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Q: Fachverband Quantenoptik und Photonik

Q 12: Quantum Information: Concepts and Methods 2

Q 12.2: Vortrag

Montag, 14. März 2011, 14:45–15:00, SCH A118

Solving frustration-free spin models — •Niel de Beaudrap¹, Matthias Ohliger¹, Tobias J. Osborne², and Jens Eisert¹ — ¹Universität Potsdam, Institut für Physik und Astronomie, Karl-Liebknecht-Strasse 24/25 14476 Potsdam — ²Leibnitz Universität Hannover, Institut für Theoretische Physik, Appelstraße 2, 30167 Hannover, Germany

We show that ground states of unfrustrated quantum spin-1/2 systems on general lattices satisfy an entanglement area law, provided that the Hamiltonian can be decomposed into nearest-neighbor interaction terms which have entangled excited states. The ground state manifold can be efficiently described as the image of a low-dimensional subspace of low Schmidt measure, under an efficiently contractible tree-tensor network. This structure gives rise to the possibility of efficiently simulating the complete ground space (which is in general degenerate). We also show how our approach gives rise to an ansatz class useful for the simulation of almost frustration-free models in a simple fashion, outperforming mean field theory.