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Title: Deterministic generation of remote entanglement with active quantum feedback

Journal Article · · Physical Review A - Atomic, Molecular, and Optical Physics
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  1. Berkeley Center for Quantum Information and Computation, Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
  2. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
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We develop and study protocols for deterministic remote entanglement generation using quantum feedback, without relying on an entangling Hamiltonian. In order to formulate the most effective experimentally feasible protocol, we introduce the notion of average-sense locally optimal feedback protocols, which do not require real-time quantum state estimation, a difficult component of real-time quantum feedback control. We use this notion of optimality to construct two protocols that can deterministically create maximal entanglement: a semiclassical feedback protocol for low-efficiency measurements and a quantum feedback protocol for high-efficiency measurements. The latter reduces to direct feedback in the continuous-time limit, whose dynamics can be modeled by a Wiseman-Milburn feedback master equation, which yields an analytic solution in the limit of unit measurement efficiency. Our formalism can smoothly interpolate between continuous-time and discrete-time descriptions of feedback dynamics and we exploit this feature to derive a superior hybrid protocol for arbitrary nonunit measurement efficiency that switches between quantum and semiclassical protocols. Lastly, we show using simulations incorporating experimental imperfections that deterministic entanglement of remote superconducting qubits may be achieved with current technology using the continuous-time feedback protocol alone.

Research Organization:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
AC04-94AL85000; AC04-94AL8
OSTI ID:
1236365
Alternate ID(s):
OSTI ID: 1546124
Report Number(s):
SAND-2015-2589J; PLRAAN; 581955
Journal Information:
Physical Review A - Atomic, Molecular, and Optical Physics, Vol. 92, Issue 6; ISSN 1050-2947
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 23 works
Citation information provided by
Web of Science

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Precise single-qubit control of the reflection phase of a photon mediated by a strongly-coupled ancilla–cavity system journal May 2018

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Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS