报告题目：Subsystem Trace Distance in Conformal Field Theory

报告人：张甲举 博士（意大利国际高等研究院(SISSA)）

报告时间：2019年6月10号（周一）15:30 - 16:30

报告地点：天津大学新校区理学院256

报告摘要：

We develop a systematic method to calculate the trace distance between two reduced density matrices in 1+1 dimensional quantum field theories. The approach exploits the path integral representation of the reduced density matrices and an ad hoc replica trick. We then extensively apply this method to the calculation of the distance between reduced density matrices of one interval of length l in eigenstates of conformal field theories. When the interval is short, using the operator product expansion of twist operators, we obtain a universal form for the leading order in l of the trace distance. We compute the trace distances among the reduced density matrices of several low lying states in two-dimensional free massless boson and fermion theories. We compare our analytic conformal results with numerical calculations in XX and Ising spin chains finding perfect agreement.

报告人简历：张甲举博士，现就职于意大利国际高等研究院（SISSA）任博士后研究员。山东师范大学物理学学士，北京大学理论物理博士。曾先后在中国科学院高能物理研究所、意大利米兰比可卡大学任博士后研究员。

代表作：

[1] J. Zhang, P. Ruggiero and P. Calabrese, Subsystem Trace Distance in Quantum Field Theory, Phys. Rev. Lett. 122 (2019) 141602, [1901.10993].
[2] W.-Z. Guo, F.-L. Lin and J. Zhang, Distinguishing Black Hole Microstates using Holevo Information, Phys. Rev. Lett. 121 (2018) 251603, [1808.02873]
[3] H. Ouyang, J.-B. Wu and J.-j. Zhang, Supersymmetric Wilson loops in N = 4 super Chern-Simons-matter theory, JHEP 11 (2015) 213, [1506.06192].
[4] B. Chen and J.-j. Zhang, On short interval expansion of Renyi entropy, JHEP 11 (2013) 164, [1309.5453].
[5] B. Chen, S.-x. Liu and J.-j. Zhang, Thermodynamics of Black Hole Horizons and Kerr/CFT Correspondence, JHEP 11 (2012) 017, [1206.2015].