München 2004 – wissenschaftliches Programm

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Q: Quantenoptik und Photonik

Q 22: Poster Quanteninformation, -kommunikation und -computer

Q 22.2: Poster

Dienstag, 23. März 2004, 14:00–16:00, Schellingstr. 3

Finite size effects in entangled rings of qubits — •Tim Meyer, Uffe V. Poulsen, Kai Eckert, Maciej Lewenstein, and Dagmar Bruss — Universit"at Hannover

We study translationally invariant rings of qubits with a finite number of sites N, and find the maximal nearest-neighbor entanglement for a fixed z component of the total spin. For small numbers of sites our results are analytical. The use of a linearized version of the concurrence allows us to relate the maximal concurrence to the ground state energy of an XXZ spin model, and to calculate it numerically for N<25. We point out some interesting finite-size effects. Finally, we generalize our results beyond nearest neighbors.