Simulation of Quantum Lattice Systems with the Tensor Renormalization Group

Datum

11.04.2012

Zeit

11:00 - 12:15

Sprecher

Robert Bamler

Sprache

en

Hauptthema

Physik

Andere Themen

Physik

Host

S. Kirchner

Beschreibung

I will describe a numerical algorithm for the efficient calculation of local expectation values in the ground state of quantum lattice systems. For a given Hamiltonian, the algorithm uses imaginary time evolution to find an approximate ground state in the form of a tensor product state (or PEPS). Tensor product states are a generalization of matrix product states, as used in the DMRG, to higher spatial dimensions. The algorithm then evaluates expectation values by means of an approximate method known as Tensor Renormalization Group (TRG). I will show that the described algorithm is also capable of simulating fermionic systems and that one can improve performance by exploiting symmetries of the Hamiltonian. Results for the antiferromagnetic Heisenberg model on the honeycomb lattice agree well with QMC calculations. For the Hubbard model on the honeycomb lattice, I find a vanishing topological entanglement entropy for all interaction strengths, contradicting QMC results. Main References: http://prl.aps.org/abstract/PRL/v99/i12/e120601 http://prl.aps.org/abstract/PRL/v103/i16/e160601

Letztmalig verändert: 11.04.2012, 09:36:37