Showing posts with label Martin Kiffner. Show all posts
Showing posts with label Martin Kiffner. Show all posts

Friday, September 1, 2017

Abstract-Terahertz field control of interlayer transport modes in cuprate superconductors



Frank Schlawin, Anastasia S. D. Dietrich, Martin Kiffner, Andrea Cavalleri, and Dieter Jaksch

https://journals.aps.org/prb/abstract/10.1103/PhysRevB.96.064526

We theoretically show that terahertz pulses with controlled amplitude and frequency can be used to switch between stable transport modes in layered superconductors, modeled as stacks of Josephson junctions. We find pulse shapes that deterministically switch the transport mode between superconducting, resistive, and solitonic states. We develop a simple model that explains the switching mechanism as a destabilization of the center-of-mass excitation of the Josephson phase, made possible by the highly nonlinear nature of the light-matter coupling.
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Thursday, July 27, 2017

Abstract-Terahertz field control of interlayer transport modes in cuprate superconductors




We theoretically show that terahertz pulses with controlled amplitude and frequency can be used to switch between stable transport modes in layered superconductors, modelled as stacks of Josephson junctions. We find pulse shapes that deterministically switch the transport mode between superconducting, resistive and solitonic states. We develop a simple model that explains the switching mechanism as a destablization of the centre of mass excitation of the Josephson phase, made possible by the highly non-linear nature of the light-matter coupling.

Wednesday, June 8, 2016

Abstract-Two-way conversion of microwave and terahertz radiation into optical fields in Rydberg gases



We show that cold Rydberg gases enable an efficient six-wave mixing process where microwave or terahertz fields are coherently converted into optical fields and vice versa. This process is made possible by the long lifetime of Rydberg states, the strong coupling of millimeter waves to Rydberg transitions and a quantum interference effect related to Electromagnetically Induced Transparency. We show that conversion efficiencies within an independent atom approach are of the order of 95% and analyse the impact of dipole-dipole interactions on our scheme. We find that effective conversion efficiencies in the presence of Rydberg-Rydberg interactions can still be as high as 85% based on an implementation with Rubidium atoms. Our frequency conversion scheme does not require cavities and can be implemented for a broad spectrum of terahertz and microwave fields due to the abundance of transitions within the Rydberg manifold.