Gaussian quantum fluctuations in the superfluid-Mott-insulator phase transition
Authors: Faccioli M., Salasnich L.
Autors Affiliation: Univ Padua, Dipartimento Fis & Astron Galileo Galilei, Via Marzolo 8, I-35131 Padua, Italy; CNR, Ist Nazl Ott, Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy
Abstract: Recent advances in cooling techniques make possible the experimental study of quantum phase transitions, which are transitions near absolute zero temperature accessed by varying a control parameter. A paradigmatic example is the superfluid-Mott transition of interacting bosons on a periodic lattice. From the relativistic Ginzburg-Landau action of this superfluid-Mott transition we derive the elementary excitations of the bosonic system, which contain in the superfluid phase a gapped Higgs mode and a gapless Goldstone mode. We show that this energy spectrum is in good agreement with the available experimental data and we use it to extract, with the help of dimensional regularization, meaningful analytical formulas for the beyond-mean-field equation of state in two and three spatial dimensions. We find that, while the mean-field equation of state always gives a second-order quantum phase transition, the inclusion of Gaussian quantum fluctuations can induce a first-order quantum phase transition. This prediction is a strong benchmark for future experiments on quantum phase transitions.
Journal/Review: PHYSICAL REVIEW A
Volume: 99 (2) Pages from: 023614-1 to: 023614-7
KeyWords: MODEL; LOCALIZATIONDOI: 10.1103/PhysRevA.99.023614Citations: 2data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2021-03-07References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here