Department of Applied Mathematics, Hanyang University (ERICA), 55 Hanyangdaehak-ro, Ansan, Gyeonggi-do, 426-791, Korea.
Centre for Engineered Quantum Systems, School of Physics, University of Sydney, Sydney, NSW, 2006, Australia.
Nat Commun. 2018 Sep 17;9(1):3792. doi: 10.1038/s41467-018-06153-w.
What is the energy cost of extracting entanglement from complex quantum systems? Operationally, we may wish to actually extract entanglement. Conceptually, we may wish to physically understand the entanglement distribution as a function of energy. This is important, especially for quantum field theory vacua, which are extremely entangled. Here we build a theory to understand the energy cost of entanglement extraction. First, we consider a toy model, and then we define the entanglement temperature, relating energy cost to extracted entanglement. Next, we give a physical argument quantifying the energy cost of entanglement extraction in some quantum field vacua. There the energy cost depends on the spatial dimension: in one dimension, for example, it grows exponentially with extracted entanglement. Next, we provide approaches to bound the energy cost of extracting entanglement more generally. Finally, we look at spin chain models numerically to calculate the entanglement temperature using matrix product states.
从复杂量子系统中提取纠缠的能量成本是多少？在操作上，我们可能希望实际提取纠缠。从概念上讲，我们可能希望从物理上理解纠缠分布作为能量的函数。这一点很重要，尤其是对于量子场论真空，它们的纠缠程度极高。在这里，我们构建了一个理解纠缠提取能量成本的理论。首先，我们考虑一个玩具模型，然后定义纠缠温度，将能量成本与提取的纠缠联系起来。接下来，我们给出了一个物理论据，量化了在一些量子场真空中提取纠缠的能量成本。在这些情况下，能量成本取决于空间维度：例如，在一维中，它随着提取的纠缠呈指数增长。接下来，我们提供了更一般地限制提取纠缠的能量成本的方法。最后，我们通过数值方法研究了自旋链模型，使用矩阵乘积态计算纠缠温度。
