About the topic
In linearised gravity, the Schwarzschild solution and its mass are related to unphysical degrees of freedom rather than physical gravitons. This motivates the study of the analog problem in electromagnetism, where the role of the black hole is played by the Coulomb solution, while mass corresponds to electric charge. When all polarisations of the photon are quantised in an indefinite metric Hilbert space, it is shown (i) that the quantum state corresponding to the classical Coulomb solution is a coherent state of longitudinal and temporal photons, and (ii) that the edge modes of a charged vacuum capacitor give a contribution to the partition function that is proportional to the area and explains the Gibbons-Hawking entropy of the system.
About the speaker
Glenn Barnich is a theoretical physicist and professor at the Université libre de Bruxelles. His research interests center on the structure of gauge and gravitational theories and on ways to quantize them. He regularly teaches a course on Quantum Field Theory in the Physics Master’s program in Luxembourg.