美国芝加哥大学Liang Jiang团队研究了弱克尔非线性玻色子系统的通用控制。相关论文发表在2025年3月10日出版的《物理评论A》杂志上。

理论上，具有弱单光子自克尔非线性的谐振器可用于在损耗远大于其非线性的情况下制备福克态。两个必要的因素是大位移和双光子（参数）驱动。研究组发现这些系统可以被控制，以在有限维子空间（其维度可以随意选择）中实现任何所需的门操作。

此外，研究组表明可以放宽双光子驱动要求，并且仅通过一个光子（线性）驱动就可以实现完全可控性。利用Trotter-Suzuki分解和基于梯度的优化来找到所需门的控制脉冲，通过使用一个小的阻塞子空间来减少计算负担。研究组还讨论了现实环境中输入功率限制以及旋转波近似校正引起的不保真度。该通用控制协议为使用具有弱非线性的各种有损系统进行量子信息处理开辟了可能性。

附：英文原文

Title: Universal control in bosonic systems with weak Kerr nonlinearities

Author: Ming Yuan, Alireza Seif, Andrew Lingenfelter, David I. Schuster, Aashish A. Clerk, Liang Jiang

Issue&Volume: 2025/03/10

Abstract: Resonators with weak single-photon self-Kerr nonlinearities can theoretically be used to prepare Fock states in the presence of a loss much larger than their nonlinearities. Two necessary ingredients are large displacements and a two-photon (parametric) drive. Here, we find that these systems can be controlled to achieve any desired gate operation in a finite-dimensional subspace (whose dimensionality can be chosen at will). Moreover, we show that the two-photon driving requirement can be relaxed and that full controllability is achievable with only one-photon (linear) drives. We make use of both Trotter-Suzuki decompositions and gradient-based optimization to find control pulses for a desired gate, which reduces the computational overhead by using a small blockaded subspace. We also discuss the infidelity arising from input power limitations in realistic settings, as well as from corrections to the rotating-wave approximation. Our universal control protocol opens the possibility for quantum information processing using a wide range of lossy systems with weak nonlinearities.

DOI: 10.1103/PhysRevA.111.032606

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.111.032606