Quantum state redistribution based on a generalized decoupling

We develop a simple protocol for a one-shot version of quantum state redistribution, which is the most general two-terminal source coding problem. The protocol is simplified from a combination of protocols for the fully quantum reverse Shannon and fully quantum Slepian-Wolf problems, with its time-reversal symmetry being apparent. When the protocol is applied to the case where the redistributed states have a tensor power structure, more natural resource rates are obtained

Evaluation of ECMWF medium-range ensemble forecasts of precipitation for river basins

Providing probabilistic forecasts using Ensemble Prediction Systems has become increasingly popular in both the meteorological and hydrological communities. Compared to conventional deterministic forecasts, probabilistic forecasts may provide more reliable forecasts of a few hours to a number of days ahead, and hence are regarded as better tools for taking uncertainties into consideration and hedging against weather risks. It is essential to evaluate performance of raw ensemble forecasts and their potential values in forecasting extreme hydro-meteorological events. This study evaluates ECMWF's medium-range ensemble forecasts of precipitation over the period 1 January 2008 to 30 September 2012 on a selected midlatitude large-scale river basin, the Huai river basin (ca. 270 000 km2) in central-east China. The evaluation unit is sub-basin in order to consider forecast performance in a hydrologically relevant way. The study finds that forecast performance varies with sub-basin properties, between flooding and non-flooding seasons, and with the forecast properties of aggregated time steps and lead times. Although the study does not evaluate any hydrological applications of the ensemble precipitation forecasts, its results have direct implications in hydrological forecasts should these ensemble precipitation forecasts be employed in hydrology

A model of rotating hotspots for 3:2 frequency ratio of HFQPOs in black hole X-ray binaries

We propose a model to explain a puzzling 3:2 frequency ratio of high frequency quasi-periodic oscillations (HFQPOs) in black hole (BH) X-ray binaries, GRO J1655-40, GRS 1915+105 and XTE J1550-564. In our model a non-axisymmetric magnetic coupling (MC) of a rotating black hole (BH) with its surrounding accretion disc coexists with the Blandford-Znajek (BZ) process. The upper frequency is fitted by a rotating hotspot near the inner edge of the disc, which is produced by the energy transferred from the BH to the disc, and the lower frequency is fitted by another rotating hotspot somewhere away from the inner edge of the disc, which arises from the screw instability of the magnetic field on the disc. It turns out that the 3:2 frequency ratio of HFQPOs in these X-ray binaries could be well fitted to the observational data with a much narrower range of the BH spin. In addition, the spectral properties of HFQPOs are discussed. The correlation of HFQPOs with jets from microquasars is contained naturally in our model.Comment: 8 pages, 4 figures. accepted by MNRA

Monoclinic phase in the relaxor-based piezo-/ ferroelectric Pb(Mg1/3_{1/3}Nb2/3)O3_{2/3})O_3-PbTiO3_3 system

A ferroelectric monoclinic phase of space group $Cm$ ($M_A$ type) has been discovered in 0.65Pb(Mg$_{1/3}$Nb$_{2/3})O_3$-0.35PbTiO$_3$ by means of high resolution synchrotron X-ray diffraction. It appears at room temperature in a single crystal previously poled under an electric field of 43 kV/cm applied along the pseudocubic [001] direction, in the region of the phase diagram around the morphotropic phase boundary between the rhombohedral (R3m) and the tetragonal (P4mm) phases. The monoclinic phase has lattice parameters a = 5.692 A, b = 5.679 A, c = 4.050 A and $\beta$ = $90.15^{\circ}$, with the b$_m$-axis oriented along the pseudo-cubic [110] direction . It is similar to the monoclinic phase observed in PbZr$_{1-x}$Ti$_x$O$_3$, but different from that recently found in Pb(Zn$_{1/3}$Nb$_{2/3})O_3$-PbTiO$_3$, which is of space group $Pm$ ($M_C$ type).Comment: Revised version after referees' comments. PDF file. 6 pages, 4 figures embedde

Momentum Distribution of Near-Zero-Energy Photoelectrons in the Strong-Field Tunneling Ionization in the Long Wavelength Limit

We investigate the ionization dynamics of Argon atoms irradiated by an ultrashort intense laser of a wavelength up to 3100 nm, addressing the momentum distribution of the photoelectrons with near-zero-energy. We find a surprising accumulation in the momentum distribution corresponding to meV energy and a \textquotedblleft V"-like structure at the slightly larger transverse momenta. Semiclassical simulations indicate the crucial role of the Coulomb attraction between the escaping electron and the remaining ion at extremely large distance. Tracing back classical trajectories, we find the tunneling electrons born in a certain window of the field phase and transverse velocity are responsible for the striking accumulation. Our theoretical results are consistent with recent meV-resolved high-precision measurements.Comment: 5 pages, 4 figure