scholarly journals On Amplification of Light in the Continuous EPR State

2003 ◽  
Vol 01 (02) ◽  
pp. 207-215 ◽  
Author(s):  
V. N. Gorbachev ◽  
A. I. Trubilko
Keyword(s):  
Quantum Correlations ◽  
Continuous Variable ◽  
The Other ◽  
Atomic Ensemble ◽  
Transparent Medium ◽  
Integrals Of Motion ◽  
Squeezed Light ◽  
Type Interaction ◽  
Epr State

Two schemes of amplification of two-mode squeezed light in the continuous variable EPR-state are considered. They are based on the integrals of motion, which allow conserving quantum correlations whereas the power of each mode may increase. One of these schemes involves a three-photon parametric process in a nonlinear transparent medium and the other is a Raman type interaction of light with atomic ensemble. A generalization to multimode squeezed light is discussed.

Measure of general quantum correlations in optomechanics

2018 ◽  
Vol 16 (05) ◽  
pp. 1850043 ◽  
Author(s):  
M. Amazioug ◽  
M. Nassik ◽  
N. Habiballah
Keyword(s):  
Bath Temperature ◽  
Quantum Correlations ◽  
Atomic Ensemble ◽  
Thermal Bath ◽  
Optomechanical System ◽  
Optomechanical Systems ◽  
Squeezed Light ◽  
Quantum Steering ◽  
Quantum Equations ◽  
Gaussian Quantum Discord

In this paper, we analyze nonclassical correlations between bipartite states in two optomechanical systems. The first system (Sec. 2) consists of two nanoresonators spatially separated by broadband squeezed light, where each cavity has a fixed mirror and a movable one. The second system (Sec. 3) is an atom-optomechanical system consisting of an atomic ensemble placed inside an optical nanoresonator with a vibrating mirror. For both optomechanical systems, we give the Hamiltonian and the explicit expression of covariance matrix leading to the quantum equations describing the dynamic evolution of the system. Then, the nonclassical correlations are quantified using the logarithmic negativity and Gaussian quantum discord. We propose also a scheme for examining the evolution of Gaussian quantum steering and its asymmetry in each system. We show that the entanglement of the two mechanical modes is very strongly related to the parameters characterizing the environment where the movable mirrors evolve, in particular the squeeze parameter, the optomechanical cooperativity and thermal bath temperature.

Levels of Quantum Correlations in the Continuous Variable Regime: Review and Experimental Illustrations with OPOs

2009 ◽  
Author(s):  
V. D’Auria ◽  
G. Keller ◽  
J. Laurat ◽  
N. Treps ◽  
T. Amri ◽  
...  
Keyword(s):  
Quantum Correlations ◽  
Continuous Variable ◽  
Variable Regime

TRANSMITTING BIPARTITE AND MULTIPARTITE CORRELATIONS VIA SPIN CHAINS UNDER PHASE DECOHERENCE

2012 ◽  
Vol 10 (06) ◽  
pp. 1250073
Author(s):  
JIAN-FENG AI ◽  
JIAN-SONG ZHANG ◽  
AI-XI CHEN
Keyword(s):  
Steady State ◽  
Anisotropy Parameter ◽  
Quantum Correlations ◽  
Spin Chains ◽  
The Other ◽  
Bipartite Entanglement ◽  
Other Hand ◽  
Long Time ◽  
Phase Decoherence ◽  
The One

We investigate the transfer of bipartite (measured by cocurrence) and multipartite (measured by global discord) quantum correlations though spin chains under phase decoherence. The influence of phase decoherence and anisotropy parameter upon quantum correlations transfer is investigated. On the one hand, in the case of no phase decoherence, there is no steady state quantum correlations between spins. On the other hand, if the phase decoherence is larger than zero, the bipartite quantum correlations can be transferred through a Heisenberg XXX chain for a long time and there is steady state bipartite entanglement. For a Heisenberg XX chain, bipartite entanglement between two spins is destroyed completely after a long time. Multipartite quantum correlations of all spins are more robust than bipartite quantum correlations. Thus, one can store multipartite quantum correlations in spin chains for a long time under phase decoherence.

Impact of Albumin-bilirubin (ALBI) score on the Prognostic Significance of Patients with Heart Failure:A Retrospective Cohort Study

2020 ◽  
Author(s):  
Su Han ◽  
Chuanhe Wang ◽  
Fei Tong ◽  
Ying Li ◽  
Zhichao Li ◽  
...  
Keyword(s):  
Hospital Mortality ◽  
Retrospective Cohort ◽  
Poor Prognosis ◽  
Prognostic Significance ◽  
Continuous Variable ◽  
The Other ◽  
Hospital Death ◽  
Net Reclassification Improvement ◽  
C Statistic ◽  
Integrated Discrimination Improvement

Abstract Objectives Liver dysfunction is prevalent in heart failure (HF) patients and it can bring a poor prognosis. Presently, albumin-bilirubin (ALBI) score has been designed as an effective and convenient scoring system for assessing liver function, but the correlation linking ALBI and in-hospital mortality in HF patients remains unclear.Methods and Results A total of 9749 patients with HF (from January 2013 to December 2018) was enrolled and retrospectively analyzed.
The main outcome is in-hospital death. We examined and analyzed ALBI as a continuous variable as well as according to 3 categories. Following adjustment for multivariable, patients which occurred in-hospital death was remarkably elevated in Tertile 3 group (ALBI>-2.27) (OR=1.670, 95% CI: 1.231~2.265, p=0.001), relative to the other two groups (Tertile 1: <-2.59; Tertile 2: -2.59~-2.27). When ALBI was inspected as a continuous variable, the incidence of HF patients with in-hospital death will increase by 8.2%. (For ALBI score per 0.1 score increasing, OR=1.082, 95% CI: 1.052~1.113, p<0.001). ALBI score for estimating in-hospital mortality under C-statistic was 0.650 (95% CI: 0.641~0.660, p<0.001) and the cut-off value of ALBI score was -2.32 with a specificity of 0.630 and a sensitivity of 0.632. Moreover, ALBI score can enhance the estimation potential of NT-proBNP (NT-proBNP+ALBI vs NT-proBNP: C-statistic: z=1.990, p=0.0467; net reclassification improvement=0.4012, p<0.001; integrated discrimination improvement= 0.0082, p<0.001). Conclusions In patients with HF, ALBI score was an independent prognosticator of in-hospital death. The predictive significance of NT-proBNP +ALBI was superior to NT-proBNP, and ALBI score can enhance the estimation potential of NT-proBNP.

scholarly journals Fidelity-based unitary operation-induced quantum correlation for continuous-variable systems

2019 ◽  
Vol 17 (04) ◽  
pp. 1950035
Author(s):  
Liang Liu ◽  
Xiaofei Qi ◽  
Jinchuan Hou
Keyword(s):  
Quantum Correlation ◽  
Quantum Correlations ◽  
Continuous Variable ◽  
Gaussian Channel ◽  
Simple Computation ◽  
Gaussian States ◽  
Text Mode ◽  
Computation Formula ◽  
Geometric Measurement ◽  
Thermal States

We propose a measure of nonclassical correlation [Formula: see text] in terms of local Gaussian unitary operations based on square of the fidelity [Formula: see text] for bipartite continuous-variable systems. This quantity is easier to be calculated or estimated and is a remedy for the local ancilla problem associated with the geometric measurement-induced nonlocality. A simple computation formula of [Formula: see text] for any [Formula: see text]-mode Gaussian states is presented and an estimation of [Formula: see text] for any [Formula: see text]-mode Gaussian states is given. For any [Formula: see text]-mode Gaussian states, [Formula: see text] does not increase after performing a local Gaussian channel on the unmeasured subsystem. Comparing [Formula: see text] in scale with other quantum correlations such as Gaussian geometric discord for two-mode symmetric squeezed thermal states reveals that [Formula: see text] is much better in detecting quantum correlations of Gaussian states.

Risk-sharing and social differentiation of demand in land-tenancy markets in southern Portugal, seventeenth–nineteenth centuries

2006 ◽  
Vol 21 (2) ◽  
pp. 287-312 ◽  
Author(s):  
RUI SANTOS
Keyword(s):  
Nineteenth Century ◽  
Risk Sharing ◽  
Continuous Variable ◽  
The Other ◽  
Social Differentiation ◽  
Land Tenancy ◽  
Southern Portugal ◽  
The One

Theoretical debates about the efficiency of sharecropping discuss risk-sharing in relation to farmers' wealth and credit, as one explanatory factor. This perspective is explored here in the southern Portuguese province of Alentejo, from the seventeenth to the mid-nineteenth century. Three points are made: (1) leasing and sharecropping coexisted on the same land; (2) there was no unequivocal relationship between risk sharing, on the one hand, and the contractual mode of tenancy (fixed-rent or sharecropping), on the other; and (3) relating risk-sharing, defined as a continuous variable, with social differentiation of demand for tenancies provides a rationale for a hypothetical long-term shift in contracts, from medieval sharecropping to fixed-rent tenancies with sharecrop subletting in the nineteenth century.

Steady-state quantum correlation measurement in hybrid optomechanical systems

2020 ◽  
pp. 2050046
Author(s):  
Tesfay Gebremariam Tesfahannes ◽  
Merkebu Dereje Getahune
Keyword(s):  
Correlation Function ◽  
Steady State ◽  
Quantum Entanglement ◽  
Quantum Correlation ◽  
Optical Cavity ◽  
Quantum Correlations ◽  
Correlation Measurement ◽  
Atomic Ensemble ◽  
Optomechanical System ◽  
Optomechanical Systems

In this paper, we investigate the steady-state of quantum correlation measurement of hybrid optomechanical systems. The first system consists of a single optomechanical system simultaneously coupled to a mechanical oscillator. While the second system is a hybrid optomechanical system consisting of an atomic ensemble placed in between the optical cavity and mirror. For both optomechanical systems, we formulate the Hamiltonian and the explicit expression of the covariance matrix leading to the dynamic of the system. Under the linearization approximation, we investigate the steady-state quantum correlations which are quantified through the correlation function of non-Hermitian operators, while the logarithmic negativity is used to quantify the amount of quantum entanglement between the subsystems. Furthermore, our proposed quantum correlation function can be used to quantify the entangled bipartite states that are correlative and transfer information. It is found that the transfer of quantum correlations between the subsystem is related to the detuning and coupling strength. Our results provide a realistic route toward remote quantum entanglement detection and a framework of future realistic fiber-optic quantum network operating applications.

QUANTUM CORRELATIONS IN THE ENTANGLEMENT DISTILLATION PROTOCOLS

2013 ◽  
Vol 11 (03) ◽  
pp. 1350029
Author(s):  
SHAO-XIONG WU ◽  
JUN ZHANG ◽  
CHANG-SHUI YU ◽  
HE-SHAN SONG
Keyword(s):  
Quantum Entanglement ◽  
Quantum Correlation ◽  
Quantum Discord ◽  
Quantum Correlations ◽  
The Other ◽  
Entangled States ◽  
Entanglement Distillation

We study the quantum correlations between source and target pairs in different protocols of entanglement distillation of one kind of entangled states. We find that there does not exist any quantum correlation in the standard recurrence distillation protocol, while quantum discord and even quantum entanglement are always present in the other two cases of the improved distillation protocols. In the three cases, the distillation efficiency improved with the quantum correlations enhanced.

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