On measurement and quantum nondemolition

Chai Jin-hua, Guo Guang-Can

A scheme of quantum nondemolition (QND) measurement is proposed for phonons in a Raman-active crystal by using a beam of squeezed Stokes light. The results of the theoretical calculation show that the QND measurements for the quadrature component of the phonons can be performed.

V. P. Belavkin

Ulrik L. Andersen, B. C. Buchler, Ping Koy Lam +2 more

Quantum Nondemolition (QND) measurements are carried out using a stable amplitude squeezed beam. The performance of the QND measurement is substantially enhanced by an electro-optic feedforward loop, which improves the signal transfer efficiency.

Александр Семенович Холево

Kohji Takashima, Munehiro Nishida, Shigemasa Matsuo +1 more

Quantum nondemolition (QND) measurements allow us to measure an observable of a quantum system without introducing a back‐action on this observable due to the measurement itself. Here we propose a method for the QND measurement of a superconducting flux qubit by extending the spin QND measurement. Under an adequate condition, qubit and interaction Hamiltonian satisfy QND conditions and then QND measurement of a superconducting flux qubit is possible.

Časlav Brukner