6533b856fe1ef96bd12b3313

RESEARCH PRODUCT

Engineering Ising-XY spin models in a triangular lattice via tunable artificial gauge fields,

Ludwig MatheyMaciej LewensteinJuliette SimonetRobert HöppnerPhilipp HaukeKlaus SengstockAndré EckardtPatrick WindpassingerPatrick WindpassingerJulian StruckMalte WeinbergC. ÖLschläger

subject

PhysicsCondensed Matter::Quantum GasesOptical latticeCondensed matter physicsPhysics::OpticsGeneral Physics and AstronomyFOS: Physical sciences01 natural sciencesSymmetry (physics)010305 fluids & plasmasMagnetic fieldParamagnetismQuantum Gases (cond-mat.quant-gas)Quantum mechanics0103 physical sciencesComputer Science::Programming LanguagesAntiferromagnetismCondensed Matter::Strongly Correlated ElectronsHexagonal latticeIsing model010306 general physicsCondensed Matter - Quantum GasesComputer Science::DatabasesSpin-½

description

Emulation of gauge fields for ultracold atoms provides access to a class of exotic states arising in strong magnetic fields. Here we report on the experimental realisation of tunable staggered gauge fields in a periodically driven triangular lattice. For maximal staggered magnetic fluxes, the doubly degenerate superfluid ground state breaks both a discrete Z2 (Ising) symmetry and a continuous U(1) symmetry. By measuring an Ising order parameter, we observe a thermally driven phase transition from an ordered antiferromagnetic to an unordered paramagnetic state and textbook-like magnetisation curves. Both the experimental and theoretical analysis of the coherence properties of the ultracold gas demonstrate the strong influence of the Z2 symmetry onto the condensed phase.