Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 51: Superconductivity: Tunneling, Josephson Junctions, SQUIDs
TT 51.9: Vortrag
Mittwoch, 9. März 2016, 17:15–17:30, H19
Stabilized superconductivity in periodically driven Josephson junction chains — •Junichi Okamoto1, 2, 3, Andrea Cavalleri4,5, and Ludwig Mathey1,2,3 — 1Center for Optical Quantum Technologies, University of Hamburg, Hamburg, Germany — 2Institute of Laser Physics, University of Hamburg, Hamburg, Germany — 3The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany — 4Max Planck Institute for the Structure and Dynamics of Matter — 5University of Oxford
Motivated by recent pump-probe experiments indicating enhanced coherent c-axis transport in an underdoped YBCO, a typical high-Tc superconductor, we study a system of capacitively coupled alternating Josephson junctions periodically driven by laser pulses. Using Langevin simulations, we show that the reduction of current fluctuations is realized through the Kapitza effect for high-frequency driving. In this regime superfluid density calculated from the imaginary part of conductivity is indeed enhanced compared to the thermal value. Calculations based on effective models with renormalized parameters explain this enhancement of superfluid density and other features of driven states.