scholarly journals A local-time-induced unique pointer basis

Author(s):  
J. Jeknić-Dugić ◽  
M. Arsenijević ◽  
M. Dugić

There is a solution to the problem of asymptotic completeness in many-body scattering theory that offers a specific view of the quantum unitary dynamics which allows for the straightforward introduction of local time for every, at least approximately closed, many-particle system. In this approach, time appears as a hidden classical parameter of the unitary dynamics of a many-particle system. We show that a closed many-particle system can exhibit behaviour that is characteristic for open quantum systems and there is no need for the ‘state collapse’ or environmental influence. On the other hand, closed few-particle systems bear high quantum coherence. This local-time scheme encompasses concepts including ‘emergent time’, ‘relational time’ as well as the ‘hybrid system’ models with possibly induced gravitational uncertainty of time.

2018 ◽  
Vol 98 (2) ◽  
Author(s):  
I. Vakulchyk ◽  
I. Yusipov ◽  
M. Ivanchenko ◽  
S. Flach ◽  
S. Denisov

2011 ◽  
Vol 13 (8) ◽  
pp. 085007 ◽  
Author(s):  
M Müller ◽  
K Hammerer ◽  
Y L Zhou ◽  
C F Roos ◽  
P Zoller

Symmetry ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2445
Author(s):  
Mariam Algarni ◽  
Kamal Berrada ◽  
Sayed Abdel-Khalek ◽  
Hichem Eleuch

In this manuscript, we examine the dynamical behavior of the coherence in open quantum systems using the l1 norm. We consider a two-qubit system that evolves in the framework of Kossakowski-type quantum dynamical semigroups (KTQDSs) of completely positive maps (CPMs). We find that the quantum coherence can be asymptotically maintained with respect to the values of the system parameters. Moreover, we show that the quantum coherence can resist the effect of the environment and preserve even in the regime of long times. The obtained results also show that the initially separable states can provide a finite value of the coherence during the time evolution. Because of such properties, several states in this type of environments are good candidates for incorporating quantum information and optics (QIO) schemes. Finally, we compare the dynamical behavior of the coherence with the entire quantum correlation.


2015 ◽  
Vol 22 (02) ◽  
pp. 1550008
Author(s):  
A. Werpachowska

We present the reduced operator approximation: a simple, physically transparent and computationally efficient method of modelling open quantum systems. It employs the Heisenberg picture of the quantum dynamics, which allows us to focus on the system degrees of freedom in a natural and easy way. We describe different variants of the method, low- and high-order in the system–bath interaction operators, defining them for either general quantum harmonic oscillator baths or specialising them for independent baths with Lorentzian spectral densities. Its wide applicability is demonstrated on the examples of systems coupled to different baths (with varying system–bath interaction strength and bath memory length), and compared with the exact pseudomode and the popular quantum state diffusion approach. The method captures the decoherence of the system interacting with the bath, while conserving the total energy. Our results suggest that quantum coherence effects persist in open quantum systems for much longer times than previously thought.


Author(s):  
J. Jeknić-Dugić ◽  
M. Arsenijević ◽  
M. Dugić

Recently we pointed out the so-called local time scheme as a novel approach to quantum foundations that solves the preferred pointer-basis problem. In this paper, we introduce and analyse in depth a rather non-standard dynamical map that is imposed by the scheme. On the one hand, the map does not allow for introducing a properly defined generator of the evolution nor does it represent a quantum channel. On the other hand, the map is linear, positive, trace preserving and unital as well as completely positive, but is not divisible and therefore non-Markovian. Nevertheless, we provide quantitative criteria for dynamical emergence of time-coarse-grained Markovianity, for exact dynamics of an open system, as well as for operationally defined approximation of a closed or open many-particle system. A closed system never reaches a steady state, whereas an open system may reach a unique steady state given by the Lüders–von Neumann formula; where the smaller the open system, the faster a steady state is attained. These generic findings extend the standard open quantum systems theory and substantially tackle certain cosmological issues.


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