Conductance and thermopower fluctuations in interacting quantum dots

Fuente: arXiv
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Main Authors: Shackleton, Leyna, Anderson, Laurel E., Kim, Philip, Sachdev, Subir
Format: Preprint
Published: 2023
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author Shackleton, Leyna
Anderson, Laurel E.
Kim, Philip
Sachdev, Subir
author_facet Shackleton, Leyna
Anderson, Laurel E.
Kim, Philip
Sachdev, Subir
contents We model an interacting quantum dot of electrons by a Hamiltonian with random and all-to-all single particle hopping (of r.m.s. strength $t$) and two-particle interactions (of r.m.s. strength $J$). For $t \ll J$, such a model has a regime exhibiting the non-quasiparticle physics of the Sachdev-Ye-Kitaev model at temperatures $E_{\rm coh} \ll T \ll J$, and that of a renormalized Fermi liquid at $T \ll E_{\rm coh}$, where $E_{\rm coh} = t^2 / J$. Extending earlier work has computed the mean thermoelectric properties of such a dot weakly coupled to two external leads, we compute the sample-to-sample fluctuations in the conductance and thermopower of such a dot, and describe several distinct regimes. In all cases, the effect of the SYK interactions is to reduce the strength of the sample-to-sample fluctuations. We also find that in the regime where the mean transport co-efficients are determined only by the value of $J$ at leading order, the sample-to-sample fluctuations can be controlled by the influence of the smaller $t$.
format Preprint
id arxiv_https___arxiv_org_abs_2309_05741
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Conductance and thermopower fluctuations in interacting quantum dots
Shackleton, Leyna
Anderson, Laurel E.
Kim, Philip
Sachdev, Subir
Strongly Correlated Electrons
Disordered Systems and Neural Networks
Mesoscale and Nanoscale Physics
High Energy Physics - Theory
We model an interacting quantum dot of electrons by a Hamiltonian with random and all-to-all single particle hopping (of r.m.s. strength $t$) and two-particle interactions (of r.m.s. strength $J$). For $t \ll J$, such a model has a regime exhibiting the non-quasiparticle physics of the Sachdev-Ye-Kitaev model at temperatures $E_{\rm coh} \ll T \ll J$, and that of a renormalized Fermi liquid at $T \ll E_{\rm coh}$, where $E_{\rm coh} = t^2 / J$. Extending earlier work has computed the mean thermoelectric properties of such a dot weakly coupled to two external leads, we compute the sample-to-sample fluctuations in the conductance and thermopower of such a dot, and describe several distinct regimes. In all cases, the effect of the SYK interactions is to reduce the strength of the sample-to-sample fluctuations. We also find that in the regime where the mean transport co-efficients are determined only by the value of $J$ at leading order, the sample-to-sample fluctuations can be controlled by the influence of the smaller $t$.
title Conductance and thermopower fluctuations in interacting quantum dots
topic Strongly Correlated Electrons
Disordered Systems and Neural Networks
Mesoscale and Nanoscale Physics
High Energy Physics - Theory
url https://arxiv.org/abs/2309.05741