New Approach to Thermal Bethe Ansatz

C. Destri; H. J. de Vega

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arXiv · hep-th/9203064

New Approach to Thermal Bethe Ansatz

C. Destri·H. J. de Vega

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Abstract

We present a new approach to the calculation of thermodynamic functions for crossing-invariant models solvable by Bethe Ansatz. In the case of the XXZ Heisemberg chain we derive, for arbitrary values of the anysotropy, a {\bf single} non--linear integral equation from which the free energy can be exactly calculated. The high--temperature expansion follows in a sistematic and relatively simple way. For low temperatures we obtain the correct central charge and predict the analytic structure of the full expansion around $T=0$. Furthermore, we derive a single non-linear integral equation describing the finite--size ground--state energy of the Sine--Gordon quantum field theory. PACS: 05.30, 03.70. 75.10.5

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C. Destri, H. J. de Vega. 1992-05-26. New Approach to Thermal Bethe Ansatz. https://arxiv.org/abs/hep-th/9203064

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