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arXiv · 1801.01862

High-order symbolic strong-coupling expansion for the Bose-Hubbard model

Tao Wang·Xue-Feng Zhang·Chun-Feng Hou·Sebastian Eggert·Axel Pelster
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Abstract

Combining the process-chain method with a symbolized evaluation we work out in detail a high-order symbolic strong-coupling expansion (HSSCE) for determining the quantum phase boundaries between the Mott insulator and the superfluid phase of the Bose-Hubbard model for different fillings in hypercubic lattices of different dimensions. With a subsequent Pad{é} approximation we achieve for the quantum phase boundaries a high accuracy, which is comparable to high-precision quantum Monte-Carlo simulations, and show that all the Mott lobes can be rescaled to a single one. As a further cross-check, we find that the HSSCE results coincide with a hopping expansion of the quantum phase boundaries, which follow from the effective potential Landau theory (EPLT).

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Tao Wang, Xue-Feng Zhang, Chun-Feng Hou, Sebastian Eggert, Axel Pelster. 2018-09-19. High-order symbolic strong-coupling expansion for the Bose-Hubbard model. https://doi.org/10.1103/physrevb.98.245107

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