Hannover 2010 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 44: Quantum Information: Concepts and Methods III
Q 44.5: Vortrag
Donnerstag, 11. März 2010, 11:30–11:45, E 214
Decoherence of spin gases induced by many-body phase gates — •Tatjana Carle1, Wolfgang Dür1,2, Hans J. Briegel1,2, and Barbara Kraus1 — 1Institut für Theoretische Physik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck — 2Institut für Quantenoptik und Quanteninformation der Österreichischen Akademie der Wissenschaften, Technikerstraße 21a, A-6020 Innsbruck
We present a new approach to study the properties of many-particle systems subject to decoherence. In particular, we consider a spin gas, which is a natural extension of a classical gas where the particles move along a classical trajectory, but carry a quantum degree of freedom, which interacts during collisions. Formerly, two-body collisions between the system and bath, which were described by two-body phase gates leading to a dephasing environment, were considered. There the evolution of the system and the entanglement has been investigated. Here we consider a system of particles (qubits) which is interacting via more-body phase gates with its surrounding. We study the entanglement properties of the multipartite system depending on the number of qubits the phase gate is acting on. We calculate the reduced density matrix and decoherence maps which gives us insight into the entanglement properties and time evolution of the system. In order to do so we make use of a new class of quantum states called LME states (Locally-Maximally-Entanglable), which are generated by n-body phase gates. Since the calculations are exact we treat Markovian as well as Non-Markovian scenarios and compare them to each other.