Quantum transition-edge detectors

摘要: Small perturbations to systems near critical points of quantum phase transitions can induce drastic changes in the system properties. Here I show that this sensitivity be exploited for weak-signal detection applications. This is done by relating a widely studied signature chaos and known as Loschmidt echo minimum error probability detector noting echo, therefore error, significantly reduced point. Three examples, namely, Ising model, optical parametric oscillator Dicke are presented illustrate concept. For latter two detectable perturbation exhibit Heisenberg scaling with respect number detectors, even though detectors not entangled no special state preparation specified.