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arXiv · 1505.03620

Optimization of finite-size errors in finite-temperature calculations of unordered phases

Deepak Iyer·Mark Srednicki·Marcos Rigol
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Abstract

It is common knowledge that the microcanonical, canonical, and grand-canonical ensembles are equivalent in thermodynamically large systems. Here, we study finite-size effects in the latter two ensembles. We show that contrary to naive expectations, finite-size errors are exponentially small in grand canonical ensemble calculations of translationally invariant systems in unordered phases at finite temperature. Open boundary conditions and canonical ensemble calculations suffer from finite-size errors that are only polynomially small in the system size. We further show that finite-size effects are generally smallest in numerical linked cluster expansions. Our conclusions are supported by analytical and numerical analyses of classical and quantum systems.

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Deepak Iyer, Mark Srednicki, Marcos Rigol. 2015-05-14. Optimization of finite-size errors in finite-temperature calculations of unordered phases. https://doi.org/10.1103/physreve.91.062142

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