2013/08/13 by Mankei Tsang · 2 citations
Computer Science · Physics and Astronomy · #Neural Networks and Reservoir Computing #Quantum Information and Cryptography #Quantum and electron transport phenomena
paper · doi:10.1103/physreva.88.021801
openalex publication_date 2013/08/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 can be exploited for weak-signal detection applications. This is done by relating a widely studied signature of quantum chaos and quantum phase transitions known as the Loschmidt echo to the minimum error probability for a quantum detector and noting that the echo, and therefore the error, can be significantly reduced near a critical point. Three examples, namely, the quantum Ising model, the optical parametric oscillator model, and the Dicke model, are presented to illustrate the concept. For the latter two examples, the detectable perturbation can exhibit a Heisenberg scaling with respect to the number of detectors, even though the detectors are not entangled and no special quantum state preparation is specified.