Superconductors are materials that conduct electrical currents without any loss below a certain temperature. Normally, high magnetic fields destroy superconductivity, turning the material into a normal conductor.
Novel experiments on organic superconductors revealed a new superconducting phase between the normal conducting and the superconducting state.
Prof. Peter Fulde from the Max Planck Institute for the Physics of Complex Systems in Dresden and Prof. Richard Ferrell predicted the existence of this special superconducting state in 1964, characterized by a spatial modulation of the superconductivity. At about the same time, two further researchers independently predicted the same phase. Therefore, the state is called Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state.
The methodology behind constructing a quantum channel between Space and Earth got a big boost as a research team, led by Paolo Villoresi and Cesare Barbieri from Padova University, have been able to identify individual returning photons after firing and reflecting them off of a space satellite in orbit almost 1,500 kilometres above the earth.
They say their work improves the feasibility of building a completely secure channel for global communication, via satellites in space, using quantum mechanics.
The research team fired photons directly at the Japanese Ajisai Satellite and have been able to prove that the photons received back at the Matera ground-based station, in southern Italy, are the same as those originally emitted.
Graphene, a single-atom-thick sheet of graphite, is a new material which combines aspects of semiconductors and metals.
University of Maryland physicists have shown that in graphene the intrinsic limit to the mobility, a measure of how well a material conducts electricity, is higher than any other known material at room temperature - and 100 times faster than in silicon.
A team of researchers led by physics professor Michael S. Fuhrer of the university's Center for Nanophysics and Advanced Materials, and the Maryland NanoCenter said the findings are the first measurement of the effect of thermal vibrations on the conduction of electrons in graphene, and show that thermal vibrations have an extraordinarily small effect on the electrons in graphene.
Researchers at the National Institute of Standards and Technology (NIST) have set the stage for building the “evolutionary link” between the microelectronics of today built from semiconductor compounds and future generations of devices made largely from complex organic molecules. In an upcoming paper in the Journal of the American Chemical Society, a NIST team demonstrates that a single layer of organic molecules can be assembled on the same sort of substrate used in conventional microchips.
The ability to use a silicon crystal substrate that is compatible with the industry-standard CMOS (complementary metal oxide semiconductor) manufacturing technology paves the way for hybrid CMOS-molecular device circuitry—the necessary precursor to a “beyond CMOS” totally molecular technology—to be fabricated in the near future.
Side and top views of the NIST molecular resistor. Above are schematics showing a cross-section of the full device and a close-up view of the molecular monolayer attached to the CMOS-compatible silicon substrate. Below is a photomicrograph looking down on an assembled resistor indicating the location of the well. Credit: NIST
Researchers at NIST and the Joint Quantum Institute (NIST/University of Maryland) have developed a new method for creating pairs of entangled photons, particles of light whose properties are interlinked in a very unusual way dictated by the rules of quantum physics. The researchers used the photons to test one of the fundamental concepts in quantum theory.
In the experiment, the researchers sent a pulse of light into both ends of a twisted loop of optical fiber. Pairs of photons of the same color traveling in either direction will, every so often, interact in a process known as “four-wave mixing,” converting into two new, entangled photons, one that is redder and the other that is bluer than the originals.
Three-dimensional view of photon-induced fragmentation of a deuterium molecule, showing the angular distribution of one ejected electron in the plane containing the molecular and light polarization axes. Another escaping electron of the same energy is emitted upwards out of the plane. The direction of the molecular axis is given by the exploding nuclei (in green). Credit: Lawrence Berkeley National Lab
Everyone knows computer chips have increased in speed and shrunk in size over the past few decades and their interconnects, the copper wires that transport signals around the chip and to other chips, have shrunk also. As interconnects get smaller, the copper’s resistance increases and its ability to conduct electricity degrades. This means fewer electrons are able to pass through the copper successfully, and any lingering electrons are expressed as heat. This heat can have negative effects on both a computer chip’s speed and performance.
The $260 billion semiconductor industry won't get too excited just yet but they have to take notice of a Rensselaer Polytechnic Institute study comparing the performance of copper nanowires and carbon nanotube bundles for interconnects. It is the first study to examine copper nanowire using quantum mechanics rather than empirical laws.
As most people following physics research at some level or other will have noticed, physicists love symmetries. In fact, it can be and has been said that all of modern theoretical physics is based on a bunch of symmetry principles from which the rest follows.
While that may be a bit overly reductionist (experimental input plays an important part in the construction of a scientific theory after all), it is certainly true that symmetry considerations play a huge role in the building of our theories. But why is that so? The answer is that there are a number of mathematical theorems that link the existence (or absence) of certain symmetries in the mathematical formulation of a theory to physical features of the reality described by that theory: the laws of nature are constrained by symmetry.
Emmy Noether (1882-1935) (from Wikimedia Commons)
Researchers at the National Institute of Standards and Technology (NIST) and the University of Maryland have developed a new optical method that can detect individual neutrons and record them over a range of intensities at least a hundred times greater than existing detectors.
The new detector, described at the March Meeting of the American Physical Society by Charles Clark, a Fellow of the Joint Quantum Institute of NIST and the University of Maryland, promises to improve existing neutron measurements and enable tests of new phenomena beyond the Standard Model, the basic framework of particle physics.
Neutron absorption by 3He yields tens of Lyman alpha photons, which result from the most fundamental energy jump in the hydrogen atom. This schematic illustrates the operation of a prototype Lyman alpha neutron detector. Credit: NIST
Radio waves accelerate electrons within Jupiter’s magnetic field in the same way as they do on Earth, according to new research. The discovery overturns a theory that has held sway for more than a generation and has important implications for protecting Earth-orbiting satellites.
Using data collected at Jupiter by the Galileo spacecraft, Dr Richard Horne of British Antarctic Survey (BAS) and colleagues from the University of California, Los Angeles, and the University of Iowa found that a special type of very low frequency radio wave is strong enough to accelerate electrons up to very high energies inside Jupiter’s magnetic field.
This week, NASA's Wilkinson Microwave Anisotropy Probe (WMAP) showed off three key findings contained in five years of data:
(1)New evidence that a sea of cosmic neutrinos permeates the universe
(2) Clear evidence the first stars took more than a half-billion years to create a cosmic fog
(3)Tight new constraints on the burst of expansion in the universe's first trillionth of a second
"We are living in an extraordinary time," said Gary Hinshaw of NASA's Goddard Space Flight Center in Greenbelt, Md. "Ours is the first generation in human history to make such detailed and far-reaching measurements of our universe."
WMAP measures the composition of the universe.