Measurement-Based Quantum Correlations for Quantum Information Processing

Multiple quantum (MQ) NMR is an effective tool for the generation of a large cluster of correlated particles, which, in turn, represent a basis for quantum information processing devices. Studying the available exactly solvable models clarifies many aspects of the quantum information. In this study, we consider two exactly solvable models in the MQ NMR experiment: (i) the isolated system of two spin- particles (dimers) and (ii) the large system of equivalent spin- particles in a nanopore. The former model is used to describe the quantum correlations and their relations with the MQ NMR coherences, whereas the latter helps one to model the creation and decay of large clusters of correlated particles.

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Measurement-induced nonlocality in the two-qubit Heisenberg XY model

International Journal of Modern Physics B ◽

10.1142/s0217979215500988 ◽

2015 ◽

Vol 29 (15) ◽

pp. 1550098 ◽

Cited By ~ 8

Author(s):

Wen-Xue Chen ◽

Yu-Xia Xie ◽

Xiao-Qiang Xi

Keyword(s):

Magnetic Field ◽

Information Processing ◽

Quantum Information ◽

External Magnetic Field ◽

Potential Application ◽

Quantum Correlation ◽

Quantum Information Processing ◽

Quantum Correlations ◽

Xy Model ◽

Anisotropic Parameter

Quantum correlations are essential for quantum information processing (QIP). Measurement-induced nonlocality (MIN) is a good measure of quantum correlation, and is favored for its conceptual implication and potential application. We investigated here the particular behaviors of the geometric and entropic measures of MIN in the two-qubit Heisenberg XY model and revealed the effects of anisotropic parameter γ and the external magnetic field B on them. Our results showed that both γ and B can serve as efficient controlling parameters for tuning MIN in the XY model.

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DYNAMICAL CONTROL OF QUANTUM CORRELATIONS IN A COMMON ENVIRONMENT

International Journal of Quantum Information ◽

10.1142/s0219749913500123 ◽

2013 ◽

Vol 11 (01) ◽

pp. 1350012 ◽

Cited By ~ 5

Author(s):

HONGTING SONG ◽

YU PAN ◽

ZAIRONG XI

Keyword(s):

Information Processing ◽

Quantum Information ◽

Quantum Information Processing ◽

Quantum Correlations ◽

Quantum Systems ◽

Common Environment ◽

Qubit System ◽

Long Time ◽

Dynamical Control

Quantum correlations (QC) are generally considered to be the crucial resource for quantum information processing, however, in practice, the inevitable interaction of the quantum systems with the environment can cause decoherence and thus destroy the QC. In this paper, by comparatively studying the model of a two-qubit system in a common environment with and without dynamical control, we show that dynamical control can be exploited to protect QC from being completely destroyed for a long time. For certain product states, the dynamical control can even be used to generate the QC.

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Thermal quantum correlations in a two-qubit Heisenberg XYZ model with different magnetic fields

International Journal of Quantum Information ◽

10.1142/s021974991550046x ◽

2015 ◽

Vol 13 (06) ◽

pp. 1550046 ◽

Cited By ~ 1

Author(s):

Zheng Hu ◽

Yu-Chen Wang ◽

Xi-Wen Hou

Keyword(s):

Magnetic Field ◽

Information Processing ◽

Quantum Information ◽

Magnetic Fields ◽

Finite Temperature ◽

Quantum Discord ◽

Quantum Information Processing ◽

Quantum Correlations ◽

Field Coupling ◽

Magnetic Field Coupling

Two kinds of thermal quantum correlations, measured respectively by quantum discord (QD) and the generalized negativity (GN), are studied for various magnetic fields, couplings, and temperatures in a two-qubit Heisenberg XYZ model. It is shown that QD and GN can exhibit a similar behavior in some regions of magnetic field, coupling, and temperature, while they behave in a contrary manner in other regions. For example, QD may increase with suitable magnetic fields, couplings, and temperature when GN decreases. QD is more robust against temperature than GN, and can reveal a kink at a suitable coupling at finite temperature while GN cannot. Moreover, a nearly unchanged QD or GN can be obtained in a large region of magnetic field, coupling, and temperature. These adjustable QD and GN via the varied magnetic field, coupling, and temperature may have significant applications in quantum information processing.

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Quantum information processing by nuclear magnetic resonance on quadrupolar nuclei

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2011.0365 ◽

2012 ◽

Vol 370 (1976) ◽

pp. 4770-4793 ◽

Cited By ~ 7

Author(s):

João Teles ◽

Eduardo R. DeAzevedo ◽

Jair C. C. Freitas ◽

Roberto S. Sarthour ◽

Ivan S. Oliveira ◽

...

Keyword(s):

Nuclear Magnetic Resonance ◽

Information Processing ◽

Quantum Information ◽

Magnetic Resonance ◽

Quantum Information Processing ◽

Quantum Correlations ◽

Quadrupolar Nuclei ◽

Quadrupole Resonance ◽

State Tomography ◽

Nuclear Magnetic

Nuclear magnetic resonance is viewed as an important technique for the implementation of many quantum information algorithms and protocols. Although the most straightforward approach is to use the two-level system composed of spin nuclei as qubits, quadrupolar nuclei, which possess a spin greater than , are being used as an alternative. In this study, we show some unique features of quadrupolar systems for quantum information processing, with an emphasis on the ability to execute efficient quantum state tomography (QST) using only global rotations of the spin system, whose performance is shown in detail. By preparing suitable states and implementing logical operations by numerically optimized pulses together with the QST method, we follow the stepwise execution of Grover's algorithm. We also review some work in the literature concerning the relaxation of pseudo-pure states in spin systems as well as its modelling in both the Redfield and Kraus formalisms. These data are used to discuss differences in the behaviour of the quantum correlations observed for two-qubit systems implemented by spin and quadrupolar spin systems, also presented in the literature. The possibilities and advantages of using nuclear quadrupole resonance experiments for quantum information processing are also discussed.

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