scholarly journals Experimentally Demonstrate the Spin-1 Information Entropic Inequality Based on Simulated Photonic Qutrit States

Entropy ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 219
Author(s):  
Lianzhen Cao ◽  
Xia Liu ◽  
Yang Yang ◽  
Qinwei Zhang ◽  
Jiaqiang Zhao ◽  
...  
Keyword(s):  
Quantum Information ◽  
Quantum Correlation ◽  
Quantum Information Processing ◽  
Quantum Correlations ◽  
Quantum Systems ◽  
Enhancement Effect ◽  
Nonlinear Optical Effect ◽  
Higher Dimensional ◽  
Entropic Inequality ◽  
First Time

Quantum correlations of higher-dimensional systems are an important content of quantum information theory and quantum information application. The quantification of quantum correlation of high-dimensional quantum systems is crucial, but difficult. In this paper, using the second-order nonlinear optical effect and multiphoton interference enhancement effect, we experimentally implement the photonic qutrit states and demonstrate the spin-1 information entropic inequality for the first time to quantitative quantum correlation. Our work shows that information entropy is an important way to quantify quantum correlation and quantum information processing.

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

2015 ◽  
Vol 29 (15) ◽  
pp. 1550098 ◽  
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.

scholarly journals Quantum Reactivity: An Indicator of Quantum Correlation

Entropy ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 6
Author(s):  
Shahabeddin M. Aslmarand ◽  
Warner A. Miller ◽  
Verinder S. Rana ◽  
Paul M. Alsing
Keyword(s):  
Quantum Correlation ◽  
Quantum Discord ◽  
Triangle Inequality ◽  
Singlet State ◽  
Higher Dimensions ◽  
Quantum Correlations ◽  
Information Geometry ◽  
Quantum Systems ◽  
Geometric Quantity ◽  
Higher Dimensional

Geometry is often a valuable guide to complex problems in physics. In this paper, we introduce a novel geometric quantity called quantum reactivity (QR) to probe quantum correlations in higher-dimensional quantum systems. Much like quantum discord, QR is not a measure of quantum entanglement but can be useful in quantum information processes where a notion of quantum correlation in higher dimensions is needed. Both quantum discord and QR are extendable to an arbitrarily large number of qubits; however, unlike discord, QR satisfies the invariance under unitary operations. Our approach parallels Schumacher’s singlet state triangle inequality, which used an information geometry-based entropic distance. We use a generalization of information distance to area, volume, and higher-dimensional volumes and then use these to define a quantity that we call QR, which is the familiar ratio of surface area to volume. We examine a spectrum of multipartite states (Werner, W, GHZ, randomly generated density matrices, etc.) and demonstrate that QR can provide an ordering of these quantum states as to their degree of quantum correlation.

DYNAMICAL CONTROL OF QUANTUM CORRELATIONS IN A COMMON ENVIRONMENT

2013 ◽  
Vol 11 (01) ◽  
pp. 1350012 ◽  
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.

Thermal geometric discords in a two-qutrit system

2016 ◽  
Vol 14 (03) ◽  
pp. 1650016 ◽  
Author(s):  
Ya-Li Yuan ◽  
Xi-Wen Hou
Keyword(s):  
Magnetic Field ◽  
Quantum Information ◽  
Magnetic Fields ◽  
Weak Magnetic Field ◽  
Quantum Discord ◽  
Quantum Information Processing ◽  
Thermal State ◽  
Quantum Correlations ◽  
High Dimensional ◽  
Lower Temperature

The investigation of quantum discord has mostly focused on two-qubit systems due to the complicated minimization involved in quantum discord for high-dimensional states. In this work, three geometric discords are studied for the thermal state in a two-qutrit system with various couplings, external magnetic fields, and temperatures as well, where the entanglement measured in terms of the generalized negativity is calculated for reference. It is shown that three geometric discords are more robust against temperature and magnetic field than the entanglement negativity. However, all four quantities exhibit a similar behavior at lower temperature and weak magnetic field. Remarkably, three geometric discords at finite temperature reveal the phenomenon of double sudden changes at different magnetic fields while the negativity does not. Moreover, the hierarchy among three discords is discussed. Those adjustable discords with the varied coupling, temperature, and magnetic field are useful for the understanding of quantum correlations in high-dimensional states and quantum information processing.

scholarly journals Quantum technologies with hybrid systems

2015 ◽  
Vol 112 (13) ◽  
pp. 3866-3873 ◽  
Author(s):  
Gershon Kurizki ◽  
Patrice Bertet ◽  
Yuimaru Kubo ◽  
Klaus Mølmer ◽  
David Petrosyan ◽  
...  
Keyword(s):  
Quantum Information ◽  
Secure Communication ◽  
Quantum Information Processing ◽  
Quantum Systems ◽  
Quantum States ◽  
Current Direction ◽  
Ongoing Effort ◽  
Hybrid Quantum Systems ◽  
Physical Components

An extensively pursued current direction of research in physics aims at the development of practical technologies that exploit the effects of quantum mechanics. As part of this ongoing effort, devices for quantum information processing, secure communication, and high-precision sensing are being implemented with diverse systems, ranging from photons, atoms, and spins to mesoscopic superconducting and nanomechanical structures. Their physical properties make some of these systems better suited than others for specific tasks; thus, photons are well suited for transmitting quantum information, weakly interacting spins can serve as long-lived quantum memories, and superconducting elements can rapidly process information encoded in their quantum states. A central goal of the envisaged quantum technologies is to develop devices that can simultaneously perform several of these tasks, namely, reliably store, process, and transmit quantum information. Hybrid quantum systems composed of different physical components with complementary functionalities may provide precisely such multitasking capabilities. This article reviews some of the driving theoretical ideas and first experimental realizations of hybrid quantum systems and the opportunities and challenges they present and offers a glance at the near- and long-term perspectives of this fascinating and rapidly expanding field.

scholarly journals Experimental quantification of spatial correlations in quantum dynamics

Quantum ◽  
2018 ◽  
Vol 2 ◽  
pp. 90 ◽  
Author(s):  
Lukas Postler ◽  
Ángel Rivas ◽  
Philipp Schindler ◽  
Alexander Erhard ◽  
Roman Stricker ◽  
...  
Keyword(s):  
Quantum Information ◽  
Quantum Dynamics ◽  
Quantum Information Processing ◽  
Tomographic Reconstruction ◽  
Quantum Systems ◽  
Theoretical Research ◽  
Spatial Correlations ◽  
Correlation Measure ◽  
Quantum Process ◽  
Composite Quantum System

Correlations between different partitions of quantum systems play a central role in a variety of many-body quantum systems, and they have been studied exhaustively in experimental and theoretical research. Here, we investigate dynamical correlations in the time evolution of multiple parts of a composite quantum system. A rigorous measure to quantify correlations in quantum dynamics based on a full tomographic reconstruction of the quantum process has been introduced recently [Á. Rivas et al., New Journal of Physics, 17(6) 062001 (2015).]. In this work, we derive a lower bound for this correlation measure, which does not require full knowledge of the quantum dynamics. Furthermore we also extend the correlation measure to multipartite systems. We directly apply the developed methods to a trapped ion quantum information processor to experimentally characterize the correlations in quantum dynamics for two- and four-qubit systems. The method proposed and demonstrated in this work is scalable, platform-independent and applicable to other composite quantum systems and quantum information processing architectures. We apply the method to estimate spatial correlations in environmental noise processes, which are crucial for the performance of quantum error correction procedures.

scholarly journals Remote State Design for Efficient Quantum Metrology with Separable and Non-Teleporting States

2021 ◽  
Vol 3 (1) ◽  
pp. 228-241
Author(s):  
Rahul Raj ◽  
Shreya Banerjee ◽  
Prasanta K. Panigrahi
Keyword(s):  
Parameter Estimation ◽  
Quantum Information ◽  
Fisher Information ◽  
Quantum Information Processing ◽  
Quantum Fisher Information ◽  
Quantum Correlations ◽  
Quantum States ◽  
Quantum Metrology ◽  
High Quantum ◽  
Non Local

Measurements leading to the collapse of states and the non-local quantum correlations are the key to all applications of quantum mechanics as well as in the studies of quantum foundation. The former is crucial for quantum parameter estimation, which is greatly affected by the physical environment and the measurement scheme itself. Its quantification is necessary to find efficient measurement schemes and circumvent the non-desirable environmental effects. This has led to the intense investigation of quantum metrology, extending the Cramér–Rao bound to the quantum domain through quantum Fisher information. Among all quantum states, the separable ones have the least quantumness; being devoid of the fragile non-local correlations, the component states remain unaffected in local operations performed by any of the parties. Therefore, using these states for the remote design of quantum states with high quantum Fisher information can have diverse applications in quantum information processing; accurate parameter estimation being a prominent example, as the quantum information extraction solely depends on it. Here, we demonstrate that these separable states with the least quantumness can be made extremely useful in parameter estimation tasks, and further show even in the case of the shared channel inflicted with the amplitude damping noise and phase flip noise, there is a gain in Quantum Fisher information (QFI). We subsequently pointed out that the symmetric W states, incapable of perfectly teleporting an unknown quantum state, are highly effective for remotely designing quantum states with high quantum Fisher information.

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