Abstract: The mechanism of high-temperature superconductivity in copper-oxide compounds (cuprates) is still unknown since its discovery thirty years ago. The conventional superconductivity originates from the coherent movement of Cooper pairs, in which the two interacted electrons are mediated by lattice vibrations (phonons), and the studies of many-body effects have provided direct evidence for the success of BCS theory. Electron pairing has been well established in cuprate superconductors, but the mechanism of the pairing remains unclear. Similar to that in conventional superconductors, the study of many-body effects in cuprate high-temperature superconductor is important in revealing the pairing mechanism of high-temperature superconductivity. With a great improvement of instrumental resolutions, angle-resolved photoemission spectroscopy (ARPES) plays an important role in probing the many-body effects. In recent years, the time- and angle-resolved photoemission spectroscopy (trARPES) which added a unique time dimension to the conventional ARPES, has become a powerful tool in studying many-body effects dynamics. Here, we summary our past study on the many-body effects in the cuprate superconductor Bi2Sr2CaCu2O8+ using trARPES and ultra-high resolution ARPES, including the momentum dependence of many-body effects, the extraction of pairing self-energy, and the stimulated emission of bosons.

Key words: cuprate; photoemission; time-resolved; many-body effect