Majorana fermions detection based on a coupled quantum dot-nanomechanical resonator system

Abstract

Motivated by a recent experiment providing evidence for Majorana zero modes in iron (Fe) chains on the superconducting Pb surface, in the present work, an optical method for probing Majorana fermions is proposed theoretically, which is very different from the current tunneling spectroscopy experiments with electrical means. The optical detection proposal consists of a hybrid quantum dot-nanomechanical resonator system driven by one strong pump field and one weak probe field. With the optical means, the signal in the coherent optical spectrum indicates a distinct signature of Majorana fermions in the end of iron chains when the quantum dot coupled to Majorana fermions. In addition, an optical scheme for determining the coupling strength between Majorana fermions and the quantum dot is also introduced, which affords a straightforward method to measure such coupling. We further investigate the role of the nanomechanical resonator in the hybrid system. The vibration of the nanomechanical resonator behaving as a phonon cavity will enhance the exciton resonance spectrum, which is robust for the detection of Majorana fermions. This optical scheme affords a potential supplement to detecte Majorana fermions and supports to use Majorana fermions in Fe chains as qubits for potential applications in quantum computing devices.