Experimental study of non-classicality indicators and extremal quantum correlations in two-qubit states

2011 ◽  
Author(s):  
A. Chiuri ◽  
G. Vallone ◽  
M. Paternostro ◽  
G. Adesso ◽  
P. Mataloni
Keyword(s):  
Experimental Study ◽  
Quantum Correlations ◽  
Qubit States

scholarly journals Extremal quantum correlations: Experimental study with two-qubit states

2011 ◽  
Vol 84 (2) ◽  
Author(s):  
A. Chiuri ◽  
G. Vallone ◽  
M. Paternostro ◽  
P. Mataloni
Keyword(s):  
Experimental Study ◽  
Quantum Correlations ◽  
Qubit States

scholarly journals Quantum correlations of two-qubit states with one maximally mixed marginal

2014 ◽  
Vol 90 (2) ◽  
Author(s):  
Antony Milne ◽  
David Jennings ◽  
Sania Jevtic ◽  
Terry Rudolph
Keyword(s):  
Quantum Correlations ◽  
Qubit States

Local quantum uncertainty and trace distance discord dynamics for two-qubit X states embedded in non-Markovian environment

2018 ◽  
Vol 32 (20) ◽  
pp. 1850218 ◽  
Author(s):  
Youssef Khedif ◽  
Mohammed Daoud
Keyword(s):  
Quantum Correlations ◽  
Trace Distance ◽  
Markovian Environment ◽  
Quantum Uncertainty ◽  
Local Quantum Uncertainty ◽  
Local Quantum ◽  
Limiting Case ◽  
Analytical Expressions ◽  
Qubit States ◽  
Markovian Regime

We investigate the behavior of quantum correlations in some specific Werner-like two-qubit states, where the qubit interacts individually with non-Markovian environment. We employ the local quantum uncertainty and trace distance discord to quantify the amount of quantum correlations between the evolved qubits and the corresponding analytical expressions are derived. For specific values of the parameters characterizing the whole system, the dynamics of quantum correlations exhibits collapse and revival phenomena. The influence of the non-Markovianity is also investigated to analyze the monotonic decay of quantum correlations in the limiting case of Markovian regime. Furthermore, we show that trace distance discord captures quantum correlations that cannot be revealed by local quantum uncertainty in some particular situations.

Quantum correlations in a family of bipartite separable qubit states

2017 ◽  
Vol 16 (3) ◽  
Author(s):  
Chuanmei Xie ◽  
Yimin Liu ◽  
Jianlan Chen ◽  
Zhanjun Zhang
Keyword(s):  
Quantum Correlations ◽  
Qubit States

scholarly journals Intrinsic degree of coherence of two-qubit states and measures of two-particle quantum correlations

2020 ◽  
Vol 37 (4) ◽  
pp. 1224
Author(s):  
Nilakantha Meher ◽  
Abu Saleh Musa Patoary ◽  
Girish Kulkarni ◽  
Anand K. Jha
Keyword(s):  
Quantum Correlations ◽  
Degree Of Coherence ◽  
Qubit States

scholarly journals A recursive approach for geometric quantifiers of quantum correlations in multiqubit Schrödinger cat states

2015 ◽  
Vol 29 (19) ◽  
pp. 1550124 ◽  
Author(s):  
M. Daoud ◽  
R. Ahl Laamara ◽  
S. Seddik
Keyword(s):  
Quantum Discord ◽  
Quantum Correlations ◽  
Correlation Matrices ◽  
Pairwise Correlation ◽  
Logical Qubits ◽  
Schrödinger Cat ◽  
Cat States ◽  
Qubit States ◽  
Symmetric States ◽  
Recursive Relations

A recursive approach to determine the Hilbert–Schmidt measure of pairwise quantum discord in a special class of symmetric states of k qubits is presented. We especially focus on the reduced states of k qubits obtained from a balanced superposition of symmetric n-qubit states (multiqubit Schrödinger cat states) by tracing out n-k particles (k = 2, 3, …, n-1). Two pairing schemes are considered. In the first one, the geometric discord measuring the correlation between one qubit and the parity grouping (k-1) qubits is explicitly derived. This uses recursive relations between the Fano–Bloch correlation matrices associated with subsystems comprising k, k-1, … and two particles. A detailed analysis is given for two-, three- and four-qubit systems. In the second scheme, the subsystem comprising the (k-1) qubits is mapped into a system of two logical qubits. We show that these two bipartition schemes are equivalents in evaluating the pairwise correlation in multiqubits systems. The explicit expressions of classical states presenting zero discord are derived.

THERMAL DISCORD AND NEGATIVITY IN A TWO-SPIN-QUTRIT SYSTEM UNDER DIFFERENT MAGNETIC FIELDS

2013 ◽  
Vol 11 (08) ◽  
pp. 1350070 ◽  
Author(s):  
XIAO-JING LI ◽  
HUI-HUI JI ◽  
XI-WEN HOU
Keyword(s):  
Magnetic Fields ◽  
Quantum Discord ◽  
Strong Field ◽  
Quantum Correlations ◽  
Mixed States ◽  
Classical Correlation ◽  
Lower Temperature ◽  
Qubit States ◽  
Quantum And Classical Correlations

The characterization of quantum discord (QD) has been well understood only for two-qubit states and is little known for mixed states beyond qubits. In this work, thermal quantum discord is studied for a qutrit system in different magnetic fields, where classical correlation and entanglement negativity are calculated for comparison. It is shown that the discord is more robust against temperature than the negativity. For a suitable region of magnetic field and its direction, the discord is non-zero while the negativity is zero. When the system is at a lower temperature, these three quantities, however, display a similar behavior for the varied field and direction, and their discontinuities come from crossovers between different ground states in the system. Moreover, the inequality between the quantum and classical correlations depends upon the system parameters as well as the temperature. In particular, both correlations are equal at a suitable field, direction, and temperature. Remarkably, such an equality remains for a strong field in the antiparallel direction, while both correlations in two-qubit systems are identical for any antiparallel field and temperature. These are useful for quantum information and understanding quantum correlations in qutrit mixed states.

Quantum correlations dynamics of three-qubit states coupled to an XY spin chain: Role of coupling strengths

2017 ◽  
Vol 26 (10) ◽  
pp. 100501 ◽  
Author(s):  
Shao-Ying Yin ◽  
Qing-Xin Liu ◽  
Jie Song ◽  
Xue-Xin Xu ◽  
Ke-Ya Zhou ◽  
...  
Keyword(s):  
Spin Chain ◽  
Quantum Correlations ◽  
Coupling Strengths ◽  
Xy Spin Chain ◽  
Qubit States

Quantum correlations of three-qubit states driven by a classical random external field

2015 ◽  
Vol 90 (3) ◽  
pp. 035103 ◽  
Author(s):  
Youneng Guo ◽  
Maofa Fang ◽  
Shiyang Zhang ◽  
Xiang Liu
Keyword(s):  
External Field ◽  
Quantum Correlations ◽  
Qubit States ◽  
Random External Field
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