 2023 Simon Lichtinger

Daydreaming brain A rat engaged in self-referential processing. The image also shows the default mode network as revealed by fMRI. (Courtesy: CC BY 4.0/Shih Lab, Long-Evans rat image provided by Tzu-Hao Harry Chao)

When was the last time you daydreamt? Paying no particular attention to the outside world, engaged in introspection or memory recall, your mental state feels altered. This difference is reflected in global patterns of brain activity – the default mode network (DMN). Identified 20 years ago and the focus of much research activity since, the DMN connects several brain regions through distinct low-frequency oscillations.

 

An expanding universe is simulated in a quantum droplet

22 Mar 2023 Campbell McLauchlan

Big and small: illustration of how a tiny Bose–Einstein condensate has been used to simulate the expansion of space that occurred moments after the Big Bang. (Courtesy: Campbell McLauchlan)

Unfortunately for the field of cosmology, there is only one universe. This makes performing experiments in the same way as other scientific fields quite a challenge. But it turns out that the universe and the quantum fields that permeate it are highly analogous to quantum fluids like Bose–Einstein condensates (BECs), at least from a mathematical point of view. These fluids can be the subject of experiments, allowing cosmology to be studied in the lab.

 

Gravitational waves from merging black holes go nonlinear

21 Mar 2023

Soon to be ringing: artist’s impression of two black holes that are about to merge. (Courtesy: NASA)

Two independent teams have shown that gravitational waves emanating from the distorted remnants of black hole mergers should interact with themselves. By including these nonlinear effects in their models, one team, led by Keefe Mitman at Caltech, found they could replicate gravitational wave signals from simulated “ringing” black holes up to 100 times more accurately than previous approaches. The other team came to a similar conclusion and was led by Mark Ho-Yeuk Cheung at Johns Hopkins University

 

Black holes destroy nearby quantum superpositions, thought experiment reveals

02 Mar 2023

Killing horizon: a thought experiment suggests that the presence of a black hole can decohere a quantum superposition. (Courtesy: Shutterstock/Rost9)

A new thought experiment suggests that the mere presence of a black hole can destroy a nearby quantum spatial superposition. Developed by physicists in the US, the experiment implies that the long-range gravitational field of the particle in the superposition will interact with the black hole’s event horizon, causing cause the quantum superposition to decohere within finite time.

 

Breakthrough in quantum error correction could lead to large-scale quantum computers

20 Mar 2023

Surface code: illustration of how error correction works for bit and phase flips. The measure qubits on light blue backgrounds check for phase flip errors while the measure qubits on dark blue backgrounds check for bit flip errors. In this example the measure qubits on reddish backgrounds are registering the errors. (Courtesy: Google Quantum AI)

Researchers at Google Quantum AI have made an important breakthrough in the development of quantum error correction, a technique that is considered essential for building large-scale quantum computers that can solve practical problems. The team showed that computational error rates can be reduced by increasing the number of quantum bits (qubits) used to perform quantum error correction. This result is an important step towards creating fault-tolerant quantum computers.

 

Laser interferometry moves closer to shot-noise-limited measurements

13 Mar 2023 Isabelle Dumé

Mapping thermomechanical resonance: thermomechanical modes in a calcium niobate resonator device. (Courtesy: Chinese Phys. Lett. 10.1088/0256-307X/40/3/038102)

Researchers have moved a step closer to achieving quantum-noise-limited measurements using laser interferometry – a technique routinely employed for detecting the motion and displacement of tiny objects such as nanomechanical resonators with ultrasensitive precision. By reducing the contribution of all noises other than shot noise from 92.6% to 62.4%, they achieved a displacement sensitivity of 1.2 fm/Hz1/2. The team says that this is the best value reported to date for any resonator based on two-dimensional (2D) materials using interferometry.

 

Photoexcited electrons from fullerene help create high-speed switch

20 Mar 2023 Isabelle Dumé

Fullerene switch: artist’s rendering of a fullerene switch with incoming electron and red laser light pulses. (Courtesy: ©2023 Yanagisawa et al.)

Light-induced electron emissions from fullerene, a carbon-based molecule, can be used to make an ultrafast switch. The new device, developed by a team headed up at the University of Tokyo, Japan, has a switching speed that’s four to five orders of magnitude faster than that of current solid-state transistors used in modern-day computers. The path of the electrons produced from the emission sites in the molecule can be controlled on the sub-nanometre scale using pulses of laser light.

 

Colloidal mixture exists in up to six phases at once

14 Feb 2023 Isabelle Dumé

Two-phase equilibrium: A binary colloidal mixture can exist in up to six phases at the same time. (Courtesy: R Tuiner)

A binary colloidal mixture can exist in up to six phases at the same time, according to new theoretical work by researchers in the Netherlands and France. The result, obtained using a simple algebraic model, has applications for predicting the phase stability of common colloidal materials such as paint and mayonnaise.

Tried our cryptic medical-physics word search? Here’s the solution

01 Mar 2023

How well do you know your medical physics? Here are the answers to our cryptic word search, created by Ian Randall.

Answers

Wireless put hit music in pronoun, killing cancer cells [RADIOTHERAPY]

Exposure measurement? Note sounds like beautiful proportion [DOSIMETRY]

Particle physicists rarely order tapas or nachos, initially [PROTON]

 

Friction at the microscale depends unexpectedly on sliding speed

02 Feb 2023 Isabelle Dumé

Speed-dependent friction. (Courtesy: Department of Physics, University of Basel and Scixel)

Friction at the atomic scale appears to depend on the speed at which two surfaces move past each other. This surprising behaviour was observed as the tip of an atomic force microscope (AFM) moves along a graphene coating, and researchers at the universities of Basel in Switzerland and Tel Aviv in Israel say it results from surface corrugation induced by a mismatch in graphene’s lattice structure. The finding, together with observations that the frictional force scales differently in different velocity regimes, could have applications in devices such as hard disks and moving components in satellites or space telescopes that require ultralow friction.

 

From barren sands to extreme architecture: building the first Martian metropolis

15 Mar 2023

Ian Randall reviews The First City on Mars: an Urban Planner’s Guide to Settling the Red Planet by Justin Hollander

Fast and furious Justin Hollander’s book is a whistle-stop tour of the particular demands of settling on Mars. (Courtesy: NASA)

Much has been written on the history and immediate future of space exploration – particularly with regard to the present race to put the first humans on Mars. So, it is refreshing to take a more long-term, forward-looking perspective on the subject, with urban planning expert Justin Hollander in his new book, The First City on Mars: an Urban Planner’s Guide to Settling the Red Planet.

 

Hydrogel helps grow new tissue in areas of brain damage

10 Mar 2023 Tami Freeman

Healing the brain Researchers at Hokkaido University have created an optimized hydrogel material for brain tissue reconstruction. (Courtesy: Satoshi Tanikawa et al Scientific Reports)

Brain haemorrhage and brain cancer are major causes of death and disability worldwide. The brain is particularly vulnerable to ischemic damage, in which loss of blood supply leads to the loss of brain tissue volume and the formation of a cavity. And unlike other parts of the body where spontaneous wound healing processes occurs, loss of neuronal tissue is irreversible.

 

Personalized approach improves cervical cancer treatment

14 Mar 2023 Serene Pauly

Brachytherapy afterloader Brachytherapy plays a key role in the treatment of locally advanced cervical cancer. (Courtesy: Elekta)

Cervical cancer is the fourth most common cancer among women globally. According to the World Health Organization, there were an estimated 604 000 new cases and 342 000 deaths in 2020. While surgery and chemotherapy can be used to treat early-stage disease, locally advanced cervical cancer is typically managed with a combination of chemoradiation and brachytherapy.

 

Real-time monitoring of brain tissue oxygenation could personalize radiotherapy

16 Mar 2023

Tracking oxygenation A functional near-infrared spectroscopy device attached to the patient’s forehead measures changes in haemoglobin and tissue oxygenation levels as the patient receives a dose of radiation. (Courtesy: T Myllylä et al J. Biomed. Opt. 10.1117/1.JBO.28.1.015002)

Blood flow and oxygen supply to tumours change over the first few weeks of radiotherapy. Scientists currently believe that reoxygenation occurs due to tumour shrinkage, decreased oxygen consumption and increased perfusion. Clinicians hope that these and other possible changes might be exploited to improve a patient’s response to radiation therapy.

 

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

Want to take part in this webinar?

Join the audience

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.