Controllable Fano resonance and fast to slow light in a hybrid semiconductor/superconductor ring device mediated by Majorana fermions

We demonstrate theoretically the Fano resonance and the conversion from fast to slow light in a hybrid quantum dot-semiconductor/superconductor ring device, where the QD is coupled to a pair of MFs appearing in the hybrid S/S ring device. The absorption spectra of the weak probe field can exhibit a series of asymmetric Fano line shapes and their related propagation properties such as fast and slow light effects are investigated based on the hybrid system for suitable parametric regimes. The positions of the Fano resonances can be determined by the parameters, such as different detuning regimes and QD-MFs coupling strengths. Further, the transparency windows (the absorption dip approaches zero) in the probe absorption spectra are accompanied by the rapid dispersion, which indicates the slow or fast light effect, and tunable fast-to-slow light propagation (or vice versa) can be achieved by controlling different parameter regimes. Our study may provide an all-optical means to investigate MFs and open up promising applications in quantum information processing based on MFs in solid state devices.