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TT: Fachverband Tiefe Temperaturen
TT 50: Correlated Electrons: Frustrated Magnets - Theory
TT 50.15: Talk
Wednesday, March 9, 2016, 19:00–19:15, H18
1/d expansion for the transverse-field Ising model — •Darshan G. Joshi and Matthias Vojta — Institut für Theoretische Physik, Technische Universität Dresden
Analytic 1/d expansion method, previously developed for coupled-dimer magnets, is applied to the transverse-field Ising model (d>1) at zero temperature. We introduce auxiliary Bosons to map the spin Hamiltonian onto a Bosonic Hamiltonian. The hard-core constraint from the physical Hilbert space is implemented using the projection operator. The 1/d expansion is employed in both, the paramagnetic as well as the ferromagnetic, phases. We present 1/d expansion for static as well as dynamic observables, including the phase boundary. We thus have a consistent description of the entire phase diagram, including the quantum critical point.