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Quantum Brownian Motion at Strong Dissipation Probed by Superconducting Tunnel Junctions
Berthold Jäck1, Jacob Senkpiel1, Markus Etzkorn1
1Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany.
Physical Review Letters
|October 21, 2017
Summary
We explored quantum dynamics in superconducting tunnel junctions at ultralow temperatures. Our findings show overdamped quantum systems exhibit quasiclassical behavior with quantum effects as leading corrections.
Area of Science:
- Quantum physics
- Condensed matter physics
- Superconductivity
Background:
- Superconducting tunnel junctions are crucial for quantum technologies.
- Understanding quantum dynamics in dissipative systems is a key challenge.
- High damping and ultralow temperatures create unique quantum regimes.
Purpose of the Study:
- To investigate the phase dynamics of superconducting tunnel junctions under high damping at ultralow temperatures.
- To experimentally verify theoretical predictions of quantum Smoluchowski equation in overdamped systems.
- To demonstrate quasiclassical dynamics in quantum systems with leading quantum corrections.
Main Methods:
- Current-biased measurements on a small-capacitance Josephson junction.
- Utilizing a scanning tunneling microscope in a low impedance environment.
- Experiments conducted at milli-Kelvin temperatures.
Main Results:
- Experimental findings accurately described by a quantum phase diffusion model.
- Demonstrated that overdamped quantum systems follow quasiclassical dynamics.
- Identified significant quantum effects as leading corrections in these dynamics.
Conclusions:
- Quantum Smoluchowski equation accurately models overdamped quantum Brownian motion.
- Experimental evidence supports the transition to quasiclassical dynamics in specific quantum regimes.
- Highlights the importance of environmental interactions in quantum system dynamics.
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