# KMS condition The Kobo-Martin-Schwinger (KMS) condition ensures $n$-point functions satisfy the appropriate fluctuation-dissipation theorems. For example, in a local QFT, let there be $n$ points along a worldline, then KMS requires$\left\langle\phi_1(t_1) \phi_2(t_2) \ldots \phi_n(t_n)\right\rangle=\left\langle\phi_2(t_2) \ldots \phi_n(t_n) \phi_1(t_1+2 \pi i)\right\rangle.$ ## Refs - original: - [[1957#Kubo]] and [[1959#Martin, Schwinger]] - KMS condition in different inertial frames: - [[2024#Passegger, Verch]] - fixing the thermal [[0103 Two-point functions|two-point function]] using KMS - [[2025#Buric, Gusev, Parnachev]]