Feedback preparation of maximally entangled states of two‐qubit systems

Bell states are the maximally entangled states in two-qubit quantum systems, and play a significant role in quantum computation and quantum communication. Feedback control of stochastic quantum systems usually suffers from timedelay problems caused by the computation time of filter states and control input. This paper addresses the preparation of Bell states in two-qubit systems with a constant delay time. A Lyapunov method is used to design a switching control law and a constant is introduced in the control input to compensate for the computation time of estimate states and feedback control input, thereby stabilizing the target Bell state globally. Numerical results show the effectiveness of the proposed control law.

show abstract

“…infinite[29]. Combined with Step 1 we conclude that the system state will eventually remain in S <1− γ…”

mentioning

confidence: 67%

“…Inspired by the control synthesis in [17] and [29], we use two control channels H 1 and H 2 . Let the control law of H 1 be a constant 1, and we only design the control law u (2) (t − τ)(denoted as u (2) hereafter).…”

Section: Andmentioning

confidence: 99%

Feedback preparation of Bell states for two-qubit systems with time delay

Liu

Dong

Petersen

et al. 2019

2019 American Control Conference (ACC)

Self Cite

View full text Add to dashboard Cite

show abstract

“…control [11]- [14], stochastic and robust quantum control [15]- [18], quantum learning control [19]- [21], and quantum sliding mode control [22], [23]. Among these methods, due to simplicity in the controller design and intuitive physical meaning, quantum Lyapunov control has been extensively studied and used in the control of closed and open quantum systems [11]- [14], [24]- [34].…”

Section: Introductionmentioning

confidence: 99%

Lyapunov Control of High-Dimensional Closed Quantum Systems Based on Particle Swarm Optimization

Guan

Kuang

et al. 2020

IEEE Access

Self Cite

View full text Add to dashboard Cite

For high-dimensional closed quantum systems, this paper proposes a novel quantum Lyapunov control scheme based on the particle swarm optimization algorithm and achieves a high-probability population transfer of the system to a non-isolated target eigenstate in the LaSalle invariant set under usual smooth Lyapunov control laws. Via a quadratic Lyapunov function with unknown parameters, a control law with the unknown parameters is designed; based on the LaSalle invariance principle and the energylevel connectivity graph, the stability of the system is analyzed; by using the particle swarm optimization algorithm, a set of optimal parameters is obtained to achieve the control goal. In particular, we propose a path planning method based on the energy-level connectivity graph to determine the initial values of the unknown parameters, which is such that the optimization algorithm can efficiently and conveniently find a set of optimal solutions of the unknown parameters. Numerical simulation experiments on a five-level quantum system and a three-qubit system demonstrate that the proposed Lyapunov control scheme based on the particle swarm optimization algorithm has a good control effect. INDEX TERMS High-dimensional quantum systems, Lyapunov control, particle swarm optimization algorithm, parameter optimization, initial values, energy-level connectivity graph.

show abstract

“…Several typical control methodologies have been applied to quantum systems, e.g. optimal control [4–6], Lyapunov control [7–10], and feedback and robust control [11–16]. It should be pointed out that any actual quantum system is inevitably affected by environmental disturbances or parameter fluctuations, which will introduce uncertainties into the controlled system.…”

Section: Introductionmentioning

confidence: 99%