Extreme nonlinear dynamics of driven superconductors

ended

Due to very long energy relaxation times and strong non-linearities superconductors are the workhorse of many solid state quantum technologies. Previous studies have shown that a periodically excited superconductor can be taken to a new highly-nonlinear regime where quasiparticles perform synchronous collective Rabi oscillations. SUPERDYN will address all the challenges to observe these and similar highly nonlinear states in experiments. In particular, we will analyse thermalization process beyond a mean-field dynamics i.e. taking into account the effect of the environment, residual interactions and disorder. Results obtained with non-equilibrium diagrammatic techniques (Keldysh) will be validated comparing with computations within non-equilibrium dynamical mean-field theory (DMFT). Both the transient nonlinearities and the steady-state nonlinearities will be studied. In the latter case we expect typical effects of nonlinear quantum optics as induced transparency. A microwave device will be designed to measure these effects. This will require developing beyond state-of-the-art software and techniques to treat quasiparticle excitations and low-energy plasma modes on an equal footing. We will also develop a new variational method to obtain optimum driving protocols to obtain a desired transient superconducting state. The project will benefit from the synergies with various experimental groups. Secondments in a leading DMFT group and a leading experimental group developing quantum devices will complement the formation. The Experienced Researcher will be taken to a leadership position in the field of nonequilibrium superconductivity and solid-state quantum technologies with excellent future career prospects.