Hannover 2003 – scientific programme
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Q: Quantenoptik
Q 37: Quanteninformation 4
Q 37.6: Talk
Thursday, March 27, 2003, 15:15–15:30, F102
Entanglement and Decoherence of a Schrödinger cat state — •Andrea Nemes Salgueiro and Juan Ignacio Cirac — Max-Planck-Institut für Quantenoptik, 85748 Garching
Multi-particle entangled states realized in many recent experiments can be described to a good approximation by |ψ⟩=1/√K(|φ1⟩⊗ N+|φN⟩⊗ N), where |ψ⟩ is a state of N two-level systems (qubits) and K is the normalization. We investigate decoherence and quantify the entanglement of these states when they are coupled collectively or independently with the environment. In particular, we are interested in characterizing the time scale for decoherence and for the decay of entanglement. As a measure of entanglement we choose the negativity which is defined as the sum of the absolute value of the eigenstates of the partial transpose.