Abstract
We present an extension of the classical Johnson-Nyquist theorem for multiport classical electrical passive linear networks by Twiss [J. Appl. Phys. 26, 599 (1955)] to the quantum case. Conversely, we extend the quantum fluctuation-dissipation result for one port electrical systems to the multiport case, both reciprocal and nonreciprocal, performing a detailed quantum analysis of the canonical Foster lossless immittance expansions. Our results are extended to lossy systems by depicting resistive components as continuous limits of purely lossless lumped-element networks. Simple circuit examples are analyzed, including a linear system lacking a direct impedance representation.
- Received 9 November 2021
- Accepted 20 July 2022
DOI:https://doi.org/10.1103/PhysRevB.106.054504
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