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20 nov 2014 17:00

Synopsis: Beer Forms Sudsy Surprise

An investigation of the pub prank “beer tapping” provides a better understanding of gas-driven eruptions that occur in carbonated beverages, as well as in volcanic environments. Published Thu Nov 20, 2014

fisica | physics - spotlighting exceptional research

19 nov 2014 17:00

Synopsis: Magnetoresistance That Doesn’t Stop

A near perfect balance between electrons and holes explains why WTe_{2}’s huge magnetoresistence doesn’t saturate at high fields, reaching 13 million percent at 60 tesla. Published Wed Nov 19, 2014

fisica | physics - spotlighting exceptional research

18 nov 2014 17:00

Synopsis: Quantum Search Gets an Update

A well-known quantum search method, called Grover’s algorithm, has been modified to handle a wider variety of search problems. Published Tue Nov 18, 2014

fisica | physics - spotlighting exceptional research

17 nov 2014 17:00

Synopsis: Unraveling the Vortex

The destruction of a magnetic vortex in a permalloy chip is imaged in real time. Published Mon Nov 17, 2014

fisica | physics - spotlighting exceptional research

17 nov 2014 17:00

Viewpoint: Time Trials for Fundamental Constants

Single-ion clocks yield new limits on how much the proton-to-electron mass ratio and the fine structure constant change over time. Published Mon Nov 17, 2014

fisica | physics - spotlighting exceptional research

14 nov 2014 17:00

Focus: Using Plasma to Manipulate Light

The polarization of an intense laser beam can theoretically be controlled by mixing it with a second beam in a plasma. Published Fri Nov 14, 2014

fisica | physics - spotlighting exceptional research

13 nov 2014 02:00

Reversal of thermal rectification in one-dimensional nonlinear composite system

Using nonequilibrium molecular dynamics simulations, a comprehensive study of the asymmetric heat conduction in the composite system consisting of the Frenkel—Kontorova (FK) model and Fermi—Pasta—Ulam (FPU) model is conducted. The calculated results show that in a larger system, the rectifying direction can be reversed only by adjusting the thermal bias. Moreover, the rectification reversal depends critically on the system size and the properties of the interface. The mechanisms of the two types of asymmetric heat conduction induced by nonlinearity are discussed. Considering the novel asymmetric heat conduction in the system, it may possess possible applications to manage the thermal rectification in situ directionally without re-building the structure.

fisica | chinese physics b latest papers

13 nov 2014 02:00

Localization and recurrence of a quantum walk in a periodic potential on a line

We present a numerical study of a model of quantum walk in a periodic potential on a line. We take the simple view that different potentials have different affects on the way in which the coin state of the walker is changed. For simplicity and definiteness, we assume that the walker's coin state is unaffected at sites without the potential, and rotated in an unbiased way according to the Hadamard matrix at sites with the potential. This is the simplest and most natural model of a quantum walk in a periodic potential with two coins. Six generic cases of such quantum walks are studied numerically. It is found that, of the six cases, four cases display significant localization effect where the walker is confined in the neighborhood of the origin for a sufficiently long time. Associated with such a localization effect is the recurrence of the probability of the walker returning to the neighborhood of the origin.

fisica | chinese physics b latest papers

13 nov 2014 02:00

High- Q cavity based on gradated one-dimensional photonic crystal

A high quality-factor ( Q ) cavity based on a one-dimensional (1D) photonic crystal with gradated elliptical holes was designed using FDTD simulation. Different gradient profiles of the mirror holes were found to correspond to different Q -values of the cavities. A simple strategy is proposed to construct high- Q cavities by using an S-shaped gradient profile for the elliptical holes' minor axes, such as a cosine function or Gaussian function. Using such a strategy, a Q value exceeding two million is obtained with only ten mirror holes in a cavity.

fisica | chinese physics b latest papers

13 nov 2014 02:00

Bi 0.9 Ba 0.1 FeO 3 (BBFO)/La 2/3 Sr 1/3 MnO 3 (LSMO) heterostructures are fabricated on LaAlO 3 (100) substrates by pulsed laser deposition. Giant remnant polarization value (~ 85 μC/cm 2 ) and large saturated magnetization value (~ 12.4 emu/cm 3 ) for BBFO/LSMO heterostructures are demonstrated at room temperature. Mixed ferroelectric domain structures and low leakage current are observed and in favor of enhanced ferroelectric properties in the BBFO/LSMO heterostructures. The magnetic field-dependent magnetization measurements reveal the enhancement in the magnetic moment and improved magnetic hysteresis loop originating from the BBFO/LSMO interface. The heterostructure is proved to be effective in enhancing the ferroelectric and ferromagnetic performances in multiferroic BFO films at room temperature.

fisica | chinese physics b latest papers