Room-temperature ultrasensitive mass spectrometer via dynamical decoupling

We propose an ultrasensitive mass spectrometer based on a coupled quantum-bit-oscillator system. Under dynamical decoupling control of the quantum bit (qubit), the qubit coherence exhibits a comb structure in the time domain. The time-comb structure enables high-precision measurements of oscillator frequency, which can be used as an ultrasensitive mass spectrometer. We show that, in the ideal case, the sensitivity η of the proposed mass spectrometer has better performance at higher temperature and scales with the temperature T as η∼T-1/2. While taking into account qubit and oscillator decay, the optimal sensitivity reaches a universal value independent of environmental temperature T. The measurement sensitivity η also shows an improved dependence on the control-pulse number N as η∼N-3/2, in comparison with the N-1/2 scaling in previous magnetometry studies. With the present technology on solid-state spin qubit and high-quality optomechanical system, our proposal is feasible to realize an ultrasensitive room-temperature mass spectrometer.