Quantum Monte Carlo algorithms using coherent states

We consider several algorithms for discrete approximations for path integrals to be used in the study of the thermodynamics of boson and spin systems. We use coherent states as an expansion basis for both bosons and spins (Bloch coherent states) and compare algorithms using matrix elements or diagon...

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Bibliographic Details
Published in:Physica A 1994-06, Vol.207 (4), p.584-607
Main Authors: Vieira, V.R., Sacramento, P.D.
Format: Article
Language:English
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Summary:We consider several algorithms for discrete approximations for path integrals to be used in the study of the thermodynamics of boson and spin systems. We use coherent states as an expansion basis for both bosons and spins (Bloch coherent states) and compare algorithms using matrix elements or diagonal representatives or both. Since the overlaps between the coherent states are in general complex, the use of the algorithms in the quantum Monte Carlo study carries the so-called sign problem. In the case of a simple harmonic oscillator we find that some algorithms in phase space give better accuracy than the traditional algorithm in configuration space. In the case of a spin in a magnetic field we find that the algorithms using the diagonal representative yield better results than those with matrix elements.
ISSN:0378-4371
1873-2119
DOI:10.1016/0378-4371(94)90212-7