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arXiv:2604.15595

Exact Analysis of a One-Dimensional Yang-Gaudin Model with Two-Body Loss

Ryutaro Katsuta, Shun Uchino

Published Apr 17, 2026• 0 citations
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Abstract

We show that the one-dimensional Yang-Gaudin model with two-body loss remains exactly solvable irrespective of whether constituent particles are bosons or fermions. By relating the Liouvillian spectrum to the right eigenvalues of a non-Hermitian effective Hamiltonian obtained by complexifying the interaction strength, we derive a general expression for the initial particle-loss rate. We then solve the two-body problem exactly and show that, in the bosonic singlet sector, the effective Hamiltonian has real right eigenvalues and the master equation admits steady-state solutions. For many-body systems with three or more particles, we further show that dissipation reverses which spin configurations are most stable: in bosonic systems it favors antiferromagnetic-like configurations over ferromagnetic-like ones, whereas in fermionic systems it favors ferromagnetic-like configurations over antiferromagnetic-like ones.

DOI
10.48550/arxiv.2604.15595

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We study an interacting one-dimensional gas of spin-1/2 fermions with two-body losses. The dynamical phase diagram that characterizes the approach to the stationary state displays a wide quantum Zeno region, identified by a peculiar behavior of the lowest eigenvalues of the associated non-Hermitian Hamiltonian. We characterize the universal dynamics of this Zeno regime using an approximation scheme based on an effective decoupling of charge and spin degrees of freedom, where the latter effectively evolve according to a non-Hermitian Heisenberg Hamiltonian. We present detailed results for the time evolution from initial states with one particle per site with either incoherent or antiferromagnetic spin order, showing how peculiar charge properties witnessed by the momentum distribution function build up in time.
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