title: Quantum ice: a quantum Monte Carlo study.
abstract: Ice states, in which frustrated interactions lead to a macroscopic ground-state degeneracy, occur in water ice, in problems of frustrated charge order on the pyrochlore lattice, and in the family of rare-earth magnets collectively known as spin ice. Of particular interest at the moment are "quantum spin-ice" materials, where large quantum fluctuations may permit tunnelling between a macroscopic number of different classical ground states. Here we use zero-temperature quantum Monte Carlo simulations to show how such tunnelling can lift the degeneracy of a spin or charge ice, stabilizing a unique "quantum-ice" ground state-a quantum liquid with excitations described by the Maxwell action of (3+1)-dimensional quantum electrodynamics. We further identify a competing ordered squiggle state, and show how both squiggle and quantum-ice states might be distinguished in neutron scattering experiments on a spin-ice material.
authors.affiliation: H. H. Wills Physics Laboratory, University of Bristol, Bristol, United Kingdom.
authors.forename: Nic
authors.initials: N
authors.lastname: Shannon
authors.forename: Olga
authors.initials: O
authors.lastname: Sikora
authors.forename: Frank
authors.initials: F
authors.lastname: Pollmann
authors.forename: Karlo
authors.initials: K
authors.lastname: Penc
authors.forename: Peter
authors.initials: P
authors.lastname: Fulde