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Blog – Page 9,574

Some call it a SASER and others call it a PHASER.

How do you whisper to someone across the room? With lasers, of course. MIT has developed a system using lasers to transmit audio signals directly to the ear, and no one else in the area can hear them. As a nice bonus, the laser won’t burn your skin or eyes should you turn your head at the wrong moment.

The laser system leverages what is known as the photoacoustic effect. That simply means that the absorption of light waves by a material produces sound waves. In this case, the light is absorbed by water molecules in the air, but the researchers learned to very carefully tune the laser to control where the sound appears. It’s essentially a narrow cone of sound.

Making sound with a laser is one thing, but creating specific tones or transmitting a message is much harder. The team evaluated two methods for doing this. First, there’s the laser sweeping technique, which involves altering the wavelength of light to create different sounds. The traditional photoacoustic method uses varying power to encode a message.

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Three newly discovered worlds are among the smallest and nearest we’ve ever detected.

NASA’s Transiting Exoplanet Survey Satellite, or TESS — a super-powerful orbiting telescope designed to hunt for alien worlds — found the planets orbiting a star just 73 light-years away.

One is a rocky “super-Earth” that’s more massive than our home planet but lighter than giants like Neptune. The other two are icy “sub-Neptunes” that are about half the size of Neptune.

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A small, portable breath monitor can quickly and accurately detect acute respiratory distress syndrome, researchers report.

Acute respiratory distress syndrome (ARDS) is an often deadly disease that causes fluid to leak into the lungs and demands early diagnosis.

To detect the condition today, doctors rely heavily on their own judgment and time-consuming tests. The researchers say their new technology could improve survival rates and lower the cost of care.

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This week’s podcast features an interview with Ray LaPierre, who heads up the department of engineering physics at McMaster University in Canada. Ray talks to fellow Canadian Hamish Johnston about his research in semiconductor nanowires, in particular for use in photonics and quantum computers, and also shares his experiences of working at JDS Uniphase during the telecoms boom.

Physics World’s Anna Demming also joins the podcast to describe a flurry of new results in the emerging field of twistronics – where two layers of graphene are stacked on top of each other but twisted at a slight angle to each other. The discovery last year that bilayer graphene can become a superconductor if the two graphene layers are twisted at the so-called magic angle of 1.1º won Physics World’s 2018 Breakthrough of the Year, and since then the race has been on to investigate other angle-dependent properties of twisted bilayer graphene. Anna describes how different research teams are now trying to work out what causes these intriguing effects.

We also talk to industry editor Margaret Harris about the importance of technology and engineering for scientific progress. Margaret shares her own “light-bulb” moment, when she realized that new laser technology could have saved hours of experimental time during her PhD, and also highlights several articles in the latest Physics World Focus on Instruments and Vacuum that highlight how breakthrough scientific discoveries rely on developments in the enabling technologies – including the first images of a black hole that were revealed in April.

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Atish Dabholkar, a theoretical physicist from India, has been appointed as the new director of Abdus Salam International Centre for Theoretical Physics (ICTP) in Trieste, Italy.

He is currently the head of ICTP’s high energy, cosmology and astroparticle physics section. He joined the centre in 2014 on secondment from Sorbonne Université and the National Center for Scientific Research, where he has been a research director since 2007. Mr. Dabholkar will take up his duties as ICTP director with the rank of Assistant Director General of the United Nations Educational, Scientific and Cultural Organization (UNESCO). He will succeed Fernando Quevedo, who has led the centre since 2009.

“It’s an honour and a great responsibility to be chosen as ICTP’s next director. ICTP is a one-of-a-kind institution with a very high level of research and a unique global mission for international cooperation through science. It was envisioned as an international hub for excellence in science and as an anchor to build scientific capacity and a culture of science around the globe. This vision remains valid today even after five decades, but needs to be implemented keeping in mind changing realities and priorities,” he said in a statement.

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The phenomenon known as “tunneling” is one of the best-known predictions of quantum physics, because it so dramatically confounds our classical intuition for how objects ought to behave. If you create a narrow region of space that a particle would have to have a relatively high energy to enter, classical reasoning tells us that low-energy particles heading toward that region should reflect off the boundary with 100% probability. Instead, there is a tiny chance of finding those particles on the far side of the region, with no loss of energy. It’s as if they simply evaded the “barrier” region by making a “tunnel” through it.

It’s very important to note that this phenomenon is absolutely and unquestionably real, demonstrated in countless ways. The most dramatic of these is sunlight— the Sun wouldn’t be able to fuse hydrogen into helium without quantum tunneling— but it’s also got more down-to-earth technological applications. Tunneling serves as the basis for Scanning Tunneling Microscopy, which uses the tunneling of electrons across a tiny gap between a sharp tip and a surface to produce maps of that surface that can readily resolve single atoms. It’s also essential for the Josephson effect, which is the basis of superconducting detectors of magnetic fields and some of the superconducting systems proposed for quantum computing.

So, there is absolutely no debate among physicists about whether quantum tunneling is a thing that happens. Physicists get a bit twitchy without something to argue over, though, and you don’t have to dig into tunneling (heh) very far to find a disputed question, namely “How long does quantum tunneling take?”

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