Effect of electron-hole asymmetry on $\Delta_T$ noise in metal/quantum point contact/metal and metal/quantum point contact/superconductor junctions

Abstract:This work examines charge $\Delta_T$ noise in two-terminal hybrid nanostructures featuring a quantum point contact (QPC), realized either between two normal metallic leads (NQN) or between a normal metal and a superconducting lead (NQS). The energy-dependent transmission of a QPC breaks electron-hole (e-h) symmetry, leading to a finite thermovoltage under an applied temperature and voltage bias. In contrast, in earlier studies on hybrid junctions incorporating insulating barriers, as electron-hole symmetry is preserved, have vanishing thermovoltage, and consequently, charge $\Delta_T$ noise is calculated at zero thermovoltage. In our setup, the broken e-h symmetry allows for a finite thermovoltage, at which we compute the corresponding charge $\Delta_T$ noise. Unlike earlier studies restricted by electron-hole symmetry and vanishing thermovoltage, our work establishes a self-consistent thermoelectric noise framework in mesoscopic hybrid junctions, revealing how Andreev reflection fundamentally reshapes charge $\Delta_T$ noise once electron-hole symmetry is broken. This broad access to charge fluctuation signatures provides a more comprehensive understanding of non-equilibrium transport in linear response. To the best of our knowledge, this is the first work that systematically explores the interplay between Andreev reflection and electron-hole symmetry breaking in the context of quantum noise and $\Delta_T$ noise in mesoscopic hybrid structures.

Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Mathematical Physics (math-ph); Applied Physics (physics.app-ph); Quantum Physics (quant-ph)

arXiv:2601.00402 [cond-mat.mes-hall]

(or arXiv:2601.00402v2 [cond-mat.mes-hall] for this version)

https://doi.org/10.48550/arXiv.2601.00402 Focus to learn more arXiv-issued DOI via DataCite

Phys. Rev. B (2026)

https://doi.org/10.1103/gtjm-rsqk Focus to learn more DOI(s) linking to related resources

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