title: Weak first-order superfluid-solid quantum phase transitions.
abstract: We study superfluid-solid zero-temperature transitions in two-dimensional lattice boson-spin models using worm-algorithm Monte Carlo simulations. We observe that such transitions are typically first order with the exception of special high-symmetry points which require fine-tuning in the Hamiltonian parameter space. We present evidence that the superfluid-checkerboard solid and superfluid-valence-bond solid transitions at half-integer filling factor are extremely weak first-order transitions and in small systems can be confused with continuous or high-symmetry points.
authors.affiliation: Department of Engineering Science and Physics, The College of Staten Island, City University of New York, Staten Island, New York 10314, USA.
authors.forename: Anatoly
authors.initials: A
authors.lastname: Kuklov
authors.forename: Nikolay
authors.initials: N
authors.lastname: Prokof'ev
authors.forename: Boris
authors.initials: B
authors.lastname: Svistunov