CQuIC Seminars
Quantum reservoir engineering in circuit QED
Presented by Steve Girvin, Yale University
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]. A more complex scheme has been used to autonomously stabilize an entangled Bell state for a pair of qubits [2]. Other ideas are being developed for stabilizing Schroedinger Cat states of photons [3] for use in autonomous quantum error correction schemes.
[1.] "Cavity-assisted quantum bath engineering," K.W. Murch, et al., Phys. Rev. Lett. 109, 183602 (2012).
[2.] "˜Autonomously stabilized entanglement between two superconducting quantum bits,"
S. Shankar, et al., Nature 504, 419-422 (2013).
[3.] "˜Dynamically protected cat-qubits: a new paradigm for universal quantum computation," Mazyar Mirrahimi, et al., New J. Phys. 16, 045014 (2014).
3:30 pm, Thursday, January 15, 2015
PAIS-2540, PAIS
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