scholarly journals Experimental Feedback Control of Quantum Systems Using Weak Measurements

2010 ◽  
Vol 104 (8) ◽  
Author(s):  
G. G. Gillett ◽  
R. B. Dalton ◽  
B. P. Lanyon ◽  
M. P. Almeida ◽  
M. Barbieri ◽  
...  
Keyword(s):  
Feedback Control ◽  
Quantum Systems ◽  
Weak Measurements ◽  
Control Of Quantum Systems

The regime of good control

2009 ◽  
Vol 9 (5&6) ◽  
pp. 395-405
Author(s):  
J. Li ◽  
K. Jacobs
Keyword(s):  
Steady State ◽  
Feedback Control ◽  
Nonlinear Systems ◽  
Equations Of Motion ◽  
Good Control ◽  
Classical Case ◽  
Quantum Systems ◽  
Single Qubit ◽  
Control Of Quantum Systems ◽  
Steady State Performance

We derive the equations of motion describing the feedback control of quantum systems in the regime of ``good control", in which the control is sufficient to keep the system close to the desired state. One can view this regime as the quantum equivalent of the ``linearized" regime for feedback control of classical nonlinear systems. Strikingly, while the dynamics of a single qubit in this regime is indeed linear, that of all larger systems remains nonlinear, in contrast to the classical case. As a first application of these equations, we determine the steady-state performance of feedback protocols for a single qubit that use unbiased measurements.

scholarly journals Closed-Loop and Robust Control of Quantum Systems

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Chunlin Chen ◽  
Lin-Cheng Wang ◽  
Yuanlong Wang
Keyword(s):  
Robust Control ◽  
Feedback Control ◽  
Quantum Control ◽  
Closed Loop ◽  
Learning Control ◽  
Quantum Systems ◽  
General Idea ◽  
Control Measurement ◽  
Control Of Quantum Systems ◽  
Control Feedback

For most practical quantum control systems, it is important and difficult to attain robustness and reliability due to unavoidable uncertainties in the system dynamics or models. Three kinds of typical approaches (e.g., closed-loop learning control, feedback control, and robust control) have been proved to be effective to solve these problems. This work presents a self-contained survey on the closed-loop and robust control of quantum systems, as well as a brief introduction to a selection of basic theories and methods in this research area, to provide interested readers with a general idea for further studies. In the area of closed-loop learning control of quantum systems, we survey and introduce such learning control methods as gradient-based methods, genetic algorithms (GA), and reinforcement learning (RL) methods from a unified point of view of exploring the quantum control landscapes. For the feedback control approach, the paper surveys three control strategies including Lyapunov control, measurement-based control, and coherent-feedback control. Then such topics in the field of quantum robust control asH∞control, sliding mode control, quantum risk-sensitive control, and quantum ensemble control are reviewed. The paper concludes with a perspective of future research directions that are likely to attract more attention.

scholarly journals Multiparticle quantum plasmonics

Nanophotonics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1243-1269 ◽  
Author(s):  
Chenglong You ◽  
Apurv Chaitanya Nellikka ◽  
Israel De Leon ◽  
Omar S. Magaña-Loaiza
Keyword(s):  
Quantum Dynamics ◽  
Degrees Of Freedom ◽  
Single Photon ◽  
Quantum Systems ◽  
Many Body ◽  
Statistical Fluctuations ◽  
Quantum Plasmonics ◽  
Control Of Quantum Systems ◽  
Multiparticle Systems ◽  
Quantum Photonics

AbstractA single photon can be coupled to collective charge oscillations at the interfaces between metals and dielectrics forming a single surface plasmon. The electromagnetic near-fields induced by single surface plasmons offer new degrees of freedom to perform an exquisite control of complex quantum dynamics. Remarkably, the control of quantum systems represents one of the most significant challenges in the field of quantum photonics. Recently, there has been an enormous interest in using plasmonic systems to control multiphoton dynamics in complex photonic circuits. In this review, we discuss recent advances that unveil novel routes to control multiparticle quantum systems composed of multiple photons and plasmons. We describe important properties that characterize optical multiparticle systems such as their statistical quantum fluctuations and correlations. In this regard, we discuss the role that photon-plasmon interactions play in the manipulation of these fundamental properties for multiparticle systems. We also review recent works that show novel platforms to manipulate many-body light-matter interactions. In this spirit, the foundations that will allow nonexperts to understand new perspectives in multiparticle quantum plasmonics are described. First, we discuss the quantum statistical fluctuations of the electromagnetic field as well as the fundamentals of plasmonics and its quantum properties. This discussion is followed by a brief treatment of the dynamics that characterize complex multiparticle interactions. We apply these ideas to describe quantum interactions in photonic-plasmonic multiparticle quantum systems. We summarize the state-of-the-art in quantum devices that rely on plasmonic interactions. The review is concluded with our perspective on the future applications and challenges in this burgeoning field.

Mixed LQG and H∞ coherent feedback control for linear quantum systems

2016 ◽  
Vol 90 (12) ◽  
pp. 2575-2588 ◽  
Author(s):  
Lei Cui ◽  
Zhiyuan Dong ◽  
Guofeng Zhang ◽  
Heung Wing Joseph Lee
Keyword(s):  
Feedback Control ◽  
Quantum Systems ◽  
Linear Quantum
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