近日，德国马克斯普朗克复杂系统物理研究所的Gabriel O. Alves与巴西圣保罗州立大学的Marcelo A. F. Santos等人合作并取得一项新进展。经过不懈努力，他们实现了高斯系统的碰撞测温。相关研究成果已于2024年11月14日在国际知名学术期刊《物理评论A》上发表。

该研究团队研究了一种基于高斯系统的量子测温方案——碰撞模型。这类方案的一个关键未解问题是，量子费舍尔信息（QFI）随辅助量子比特（ancillas）数量的定标情况。在基于量子比特的实现中，由于希尔伯特空间尺寸随粒子数呈指数增长，这一问题难以评估。

本研究聚焦于高斯碰撞模型，该模型能够评估任意大小系统的QFI定标情况。这种数值灵活性，使研究人员能够探索该模型在广泛配置下的测温特性。尽管该模型的随机过程具有无限马尔可夫阶数，但研究人员仍对QFI的行为进行了简单的唯象分析，估算了渐近费舍尔信息密度，并探讨了随着辅助量子比特数量增加，相关性的瞬态效应如何依赖于模型的物理参数。

附：英文原文

Title: Collisional thermometry for Gaussian systems

Author: Gabriel O. Alves, Marcelo A. F. Santos, Gabriel T. Landi

Issue&Volume: 2024/11/14

Abstract: We investigate a quantum thermometry scheme-based collision model with Gaussian systems. A key open question of these schemes concerns the scaling of the quantum Fisher information (QFI) with the number of ancillas. In qubit-based implementations this question is difficult to assess, due to the exponentially growing size of the Hilbert space. Here we focus on Gaussian collision models, which allow for the scaling of the QFI to be evaluated for arbitrarily large sizes. This numerical flexibility enables us to explore the thermometric properties of the model for a wide range of configurations. Despite the infinite Markov order of the stochastic process of the model, we provide a simple phenomenological analysis for the behavior of the QFI, estimating the asymptotic Fisher information density and how the transient effects of correlations for an increasing number of ancillas depend on the physical parameters of the model.

DOI: 10.1103/PhysRevA.110.052421

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.052421