Evolution of any finite open quantum system always admits a Kraus-type representation, although it is not always completely positive

2004 ◽  
Vol 70 (5) ◽  
Author(s):  
D. Salgado ◽  
J. L. Sánchez-Gómez ◽  
M. Ferrero
Quanta ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 34-41
Author(s):  
Sudha Sudha ◽  
B. N. Karthik ◽  
A. R. Usha Devi ◽  
A. K. Rajagopal

In their seminal 1961 paper, Sudarshan, Mathews and Rau investigated properties of the dynamical A and B maps acting on n-dimensional quantum systems. The nature of dynamical maps in open quantum system evolutions has attracted great deal of attention in the later years. However, the novel paper on the A and B dynamical maps has not received its due attention. In this tutorial article, we review the properties of A and B forms associated with the dynamics of finite dimensional quantum systems. In particular, we investigate a canonical structure associated with the A form and establish its equivalence with the associated B form. We show that the canonical structure of the A form captures the completely positive (not completely positive) nature of the dynamics in a succinct manner. This feature is illustrated through physical examples of qubit channels.Quanta 2021; 10: 34–41.


2020 ◽  
Vol 2 (2) ◽  
Author(s):  
S. Hernández-Gómez ◽  
S. Gherardini ◽  
F. Poggiali ◽  
F. S. Cataliotti ◽  
A. Trombettoni ◽  
...  

2015 ◽  
Vol 17 (38) ◽  
pp. 25629-25641 ◽  
Author(s):  
Xiaoqing Wang ◽  
Gerhard Ritschel ◽  
Sebastian Wüster ◽  
Alexander Eisfeld

We elucidate the difference between various parameter extraction methods and demonstrate sensitivity to molecular dynamics equilibration.


2020 ◽  
Vol 102 (6) ◽  
Author(s):  
Zhao-Di Liu ◽  
Yong-Nan Sun ◽  
Bi-Heng Liu ◽  
Chuan-Feng Li ◽  
Guang-Can Guo ◽  
...  

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.


2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Henrik P. Lüschen ◽  
Pranjal Bordia ◽  
Sean S. Hodgman ◽  
Michael Schreiber ◽  
Saubhik Sarkar ◽  
...  

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