Berlin 2005 – scientific programme

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TT: Tiefe Temperaturen

TT 13: Transport - Quantum Coherence and Quantum Information Systems

TT 13.14: Talk

Saturday, March 5, 2005, 12:15–12:30, TU H3027

Theoretical Description of Cavity-QED with Superconducting Flux Qubits — •Markus J. Storcz¹, Matteo Mariantoni², Rudolf Gross², and Frank K. Wilhelm¹ — ¹Physics Department and CeNS, Ludwig-Maximilians-Universität München — ²Walther-Meißner-Institute Garching

The symbiosis of cavity-quantum-electrodynamics (cQED) and superconducting quantum bit (qubit) circuits has gained great interest lately. This scheme can drastically improve the decoherence properties of superconducting qubits and allows for the manipulation and read-out of qubits more easily than existing architectures. We point out the special design requirements for placing a superconducting qubit circuit inside an e.m. cavity. In particular we explore one possible realization, which is to embed a three Josephson-junction flux qubit into a high quality factor microstrip resonator that can serve as the cavity. Moreover, we investigate the control and read-out of flux qubits in the cavity, and propose a scheme for coupling several qubits by way of cavity modes. We explore the limits of the Jaynes-Cummings model that is commonly used to describe the strongly coupled cavity-qubit system and compare this to a Spin-Boson model. We derive a description of the dissipative cavity-qubit system and its interaction with a photon field (i.e. in the case of flux qubits a microwave field) to analyze the characteristic decay rates of the system.