Heidelberg 2015 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 3: Quantum Information: Concepts and Methods I

Q 3.4: Vortrag

Montag, 23. März 2015, 12:30–12:45, K/HS1

Preparation of Schrödinger cat states of a Rydberg atom — •Eva-Katharina Dietsche, Adrien Signoles, Adrien Facon, Dorian Grosso, Igor Dotsenko, Serge Haroche, Jean-Michel Raimond, Michel Brune, and Sebastien Gleyzes — Laboratoire Kastler Brossel, College de France, ENS-PSL, UPMC-Sorbonne Universite, CNRS, 11 Place Marcelin Berthelot 75005 Paris, France

The Stark manifold of a Rydberg atom is large Hilbert space in which we can create non-classical states, like a Schrödinger cat state.

We demonstrated the generation of large angular momentum non-classical states using Quantum Zeno dynamics. Here, under the effect of a sigma+ radio-frequency field, the atom initially in the circular state behaves as a J=25 spin, which rotates between the north pole and the south pole of a generalized Bloch sphere. By repeatedly asking the system 'have you crossed a given latitude?', we can confine the evolution of the spin to the polar cap of the Bloch sphere. When the spin state reaches this limiting latitude, the phase space distribution disappears from one side of the limiting latitude to reappear on the other side, while being transiently in a superposition of two spin coherent states with different phases. This leads to the deterministic preparation of Schrödinger cat states of the angular momentum.

Quantum Zeno dynamics therefore provides a new method to tailor the Hilbert space to create non-classical superpositions of Stark sub-levels. Those states are very sensitive to small variations of electric and magnetic fields, and could be used for quantum metrology beyond the standard quantum limit.