scholarly journals Diagnosing steerability of a bipartite state with the nonsteering threshold

2020 ◽  
Vol 102 (1) ◽  
Author(s):  
Xiaohua Wu ◽  
Tao Zhou
Keyword(s):  
Bipartite State

Teleportation of an unknown bipartite state via non-maximally entangled two-particle state

2006 ◽  
Vol 15 (5) ◽  
pp. 915-918 ◽  
Author(s):  
Cao Hai-Jing ◽  
Guo Yan-Qing ◽  
Song He-Shan
Keyword(s):  
Particle State ◽  
Bipartite State

Measurement of quantum correlation by Frobenius norm in non-Markovian system

2018 ◽  
Vol 16 (03) ◽  
pp. 1850022 ◽  
Author(s):  
Juju Hu ◽  
Shuqin Liu ◽  
Yinghua Ji
Keyword(s):  
Density Matrix ◽  
Quantum System ◽  
Quantum Correlation ◽  
Quantum Discord ◽  
Frobenius Norm ◽  
Easy Method ◽  
Test Matrix ◽  
Research Results ◽  
Bipartite State ◽  
Markovian System

In order to measure the quantum correlation of a bipartite state quickly, an easy method is to construct a test matrix through the commutations among the blocks of its density matrix. Then, the Frobenius norm of the test matrix can be used to measure the quantum correlation. In this paper, we apply the measurement by Frobenius norm ([Formula: see text] to the dynamics evolution of the non-Markovian quantum system and compare it with the typical quantum discord ([Formula: see text] proposed by Ollivier and Zurek. The research results show that [Formula: see text] can indeed measure the quantum correlation of a bipartite state as same as [Formula: see text]. Further studies find that there are still differences between the two measurements: in some regions, when [Formula: see text] is zero, [Formula: see text] is not zero. It indicates that [Formula: see text] is more detailed than [Formula: see text] to measure quantum correlation of a bipartite state.

scholarly journals Volumes of conditioned bipartite state spaces

2014 ◽  
Vol 48 (3) ◽  
pp. 035306 ◽  
Author(s):  
Simon Milz ◽  
Walter T Strunz
Keyword(s):  
State Spaces ◽  
Bipartite State

REVIEW ON SYSTEM-SPIN ENVIRONMENT DYNAMICS OF QUANTUM DISCORD

2012 ◽  
Vol 27 (01n03) ◽  
pp. 1345055 ◽  
Author(s):  
BEN-QIONG LIU ◽  
BIN SHAO ◽  
JUN-GANG LI ◽  
JIAN ZOU
Keyword(s):  
Quantum Discord ◽  
Open Systems ◽  
Quantum Phase Transitions ◽  
Physical Models ◽  
Quantum Computers ◽  
Bipartite State ◽  
External Perturbations ◽  
Mathematical Properties ◽  
Spin Pairs ◽  
The Relationship

Recent work has relatively comprehensively studied the quantum discord, which is supposed to account for all the nonclassical correlations present in a bipartite state (including entanglement), and provide computational speedup and quantum enhancement even in separable states. Firstly, we introduce several different indicators of nonclassical correlations, including their definitions and interpretations, mathematical properties, and the relationship between them. Secondly, we review two major topics of quantum discord. One is the remarkable behavior at quantum phase transitions. The pairwise quantum discord for nearest neighbors as well as distant spin pairs can perfectly signal the critical behavior of many physical models, even at finite temperatures. The other is quantum discord dynamics in open systems, especially for "system-spin environment" models. Quantum discord is more robust than entanglement against external perturbations. It can be created, greatly amplified or protected under certain conditions, and presents promising applications in quantum technologies such as quantum computers.

Non-zero discord bipartite state generation via classical second-order interference

2017 ◽  
Author(s):  
Yong-Su Kim ◽  
Yujun Choi ◽  
Hyang-Tag Lim ◽  
Kanghee Hong ◽  
Jiwon Yune ◽  
...  
Keyword(s):  
Second Order ◽  
Bipartite State ◽  
State Generation

scholarly journals ENTANGLEMENT DYNAMICS AND SPIN-SQUEEZING OF THE NONLINEAR TAVIS–CUMMINGS MODEL MEDIATED BY A NONLINEAR BINOMIAL FIELD

2010 ◽  
Vol 08 (06) ◽  
pp. 1023-1044 ◽  
Author(s):  
M. S. ATETO
Keyword(s):  
Nonlinear Medium ◽  
General Rule ◽  
Spin Squeezing ◽  
Space Distribution ◽  
Entanglement Dynamics ◽  
Cavity Field ◽  
Bipartite State ◽  
Cat States ◽  
Insight Into

We show that spin-squeezing implies entanglement for the quantum tripartite state, where the subsystem of the bipartite state is identical. We study the relation between spin-squeezing parameters and entanglement through the quantum entropy of a system, starting initially in a pure state when the cavity is binomial. We show that spin-squeezing can be a convenient tool to give some insight into the subsystems entanglement dynamics when the bipartite subsystem interacts simultaneously with the cavity field subsystem, especially when the interaction occurs off-resonantly without and with a nonlinear medium contained in the cavity field subsystem. We illustrate that, in the case of large off-resonance interaction, spin-squeezing clarifies the properties of entanglement almost with full success. However, it is not a general rule when the cavity is assumed to be filled with a nonlinear medium. In this case, we illustrate that the insight into entanglement dynamics becomes more clear in the case of a weak nonlinear medium than in strong nonlinear medium. In parallel, the role of the phase-space distribution in quantifying entanglement is also studied. The numerical results of Husimi Q-function show that the integer strength of the nonlinear medium produces Schrödinger cat states, which is necessary for quantum entanglement.

scholarly journals UNITARY LOCAL INVARIANCE

2005 ◽  
Vol 03 (04) ◽  
pp. 655-659 ◽  
Author(s):  
MATTEO G. A. PARIS
Keyword(s):  
Singular Values ◽  
Complete Characterization ◽  
Bipartite State ◽  
Local Invariance ◽  
The Matrix ◽  
Pure States

We address unitary local (UL) invariance of bipartite pure states. Given a bipartite state |Ψ〉〉 = ∑ij ψij |i〉1 ⊗ |j〉2 the complete characterization of the class of local unitaries U1 ⊗ U2 for which U1 ⊗ U2|Ψ〉〉 = |Ψ〉〉 is obtained. The two relevant parameters are the rank of the matrix Ψ, [Ψ]ij = ψij, and the number of its equal singular values, i.e. the degeneracy of the eigenvalues of the partial traces of |Ψ〉〉.

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