Stochastic feedback control of quantum transport to realize a dynamical ensemble of two nonorthogonal pure states

Shakib Daryanoosh, Howard M. Wiseman, Tobias Brandes

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

A Markovian open quantum system which relaxes to a unique steady state rho(SS) of finite rank can be decomposed into a finite physically realizable ensemble (PRE) of pure states. That is, as shown by R. I. Karasik and H. M. Wiseman [Phys. Rev. Lett. 106, 020406 (2011)], in principle there is a way to monitor the environment so that in the long-time limit the conditional state jumps between a finite number of possible pure states. In this paper we show how to apply this idea to the dynamics of a double quantum dot arising from the feedback control of quantum transport, as previously considered by C. Poltl, C. Emary, and T. Brandes [Phys. Rev. B 84, 085302 (2011)]. Specifically, we consider the limit where the system can be described as a qubit, and show that while the control scheme can always realize a two-state PRE, in the incoherent-tunneling regime there are infinitely many PREs compatible with the dynamics that cannot be so realized. For the two-state PREs that are realized, we calculate the counting statistics and see a clear distinction between the coherent and incoherent regimes.

Original languageEnglish
Article number085127
Pages (from-to)085127-1-085127-11
Number of pages11
JournalPhysical Review B
Volume93
Issue number8
DOIs
Publication statusPublished - 18 Feb 2016
Externally publishedYes

Bibliographical note

Erratum can be found in Physical Review B Volume 93 Article 119902(E), http://dx.doi.org/10.1103/PhysRevB.93.119902

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