Dielectric mirrors are made of multiple layers of transparent materials, each of which reflects a small fraction of the light that hits it. At a specific layer thickness, the reflected light waves merge and amplify, intensifying the reflection. In earlier dielectric mirrors, the efficiency of the mirror fell as the angle of reflected light increased […]
Helium-3 flows without friction when it is cooled below the superfluid transition temperature of 2.6 millikelvin. In the superfluid state the helium-3 atoms, which are fermions and therefore obey the Pauli exclusion principle, form Cooper pairs which obey Bose statistics. Since the pairs do not have to obey the exclusion principle, they can all occupy […]
The CXB covers a range of photon energies, with a peak around 40 kiloelectron volts (keV). The soft X-ray part of the background – photon energies between about 0.5 and 2 keV – was extensively studied with ROSAT satellite, and most of it has been resolved into individual objects, mostly distant active galactic nuclei (AGN) […]
Allegre, a former director of the Institut de Physique du Globe in Paris, was appointed to the government in June 1997 after a distinguished career as a geophysicist and a long association with the newly-appointed prime minister, Lionel Jospin. His controversial decisions included abandoning plans to build the SOLEIL synchrotron source in France and reducing […]
Klaus Dieter Liss from the European Synchrotron Radiation Facility in Grenoble, France, and colleagues have created a cavity that traps X-ray photons between two thin plates of silicon (Nature 404 371). The cavity is able to select a narrow band of X-ray wavelengths from the broad spectrum emitted by the source, and will also allow […]
Four years ago John Pendry of Imperial College, London, described how a composite copper structure could be used to create a material with negative electric permittivity, and more recently he proposed how the magnetic permeability could be made negative as well. Since the permittivity and permeability describe how the material responds to applied electric and […]
Van der Laan, Carra and Schütz-Gmeineder share the prize for their work on X-ray magnetic dichroism, a technique in which circularly polarized X-rays are used to study magnetic structures. By measuring the difference in the scattering of right- and left-hand-polarized radiation, it is possible to obtain information about the material that cannot be obtained with […]
Stirling is no stranger to Grenoble, having worked at the nearby Institut Laue-Langevin (ILL) neutron source for 14 years, and later chairing the ILL scientific council. He currently uses X-rays from the ESRF and other synchrotron sources to study magnetic structures and phase transitions in magnetic materials. Stirling was also closely involved in the construction […]
“Microlensing is the only way low-mass planets can be detected from the ground,” says Sun Hong Rhie from the University of Notre Dame and a member of MPS team. Rhie and his colleague David Bennett have proposed a space-based observatory called GEST that would use microlensing techniques to search for other low-mass planets. GEST would […]
For ‘short’ races the average speed of a world-record performance declines sharply with increasing distance. However, above a certain distance, the decline is more gentle. For both running and swimming the change in exponent occurs between about 150 and 170 seconds. This corresponds to a change from ‘anaerobic’ respiration – in which the body predominately […]
