An uptodate list is available on Google Scholar.
”#” These authors contributed equally.
“*” Corresponding author.
Journal Papers
2023

Comparison of differential evolution, particle swarm optimization, quantumbehaved particle swarm optimization, and quantum evolutionary algorithm for preparation of quantum states
Xin Cheng, Xiujuan Lu, Yanan Liu, and Sen Kuang
Chinese Physics B, 2023

Greedy versus mapbased optimized adaptive algorithms for randomtelegraphnoise mitigation by spectator qubits
Behnam Tonekaboni, Areeya Chantasri, Hongting Song, Yanan Liu, and Howard M Wiseman
Physical Review A, 2023

A quantum ticking selfoscillator using delayed feedback
Yanan Liu*, William J Munro, and Jason Twamley*
New Journal of Physics, 2023
Selfsustained oscillators (SSOs) is a commonly used method to generate classical clock signals and SSOs using delayed feedback have been developed commercially which possess ultralow phase noise and drift. Research into the development of quantum selfoscillation, where one can also have a periodic and regular output tick, that can be used to control quantum and classical devices has received much interest and quantum SSOs so far studied suffer from phase diffusion which leads to the smearing out of the quantum oscillator over the entire limit cycle in phase space seriously degrading the system’s ability to perform as a selfoscillation. In this paper, we explore quantum versions of timedelayed SSOs, which has the potentials to develop a ticking quantum clock. We first design a linear quantum SSO which exhibits perfect oscillation without phase diffusion. We then explore a nonlinear delayed quantum SSO but find it exhibits dephasing similar to previously studied nondelayed systems.
2022

Approximate bangbang control assisted rapid switching feedback stabilization for stochastic qubit systems
Gan Li#, Yanan Liu#, Sen Kuang, and Chengdi Xiang
Journal of the Franklin Institute, 2022

Faulttolerant H∞ control for optical parametric oscillators with pumping fluctuations
Yanan Liu, Daoyi Dong, Ian R Petersen, and Hidehiro Yonezawa
Automatica, 2022
Optical Parametric Oscillators (OPOs) have wide applications in quantum optics for generating squeezed states and developing advanced technologies. When the phase or/and the amplitude of the pumping field for an OPO have fluctuations due to fault signals, timevarying uncertainties will be introduced in the dynamic parameters of the system. In this paper, we investigate how to design a faulttolerant controller for an OPO with a disturbance input and timevarying uncertainties, which can achieve the required performance of the quantum system. We apply robust control theory to a quantum system, and design a passive controller and an active controller based on the solutions to two Riccati equations. The passive controller has a simple structure and is easy to be implemented by using only passive optical components, while the active quantum controller may achieve improved performance. The control performance of the proposed two controllers and one controller that was designed without consideration of system uncertainties is compared by numerical simulations in a specific OPO, and the results show that the designed controllers work effectively for fluctuations in both the phase and amplitude of the pumping field.
2021

Twostep feedback preparation of entanglement for qubit systems with time delay
Yanan Liu, Daoyi Dong, Sen Kuang, Ian R Petersen, and Hidehiro Yonezawa
Automatica, 2021
Quantum entanglement plays a fundamental role in quantum computation and quantum communication. Feedback control has been widely used in stochastic quantum systems to generate given entangled states since it has good robustness, where the time required to compute filter states and conduct filterbased control usually cannot be ignored in many practical applications. This paper designed two control strategies based on the Lyapunov method to prepare a class of entangled states for qubit systems with a constant delay time. The first one is bang–banglike control strategy, which has a simple form with switching between a constant value and zero, the stability of which is proved. Another control strategy is switching Lyapunov control, where a constant delay time is introduced in the filterbased feedback control law to compensate for the computation time. Numerical results on a twoqubit system illustrate the effectiveness of these two proposed control strategies.

Rapid feedback stabilization of quantum systems with application to preparation of multiqubit entangled states
Sen Kuang, Gan Li, Yanan Liu, Xiaqing Sun, and Shuang Cong
IEEE Transactions on Cybernetics, 2021

FaultTolerant Coherent H∞ Control for Linear Quantum Systems
Yanan Liu, Daoyi Dong, Ian R Petersen, Qing Gao, Steven X Ding, Shota Yokoyama, and Hidehiro Yonezawa
IEEE Transactions on Automatic Control, 2021
Robustness and reliability are two key requirements for developing practical quantum control systems. The purpose of this article is to design a coherent feedback controller for a class of linear quantum systems suffering from Markovian jumping faults so that the closedloop quantum system has both fault tolerance and H∞ disturbance attenuation performance. This article first extends the physical realization conditions from the timeinvariant case to the timevarying case for linear stochastic quantum systems. By relating the faulttolerant H∞ control problem to the dissipation properties and the solutions of Riccati differential equations, an H∞ controller for the quantum system is then designed by solving a set of linear matrix inequalities. In particular, an algorithm is employed to introduce additional quantum inputs and to construct the corresponding input matrices to ensure the physical realizability of the quantum controller. Also, we propose a real application of the developed faulttolerant control strategy to quantum optical systems. A linear quantum system example from quantum optics, where the amplitude of the pumping field randomly jumps among different values due to the fault processes, can be modeled as a linear Markovian jumping system. It is demonstrated that a quantum H∞ controller can be designed and implemented using some basic optical components to achieve the desired control goal for this class of systems.
2019

Filterbased feedback control for a class of Markovian open quantum systems
Yanan Liu, Daoyi Dong, Ian R Petersen, and Hidehiro Yonezawa
IEEE Control Systems Letters, 2019
This letter considers target state preparation for Markovian open quantum systems subject to continuous measurement. Conditions on invariant and attractive subspaces are investigated, which ensure the stabilization of the target state/subspace. For a class of open quantum systems with time delay in the feedback loop, a bangbanglike control law is proposed, and the stability of the feedback control strategy is proved. An example of fourlevel Markovian open quantum systems is presented to demonstrate the effectiveness of the proposed control strategy.
2017

Feedback stabilization of Ndimensional stochastic quantum systems based on bangbang control
Xiaqing Sun, Sen Kuang, Yanan Liu, Juan Zhou, and Shuang Cong
Control Theory and Technology, 2017
2016

Lyapunovbased feedback preparation of GHZ entanglement of N qubit systems
Yanan Liu, Sen Kuang, and Shuang Cong
IEEE transactions on cybernetics, 2016
Conference Papers
2022

Learning Control with Evolution Strategy for Inhomogeneous Open Quantum Ensembles
Chunxiang Song, Yanan Liu, David McManus, and Daoyi Dong
In 2022 IEEE International Conference on Systems, Man, and Cybernetics (SMC), 2022
2020

Coherent H∞ control for Markovian jump linear quantum systems
Yanan Liu, Daoyi Dong, Ian R Petersen, Qing Gao, Steven X Ding, and Hidehiro Yonezawa
IFACPapersOnLine, 2020
2019

Feedback preparation of Bell states for twoqubit systems with time delay
Yanan Liu, Daoyi Dong, Ian R Petersen, Sen Kuang, and Hidehiro Yonezawa
In 2019 American Control Conference (ACC), 2019

Control Allocation Based Sliding Mode Fault Tolerant Control
Ahmadreza Argha, Steven W Su, Yanan Liu, and Branko G Celler
In 2019 American Control Conference (ACC), 2019