Far From Equilibrium Quantum Simulators

这是奖学金“脱离平衡的相干量子物质——从基础物理学到应用”的延伸。最初的项目涉及广泛的光子系统中的集体现象，以探索物质的基本性质及其在器件应用中的应用。扩展现在将集中在强相互作用和大质量光子的系统上，这些光子被放置在人工制造的晶格势中，模仿真实的固体，并将它们用作量子模拟器。自从量子模拟的想法被提出以来，寻找合适的物理平台一直是量子技术最活跃的分支之一。量子模拟涉及到创建和控制更简单的系统来模拟更复杂和难以理解的系统的行为。由于它们的轻质量，光子已经被证明在高温、室温下表现出量子效应，并且可以很容易地与其他技术应用平台集成。因此，用光子创造合成量子物质来模拟人们知之甚少的晶格系统（比如真实的固体）的想法特别有吸引力。然而，光子不能被完美地捕获并与它们的环境解耦，这导致了非平衡耗散条件，如果与强相互作用和相关性相结合，则很难描述，但与现实生活中的应用特别相关。该项目的主要目的是设计有效的新理论和计算方法，与实验组合作处理光子驱动耗散晶格系统中的强相关性和纠缠，并使用这些方法设计实验探索的协议，以量子模拟的精神。我们将重点关注两个特别有前途的平台：极化子晶格，即特别设计的半导体结构，以及与微波光子耦合的超导电路。我们的研究将解决强相互作用与强耗散和非平衡条件相结合时的相变、有序、对称性和拓扑等基本问题，以及相关如何形成和传播的实际问题，以及如何控制和保护它们免受外部世界的破坏性影响。

This is an extension of the Fellowship "Coherent quantum matter out of equilibrium - from fundamental physics towards applications". The original project concerned collective phenomena in a wide range of photonic systems to explore the fundamental properties of matter and their use for device applications. The extension will now focus on systems of strongly interacting and massive photons, placed in artificially made lattice potentials mimicking real solids, and their use as quantum simulators. Ever since the idea of quantum simulations, which involves the creation and control of simpler systems to model the behaviour of more complex and poorly understood systems, have been proposed, the search for suitable physical platforms has been one of the most active branches of Quantum Technologies. Due to their light mass, photons have been shown to exhibit quantum effects at high, up-to-room temperatures and can be easily integrated with other platforms for technological applications. Thus, the idea of creating synthetic quantum matter out of photons to simulate poorly understood lattice systems, such as real solids, has been particularly attractive. However, photons cannot be perfectly trapped and decoupled from their environment, which leads to non-equilibrium dissipative conditions, that are challenging to describe if combined with strong interactions and correlations, but particularly relevant for real life applications. The main aim of the project is to devise effective new theoretical and computational methods to treat strong correlations and entanglement in driven-dissipative lattice systems of photons in collaboration with experimental groups, and to use these methods to design protocols for experimental exploration of those in the spirit of quantum simulation. We will focus on two particularly promising platforms: polariton lattices i.e. specially engineered semiconductor structures, and superconducting circuits coupled to microwave photons. Our research will address fundamental problems of phase transitions, orders, symmetry and topology when strong interactions combine with strong dissipation and non-equilibrium conditions, as well as practical questions how correlations form and propagate, and how they can be controlled and protected from the destructive influence of the outside world.