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Microwave-induced thermal escape in Josephson junctions
N Grønbech-Jensen1, M G Castellano, F Chiarello
1Department of Applied Science, University of California, Davis, California 95616, USA.
Physical Review Letters
|September 28, 2004
Summary
Microwave radiation can cause Josephson tunnel junctions to exhibit multivalued switching currents at higher temperatures than expected. This phenomenon, driven by plasma frequency oscillations, aligns with simulations of the classical Josephson junction model.
Area of Science:
- Quantum mechanics
- Condensed matter physics
- Superconductivity
Background:
- Josephson tunnel junctions are key components in superconducting electronics.
- Understanding thermal activation processes is crucial for device stability.
- Microwave radiation effects on these junctions are not fully characterized.
Purpose of the Study:
- To investigate thermal activation in Josephson tunnel junctions under microwave radiation.
- To explore the influence of microwave-induced plasma frequency oscillations on switching currents.
- To compare experimental findings with numerical simulations.
Main Methods:
- Experimental measurements of switching currents in Josephson tunnel junctions.
- Numerical simulations of a thermally driven classical Josephson junction model.
- Analysis of switching current behavior as a function of applied signal frequency and temperature.
Main Results:
- Multivalued switching currents observed in a temperature range significantly above the classical-quantum crossover.
- Experimental data shows excellent agreement with predicted Josephson plasma frequency dependencies.
- Numerical simulations accurately replicate the observed experimental behavior.
Conclusions:
- Microwave radiation can induce complex thermal activation behaviors in Josephson junctions.
- The classical Josephson junction model effectively describes phenomena beyond the typical quantum regime.
- Experimental and simulation results confirm the role of plasma frequency oscillations.
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