近日，荷兰阿姆斯特丹大学的Rene Gerritsma与德国汉堡大学的Antonio Negretti等人合作并取得一项新进展。他们在耦合至超冷原子气体的被捕获离子中实现了声子介导的量子门。相关研究成果已于2024年12月5日在国际知名学术期刊《物理评论A》上发表。

该研究团队研究了在超冷原子气体环境中，被捕获离子之间通过声子介导的量子比特-量子比特相互作用的动力学。通过推导并求解描述组合系统的主方程，研究人员发现原子的存在会导致运动退相干，从而降低量子门的质量。

另一方面，研究人员通过计算发现，该气体可用于在电场噪声引起的外部加热环境下保持离子晶体处于低温状态。研究人员证明，通过调节原子-离子散射长度，可以调整离子的冷却速率，并有可能在量子门操作期间暂时减小气体对离子的影响，同时确保离子在较长时间内保持低温。

这样，被捕获离子量子计算机就可以通过缓冲气体进行冷却。该系统还可用于量子增强的原子-离子相互作用测量或原子浴特性的研究。

附：英文原文

Title: Phonon-mediated quantum gates in trapped ions coupled to an ultracold atomic gas

Author: Lorenzo Oghittu, Arghavan Safavi-Naini, Antonio Negretti, Rene Gerritsma

Issue&Volume: 2024/12/05

Abstract: We study the dynamics of phonon-mediated qubit-qubit interactions between trapped ions in the presence of an ultracold atomic gas. By deriving and solving a master equation to describe the combined system, we show that the presence of the atoms causes the quantum gate quality to reduce because of motional decoherence. On the other hand, we calculate that the gas may be used to keep the ion crystal cold in the presence of external heating due to electric-field noise. We show that tuning the atom-ion scattering length allows one to tune the cooling rate of the ions and would make it possible to temporarily reduce the effects of the gas during a quantum gate while keeping the ions cold over long timescales. In this way, the trapped ion quantum computer may be buffer gas cooled. The system may also be used for quantum-enhanced measurements of the atom-ion interactions or properties of the atomic bath.

DOI: 10.1103/PhysRevA.110.063307

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.063307