Macroscopic quantum tunneling and energy-level quantization in the zero voltage state of the current-biased Josephson junction

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:6854992

Martinis, J M

A macroscopic variable, the phase difference across a Josephson junction, is shown to obey quantum mechanics by observing the phenomena of energy-level quantization and quantum tunneling. The relevant parameters of the junction were determined in situ in the thermal regime from the dependence of the escape rate on bias current and from resonant activation in the presence of microwaves. The first observation of quantized energy levels for this system if reported. The positions of these energy levels are in quantitative agreement with the quantum-mechanical predictions based on the measured junction parameters. A model is presented that predicts correctly the observed resonance shapes. The measured value of the escape rate out of the zero-voltage state for an underdamped (Q approx. 30) junction was found to be independent of temperature at low temperatures. This low temperature escape rate was in excellent agreement with the prediction for macroscopic quantum tunneling, with no adjustable parameters.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 6854992
• Country of Publication: United States
• Language: English

Related Subjects

420201* -- Engineering-- Cryogenic Equipment & Devices
657002 -- Theoretical & Mathematical Physics-- Classical & Quantum Mechanics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ENERGY LEVELS
JOSEPHSON JUNCTIONS
JUNCTIONS
MATHEMATICAL MODELS
MECHANICS
QUANTIZATION
QUANTUM MECHANICS
RESONANCE
SUPERCONDUCTING JUNCTIONS
TUNNEL EFFECT