Macroscopic quantum tunneling in quartic and sextic potentials: application to a phase qubit

Abstract

Macroscopic quantum tunneling of the phase is a fundamental phenomenon in the quantum dynamics of superconducting nanocircuits. The tunneling rate can be controlled in such circuits, where the potential landscape for the phase can be tuned with different external bias parameters. Precise theoretical knowledge of the macroscopic quantum tunneling rate is required in order to simulate and understand the experiments. We present a derivation, based on the instanton technique, of an analytical expression of the escape rate in general quartic and symmetric sextic potentials comprising two escape paths. These new potentials were recently realized when creating a noise-insensitive phase qubit in the camel-back potential of a dc SQUID.

8 pages, 6 figures

References in corpus (6)

• Direct Observation of Tunneling and Nonlinear Self-Trapping in a single Bosonic Josephson Junction
• Observation of quantum oscillations between a Josephson phase qubit and a microscopic resonator using fast readout
• Coherent oscillations in a superconducting multi-level quantum system
• Temperature dependence of coherent oscillations in Josephson phase qubits
• Quantum dynamics in a camel-back potential of a dc SQUID
• Multilevel effects in the Rabi oscillations of a Josephson phase qubit

Cited by in corpus (4)

• Variational study of two-impurity spin-boson model with a common Ohmic bath: Ground-state phase transitions
• Two-dimensional macroscopic quantum tunneling in multi-gap superconductor Josephson junctions
• Thermodynamics of Maximum Transition Entropy for Quantum Assemblies
• Mesoscopic electron transport and atomic gases, a review of Frank W. J. Hekking's scientific work