Data di Pubblicazione:
2011
Citazione:
Qubit thermometry for micromechanical resonators / M. Brunelli, S. Olivares, M. Paris. - In: PHYSICAL REVIEW A. - ISSN 1050-2947. - 84:3(2011), pp. 032105.032105.1-032105.032105.9.
Abstract:
We address estimation of temperature for a micromechanical oscillator lying arbitrarily close to its quantum
ground state. Motivated by recent experiments, we assume that the oscillator is coupled to a probe qubit via
Jaynes-Cummings interaction and that the estimation of its effective temperature is achieved via quantum-limited
measurements on the qubit. We first consider the ideal unitary evolution in a noiseless environment and then
take into account the noise due to nondissipative decoherence. We exploit local quantum estimation theory to
assess and optimize the precision of estimation procedures based on the measurement of qubit population and to
compare their performances with the ultimate limit posed by quantum mechanics. In particular, we evaluate the
Fisher information (FI) for population measurement, maximize its value over the possible qubit preparations and
interaction times, and compare its behavior with that of the quantum Fisher information (QFI). We found that
the FI for population measurement is equal to the QFI, i.e., population measurement is optimal, for a suitable
initial preparation of the qubit and a predictable interaction time. The same configuration also corresponds to the
maximum of the QFI itself. Our results indicate that the achievement of the ultimate bound to precision allowed
by quantum mechanics is in the capabilities of the current technology.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
M. Brunelli, S. Olivares, M. Paris
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