Coupling two order parameters in a quantum gas
Coupling two order parameters in a quantum gas
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耦合量子气体中的二阶参数
DOI：
10.1038/s41563-018-0118-1
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发表时间：
2017
期刊：
影响因子：
41.2
通讯作者：
T. Donner
中科院分区：
文献类型：
--
作者：
A. Morales;P. Zupancic;J. Léonard;T. Esslinger;T. Donner
控制物质以同时支持耦合特性具有基础和技术重要性1（例如，在多铁性2 -5或高温超导体6 -9中）。然而，确定负责同时存在不同订单的微观机制是困难的，使得难以预测材料现象10，11或修改properties 12 -16。在这里，使用量子气体在微观水平上设计可调节的相互作用，我们展示了两个订单的竞争，共存和相互增强的场景。对于增强场景，一个阶的存在降低了另一个阶的临界点。我们的系统是通过玻色-爱因斯坦凝聚体实现的，该凝聚体可以在两个光学谐振器中进行自组织相变，从而产生两个不同的晶体密度级。我们通过测量复合序参量和基本激发来表征这些订单之间的耦合，并用来自微观哈密顿量的平均场自由能模型来解释我们的结果。我们的系统非常适合于探索量子三临界点18，并可以扩展到研究自旋和密度阶数19作为温度的函数20的相互作用。超冷原子可以模拟单阶量子相位，但不同阶数参数的耦合尚未显示。在这里，这是证明使用两个光学谐振器，促进探索多阶系统，如多铁性。
Controlling matter to simultaneously support coupled properties is of fundamental and technological importance1 (for example, in multiferroics2–5 or high-temperature superconductors6–9). However, determining the microscopic mechanisms responsible for the simultaneous presence of different orders is difficult, making it hard to predict material phenomenology10,11 or modify properties12–16. Here, using a quantum gas to engineer an adjustable interaction at the microscopic level, we demonstrate scenarios of competition, coexistence and mutual enhancement of two orders. For the enhancement scenario, the presence of one order lowers the critical point of the other. Our system is realized by a Bose–Einstein condensate that can undergo self-organization phase transitions in two optical resonators17, resulting in two distinct crystalline density orders. We characterize the coupling between these orders by measuring the composite order parameter and the elementary excitations and explain our results with a mean-field free-energy model derived from a microscopic Hamiltonian. Our system is ideally suited to explore quantum tricritical points18 and can be extended to study the interplay of spin and density orders19 as a function of temperature20.Ultracold atoms can model single-order quantum phases, but coupling of different order parameters has not been shown. Here, this is demonstrated using two optical resonators, facilitating exploration of multiple-order systems such as multiferroics.
影响因子：
2.9
作者：
S. Gopalakrishnan;Yulia E. Shchadilova;E. Demler
通讯作者：
S. Gopalakrishnan;Yulia E. Shchadilova;E. Demler
影响因子：
19.6
作者：
Friedemann, Sven;Duncan, Will J.;Grosche, F. Malte
通讯作者：
Grosche, F. Malte