Regensburg 2007 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 20: Correlated Electrons - Poster Session

TT 20.78: Poster

Wednesday, March 28, 2007, 14:00–17:45, Poster A

Efficient simulation of one-dimensional many-body quantum systems — •Alex Cojuhovschi, Malcolm Einhellinger, and Eric Jeckelmann — Institut für Theoretische Physik, Leibniz Universität Hannover

Vidal's time-evolving block decimation (TEBD) algorithm allows for the accurate simulation of the ground state and the time evolution in one-dimensional many-body quantum systems. Although density-matrix renormalization group (DMRG) methods seem more versatile and efficient than the TEBD algorithm on sequential computers, extensively parallelized DMRG codes have shown a good scalability only up to 8 or 16 processors, which severely restricts their use on modern parallel supercomputers. We show that the TEBD algorithm can be easily parallelized and has a much better scalability than DMRG codes for large systems. This could enable the use of massively parallel computers for this type of simulations.

Furthermore, we have investigated the time-evolution of the density-matrix spectrum in non-interacting electron systems out of equilibrium such as two reservoirs coupled through a quantum dot. This allows us to devise more efficient procedures for simulating large non-interacting subsystems (such as charge or heat reservoirs) in DMRG and TEBD approaches to the time evolution of quantum systems.