Testing Quantumness: From Artificial Quantum Arrays to Lattice Spin Models and Spin Liquids

量子力学是物理学中最可靠的理论之一。在过去的二十年里，实验技术取得了稳定而惊人的进步，没有迹象表明量子力学即使在描述宏观系统时也是失败的。我们现在正处于“第二次量子革命”的开端，重要的研究工作正在从理解量子力学系统转向应用宏观系统的本质量子特性，以开发新的量子技术（例如，在量子计算中）。然而，直接模拟具有量子力学行为的足够大的系统实际上是不可能的，因为它需要天文数字的计算资源。目前量子工程的发展已经使我们面临这个障碍。因此，有必要开发一套近似方法，这些方法至少在平均水平上足够精确，以便为更大的人工量子系统的开发提供理解和指导，从而使基础科学和尖端技术都受益。此外，表现为量子力学的磁性材料，需要对它们的“量子性”进行同样的处理，在这种情况下是在热力学极限下。这个项目的目标是发展这样一个一般的理论，并将其应用于一些重要的问题。

Quantum mechanics is one of the best-confirmed theories in physics. Over the last two decades of steady and spectacular improvements in experimental techniques, there were no indications that quantum mechanics fails even when describing macroscopic systems. We are now at the beginning of a "second quantum revolution'', where significant research efforts are being shifted from understanding quantum mechanical systems to applying essentially quantum properties of macroscopic systems in order to develop new quantum technologies (e.g., in quantum computing). However, direct simulation of large enough systems with quantum mechanical behaviour is practically impossible, because of the astronomical computational resources it requires. Current developments in quantum engineering already brought us to face this barrier. It is therefore necessary to develop a set of approximate approaches, which are nonetheless precise enough, at least on average, to provide the understanding of and a guidance to the development of still larger artificial quantum systems, to the benefit of both fundamental science and cutting edge technology. In addition, magnetic materials, behaving quantum mechanically, require the same treatment with respect to their "quantumness", in this case in the thermodynamic limit. The goal of this project is to develop such a general theory and apply it to a number of important problems.