中国物理学会高能物理分会第十三届全国粒子物理学术会议（2021）

Cosmic photons from astrophysical sources are ideal for investigating the Lorentz symmetry violation (LV). A series of studies on high energy gamma-ray burst (GRB) photons suggest a light speed variation with linear energy dependence at the Lorentz violation scale of $3.6*10^{17}$ GeV, with subluminal propagation of high energy photons in cosmological space. I show that a string theory model for space-time foam provides an interpretation for this light speed variation. I also show that stringent constraints on Lorentz violation in the photon sector from complementary astrophysical observations can also be explained and understood in the space-time foam context.