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| Format: | Preprint |
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2026
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| Online Access: | https://arxiv.org/abs/2605.28993 |
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| _version_ | 1866913168724328448 |
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| author | Chaudhary, Pragya |
| author_facet | Chaudhary, Pragya |
| contents | We investigate memory effects and quantum transport in two-dimensional lattice systems within the framework of non-equilibrium Green's functions and Schwinger-Keldysh non-equilibrium quantum field theory. Starting from a 2D tight-binding Hamiltonian, we employ the Dyson expansion on the Keldysh contour and the second-order Born and self-consistent Born Approximation to derive the electronic self-energies associated with elastic and inelastic scattering mechanisms.Static disorder produces a local self-energy and a rapidly decaying memory kernel, characteristic of Markovian dynamics, whereas electron-phonon coupling generates temporally nonlocal self-energies and genuine Non-Markovian behavior. We demonstrate that these distinct memory signatures are directly reflected in the spectral function, which we propose as a diagnostic probe of non-equilibrium memory effects. Further we explore 1PI and 2PI effective actions to see their memory perspectives studying their coarse-graining behavior. Building on this theoretical framework, we further apply the conventional NEGF formalism to two paradigmatic two-dimensional models-the Hofstadter and an RKKY-coupled system to explore how different microscopic Hamiltonians influence Markovian and Non-Markovian nature. Our results provide a unified connection between scattering mechanisms, memory effects, and quantum transport in low-dimensional systems. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2605_28993 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Reinterpreting Memory Effects in Nonequilibrium Systems: From Temporal Dynamics to Steady-State Signatures via NEGF Chaudhary, Pragya Mesoscale and Nanoscale Physics We investigate memory effects and quantum transport in two-dimensional lattice systems within the framework of non-equilibrium Green's functions and Schwinger-Keldysh non-equilibrium quantum field theory. Starting from a 2D tight-binding Hamiltonian, we employ the Dyson expansion on the Keldysh contour and the second-order Born and self-consistent Born Approximation to derive the electronic self-energies associated with elastic and inelastic scattering mechanisms.Static disorder produces a local self-energy and a rapidly decaying memory kernel, characteristic of Markovian dynamics, whereas electron-phonon coupling generates temporally nonlocal self-energies and genuine Non-Markovian behavior. We demonstrate that these distinct memory signatures are directly reflected in the spectral function, which we propose as a diagnostic probe of non-equilibrium memory effects. Further we explore 1PI and 2PI effective actions to see their memory perspectives studying their coarse-graining behavior. Building on this theoretical framework, we further apply the conventional NEGF formalism to two paradigmatic two-dimensional models-the Hofstadter and an RKKY-coupled system to explore how different microscopic Hamiltonians influence Markovian and Non-Markovian nature. Our results provide a unified connection between scattering mechanisms, memory effects, and quantum transport in low-dimensional systems. |
| title | Reinterpreting Memory Effects in Nonequilibrium Systems: From Temporal Dynamics to Steady-State Signatures via NEGF |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2605.28993 |