Black hole radiation with short distance dispersion, an analytical S-matrix approach

Local and non-local properties of Hawking radiation in the presence of short distance dispersion are computed using connection formulae. The robustness of the spectrum and that of the two-point function are explained by showing that the leading deviations from the relativistic expressions decrease with the inverse of the spatial extension of the near horizon region. This region corresponds to a portion of de Sitter space with a preferred frame. We show that the phases of the Bogoliubov coefficients are relevant for the two-point function in black and white holes, and also for the black hole laser effect. We also present an unexpected relation between the spectra obtained with sub and with superluminal dispersion and we apply our formalism to massive fields. Our predictions are validated by numerical analysis.