Bremen 2017 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 15: Quantenaspekte der Gravitation und vereinheitlichender Theorien 1

GR 15.3: Talk

Thursday, March 16, 2017, 17:30–17:50, SFG 0140

Hawking radiation: Comparison of pure-state and thermal description — •Yi-Fan Wang and Claus Kiefer — Institut für Theoretische Physik, Universität zu Köln, Zülpicher Straße 77, 50937 Köln

We present the power spectral densities for a quantum field in the background of a Schwarzschild black hole and compare the cases of the field being in a pure state and in the usual thermal state. In the low-energy regime the densities strongly differ, while at high energies they practically coincide. We define a distance measure between the resulting two density operators and evaluate it assuming an UV cutoff and discrete field energy levels. We find that the distance is exponentially small with respect to the number of the levels as well as the ratio of the cutoff and the Hawking temperature. We finally discuss the operational meaning of a vanishing distance.