Majorana fermions induced Fano resonance and fast-to-slow light in a hybrid semiconductor/superconductor ring device

We demonstrate theoretically the Fano resonance and the conversion from fast to slow light in a hybrid quantum dot (QD)–semiconductor/superconductor (S/S) ring device, where the QD is coupled to a pair of Majorana fermions (MFs) appearing in the hybrid QD–S/S ring device. The absorption spectra of the weak probe field can exhibit a series of asymmetric Fano line shapes, and their related optical 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 (i.e., the absorption dip approaches zero) in the probe absorption spectra are accompanied by the rapid steep dispersion of the Fano resonance profile, which promises the slow- or fast-light effect, and even tunable fast-to-slow light propagation (or vice versa) can be achieved by controlling different parameter regimes. Therefore, Fano resonance may indicate another means to investigate MFs and the investigation may open up promising applications in quantum information processing based on MFs in solid-state devices.