Dressed quantum trajectories: novel approach to the non-Markovian dynamics of open quantum systems on a wide time scale

A universal scheme is introduced to speed up the dynamics of a driven open quantum system along a prescribed trajectory of interest. This framework generalizes counterdiabatic driving to open quantum processes. Shortcuts to adiabaticity designed in this fashion can be implemented in two alternative physical scenarios: one characterized by the presence of balanced gain and loss, the other involves non-Markovian dynamics with time-dependent Lindblad operators. As an illustration, we engineer superadiabatic cooling, heating, and isothermal strokes for a two-level system, and provide a protocol for the fast thermalization of a quantum oscillator.

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Gaussian Quantum Trajectories for the Variational Simulation of Open Quantum-Optical Systems

Applied Sciences ◽

10.3390/app8091427 ◽

2018 ◽

Vol 8 (9) ◽

pp. 1427 ◽

Cited By ~ 7

Author(s):

Wouter Verstraelen ◽

Michiel Wouters

Keyword(s):

Open Quantum Systems ◽

Computational Cost ◽

System Size ◽

Quantum Systems ◽

Optical Systems ◽

Quantum Trajectory ◽

Quantum Trajectories ◽

Open Quantum ◽

Quantum Optical ◽

Bistability Regime

We construct a class of variational methods for the study of open quantum systems based on Gaussian ansatzes for the quantum trajectory formalism. Gaussianity in the conjugate position and momentum quadratures is distinguished from Gaussianity in density and phase. We apply these methods to a driven-dissipative Kerr cavity where we study dephasing and the stationary states throughout the bistability regime. Computational cost proves to be similar to the Truncated Wigner Approximation (TWA) method, with at most quadratic scaling in system size. Meanwhile, strong correspondence with the numerically-exact trajectory description is maintained so that these methods contain more information on the ensemble constitution than TWA and can be more robust.

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FEEDBACK IN OPEN QUANTUM SYSTEMS

Modern Physics Letters B ◽

10.1142/s0217984995000590 ◽

1995 ◽

Vol 09 (11n12) ◽

pp. 629-654 ◽

Cited By ~ 6

Author(s):

H. M. WISEMAN

Keyword(s):

System Dynamics ◽

Feedback Loop ◽

Open Quantum Systems ◽

Quantum Systems ◽

Feedback Mechanism ◽

The Other ◽

Langevin Equations ◽

Quantum Trajectories ◽

Classical Counterpart ◽

Open Quantum

Open quantum systems continually lose information to their surroundings. In some cases this information can be readily retrieved from the environment and put to good use by engineering a feedback loop to control the system dynamics. Two cases are distinguished: one where the feedback mechanism involves a measurement of the environment, and the other where no measurement is made. It is shown that the latter case can always replicate the former, but not vice versa. This emphasizes the quantum nature of the information being fed back. Two approaches are used to describe the feedback: quantum trajectories (which apply only for feedback based on measurement) and quantum Langevin equations (which can be used in either case), and the results are shown to be equivalent. The obvious applications for the theory are in quantum optics, where the information is lost by radiation damping and can be retrieved by photodetection. A few examples are discussed, one of which is particularly interesting as it has no classical counterpart.

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