Every Sunday physics news of the week takes a look at the top physics news published throughout the week. So here are the top 3 news stories, plus some additional links. If you would like to receive these news straight to your email, please register for our email newsletter.
Accelerators are invaluable tools in many different fields of physics, however, they are big and expensive. Probably the best known example is, of course, the Large Hadron Collider, which is home for the big discovery of the Higgs boson. Now imagine an accelerator as small as a football stadium, or even smaller, that could achieve the same results as the Large Hadron Collider. That could be possible with laser-plasma accelerators, which scientists have been trying to build for two decades.
A new theoretical study predicts that building such accelerators may be easier than previously thought. The authors are Carlo Benedetti, Carl Schroeder, Eric Esarey, and Wim Leemans, physicists at Lawrence Berkeley National Laboratory’s Berkeley Lab Laser Accelerator (BELLA) Center. The laser-plasma accelerators described in their paper work by blasting a powerful laser beam into a plasma, a cloud of unattached electrons and ions. “Imagine that the plasma is the lake and the laser is the motorboat. When the laser plows through the plasma, the pressure created by its photons pushes the electrons out of the way. They wind up surfing the wake, or wakefield, created by the laser as it moves down the accelerator,” said Wim Leemans. If the models turns out to be correct, the price and size of accelerators and many medical applications could be reduced significantly.
Particle accelerators are about to get much smaller
Scientists are working hard to come up with a working theory of quantum gravity. That, of course, requires experimental studies of gravity in extreme situations, where quantum effects become significant.
In a new proposed experiment in this area, two toaster-sized “nanosatellites” carrying entangled condensates orbit around the Earth, until one of them moves to a different orbit with a different gravitational field strength. As a result of the change in gravity, the entanglement between the condensates is predicted to degrade by up to 20%. “Our work shows that it is possible to test gravitational effects, which are thought to affect classical systems at large and very large scales, with genuinely (small) entangled quantum systems. Our results aid the understanding of the effects of relativity on entanglement, an important resource for quantum information processing,” said David Edward Bruschi, the author of the recent paper describing the experiment. The experiment, which may be possible in the near future, could show the right direction for the theoretical physicists working on quantum gravity theories.
University of Pittsburgh researchers have become the first to detect a fundamental particle of light-matter interaction in metals — the exciton. The team of scientists including Hrvoje Petek and a team of physicists and chemists have observed the first excitons by observing how light and matter interact at the surface of a silver crystal.
Excitons, particles of light-matter interaction where light photons become transiently entangled with electrons in molecules and semiconductors, are known to be fundamentally important in processes such as plant photosynthesis and optical communications that are the basis for the Internet and cable TV.