JOŽEF STEFAN INSTITUTE
Department of Complex Matter
Jamova cesta 39, 1000 Ljubljana, Slovenia

Dynamics of Quantum matter

We explore non-equilibrium many-body dynamics in quantum systems that experience symmetry-breaking, topological, or jamming transitions. These systems encompass superconductors, charge-density wave, and magnetic materials.

Experimental Soft Matter Physics

The research is conducted within the “Light and Matter” research program. The interaction of light with matter is one of the most important fields of physics and optical processes are indispensable in many branches of modern industry.

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December 15 - 19, 2024 , Krvavec, Slovenia
Together with the Department of Theoretical Physics at JSI we are organizing the 13th Nonequilibrium Quantum Workshop. The workshop intends to bring together scientists working in the field of: Ultrafast ...
Home / Events / QT Future Seminar “Josephson effect in strongly disordered metallic wires”

QT Future Seminar “Josephson effect in strongly disordered metallic wires”

November 17, 2023 , 14:00 , Kuščerjev seminar, Jadranska 19

Pavel Ostrovsky, Max Planck Insitute Stuttgart

We study localization phenomena in an SNS junction with a disordered metallic wire as its normal part. Standard description of the Josephson effect in such systems is based on the Usadel equation. However, the classical approach remains valid only while the junction is shorter than the localization length in the wire. In the opposite limit, quantum effects become important and the Usadel description is no longer valid.

We develop a general theory of the Josephson effect taking into account all localization (quantum) contributions. Our theory is based on the nonlinear sigma model and can be applied to junctions of arbitrary length including very long junctions (exceeding the localization length) when a fully quantum description is required. Applied to the Josephson effect in this limit, the theory predicts three qualitatively different regimes depending on relation between the length of the junction, superconducting coherence length, and localization length. In all these regimes, we found analytical expressions for the current-phase relation and estimates for the critical current. In particular, we demonstrate that Ambegaokar-Baratoff relation can remain valid under certain conditions even in the strongly localized limit.