Physics

Capturing the coldest atoms in the universe within the confines of a laser beam, University of California, Berkeley, physicists have made a device that can map magnetic fields more precisely than ever before. Doctors now use sensitive magnetic field detectors called SQUIDS to record faint magnetic activity in the brain, while similar detectors are employed in fields ranging from geology to semiconductor manufacturing. One advantage of the new device, which is based on ultra-cold Bose Einstein condensates (BECs), is that it can measure low-frequency fields, such as slow brain waves, at a very…

Physicists at the University of Pittsburgh have demonstrated a new form of matter that melds the characteristics of lasers with those of the world’s best electrical conductors. The work introduces a new method of moving energy from one point to another as well as a low-energy means of producing a light beam like that from a laser. The new state is a solid filled with a collection of energy particles known as polaritons that have been trapped and slowed, explained lead investigator David Snoke, an associate professor in the physics and astronomy department in Pitt’s School of Arts and…

At proper frequencies, air itself can make information transmissions difficult to intercept. Stability of the signal is a problem in applications such as that but researchers at NIST have discovered a technique they say will preserve signals better. Their fiber-optic network that can be tuned across a range of visible and near-infrared frequencies while synchronizing the oscillations of light waves from different sources. The prototype NIST network demonstrates the first remote synchronization of light waves from two "frequency combs"—advanced laboratory tools for precisely measuring…

Combining diamond anvils and powerful lasers, laboratory researchers have developed a technique that should be able to squeeze materials to pressures 100 to 1,000 times greater than possible today, reproducing conditions expected in the cores of supergiant planets. Until now, these pressures have only been available experimentally next to underground nuclear explosions. "This lets us explore a new regime of chemistry and reproduce the conditions of more extreme planets," said Raymond Jeanloz, a professor of astronomy and of earth and planetary science at the University of California,…

Researchers in Italy have created an ultrashort light pulse—a single isolated burst of extreme-ultraviolet light that lasts for only 130 attoseconds (billionths of a billionth of a second). Their achievement currently represents the shortest artificial light pulse that has been reported in a refereed journal. Shining this ultrashort light pulse on atoms and molecules can reveal new details of their inner workings—providing benefits to fundamental science as well as potential industrial applications such as better controlling chemical reactions. Working at Italy's National Laboratory for…

If you’ve ever wondered about the ultimate fate of the universe, Lawrence Krauss and Robert Scherrer have some good news - sort of. In a paper published online on April 25 in the journal Physical Review D, the two physicists show that matter as we know it will remain as the universe expands at an ever-increasing clip. That is, the current status quo between matter and its alter ego, radiation, will continue as the newly discovered force of dark energy pushes the universe apart. "Diamonds may actually be forever," quips Krauss, professor of physics and astronomy at Case Western Reserve…

A Georgia Tech research team has discovered that water exhibits very different properties when it is confined to channels less than two nanometers wide – behaving much like a viscous fluid with a viscosity approaching that of molasses. Determining the properties of water on the nanoscale may prove important for biological and pharmaceutical research as well as nanotechnology. The research appears in the March 15 issue of the journal Physical Review B. Georgia Tech physicists have discovered that water behaves differently when its compressed in nano-sized channel. In these small spaces water…

n experiment called "shining light through walls" would seem hard to improve upon. But University of Florida physicists have proposed a way to do just that, a step they say considerably improves the chance of detecting one of the universe's most elusive particles, a candidate for the common but mysterious dark matter. In the journal Physical Review Letters, physicists at the University of Florida and Lawrence Livermore National Laboratory propose a redesign of the experiment currently being attempted in various forms by several groups of physicists worldwide. Although theoretical at the…

By utilizing ideas developed in disparate fields, from earthquake dynamics to random-field magnets, researchers at the University of Illinois have constructed a model that describes the avalanche-like, phase-slip cascades in the superflow of helium. Just as superconductors have no electrical resistance, superfluids have no viscosity, and can flow freely. Like superconductors, which can be used to measure extremely tiny magnetic fields, superfluids could create a new class of ultra-sensitive rotation sensors for use in precision guidance systems and other applications. But, before new…

Penn State researchers will soon provide he first demonstration of a fundamentally new method for measuring a particular quantum property of individual atoms. "This method allows us to directly and precisely measure the phase shifts that result when ultracold atoms collide, in a way that is independent of the accuracy-limiting density of the atoms," says Kurt Gibble, an associate professor of physics and principal investigator of the Penn State University research team that developed the method. Schematic of the Experiment. We collide a clock atom with atoms in another state (labeled |4, 4…