Protecting a quantum state from environmental noise by an incompatible finite-time measurement
- Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, P. O. Box 369, 13560-970 Sao Carlos, SP (Brazil)
We show that measurements of finite duration performed on an open two-state system can protect the initial state from a phase-noisy environment, provided the measured observable does not commute with the perturbing interaction. When the measured observable commutes with the environmental interaction, the finite-duration measurement accelerates the rate of decoherence induced by the phase noise. For the description of the measurement of an observable that is incompatible with the interaction between system and environment, we have found an approximate analytical expression, valid at zero temperature and weak coupling with the measuring device. We have tested the validity of the analytical predictions against an exact numerical approach, based on the superoperator-splitting method, that confirms the protection of the initial state of the system. When the coupling between the system and the measuring apparatus increases beyond the range of validity of the analytical approximation, the initial state is still protected by the finite-time measurement, according with the exact numerical calculations.
- OSTI ID:
- 22068490
- Journal Information:
- Physical Review. A, Vol. 84, Issue 2; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
Similar Records
Entanglement and the process of measuring the position of a quantum particle
Enhancement of frequency estimation by spatially correlated environments