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Author |
Hinarejos, M.; Bañuls, M.C.; Perez, A.; de Vega, I. |
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Title |
Non-Markovianity and memory of the initial state |
Type |
Journal Article |
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Year |
2017 |
Publication |
Journal of Physics A |
Abbreviated Journal |
J. Phys. A |
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Volume |
50 |
Issue |
32 |
Pages |
335301 - 17pp |
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Keywords |
non-Markovianity; quantum distinguisability; quantum fidelity |
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Abstract |
We explore in a rigorous manner the intuitive connection between the non-Markovianity of the evolution of an open quantum system and the performance of the system as a quantum memory. Using the paradigmatic case of a two-level open quantum system coupled to a bosonic bath, we compute the recovery fidelity, which measures the best possible performance of the system to store a qubit of information. We deduce that this quantity is connected, but not uniquely determined, by the non-Markovianity, for which we adopt the Breuer-Laine-Piilo measure proposed in Breuer et al (2009 Phys. Rev. Lett. 103 210401). We illustrate our findings with explicit calculations for the case of a structured environment. |
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Address |
[Hinarejos, Margarida] Univ Republica, Fac Ingn, Inst Fis, Av Julio Herrera y Reissig 565, Montevideo 11300, Uruguay, Email: Armando.Perez@uv.es |
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Publisher |
Iop Publishing Ltd |
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Language |
English |
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ISSN |
1751-8113 |
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Notes |
WOS:000405672800001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3206 |
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Permanent link to this record |
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Author |
de Vega, I.; Bañuls, M.C.; Perez, A. |
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Title |
Effects of dissipation on an adiabatic quantum search algorithm |
Type |
Journal Article |
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Year |
2010 |
Publication |
New Journal of Physics |
Abbreviated Journal |
New J. Phys. |
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Volume |
12 |
Issue |
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Pages |
123010 - 19pp |
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Keywords |
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Abstract |
According to recent studies (Amin et al 2008 Phys. Rev. Lett. 100 060503), the effect of a thermal bath may improve the performance of a quantum adiabatic search algorithm. In this paper, we compare the effects of such a thermal environment on the algorithm performance with those of a structured environment similar to the one encountered in systems coupled to an electromagnetic field that exists within a photonic crystal. Whereas for all the parameter regimes explored here, the algorithm performance is worsened by contact with a thermal environment, the picture appears to be different when one considers a structured environment. In this case we show that by tuning the environment parameters to certain regimes, the algorithm performance can actually be improved with respect to the closed system case. Additionally, the relevance of considering the dissipation rates as complex quantities is discussed in both cases. More specifically, we find that the imaginary part of the rates cannot be neglected with the usual argument that it simply amounts to an energy shift and in fact influences crucially the system dynamics. |
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Address |
[de Vega, Ines] Univ Ulm, Inst Theoret Phys, D-89069 Ulm, Germany, Email: ines.devega@uni-ulm.de |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1367-2630 |
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Notes |
ISI:000285582800002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
303 |
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Author |
Angles-Castillo, A.; Bañuls, M.C.; Perez, A.; De Vega, I. |
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Title |
Prethermalization of quantum systems interacting with non-equilibrium environments |
Type |
Journal Article |
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Year |
2020 |
Publication |
New Journal of Physics |
Abbreviated Journal |
New J. Phys. |
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Volume |
22 |
Issue |
8 |
Pages |
083067 - 17pp |
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Keywords |
open quantum systems; prethermalization; master equations |
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Abstract |
The usual paradigm of open quantum systems falls short when the environment is actually coupled to additional fields or components that drive it out of equilibrium. Here we explore the simplest such scenario, by considering a two level system coupled to a first thermal reservoir that in turn couples to a second thermal bath at a different temperature. We derive a master equation description for the system and show that, in this situation, the dynamics can be especially rich. In particular, we observe prethermalization, a transitory phenomenon in which the system initially approaches thermal equilibrium with respect to the first reservoir, but after a longer time converges to the thermal state dictated by the temperature of the second environment. Using analytical arguments and numerical simulations, we analyze the occurrence of this phenomenon, and how it depends on temperatures and coupling strengths. The phenomenology gets even richer if the system is placed between two such non-equilibrium environments. In this case, the energy current through the system may exhibit transient features and even switch direction, before the system eventually reaches a non-equilibrium steady state. |
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Address |
[Angles-Castillo, Andreu; Perez, Armando] Univ Valencia, CSIC, Dept Fis Teor, Burjassot 46100, Valencia, Spain, Email: banulsm@mpq.mpg.de |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1367-2630 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000565705900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4525 |
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Permanent link to this record |