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arXiv · 2510.03112

Analytical solution of a free-fermion chain with time-dependent ramps

Viktor Eisler·Riccarda Bonsignori·Stefano Scopa
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Abstract

We provide an exact analytical solution of the single-particle Schr\"odinger equation for a chain of non-interacting fermions subject to a time-dependent linear potential, with its slope varied as an arbitrary function of time. The resulting dynamics exhibit self-similar behavior, with a structure reminiscent of the domain wall melting problem, albeit characterized by a nontrivial time-dependent length scale and phase. Building on this solution, we derive hydrodynamic predictions for the evolution of particle density, current, and entanglement entropy along the chain. In the special case of a sudden quench, the system develops a breathing interface region, which may be interpreted as a realization of Wannier-Stark localization, as previously suggested on the basis of hydrodynamic arguments.

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Viktor Eisler, Riccarda Bonsignori, Stefano Scopa. 2025-10-03. Analytical solution of a free-fermion chain with time-dependent ramps. https://doi.org/10.1209/0295-5075%2Fae34e4

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