laboratoire pierre aigrain
électronique et photonique quantiques
laboratoire pierre aigrain

Séminaire 1er octobre 2012

Steven M. Girvin (Yale University, USA)
Quantum Reservoir Engineering in Circuit QED

Quantum systems are never completely isolated, but instead interact with degrees of freedom in the surrounding environment, eventually leading to decoherence of the system. The conventional route to long-lived quantum coherence involves minimizing coupling to the dissipative bath. Paradoxically, it is possible in principle to instead engineer specific couplings
to a quantum environment that allow dissipation to actually create and preserve coherence. I present a simple scheme to engineer the photon shot noise in a microwave cavity so that it relaxes a qubit towards any desired point on the Bloch sphere. This scheme is inspired by laser cooling in optomechanics and has recently been realized experimentally by the Siddiqi group at Berkeley [1].

[1] ‘Cavity-assisted quantum bath engineering,’ K.W. Murch, U. Vool, D. Zhou, S.J. Weber,
S.M. Girvin, I. Siddiqi, Phys. Rev. Lett. (in press) ; arXiv:1207.0053