Hannover 2010 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 55: Poster II
Q 55.15: Poster
Thursday, March 11, 2010, 16:00–19:00, Lichthof
Singlet-triplet oscillations with pairs of neutral atoms in an optical superlattice — •Stefan Trotzky1, Yu-Ao Chen1, Ute Schnorrberger1, and Immanuel Bloch1,2 — 1Ludwig-Maximilians-Universität, Schellingstrasse 4, 80799 München — 2Max-Planck-Institut für Quantenoptik, Hans Kopfermann-Strasse 1, 85748 Garching
We show the creation, detection and manipulation of effective-spin triplet and singlet pairs with ultracold 87Rb atoms in a bichromatic optical superlattice. The system is initialized with two atoms per lattice site being in two different Zeeman states |F=1;mF=−1⟩≡|↓⟩ and |1;+1⟩≡|↑⟩. When splitting the lattice sites into symmetric double-wells by means of the superlattice, we create an array of entangled triplet pairs |↑,↓⟩ + |↓,↑⟩. Subsequently, a magnetic-field gradient along the double-well axis is used to induce oscillation between the triplet and the singlet state |↑,↓⟩ − |↓,↑⟩. We detect these singlet-triplet oscillations via the symmetry of the respective wavefunction after merging the double-wells. Our method provides a tool to probe local spin-order emerging in e.g. valence-bond solid type states as well as in Fermi-Hubbard systems at low temperature.
A superexchange coupling between adjacent double-wells is employed to implement a SWAP operation, stretching the entangled pairs over more than one double-well. This operation can be seen as a step towards the creation of a multi-particle entangled state in the optical lattice, which might serve as initial state for one-way quantum computational schemes.