Physics

  2010 AUG 31 - (VerticalNews.com) -- According to recent research published in the journal Physical Review D, "We consider the version of QCD in Euclidean Landau gauge in which the restriction to the Gribov region is implemented by a local, renormalizable action. This action depends on the Gribov parameter gamma, with dimensions of (mass)(4), whose value is fixed in terms of Lambda(QCD), by the gap equation, known as the horizon condition, partial derivative Gamma/partial derivative gamma = 0, where Gamma is the quantum effective action. ...read more

  2010 AUG 31 - (VerticalNews.com) -- According to a study from Palaiseau, France, "We report an observation of spectral gain narrowing of a high-order harmonic amplified by a soft-x-ray optical-field-ionized plasma."

  "The temporal coherence and spectral linewidth of both the seeded and unseeded soft-x-ray lasers were experimentally measured using a varying-path-difference interferometer. The results showed that the high-order harmonic is subject to a strong spectral narrowing during its propagation in the plasma amplifier without rebroadening at saturation," wrote F. Tissandier and colleagues ...read more

  2010 AUG 31 - (VerticalNews.com) -- According to recent research published in the journal Physical Review B, "In the quasi-one-dimensional cuprate PrBa2Cu4O8, the Pr cations order antiferromagnetically at 17 K in zero field."

  "Through a combination of magnetic susceptibility, torque magnetometry, specific heat, and interchain transport measurements, the anisotropic temperature-magnetic-field phase diagram associated with this ordering has been mapped out. A low-temperature spin-flop transition in the Pr sublattice is found to occur at the same magnetic field strength and orientation as a dimensional crossover in the ground state of the metallic-CuO chains," wrote X.F. Xu and colleagues, University of Bristol ...read more