近日，湖南师范大学的胡佳伟&张佳林及其研究团队取得一项新进展。经过不懈努力，他们对宇宙弦时空中的纠缠捕获进行研究。相关研究成果已于2024年6月24日在国际知名学术期刊《高能物理杂志》上发表。
该研究团队研究了宇宙弦时空中局部与无质量标量场相互作用的静态探测器的纠缠捕获现象，该宇宙弦时空虽然局部平坦，但具有由亏损角定义的锥形结构。
具体来说，研究人员分析了三种探测器相对于宇宙弦的对齐方式：一是探测器与弦同侧时的平行和正交对齐，二是探测器与弦相反侧的正交对齐。对于弦同侧的对齐方式，他们观察到宇宙弦的存在对纠缠捕获具有双重影响，既可以促进也可以抑制纠缠捕获，进而影响纠缠捕获的程度以及探测器间可实现的最大分离距离。这种效应与探测器和弦之间的距离紧密相关，并且与具有反射边界的局部平坦时空中的情况形成鲜明对比，因为在反射边界中，边界总是能够扩大可实现的捕获范围。
然而，当探测器在宇宙弦的两端进行正交对齐时，研究人员发现探测器总是比没有宇宙弦的平坦时空中的探测器捕获到更多的纠缠。这与在弦同侧时探测器的行为形成了鲜明对比。值得注意的是，宇宙弦的存在探测器正交对齐时扩大了其可捕获的纠缠范围，而在平行对齐时，则总是缩小了探测器的可捕获范围。
附：英文原文
Title: Entanglement harvesting in cosmic string spacetime
Author: Ji, Ying, Zhang, Jialin, Yu, Hongwei
Issue&Volume: 2024-06-24
Abstract: We investigate the entanglement harvesting phenomenon for static detectors that locally interact with massless scalar fields in the cosmic string spacetime, which, though locally flat, features a conical structure defined by a deficit angle. Specifically, we analyze three detector alignments relative to the string: parallel and orthogonal alignments with detectors on the same side of the string, and an orthogonal alignment with detectors on opposite sides of the string. For the alignments on the same side of the string, we observe that the cosmic string’s presence can either aid or hinder entanglement harvesting, affecting both the extent of entanglement harvested and the achievable range of interdetector separation. This effect depends on the distance between the detectors and the string and differs markedly from scenarios in a locally flat spacetime with a reflecting boundary, where the boundary invariably extends the harvesting-achievable range. Conversely, for the alignment with detectors on opposite sides of the string, we find that detectors consistently harvest more entanglement than those in a flat spacetime devoid of a cosmic string. This starkly contrasts the behavior observed with detectors on the same side. Interestingly, the presence of a cosmic string expands the harvesting-achievable range for detectors in orthogonal alignment only when near the string, whereas it invariably reduces the achievable range for detectors in parallel alignment.
DOI: 10.1007/JHEP06(2024)161
Source: https://link.springer.com/article/10.1007/JHEP06(2024)161