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arXiv · 2603.24487

Order-separated tensor-network method for QCD in the strong-coupling expansion

Thomas Samberger·Jacques Bloch·Robert Lohmayer·Tilo Wettig
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Abstract

We introduce the order-separated Grassmann higher-order tensor renormalization group (OS-GHOTRG) method for QCD with staggered quarks in the strong-coupling expansion. The method allows us to determine the expansion coefficients of the partition function, from which we can obtain the strong-coupling expansions of thermodynamical observables. We use the method in two dimensions to compute the free energy, the particle-number density, and the chiral condensate as a function of the chemical potential up to third order in the inverse coupling $\beta$. Although near the phase transition the expansion is only a good approximation to the full theory at small $\beta$, we show that the range of applicability can be greatly extended by fits to judiciously chosen transition functions.

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Thomas Samberger, Jacques Bloch, Robert Lohmayer, Tilo Wettig. 2026-03-25. Order-separated tensor-network method for QCD in the strong-coupling expansion. https://arxiv.org/abs/2603.24487

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