Quantum Measurement and Control

Wiseman, Howard Mark; Milburn, G. J.

doi:10.1017/cbo9780511813948

Cited by 2,066 publications

(3,543 citation statements)

References 138 publications

Supporting

Mentioning

3,506

Contrasting

Unclassified

Order By: Relevance

“…Perhaps the simplest quantum-control scheme, well understood in quantum optics, is that due to Wiseman and Milburn [3,13]. In essence, this scheme monitors the quantum jumps of the system and, directly after each, applies a fixed control operation to the system, assumed to act instantaneously.…”

Section: Wiseman-milburn Control and The Stabilisation Of Non-equillimentioning

confidence: 99%

See 1 more Smart Citation

Feedback Control in Quantum Transport

Emary

2016

Understanding Complex Systems

View full text Add to dashboard Cite

Abstract. Quantum transport is the study of the motion of electrons through nano-scale structures small enough that quantum effects are important. In this contribution I review recent theoretical proposals to use the techniques of quantum feedback control to manipulate the properties of electron flows and states in quantum-transport devices. Quantum control strategies can be grouped into two broad classes: measurement-based control and coherent control, and both are covered here. I discuss how measurement-based techniques are capable of producing a range of effects, such as noise suppression, stabilisation of nonequillibrium quantum states and the realisation of a nano-electronic Maxwell's demon. I also describe recent results on coherent transport control and its relation to quantum networks. IntroductionFeedback control of quantum mechanical systems is a rapidly emerging topic [1,2], developed most fully in the field of quantum optics [3]. Only recently have these ideas been extended to quantum transport, a field which looks to understand and control the motion of electrons through structures on the nano-scale [4]. The aim of this contribution is to review these recent developments.Broadly speaking, quantum feedback strategies may usefully be classified into two types:• Measurement-based control, where the quantum system is subject to measurements, the classical information from which forms the basis of the feedback loop; • Coherent control, where the system, the controller and their interconnections are phase coherent such that the information flow in the feedback loop is of quantum information [5].Mirroring the situation in optics, most of the work to-date on feedback in quantum transport has been within the measurement-based paradigm. In Sec. 1.2 here, we discuss a number of different measurement-based schemes

show abstract

Section: Wiseman-milburn Control and The Stabilisation Of Non-equillimentioning

confidence: 99%

“…Feedback control of quantum mechanical systems is a rapidly emerging topic [1,2], developed most fully in the field of quantum optics [3]. Only recently have these ideas been extended to quantum transport, a field which looks to understand and control the motion of electrons through structures on the nano-scale [4].…”

Section: Introductionmentioning

confidence: 99%

Feedback Control in Quantum Transport

Emary

2016

Understanding Complex Systems

View full text Add to dashboard Cite

show abstract

“…For quantum systems, an open-loop control is conceptually simpler than a closed loop one as it does not demand feedback with respect to an output of a measurement performed on a quantum system [34]. There are various types of open-loop driving.…”

Section: Introductionmentioning

confidence: 99%

“…The simplest is a classical field (e.g., magnetic or electric) which introduces a time-dependent component to a Hamiltonian of the quantum system. The most complex is a quantum field such as n-mode bosonic field typical for quantum optical problems [34]. Somewhere in between is a classical stochastic driving (stochastic control [16]) which can be considered either as a classical field with certain degree of randomness or as a suitable stochastic limit of a quantum driving [1].…”

Section: Introductionmentioning

confidence: 99%

Leggett–Garg inequalities for a quantum top affected by classical noise

Dajka

źObejko

źUczka

2016

Quantum Inf Process

View full text Add to dashboard Cite

The violation of the Leggett-Garg inequality is studied for a quantum top (with angular momentum J z of integer or half-integer size), being driven by classical Gaussian white noise. The form of a longitudinal (J z ) or a transverse (J x ) coupling of noise to the angular momentum affects both (i) to what extent the Leggett-Garg inequality is violated and (ii) how this violation is influenced by the size j of the spinning top and direction of a coupling (transverse or longitudinal). We introduce jindependent method, using two-dimensional invariant subspace of the system Hilbert space, which allows us to find out strict analytical solution for a noise-free system and with longitudinal coupling and to extract from the whole dynamics effects purely induced by a noise. It is demonstrated that in the semi-classical limit of a large angular momentum j and for the transverse coupling, the Leggett-Garg inequalities become more strongly violated as compared to the deep quantum regime of small j.

show abstract

“…Control of quantum processes [1] such as quantum storage in open quantum system [2] collects a number of separate concepts, and has a variety of manifestations in different areas of physics [3,4]. Quantum storage is concerned with a quantum state stored in open systems in presence of leakage [5] and diffusion processes induced by either the system-environment interaction or inner-coupling between the target storage subspace and the rest of the system space.…”

Section: Introductionmentioning

confidence: 99%

Overview of quantum memory protection and adiabaticity induction by fast signal control

Jing

2015

Science Bulletin

View full text Add to dashboard Cite

A quantum memory or information processing device is subject to disturbance from its surrounding environment or inevitable leakage due to its contact with other systems. To tackle these problems, several control protocols have been proposed for quantum memory or storage. Among them, the fast-signal control or dynamical decoupling based on external pulse sequences provides a prevailing strategy aimed at suppressing decoherence and preventing the target systems from the leakage or diffusion process. In this paper, we review the applications of this protocol in protecting quantum memory under the non-Markovian dissipative noise and maintaining systems on finite speed adiabatic passages without leakage therefrom. We analyze leakage and control perturbative and nonperturbative dynamical equations including second-order master equation, quantum-state-diffusion equation, and one-component master equation derived from Feshbach PQ-partitioning technique. It turns out that the quality of fast-modulated signal control is insensitive to configurations of the applied pulse sequences. Specifically, decoherence and leakage will be greatly suppressed as long as the control sequence is able to effectively shift the system beyond the bath cutoff frequency, almost independent of the details of the control sequences which could be ideal pulses, regular rectangular pulses, random pulses and even noisy pulses.

show abstract

Quantum Measurement and Control

Cited by 2,066 publications

References 138 publications

Feedback Control in Quantum Transport

Feedback Control in Quantum Transport

Leggett–Garg inequalities for a quantum top affected by classical noise

Overview of quantum memory protection and adiabaticity induction by fast signal control

Contact Info

Product

Resources

About