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arXiv · 2504.01880

Partition function zeros of quantum many-body systems

B Sriram Shastry
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Abstract

We present a new method for calculating the Yang-Lee partition function zeros of a translationally invariant model of lattice fermions, exemplified by the Hubbard model. The method rests on a theorem involving the single electron self-energy $\Sigma_\sigma(k, i \omega_n)$ in the imaginary time Matsubara formulation. The theorem maps the Yang-Lee zeros to a set of wavevector and spin labeled virtual energies $\xi_{k \sigma}$. These, thermodynamically derived virtual energies, are solutions of equations involving the self-energy at corresponding $k\sigma$'s. Examples of the method in simplified situations are provided.

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B Sriram Shastry. 2025-04-02. Partition function zeros of quantum many-body systems. https://doi.org/10.1103/3zm3-wbjk

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