Scientific Results

Stochastic quantum Zeno by large deviation theory

Year: 2016

Authors: Gherardini S., Gupta S., Cataliotti FS., Smerzi A., Caruso F., Ruffo S.

Autors Affiliation: Univ Florence, Dept Informat Engn, Via S Marta 3, I-50139 Florence, Italy; Univ Florence, CSDC, Via G Sansone 1, I-50019 Sesto Fiorentino, Italy; Ist Nazl Fis Nucl, Via G Sansone 1, I-50019 Sesto Fiorentino, Italy;‎ Univ Florence, LENS, Via G Sansone 1, I-50019 Sesto Fiorentino, Italy;‎ QSTAR, Largo E Fermi 2, I-50125 Florence, Italy;‎ Univ Florence, Dept Phys & Astron, Via G Sansone 1, I-50019 Sesto Fiorentino, Italy;‎ Max Planck Inst Phys Komplexer Syst, Noethnitzer Str 38, D-01187 Dresden, Germany; CNR, INO, Largo E Fermi 2, I-50125 Florence, Italy; SISSA, CNISM, Via Bonomea 265, I-34136 Trieste, Italy; Ist Nazl Fis Nucl, I-34136 Trieste, Italy

Abstract: Quantum measurements are crucial for observing the properties of a quantum system, which, however, unavoidably perturb its state and dynamics in an irreversible way. Here we study the dynamics of a quantum system being subjected to a sequence of projective measurements applied at random times. In the case of independent and identically distributed intervals of time between consecutive measurements, we analytically demonstrate that the survival probability of the system to remain in the projected state assumes a large deviation (exponentially decaying) form in the limit of an infinite number of measurements. This allows us to estimate the typical value of the survival probability, which can therefore be tuned by controlling the probability distribution of the random time intervals. Our analytical results are numerically tested for Zeno-protected entangled states, which also demonstrate that the presence of disorder in the measurement sequence further enhances the survival probability when the Zeno limit is not reached (as it happens in experiments). Our studies provide a new tool for protecting and controlling the amount of quantum coherence in open complex quantum systems by means of tunable stochastic measurements.

Journal/Review: NEW JOURNAL OF PHYSICS

Volume: 18      Pages from: 013048-1  to: 013048-15

KeyWords: quantum measurements; large deviation theory; quantum Zeno; open quantum systems; disordered systems
DOI: 10.1088/1367-2630/18/1/013048

Citations: 21
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