Photons in a Ball

Abstract

The electromagnetic field inside a spherical cavity of large radius R is considered in the presence of stationary charge and current densities. R provides infra-red regularization while maintaining gauge invariance. The quantum ground state of physical photons forming the magnetic field is found to be a coherent state with a definite mean occupation number. The electric field, which is determined by the Gauss law constraint, is maintained by a minimum uncertainty coherent state, according to the projection operator approach to the quantization of constrained systems. The mean occupation number of this state is proportional to the square of the total charge. The results confirm formulae obtained previously from a calculation with a finite photon mass for infra-red regularization.

16 pages, 1 figure, v.2: added reference as in published version

References in corpus (11)

• Black Hole Formation and Classicalization in Ultra-Planckian 2 -> N Scattering
• Classical Limit of Black Hole Quantum N-Portrait and BMS Symmetry
• Black Holes and Quantumness on Macroscopic Scales
• Black holes as self-sustained quantum states, and Hawking radiation
• Non-Thermal Corrections to Hawking Radiation Versus the Information Paradox
• Thermal corpuscular black holes
• Vacuum energy, holography and a quantum portrait of the visible Universe
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• Suppressing Quantum Fluctuations in Classicalization
• Quantum Portrait of a Black Hole with Pöschl-Teller Potential
• Consistent Cosmic Microwave Background Spectra from Quantum Depletion

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• Quantum black holes in bootstrapped Newtonian gravity
• Strolling along gauge theory vacua
• Infrared scaling for a graviton condensate
• Stückelberg Formulation of Holography
• Coherent States in Gauge Theories: Topological Defects and Other Classical Configurations
• Lower dimensional corpuscular gravity and the end of black hole evaporation