Finite-frequency noise, Fano factor, $ΔT$-noise and cross-correlations in double quantum dots

• URL: http://arxiv.org/abs/2306.02146v3
• Date: Thu, 05 Dec 2024 16:49:22 GMT
• Title: Finite-frequency noise, Fano factor, $ΔT$-noise and cross-correlations in double quantum dots
• Authors: A. Crépieux, T. Q. Duong, M. Lavagna,
• Abstract summary: We study electrical current fluctuations in a double quantum dot connected to electronic reservoirs. We derive the finite-frequency noise, the Fano factor and the $Delta T$-noise.
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• Abstract: A theoretical study on electrical current fluctuations in a double quantum dot connected to electronic reservoirs is presented, with the aim of deriving the finite-frequency noise, the Fano factor and the $\Delta T$-noise. We establish a general expression for the noise in terms of Green functions in the double quantum dot and self-energies in the reservoirs. This result is then applied to model double quantum dots in various situations. For a non-interacting double quantum dot, we highlight several interesting features in the physical properties of this system. In particular, we demonstrate the possibility of obtaining a significant reduction in zero-frequency noise and Fano factor either when the system is placed in a given operating regime, or when a temperature gradient is applied between the two reservoirs, resulting in a negative $\Delta T$-noise being generated. In addition, in the vicinity of honeycomb vertices, a sign change is observed in the finite-frequency cross-correlator between the two reservoirs, in contrast to what is obtained for the zero-frequency cross-correlator, which remains negative throughout the $(\varepsilon_1,\varepsilon_2)$-plane, $\varepsilon_{1,2}$ being the level energies in each of the two dots. By using an approximate first-level numerical approach, we finally study how the finite-frequency noise in a double quantum dot evolves under the influence of Coulomb interactions.

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