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TT: Fachverband Tiefe Temperaturen

TT 23: TR: Quantum Coherence and Quantum Information Systems 2

TT 23.7: Vortrag

Mittwoch, 24. März 2010, 16:00–16:15, H18

Selection rules for multiphoton excitations in a qubit-resonator system — Thomas Niemczyk¹, •Frank Deppe^1,2, Hans Huebl¹, Edwin Menzel¹, Fredrik Hocke¹, Elisabeth Hoffmann^1,2, Manuel Schwarz¹, Achim Marx¹, and Rudolf Gross^1,2 — ¹Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany — ²Physik Department E23, Technische Universität München, 85748 Garching, Germany

The theoretical analysis of a qubit-resonator system reveals selection rules at certain symmetry points of the qubit. In the case of a superconducting flux qubit, this symmetry of the double-well potential can be broken in a controlled way by changing the external magnetic field. Only then, odd and even multiphoton processes can coexist at the same flux bias. We illustrate this phenomenon with spectroscopy measurements of a superconducting flux qubit strongly coupled to an onchip coplanar waveguide resonator. Our studies extend up to three-photon driving and clearly show the transition from strict selection rules to a regime of coexistent multiphoton excitations.

Financial support via SFB631 and the Excellence Initative via NIM is gratefully acknowledged.