Strong coupling expansion for bosons on the kagome lattice

TL;DR

This paper employs series expansion techniques to analyze phase transitions, critical points, and excitation properties of bosons on the kagome lattice, revealing insights into the Mott insulator to superfluid transition and associated critical exponents.

Contribution

It introduces a detailed series expansion analysis of bosonic phases on the kagome lattice, including multicritical points and excitation spectra, with high-order calculations of critical exponents.

Findings

Identification of clusters contributing to ground state energy, including rings.

Calculation of decay exponents of ground state correlations within the Mott phase.

Determination of quasiparticle dispersion and effective masses for particles and holes.

Abstract

We use series expansion techniques for analyzing properties of the phase transition between the Mott insulating and superfluid phase for bosons on the kagome lattice, and the multicritical point in the ground-state phase diagram for unit-filling is calculated. It is seen that of the clusters that contribute with non-zero weights to the ground state energy, many contain rings. The decay exponents of ground state correlations are also obtained within the Mott phase. For single-particle excited states, quasiparticle dispersion and effective masses for particles and holes are computed along certain symmetry cuts in the first Brillouin zone. Furthermore at eighth order, the coherence-length critical exponent is found to be comparably close to that of the 3D XY model.