论文标题
自由量子场理论中的伪熵
Pseudo Entropy in Free Quantum Field Theories
论文作者
论文摘要
伪熵是一个有趣的数量，具有简单的重力双重双重，它概括了纠缠熵，因此它取决于初始状态和最终状态。在这里，我们通过数值计算一组二维自由标量场理论和Ising自旋链来计算量子场理论中伪熵的基本特性。我们在免费标量理论中使用两个参数扩展了伪熵的高斯方法：质量$ m $和动态指数$ z $。该计算发现了伪熵的两种新型特性，除了区域定律行为外，我们认为在现场理论中是普遍的。一种是饱和行为，另一种是伪熵和平均纠缠熵之间差异的非阳性。此外，我们对Ising链的数值结果表明，伪熵可以作为新的量子顺序参数发挥作用，该参数检测两个状态是否处于相同的量子相。
Pseudo entropy is an interesting quantity with a simple gravity dual, which generalizes entanglement entropy such that it depends on both an initial and a final state. Here we reveal the basic properties of pseudo entropy in quantum field theories by numerically calculating this quantity for a set of two-dimensional free scalar field theories and the Ising spin chain. We extend the Gaussian method for pseudo entropy in free scalar theories with two parameters: mass $m$ and dynamical exponent $z$. This computation finds two novel properties of Pseudo entropy which we conjecture to be universal in field theories, in addition to an area law behavior. One is a saturation behavior and the other one is non-positivity of the difference between pseudo entropy and averaged entanglement entropy. Moreover, our numerical results for the Ising chain imply that pseudo entropy can play a role as a new quantum order parameter which detects whether two states are in the same quantum phase or not.
