Berlin 2014 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 71: Quantum information: Concepts and methods VI
Q 71.3: Vortrag
Freitag, 21. März 2014, 17:00–17:15, Kinosaal
Adaptive mode transformations in fermionic tensor networks — •Christian Krumnow1, Adam Nagy1, Reinhold Schneider2, Örs Legeza3, and Jens Eisert1 — 1Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, Berlin, Germany — 2Institute for Mathematics, Technische Universität Berlin, Berlin, Germany — 3Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, Hungary
Non-local fermionic models are frequently encountered in physics, most prominently in quantum chemistry, but also when capturing quantum lattice systems. The long-range nature of the interactions present in such systems, however, renders their straightforward numerical simulation using tensor-network methods difficult. When using a DMRG-based method, a suitable reordering of the orbitals will already reduce the computational effort. Still, one has more freedom to preprocess the Hamiltonian by means of suitable linear maps from one set of fermionic modes to another, aiming at minimising the entanglement present in the system. Here, we present an adaptive method that aims at combining advantages arising from suitable local mode transformations and matrix-product updates “on the fly” in an iterative fashion. First results – both for lattice models and for systems in quantum chemistry – suggest that by including such local mode transformations, one finds good approximations of the ground state already for low bond dimensions. In addition, we are able to recover suitable global mode transformations from the local ones for medium sized systems.