TY - JOUR

T1 - Stochastic feedback control of quantum transport to realize a dynamical ensemble of two nonorthogonal pure states

AU - Daryanoosh, Shakib

AU - Wiseman, Howard M.

AU - Brandes, Tobias

N1 - Erratum can be found in Physical Review B Volume 93 Article 119902(E), http://dx.doi.org/10.1103/PhysRevB.93.119902

PY - 2016/2/18

Y1 - 2016/2/18

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=84960154643&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/record.url?scp=84960929778&partnerID=8YFLogxK

UR - https://doi.org/10.1103/PhysRevB.93.119902

U2 - 10.1103/PhysRevB.93.085127

DO - 10.1103/PhysRevB.93.085127

M3 - Article

VL - 93

SP - 085127-1-085127-11

JO - Physical Review B: covering condensed matter and materials physics

JF - Physical Review B: covering condensed matter and materials physics

SN - 2469-9950

IS - 8

M1 - 085127

ER -