近日，法国艾克斯马赛大学及其研究小组取得一项新进展。经过不懈努力，他们探究了激光冷却俘获离子中的热双稳定性。相关研究成果已于2023年7月13日在国际知名学术期刊《物理评论A》上发表。

该研究小组发现加热速率与离子数没有明显的关系，而与振荡场密切相关。这证明了系综密度在其中起主导作用。此外，研究人员讨论了射频加热与激光冷却的竞争问题。这些发现为设计场景提供了新的思路，可以利用阈值效应来检测和量化入侵者的扰动。

(资料图)

据悉，通过将大离子云（N≥256个离子）俘获于射频（rf）势阱，并与激光冷却相耦合，可以观察到其非线性动力学导致的温度双稳态行为。该研究利用数值模拟方法，对三维大球面云的自由演化过程进行了详细研究，描述了振荡场振幅和离子数目如何影响射频加热速率以及两种稳态之间的转换过程。

附：英文原文

Title: Thermal bistability in laser-cooled trapped ions

Author: A. Poindron, J. Pedregosa-Gutierrez, C. Champenois

Issue&Volume: 2023/07/13

Abstract: The nonlinear dynamics of large ion clouds (N≥256 ions) trapped in radio-frequency (rf) traps and coupled to laser cooling give rise to a bistable behavior of the temperature. Numerical simulations of the free evolution of a large three-dimensional spherical cloud is used to characterize how the oscillating field amplitude and the ion number control the rf-heating rate and the switching between the two stable states. We show that the heating rate does not significantly depend on the ion number but strongly depends on the oscillating field. This exhibits the major role played by the density of the ensemble. The competition between the radio-frequency heating and the laser cooling is also discussed. They are used to design scenarios to take advantage of the threshold effect to detect and quantify perturbations by an intruder.

DOI: 10.1103/PhysRevA.108.013109

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.108.013109

来源：科学网 小柯机器人

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