Gradient-based closed-loop quantum optimal control in a solid-state two-qubit system

Feng, Guanru1,2; Cho, Franklin H.1,2; Katiyar, Hemant1,2; Li, Jun1,2,3,4; Lu, Dawei1,2,3,4; Baugh, Jonathan1,2,5; Laflamme, Raymond1,2,6,7

2018-11-26

10.1103/PhysRevA.98.052341

PHYSICAL REVIEW A   影响因子和分区

2469-9926

2469-9934

Quantum optimal control can play a crucial role in realizing a set of universal quantum logic gates with error rates below the threshold required for fault tolerance. Open-loop quantum optimal control relies on accurate modeling of the quantum system under control and does not scale efficiently with system size. These problems can be avoided in closed-loop quantum optimal control, which utilizes feedback from the system to improve control fidelity. In this paper, two gradient-based closed-loop quantum optimal control algorithms, the hybrid quantum-classical approach (HQCA) described by Li et al. [Phys. Rev. Lett. 118, 150503 (2017)] and the finite-difference (FD) method, are experimentally investigated and compared to the open-loop quantum optimal control utilizing the gradient ascent method. We employ a solid-state ensemble of coupled electron-nuclear spins serving as a two-qubit system. Specific single-qubit and two-qubit state preparation gates are optimized using the closed-loop and open-loop methods. The experimental results demonstrate the implemented closed-loop quantum control outperforms the open-loop control in our system. Furthermore, simulations reveal that HQCA is more robust than the FD method to gradient noise which originates from measurement noise in this experimental setting. On the other hand, the FD method is more robust to control field distortions coming from nonideal hardware.

SCI ; EI

英语

其他

Natural Sciences and Engineering Research Council of Canada[] ; Canada Foundation for Innovation[] ; Canadian Institute for Advanced Research[]

Optics ; Physics

Optics ; Physics, Atomic, Molecular & Chemical

WOS:000451329500019

AMER PHYSICAL SOC

20184906201460

Control theory ; Fault tolerance ; Finite difference method ; Quantum computers ; Quantum optics

Computer Systems and Equipment:722 ; Control Systems:731.1 ; Light/Optics:741.1 ; Numerical Methods:921.6

PHYSICS

Web of Science

1.Inst Quantum Comp, Waterloo, ON N2L 3G1, Canada
2.Univ Waterloo, Dept Phys & Astron, Waterloo, ON N2L 3G1, Canada
3.Southern Univ Sci & Technol, Dept Phys, Shenzhen 518055, Peoples R China
4.Southern Univ Sci & Technol, Shenzhen Inst Quantum Sci & Engn, Shenzhen 518055, Peoples R China
5.Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada
6.Perimeter Inst Theoret Phys, Waterloo, ON N2J 2W9, Canada
7.Canadian Inst Adv Res, Toronto, ON M5G 1Z8, Canada

Feng, Guanru,Cho, Franklin H.,Katiyar, Hemant,et al. Gradient-based closed-loop quantum optimal control in a solid-state two-qubit system[J]. PHYSICAL REVIEW A,2018,98(5).

Feng, Guanru.,Cho, Franklin H..,Katiyar, Hemant.,Li, Jun.,Lu, Dawei.,...&Laflamme, Raymond.(2018).Gradient-based closed-loop quantum optimal control in a solid-state two-qubit system.PHYSICAL REVIEW A,98(5).

Feng, Guanru,et al."Gradient-based closed-loop quantum optimal control in a solid-state two-qubit system".PHYSICAL REVIEW A 98.5(2018).