Pinning quantum phase transition for a Luttinger liquid of strongly interacting bosons

Abstract

One of the most remarkable results of quantum mechanics is the fact that many-body quantum systems may exhibit phase transitions even at zero temperature. Quantum fluctuations, deeply rooted in Heisenberg's uncertainty principle, and not thermal fluctuations, drive the system from one phase to another. Typically, the relative strength of two competing terms in the system's Hamiltonian is changed across a finite critical value. A well-known example is the Mott-Hubbard quantum phase transition from a superfluid to an insulating phase, which has been observed for weakly interacting bosonic atomic gases. However, for strongly interacting quantum systems confined to lower-dimensional geometry a novel type of quantum phase transition may be induced for which an arbitrarily weak perturbation to the Hamiltonian is sufficient to drive the transition. Here, for a one-dimensional (1D) quantum gas of bosonic caesium atoms with tunable interactions, we observe the commensurate-incommensurate quantum phase transition from a superfluid Luttinger liquid to a Mott-insulator. For sufficiently strong interactions, the transition is induced by adding an arbitrarily weak optical lattice commensurate with the atomic granularity, which leads to immediate pinning of the atoms. We map out the phase diagram and find that our measurements in the strongly interacting regime agree well with a quantum field description based on the exactly solvable sine-Gordon model. We trace the phase boundary all the way to the weakly interacting regime where we find good agreement with the predictions of the 1D Bose-Hubbard model. Our results open up the experimental study of quantum phase transitions, criticality, and transport phenomena beyond Hubbard-type models in the context of ultracold gases.

References in corpus (6)

• Many-Body Physics with Ultracold Gases
• Bosonizing one-dimensional cold atomic gases
• Phase diagram for a Bose-Einstein condensate moving in an optical lattice
• Optimized production of a cesium Bose-Einstein condensate
• Superfluid-insulator transition in a moving system of interacting bosons
• Signatures of the superfluid to Mott-insulator transition in the excitation spectrum of ultracold atoms

Cited by in corpus (12)

• Cold atom simulation of interacting relativistic quantum field theories
• Production of a dual-species Bose-Einstein condensate of Rb and Cs atoms
• 1D Quantum Liquids with Power-Law Interactions: a Luttinger Staircase with Polar Molecules
• Crossover from adiabatic to sudden interaction quench in a Luttinger liquid
• Generalized Gibbs ensemble and work statistics of a quenched Luttinger liquid
• Simulating Quantum Fields with Cavity QED
• Luttinger Liquid in Non-equilibrium Steady State
• Dimer, trimer and FFLO liquids in mass- and spin-imbalanced trapped binary mixtures in one dimension
• Bound states of Dipolar Bosons in One-dimensional Systems
• Response functions in multicomponent Luttinger liquids
• Bosonic hard spheres in quasi-one dimensional bichromatic optical lattices
• Magnetic properties of commensurate Bose-Bose mixtures in one-dimensional optical lattices