近日，美国耶鲁大学的Michel H. Devoret&Rodrigo G. Cortias及其研究团队取得一项新进展。他们对一种驱动超导电路中的非线性耗散效应进行了研究。相关研究成果已于2024年10月15日在国际知名学术期刊《物理评论A》上发表。

据悉，非平衡驱动的非线性振荡器因可作为定制Floquet哈密顿谱和稳定量子态，以用于量子信息的平台而备受关注。然而，人们通常忽略了必要的参数驱动可能会放大环境波动，从而限制其应用。

在这项工作中，该研究团队通过计算超越旋转波近似的克尔参数振荡器的有效林德布拉德算符，来捕捉这一效应。研究人员发现，相关的耗散子强烈依赖于振荡器的非线性特性和平均光子数。

特别是，研究人员针对近期由参数驱动稳定的薛定谔猫态量子比特上，逻辑寿命的测量结果进行了讨论，从而为实验数据与常规林德布拉德处理之间观察到的，三个数量级的差异提供了解释。这一系统性方法，为处理Floquet工程化非线性量子系统中的耗散效应铺平了道路。

附：英文原文

Title: Nonlinear dissipation in a driven superconducting circuit

Author: Jayameenakshi Venkatraman, Xu Xiao, Rodrigo G. Cortias, Michel H. Devoret

Issue&Volume: 2024/10/15

Abstract: Out-of-equilibrium driven nonlinear oscillators have attracted interest as a platform for tailoring Floquet Hamiltonian spectra and stabilizing quantum states for quantum information. However, it is usually ignored that the necessary parametric drive can amplify environmental fluctuations limiting applications. In this work, we capture this effect by computing the effective Lindbladian of a Kerr parametric oscillator beyond the rotating wave approximation. We find that the relevant dissipators depend strongly on the nonlinearity and the mean-photon number in the oscillator. In particular, we address recent measurements of the logical lifetime on a Schrdingers-cat qubit stabilized by a parametric drive, thereby providing an explanation for the observed three-order-of-magnitude discrepancy between experimental data and an ordinary Lindblad treatment. Our systematic approach paves the path to treat dissipative effects in Floquet-engineered nonlinear quantum systems.

DOI: 10.1103/PhysRevA.110.042411

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.042411

来源：科学网 小柯机器人