Quantum dynamics in a camel-back potential of a dc SQUID
Abstract
We investigate the quantum dynamics of a quadratic-quartic anharmonic oscillator formed by a potential well between two potential barriers. We realize this novel potential shape with a superconducting circuit comprised of a loop interrupted by two Josephson junctions, with near-zero current bias and flux bias near half a flux quantum. We investigate escape out of the central well, which can occur via tunneling through either of the two barriers, and find good agreement with a generalized double-path macroscopic quantum tunneling theory. We also demonstrate that this system exhibits an "optimal line" in current and flux bias space along which the oscillator, which can be operated as a phase qubit, is insensitive to decoherence due to low-frequency current fluctuations.
Cite
@article{arxiv.0810.2372,
title = {Quantum dynamics in a camel-back potential of a dc SQUID},
author = {E. Hoskinson and F. Lecocq and N. Didier and A. Fay and F. W. J. Hekking and W. Guichard and R. Dolata and B. Mackrodt and A. B. Zorin and O. Buisson},
journal= {arXiv preprint arXiv:0810.2372},
year = {2009}
}