Disorder overtakes order in information concentration over quantum networks

Prabhu, R.; Pradhan, Saurabh; Sen, Aditi; Sen, Ujjwal

doi:10.1103/physreva.84.042334

Cited by 33 publications

(27 citation statements)

References 119 publications

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“…In addition, adding a constant magnetic field along with the random field, we find that the component of the magnetization perpendicular to the random field gets enhanced due to the disorder, which has also been reported for several other models 17,30,31 .…”

Section: Introductionsupporting

confidence: 85%

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Disorder-induced enhancement and critical scaling of spontaneous magnetization in random-field quantum spin systems

et al. 2016

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We investigate the effect of a unidirectional quenched random field on the anisotropic quantum spin-1/2 XY model, which magnetizes spontaneously in the absence of the random field. We adopt mean-field approach for this analysis. The models considered have in general the Ising symmetry and as such exhibit ferromagnetic order in 2D and 3D in the presence of not too large disorder. Even in the special case when the model without disorder has U (1) symmetry, a small U (1)-symmetry breaking random field induces ferromagnetic long range order in 2D. The mean field approach, consequently, provides a rather good qualitative and even quantitative description, when applied not too close to the criticality. We show that spontaneous magnetization persists even in the presence of the random field but the magnitude of magnetization gets suppressed due to disorder, and the system magnetizes in the directions parallel and transverse to the random field. Our results are obtained by analytical calculations within perturbative framework and by numerical simulations. Interestingly, we show that it is possible to enhance a component of the magnetization in presence of the disorder field provided we apply an additional constant field in the XY plane. Moreover, we derive generalized expressions for the critical temperature and the scalings of the magnetization near the critical point for the XY spin system with arbitrary fixed quantum spin angular momentum.

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Section: Introductionsupporting

confidence: 85%

“…Quenched disorder in type II superconductors have been investigated by using Ginzburg-Landau theory to uncover "glassy" properties in the system 12 . In particular, considerable efforts have been dedicated to understanding the effects of disorder in spin models, both classical and quantum [13][14][15][16][17] .…”

Section: Introductionmentioning

confidence: 99%

Disorder-induced enhancement and critical scaling of spontaneous magnetization in random-field quantum spin systems

et al. 2016

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“…The study of multipartite quantum correlations in this decohered quantum state will require the characterization of a multipartite measure. Though there are known measures of multipartite entanglement [37] which can be computed in large pure quantum states [38], these measures do not uniquely generalize to the mixed state regime. In the following parts we attempt to discuss multipartite quantum correlations that shall prove useful for our study.…”

Section: Multipartite Quantum Correlationsmentioning

confidence: 99%

Enhancing robustness of multiparty quantum correlations using weak measurement

2014

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Multipartite quantum correlations are important resources for the development of quantum information and computation protocols. However, the resourcefulness of multipartite quantum correlations in practical settings is limited by its fragility under decoherence due to environmental interactions. Though there exist protocols to protect bipartite entanglement under decoherence, the implementation of such protocols for multipartite quantum correlations has not been sufficiently explored. Here, we study the effect of local amplitude damping channel on the generalized Greenberger-Horne-Zeilinger state, and use a protocol of optimal reversal quantum weak measurement to protect the multipartite quantum correlations. We observe that the weak measurement reversal protocol enhances the robustness of multipartite quantum correlations. Further it increases the critical damping value that corresponds to entanglement sudden death. To emphasize the efficacy of the technique in protection of multipartite quantum correlation, we investigate two proximately related quantum communication tasks, namely, quantum teleportation in a one sender, many receivers setting and multiparty quantum information splitting, through a local amplitude damping channel. We observe an increase in the average fidelity of both the quantum communication tasks under the weak measurement reversal protocol. The method may prove beneficial, for combating external interactions, in other quantum information tasks using multipartite resources.

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“…Unlike quenched disorder, the universality class of a phase transition is usually not affected by the presence of annealed disorder, as the partition function after averaging over random realizations can be replaced by one corresponding to an effective model which is free from the disorder. In other instances, quenched disorder spin systems have been studied to understand "glassy" properties in type II superconductors 20 , to demonstrate breakdown of thermalization in the presence of disorder 4 , to achieve quantum advantages due to the introduction of the disorder 16 and to explore disorder induced quantum phenomena such as "order from disorder" 16,21 . Significant works have also been carried out for studying the consequences of annealed disorder in the spin systems as well 22,23 .…”

Section: Introductionmentioning

confidence: 99%

Spontaneous magnetization of quantum XY spin model in joint presence of quenched and annealed disorder

et al. 2017

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We investigate equilibrium statistical properties of the quantum XY spin-1/2 model in an external magnetic field when the interaction and field parts are subjected to quenched or/and annealed disorder. The randomness present in the system are termed annealed or quenched depending on the relation between two different time scales -the time scale associated with the equilibriation of the randomness and the time of observation. Within a mean-field framework, we study the effects of disorders on spontaneous magnetization, both by perturbative and numerical techniques. Our primary interest is to understand the differences between quenched and annealed cases, and also to investigate the interplay when both of them are present in a system. We observe in particular that when interaction and field terms are respectively quenched and annealed, critical temperature for the system to magnetize in the direction parallel to the applied field does not depend on any of the disorders. Further, an annealed disordered interaction neither affects the magnetizations nor the critical temperatures. We carry out a comparative study of the different combinations of the disorders in the interaction and field terms, and point out their generic features.

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Disorder overtakes order in information concentration over quantum networks

Cited by 33 publications

References 119 publications

Disorder-induced enhancement and critical scaling of spontaneous magnetization in random-field quantum spin systems

Disorder-induced enhancement and critical scaling of spontaneous magnetization in random-field quantum spin systems

Enhancing robustness of multiparty quantum correlations using weak measurement

Spontaneous magnetization of quantum XY spin model in joint presence of quenched and annealed disorder

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