Preprint
Article
Thermal Fluctuations and Electromagnetic Noise Spectra in Quantum Statistical Mechanics
This version is not peer-reviewed.
Submitted:
12 October 2021
Posted:
13 October 2021
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Abstract
We derive the thermal noise spectrum of the Fourier transform of the electric field operator of a given wave vector starting from the quantum-statistical definitions and relate it to the complex frequency and wave vector dependent complex conductivity in a homogeneous, isotropic system of electromagnetic interacting electrons. We analyze separately the longitudinal and transverse case with their peculiarities. The Nyquist formula for vanishing frequency and wave vector, as well as its modification for non-vanishing frequencies and wave vectors follow immediately. Furthermore we discuss also the noise of the photon occupation numbers. It is important to stress that no additional assumptions at all were used in this straightforward proof.
Keywords:
fluctuations
; noise spectra
; longitudinal and transverse electric fields
; Nyquist noise
; photon number noise
Copyright: This open access article is published under a Creative Commons CC BY 4.0 license, which permit the free download, distribution, and reuse, provided that the author and preprint are cited in any reuse.
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