近日，清华大学的刘永椿课题组成功实现了耦合自旋系统中的海森堡极限自旋压缩。相关研究成果已于2023年4月18日在国际学术期刊《物理评论 A》上发表。

研究人员提出了一种通用方案，可用于在具有集体自旋-自旋相互作用的耦合自旋模型中生成自旋压缩，这种相互作用通常存在于各种系统中。他们的方案能够将耦合自旋相互作用转化为压缩相互作用，并在Heisenberg极限测量精度下实现极端压缩，其精度随着粒子数N的增加而按1/N的比例缩放。研究人员只需要使用恒定和连续的驱动场，这是一系列当前实际实验都能满足的要求。该工作大大丰富了可以生成Heisenberg极限自旋压缩的系统种类，具有广泛的量子精密测量应用。

据了解，自旋压缩在量子计量学和量子信息科学中起着关键作用。其产生是进一步应用的前提，但面临巨大挑战，因为现有物理系统很少包含所需的压缩相互作用。

附：英文原文

Title: Heisenberg-limited spin squeezing in coupled spin systems

Author: Long-Gang Huang, Xuanchen Zhang, Yanzhen Wang, Zhenxing Hua, Yuanjiang Tang, Yong-Chun Liu

Issue&Volume: 2023/04/18

Abstract: Spin squeezing plays a crucial role in quantum metrology and quantum information science. Its generation is the prerequisite for further applications but still faces an enormous challenge since the existing physical systems rarely contain the required squeezing interactions. Here we propose a universal scheme to generate spin squeezing in coupled spin models with collective spin-spin interactions, which commonly exist in various systems. Our scheme can transform the coupled spin interactions into squeezing interactions and reach the extreme squeezing with Heisenberg-limited measurement precision scaling as 1/N for N particles. Only constant and continuous driving fields are required, which is a requirement that is accessible to a series of current realistic experiments. This work greatly enriches the variety of systems that can generate the Heisenberg-limited spin squeezing, with broad applications in quantum precision measurement.

DOI: 10.1103/PhysRevA.107.042613

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.107.042613