Majorana finite frequency nonequilibrium quantum noise

Abstract

Quantum finite frequency noise is one of fundamental aspects in quantum measurements performed during quantum information processing where currently Majorana bound states offer an efficient way to implement fault-tolerant quantum computation via topological protection from decoherence or unitary errors. Thus a detailed exploration of Majorana finite frequency noise spectra, preferably in a nonequilibrium device, is a timely challenge of fundamental importance. Here we present results on finite frequency differential noise that is the derivative of the noise with respect to the frequency. This quantity has universal units of $e^2$ and scans in high detail all peculiarities of the Majorana noise clearly demonstrating its universal finite frequency features. In particular, we provide photon absorption spectra on all energy scales and reveal a rich structure including universal Majorana plateaus as well as universal Majorana resonances and antiresonances at characteristic frequencies. Our results are of immediate interest to state-of-the-art experiments involving quantum noise mesoscopic detectors able to separately measure photon absorption and emission spectra.