Entanglement-enhanced measurement of a completely unknown phase

The high-precision interferometric measurement of an unknown phase is the basis for metrology in many areas of science and technology. Quantum entanglement provides an increase in sensitivity, but present techniques have only surpassed the limits of classical interferometry for the measurement of small variations about a known phase. Here we introduce a technique that combines entangled states with an adaptive algorithm to precisely estimate a completely unspecified phase, obtaining more information per photon that is possible classically. We use the technique to make the first ab initio entanglement-enhanced optical phase measurement. This approach will enable rapid, precise determination of unknown phase shifts using interferometry.Comment: 6 pages, 4 figure

Black hole thermodynamics and modified GUP consistent with doubly special relativity

We study the black hole thermodynamics and obtain the correction terms for temperature, entropy, and heat capacity of the Schwarzschild black hole, resulting from the commutation relations in the framework of {\it Modified Generalized Uncertainty Principle} suggested by {\it Doubly Special Relativity}.Comment: 13 pages, 6 figures, minor revision, references adde

Spin-Orbit Coupling and Ion Displacements in Multiferroic TbMnO3

The electronic and magnetic properties of TbMnO3 leading to its ferroelectric (FE) polarization were investigated on the basis of relativistic density functional theory (DFT) calculations. In agreement with experiment, we show that the spin-spiral plane of TbMnO3 can be either the bc- or ab-plane, but not the ac-plane. As for the mechanism of FE polarization, our work reveals that the "pure electronic" model by Katsura, Nagaosa and Balatsky (KNB) is inadequate in predicting the absolute direction of FE polarization. For the ab-plane spin-spiral state of TbMnO3, the direction of FE polarization predicted by the KNB model is opposite to that predicted by DFT calculations. In determining the magnitude and the absolute direction of FE polarization in spin-spiral states, it is found crucial to consider the displacements of the ions from their ecntrosymmetric positions

Percutaneous pulmonary valve implantation in patients with right ventricular outflow tract dysfunction : A systematic review and meta-analysis

Background: Pulmonary valve replacement is required for patients with right ventricular outflow tract (RVOT) dysfunction. Surgical and percutaneous pulmonary valve replacement are the treatment options. Percutaneous pulmonary valve implantation (PPVI) provides a less-invasive therapy for patients. The aim of this study was to evaluate the effectiveness and safety of PPVI and the optimal time for implantation. Methods: We searched PubMed, EMBASE, Clinical Trial, and Google Scholar databases covering the period until May 2018. The primary effectiveness endpoint was the mean RVOT gradient; the secondary endpoints were the pulmonary regurgitation fraction, left and right ventricular end-diastolic and systolic volume indexes, and left ventricular ejection fraction. The safety endpoints were the complication rates. Results: A total of 20 studies with 1246 participants enrolled were conducted. The RVOT gradient decreased significantly [weighted mean difference (WMD) = -19.63 mmHg; 95% confidence interval (CI): -21.15, -18.11; p < 0.001]. The right ventricular end-diastolic volume index (RVEDVi) was improved (WMD = -17.59 ml/m(2); 95% CI: -20.93, -14.24; p < 0.001), but patients with a preoperative RVEDVi >140 ml/m(2) did not reach the normal size. Pulmonary regurgitation fraction (PRF) was notably decreased (WMD = -26.27%, 95% CI: -34.29, -18.25; p < 0.001). The procedure success rate was 99% (95% CI: 98-99), with a stent fracture rate of 5% (95% CI: 4-6), the pooled infective endocarditis rate was 2% (95% CI: 1-4), and the incidence of reintervention was 5% (95% CI: 4-6). Conclusions: In patients with RVOT dysfunction, PPVI can relieve right ventricular remodeling, improving hemodynamic and clinical outcomes

Sound propagation in density wave conductors and the effect of long-range Coulomb interaction

We study theoretically the sound propagation in charge- and spin-density waves in the hydrodynamic regime. First, making use of the method of comoving frame, we construct the stress tensor appropriate for quasi-one dimensional systems within tight-binding approximation. Taking into account the screening effect of the long-range Coulomb interaction, we find that the increase of the sound velocity below the critical temperature is about two orders of magnitude less for longitudinal sound than for transverse one. It is shown that only the transverse sound wave with displacement vector parallel to the chain direction couples to the phason of the density wave, therefore we expect significant electromechanical effect only in this case.Comment: revtex, 14 pages (in preprint form), submitted to PR

Enhanced squeezing with parity kicks

Using exponential quadratic operators, we present a general framework for studying the exact dynamics of system-bath interaction in which the Hamiltonian is described by the quadratic form of bosonic operators. To demonstrate the versatility of the approach, we study how the environment affects the squeezing of quadrature components of the system. We further propose that the squeezing can be enhanced when parity kicks are applied to the system.Comment: 4 pages, 2 figure