Stabilizing fluctuating Cooper pairs with a terahertz resonator
Abstract
Coupling quantum materials to electromagnetic cavities or resonators without external driving has gained prominence as a new control mechanism. Here we develop an equilibrium theory of a mesoscopic, disordered two-dimensional superconductor coupled to a subwavelength terahertz resonator, focusing on the interplay between superconducting phase fluctuations in the sample and electromagnetic fluctuations of the resonator. Modeling the resonator as a lumped-element circuit, we show that the coupling enhances, rather than suppresses, the superconducting transition temperature Tc. When the sample is smaller than the Pearl length, phase fluctuations near the Berezinskii--Kosterlitz--Thouless (BKT) transition strongly amplify this enhancement. Crucially, the resistive quasiparticle response of the sample must be included in the analysis: at low frequencies the superfluid shunts the normal-fluid channel, reducing the total sample impedance. For representative parameters, a 1 μm × 1 μm, $8 $nm-thick disordered film, we find a relative Tc enhancement of about 1%, an order of magnitude larger than the $0.1\% $ obtained when phase fluctuations are neglected. These results identify superconductors with soft phase fluctuations as promising platforms for equilibrium control with terahertz resonators.
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BibTeX
@misc{lindel2026stabilizing,
title = {{Stabilizing fluctuating Cooper pairs with a terahertz resonator}},
author = {Frieder Lindel and Jonathan B. Curtis and Jérôme Faist and Eugene Demler},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.40222},
eprint = {2610.40222},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.40222},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Stabilizing fluctuating Cooper pairs with a terahertz resonator
AU - Frieder Lindel
AU - Jonathan B. Curtis
AU - Jérôme Faist
AU - Eugene Demler
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.40222
UR - https://arxiv.org/abs/2610.40222
AB - Coupling quantum materials to electromagnetic cavities or resonators without external driving has gained prominence as a new control mechanism. Here we develop an equilibrium theory of a mesoscopic, disordered two-dimensional superconductor coupled to a subwavelength terahertz resonator, focusing on the interplay between superconducting phase fluctuations in the sample and electromagnetic fluctuations of the resonator. Modeling the resonator as a lumped-element circuit, we show that the coupling enhances, rather than suppresses, the superconducting transition temperature T_c. When the sample is smaller than the Pearl length, phase fluctuations near the Berezinskii--Kosterlitz--Thouless (BKT) transition strongly amplify this enhancement. Crucially, the resistive quasiparticle response of the sample must be included in the analysis: at low frequencies the superfluid shunts the normal-fluid channel, reducing the total sample impedance. For representative parameters, a 1 μm × 1 μm, $8 $nm-thick disordered film, we find a relative T_c enhancement of about 1%, an order of magnitude larger than the $0.1\% $ obtained when phase fluctuations are neglected. These results identify superconductors with soft phase fluctuations as promising platforms for equilibrium control with terahertz resonators.
ER -