Signatures of intrinsic decoherence and weak measurement on quantum correlations

2021 ◽  
Vol 19 (1) ◽  
pp. 015204
Author(s):  
S Bhuvaneswari ◽  
R Muthuganesan ◽  
R Radha

Abstract In this article, we consider a pair of spin-1/2 particles with squeezing coupling serving as the physical carrier of quantum information. We then examine the dynamics of quantum correlation quantified by the entanglement and measurement-induced nonlocality (MIN) under the intrinsic decoherence. The impact of intrinsic decoherence on the dynamical behaviors of quantum correlations is investigated. We show that the MIN quantities are more robust, while intrinsic decoherence cause sudden death in entanglement. Besides, we highlight the role of spin squeezing coupling and external magnetic field on quantum correlation measures. Finally, we investigate the impact of weak measurement on MIN.

2020 ◽  
Vol 35 (29) ◽  
pp. 2050244
Author(s):  
Lu Hou ◽  
Bin Shao ◽  
Yuguang Zhu

We study the quantum speed limit (QSL) time of the two-qubit XYZ spin chain model with the influence of intrinsic decoherence. We show that the intrinsic decoherence can suppress the evolution of this system, no matter what initial states the two qubits start from. The investigation of entanglement reveals that quantum correlation is the physical reason for the acceleration of the system. In addition, we also demonstrate that for different initial states, external magnetic field may have opposite influence on QSL time and it mainly derives from the inhibition of entanglement as magnetic field increases.


2020 ◽  
pp. 48-72
Author(s):  
Graham Scott

Using migration and navigation as a focus, this chapter looks at the movements of birds. The genetic, hormonal, and physiological control of migration is analysed as are the evolution of migratory strategies and routes. Particular emphasis is given to fuelling migration and the significance of stop-over behaviours during migratory movements. The conservation implications of migration and of movement in general are considered, and the impact upon migratory fuelling of neonicotinoids pesticides are discussed. Sections examining innate and learned route finding and the migratory cues (sun, stars, magnetic field, etc) used by birds to determine their location, and the direction in which they need to travel to arrive at a goal, are given. The role of memory in place finding and food storage is considered, as is the neurology of spatial memory. Techniques used by ornithologists to study bird movement are explained throughout the chapter.


2018 ◽  
Vol 32 (31) ◽  
pp. 1850381 ◽  
Author(s):  
Jing Yang ◽  
Qi-Xiong Mu ◽  
Yan-Xia Huang

The dynamics of the tripartite thermal entanglement measured by Negativity (N) and the tripartite quantum correlation described by measurement-induced disturbance (MID) under Ornstein–Uhlenbeck noise are investigated. This study has found that the tripartite N and MID can be preserved more effectively in the non-Markovian environment than in the short-time limit and the Markov limit cases. The short-time limit is a better approximation than the Markov limit. MID vanishes only in the asymptotic limit, while entanglement sudden death may occur, and the decreasing duration of MID far outweighs entanglement. This implies that MID is more robust than Negativity. As the noise bandwidth increases, the disentanglement time and the decay time of MID are significantly shorter. The increase of XZX[Formula: see text]+[Formula: see text]YZY three-site interaction is more effective than XZY−YZX three-site interaction to enhance Negativity and MID as well as the disentanglement time. The magnetic field diminishes Negativity and MID, but has no significant influence on the decreasing durations of both Negativity and MID.


2019 ◽  
Vol 17 (04) ◽  
pp. 1950034
Author(s):  
Weijing Li

A kind of new geometric measure of quantum correlations is formulated. The proposed formulation is in terms of the quantum Tsallis relative entropy and can naturally be viewed as a one-parameter extension quantum discordlike measure that satisfies all requirements of a good measure of quantum correlations. It is of an elegant analytic expression and contains several existing good quantum correlation measures as special cases. The partial coherence measure is also investigated.


2018 ◽  
Vol 25 (03) ◽  
pp. 1850015
Author(s):  
A.-B. A. Mohamed ◽  
M. S. Abdalla ◽  
A.-S. F. Obada

Two two-level systems generated by su(2) algebra are initially prepared in a maximum nonsymmetric Bell state and having no mutual interaction. Each su(2)-system spatially interacts with two-mode cavity field in the nondegenerate parametric amplifier type cast through operators governed by su(1, 1) Lie algebra. An analytical description for the time evolution of the final state of the total system with the effect of intrinsic decoherence is found. Therefore, the robustness of the quantum correlations between the two su(2)-system is investigated by means of geometric quantum discord, measurement-induced nonlocality and negativity. We analyze in some detail the influence of initial coherence intensities, detuning and phase decoherence parameters on the steady-state correlation. We find that the steady-state correlations can be generated and enhanced by controlling the parameters of: the initial coherence intensities, the Bargmman index and the detuning. It is shown that the phenomenon of sudden death and re-birth of entanglement, and the sudden changes of the geometric quantum correlation can be controlled by these parameters. We find that the robustness of the quantum correlation can be greatly enhanced by the Bargmman index and the resonance detuning. Negativity is the measure most susceptible to phase decoherence, while geometric quantum discord and measurement-induced nonlocality are the more robust measures.


Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2441
Author(s):  
Galina Sidorenko ◽  
Mitja Brilly ◽  
Boris Laptev ◽  
Nikolay Gorlenko ◽  
Leonid Antoshkin ◽  
...  

Based on published research on modifying the structure of water and water-containing systems, we assess external influence methods: temperature, magnetic field, light radiation, and their combination. We evaluate changes in the electrophysical, photo- and pH-metric biological, therapeutic, and other properties of water systems using non-destructive electrophysical research methods, i.e., thermometry, pH, laser interference, dynamic light scattering, microelectrophoresis, conductivity, surface tension, dielectric constant, polarimetric measurements, atomic force microscopy, and UV and EPR spectroscopy. The effects of temperature or magnetic field lead to a change in the content and size of water clusters, and physicochemical, biological, therapeutic, and other changes in the properties of water and water-containing systems. The combined effect of a magnetic field and curative mud and the impact of magnetised mineral water have a more pronounced therapeutic effect than only mineral water or curative mud. The data presented indirectly indicate structural changes in water and water-containing systems. We conclude that the primary mechanism of action of a magnetic field, light, or a combination of these factors on water and water-containing systems, including mineral water and therapeutic mud, is a change in the structure of water.


2015 ◽  
Vol 29 (15) ◽  
pp. 1550098 ◽  
Author(s):  
Wen-Xue Chen ◽  
Yu-Xia Xie ◽  
Xiao-Qiang Xi

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.


2015 ◽  
Vol 13 (05) ◽  
pp. 1550035 ◽  
Author(s):  
Wajid Hussain Joyia

We study the quantum correlations in a spin-1/2 (qubit) and spin-1 (qutrit) Heisenberg XY model separately, based on quantum discord (QD) and measurement-induced disturbance (MID) respectively. We find the evidence of the first- and second-order quantum phase transition (QPT) in both spin-1/2 and spin-1 systems. The effect of the temperature, magnetic field and Dzyaloshinskii–Moriya (DM) interactions on QPT and quantum correlation are also investigated. Finally, we observed that the QD and MID are not only vigorous for higher spin systems but also more robust than entanglement.


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