Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 5: Correlated Electrons: Spin Systems and Itinerant Magnets – Frustrated Magnets 1 (jointly with MA)

TT 5.6: Vortrag

Montag, 16. März 2015, 10:45–11:00, H 0110

Quantum Monte Carlo Study of Long-Range Transverse-Field Ising Models on the Triangular Lattice — •Stephan Humeniuk — Institut für Theoretische Physik III, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany

Motivated by recent experiments with a Penning ion trap quantum simulator, we perform Stochastic Series Expansion quantum Monte Carlo simulations of long-range transverse-field Ising models on a triangular lattice for different decay powers α of the interactions. The phase boundary for the ferromagnet is obtained as a function of α. For antiferromagnetic interactions we find that the transverse field stabilizes a clock ordered phase with sublattice magnetization (M,−M/2, −M/2) with M≈ 1 in a process known as “order by disorder” similar to the nearest neighbour antiferromagnet on the triangular lattice. Connecting the known limiting cases of nearest neighbour and infinite-range interactions, we obtain a semi-quantitative phase diagram. Magnetization curves for the ferromagnet for experimentally relevant system sizes and with open boundary conditions are presented.