Quantum Binary Decision for Driven Harmonic Oscillator
  We address the problem of determining whether or not a harmonic oscillator has been perturbed by an external force. Quantum detection and estimation theory has been used in devising optimum measurement schemes. Detection probability has been evaluated for different initial state preparations of oscillator. The corresponding lower bounds on minimum detectable perturbation intensity has been evaluated and a general bound for random phase perturbation has been also induced. 
Matteo G. A. Paris (Quantum Optics Group -- University of Pavia)