LMU
MPQ
Quantum Optics Group (LMU) - Quantum Many Body Systems Division (MPQ)

Collisional Quantum Gate Arrays

Schematic controlled collision sequence

Single atoms are initially localized to individual lattice sites. Then a coherent microwave pulse creates a superposition of two internal states (red and blue), which are moved into opposite direction. When they reach their next neighbour they can interact with these atoms via controlled collsions. After such a sequence the atoms are brought back to their original location. In fact this realizes a massivel parallel operating quantum gate array in the multi-particle system.

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Entanglement oscillations made visible
through a matter wave interference pattern (I)

The action of the collisional quantum gate array leads to entanglement oscillations in the multiparticle system. These can be made visibily in a Ramsey type interference experiment. For a disentangled state (left) the visibility of the resulting Ramsey interference pattern is rather high, whereas for an entangled state (middle) the visibility almost vanishes. A further application of the quantum gates can however restore the interference pattern again (right)

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Entanglement oscillations made visible
through a matter wave interference pattern (II)

The action of the collisional quantum gate array leads to entanglement oscillations in the multiparticle system. These can be made visibily in a Ramsey type interference experiment. For a disentangled state (left) the visibility of the resulting Ramsey interference pattern is rather high, whereas for an entangled state (middle) the visibility almost vanishes. A further application of the quantum gates can however restore the interference pattern again (right)

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Entanglement oscillations made visible
through a matter wave interference pattern (III)

The action of the collisional quantum gate array leads to entanglement oscillations in the multiparticle system. These can be made visibily in a Ramsey type interference experiment. For a disentangled state (left) the visibility of the resulting Ramsey interference pattern is rather high, whereas for an entangled state (middle) the visibility almost vanishes. A further application of the quantum gates can however restore the interference pattern again (right)

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Entanglement oscillations made visible
through a matter wave interference pattern (IV)

The action of the collisional quantum gate array leads to entanglement oscillations in the multiparticle system. These can be made visibily in a Ramsey type interference experiment. For a disentangled state (left) the visibility of the resulting Ramsey interference pattern is rather high, whereas for an entangled state (middle) the visibility almost vanishes. A further application of the quantum gates can however restore the interference pattern again (right)

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Artistic view of the controlled collision sequence

(left) Entanglement oscillations that have been observed the oscillations of the visibility of a matter wave interference pattern due to the action of the quantum gate array.

(right) Schematic view of the quantum gate arrays sequence. Initially an atom in the yellow state is split into a green and red state, which are moved in opposite directions. There they interact wirth neighbouring atoms via controlled cold collisions.

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CONTACT

Max-Planck-Institut für Quantenoptik 

Hans-Kopfermann-Str. 1
85748 Garching, Germany 

Phone: +49 (0)89 32905 - 138 
Fax: +49 (0)89 32905 - 313

Kristina Schuldt

Ludwig-Maximilians-University
Quantum Optics Chair/
Fakultät für Physik 

Schellingstr. 4
80799 Munich, Germany

Phone: +49 (0)89 2180 - 6131
Fax: +49 (0)89 2180 - 63850

Ildiko Kecskesi