scholarly journals Enhancement of quantum correlations and a geometric phase for a driven bipartite quantum system in a structured environment

2021 ◽  
Vol 103 (3) ◽  
Author(s):  
Paula I. Villar ◽  
Alejandro Soba
Author(s):  
Y. Yugra ◽  
F. De Zela

Coherence and quantum correlations have been identified as fundamental resources for quantum information tasks. As recently shown, these resources can be interconverted. In multipartite systems, entanglement represents a prominent case among quantum correlations, one which can be activated from coherence. All this makes coherence a key resource for securing the operational advantage of quantum technologies. When dealing with open systems, decoherence hinders full exploitation of quantum resources. Here, we present a protocol that allows reaching the maximal achievable amount of coherence in an open quantum system. By implementing our protocol, or suitable variants of it, coherence losses might be fully compensated, thereby leading to coherence revivals. We provide an experimental proof of principle of our protocol through its implementation with an all-optical setup.


2005 ◽  
Vol 20 (22) ◽  
pp. 1635-1654 ◽  
Author(s):  
ANGELO CAROLLO

The quantum jump method for the calculation of geometric phase is reviewed. This is an operational method to associate a geometric phase to the evolution of a quantum system subjected to decoherence in an open system. The method is general and can be applied to many different physical systems, within the Markovian approximation. As examples, two main source of decoherence are considered: dephasing and spontaneous decay. It is shown that the geometric phase is to very large extent insensitive to the former, i.e. it is independent of the number of jumps determined by the dephasing operator.


2004 ◽  
Vol 70 (4) ◽  
Author(s):  
Ingo Kamleitner ◽  
James D. Cresser ◽  
Barry C. Sanders

2003 ◽  
Vol 67 (1) ◽  
Author(s):  
S. Hamieh ◽  
J. Qi ◽  
D. Siminovitch ◽  
M. K. Ali

Entropy ◽  
2018 ◽  
Vol 20 (3) ◽  
pp. 200 ◽  
Author(s):  
◽  

The Leggett-Garg inequalities serve to test whether or not quantum correlations in time can be explained within a classical macrorealistic framework. We apply this test to thermodynamics and derive a set of Leggett-Garg inequalities for the statistics of fluctuating work done on a quantum system unitarily driven in time. It is shown that these inequalities can be violated in a driven two-level system, thereby demonstrating that there exists no general macrorealistic description of quantum work. These violations are shown to emerge within the standard Two-Projective-Measurement scheme as well as for alternative definitions of fluctuating work that are based on weak measurement. Our results elucidate the influences of temporal correlations on work extraction in the quantum regime and highlight a key difference between quantum and classical thermodynamics.


2007 ◽  
Vol 56 (7) ◽  
pp. 3937
Author(s):  
Zhou Bing-Ju ◽  
Liu Xiao-Juan ◽  
Fang Mao-Fa ◽  
Zhou Qing-Ping ◽  
Liu Ming-Wei

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jiří Svozilík ◽  
Raúl Hidalgo-Sacoto ◽  
Ievgen I. Arkhipov

Abstract A universal characterization of non-Markovianity for any open hybrid quantum systems is presented. This formulation is based on the negativity volume of the generalized Wigner function, which serves as an indicator of the quantum correlations in any composite quantum systems. It is shown, that the proposed measure can be utilized for any single or multi-partite quantum system, containing any discrete or continuous variables. To demonstrate its power in revealing non-Markovianity in such quantum systems, we additionally consider a few illustrative examples.


Entropy ◽  
2019 ◽  
Vol 21 (8) ◽  
pp. 771 ◽  
Author(s):  
Fabian Bernards ◽  
Matthias Kleinmann ◽  
Otfried Gühne ◽  
Mauro Paternostro

Recently, the concept of daemonic ergotropy has been introduced to quantify the maximum energy that can be obtained from a quantum system through an ancilla-assisted work extraction protocol based on information gain via projective measurements [G. Francica et al., npj Quant. Inf. 3, 12 (2018)]. We prove that quantum correlations are not advantageous over classical correlations if projective measurements are considered. We go beyond the limitations of the original definition to include generalised measurements and provide an example in which this allows for a higher daemonic ergotropy. Moreover, we propose a see-saw algorithm to find a measurement that attains the maximum work extraction. Finally, we provide a multipartite generalisation of daemonic ergotropy that pinpoints the influence of multipartite quantum correlations, and study it for multipartite entangled and classical states.


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