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TT: Fachverband Tiefe Temperaturen
TT 66: Superconductivity: Tunneling, Josephson Junctions, SQUIDs
TT 66.13: Vortrag
Mittwoch, 18. März 2015, 18:30–18:45, H 2053
Dynamical phase squeezing in layered superconductors (limit of two coupled junctions) — •Beilei Zhu1, Robert Höppner1, Tobias Rexin1, Andrea Cavalleri1,2,3, and Ludwig Mathey1,4 — 1ZOQ & ILP, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany — 2MPI for Structure and Dynamics of Matter, 22761 Hamburg, Germany — 3Clarendon Laboratory,Department of Physics, Oxford University, Parks Road, Oxford OX1 3PU,UK — 4The Hamburg Center for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
We study the dynamics of a layered superconductor with alternating inter-layered coupling, driven by an external potential that models a light pulse coupling to an optical phonon mode, inspired by [1,2]. We study a minimal model consisting of one strong junction and one weak junction, coupled to a heat bath. We describe this toy model using a Langevin formalism and treat it numerically. The strong junction plays as an amplifier of the external driving on the weak junction. We find that the phase fluctuations of the weak junction are squeezed under near-resonant driving of strong junction. The power spectrum demonstrates that the squeezing occurs in the low frequency regime. We also consider a quantum version for a driven single Josephson Junction.
[1] Fausti et al., Science, 331, 6014 189-191 (2011)
[2] Kaiser et al., arXiv:1205.4661