Description exacte du transport dans les résistances stochastiques quantiques et les dispositifs contrôlés. – (Michele Filippone / LPT / Seminar). – 11/07/2024, 14H

Understanding the emergence of diffusion in quantum systems remains a challenging problem in theoretical physics. An extended class of models expected to exhibit diffusive behavior is given by Quantum Stochastic Hamiltonians (QSHs), which describe lattice models affected by time- and space-dependent noise. However, the averaged dynamics of such models are governed by non-linear Lindblad equations, whose theoretical study usually relies on numerical methods or case-by-case solutions, with strong constraints on geometries and driving protocols.

In this talk, I will present a systematic method to derive exact and analytical solutions for the stationary quantum transport of QSHs in arbitrary configurations [1]. Our solution is based on an exact self-consistent Born scheme for diagrammatics in the Keldysh representation [2]. We show that most QSHs behave as diffusive “quantum stochastic resistors,” whose properties are encoded in the Keldysh component of the single-particle Green’s function. I will provide a semi-classical interpretation of such systems [3], and in particular, I will discuss how our exact solution demonstrates the validity of a new perturbation scheme in the inverse system size, named the 1/N expansion, to study out-of-equilibrium diffusive/ohmic systems.

I will conclude by discussing how our approach can be extended to describe quantum transport in continuously monitored settings. I will show that measurements trigger non-reciprocal currents in quantum devices, thus acting as a resource for power generation and quantum measurement cooling [4].

• [1] T. Jin, J. S. Ferreira, M. Filippone, T. Giamarchi, Physical Review Research 4, 013109 (2022)
• [2] P. E. Dolgirev, J. Marino, D. Sels, E. Demler, Physical Review B 102, 100301 (2020)
• [3] T. Jin, J. S. Ferreira, M. Filippone, T. Giamarchi, Physical Review Research 5, 013033 (2023)
• [4] J. S. Ferreira, T. Jin, J. Mannhart, T. Giamarchi, M. Filippone, Physical Review Letters 132, 136301 (2024) – Editors’ Suggestion