| Summary: | <p>Thanks to growing capibilities in modulating the properties of materials by selectively driving a specific degree of freedom, along with recent developments in terahertz science, it has been possible to excite and probe the Josephson mode in cuprate superconductors. It is believed that in these materials, phase fluctuations in the superconducting order parameter, which are manifested by Josephson plasmonic excitations can be important in determining the critical temperature. Current efforts in finding novel ways of enhancing superconductivity are geared towards developing ways of using coherent control of this phase to reduce thermal fluctuations, hence improving the effective critical temperature in such materials.</p> <p>With this in view, we propose a 'Doppler' Cooling scheme for layered superconductors having a bilayer structure and conduct a feasibility study to assess their applicability to such systems. By modelling a bilayer cuprate unit-cell as two coupled Josephson junctions, we find that it is possible to induce transitions between and interlayer and higher energy intralayer plasmonic mode via driving from an externally applied electromagnetic field only when the junction is current biased. Our study shows that the physics of the system allow such a scheme to be implemented. The low recoil imparted by photons at terahertz frequencies enables us to apply the same framework as for cooling of atomic systems. The relatively long lifetimes (&Tilde; 0.1 ns) against spontaneous decay estimated imply that cooling is not likely to be limited by inherent features of the scheme but will rather depend on other factors, such as the competition between cooling and rethermalisation. These factors need to be further studied to assess the experimental viability of the proposed scheme.</p>
|
|---|