The dynamics of a quantum system, undergoing unitary evolution and continuous monitoring, can be described in term of quantum trajectories. Although the averaged state fully characterizes expectation values, the entire ensemble of stochastic trajectories goes beyond simple linear observables, keeping a more attentive description of the entire dynamics. Here we go beyond the Lindblad dynamics and study the probability distribution of the expectation value of a given observable over the possible quantum trajectories. The measurements are applied to the entire system, having the effect of projecting the system into a product state. We develop an analytical tool to evaluate this probability distribution at any time t. We illustrate our approach by analyzing two paradigmatic examples: a single qubit subjected to magnetization measurements, and a free hopping particle subjected to position measurements.

Continuously monitored quantum systems beyond Lindblad dynamics / Lami, Guglielmo; Santini, Alessandro; Collura, Mario. - In: NEW JOURNAL OF PHYSICS. - ISSN 1367-2630. - 26:2(2024), pp. 1-14. [10.1088/1367-2630/ad1f0a]

Continuously monitored quantum systems beyond Lindblad dynamics

Lami, Guglielmo
;
Santini, Alessandro;Collura, Mario
2024-01-01

Abstract

The dynamics of a quantum system, undergoing unitary evolution and continuous monitoring, can be described in term of quantum trajectories. Although the averaged state fully characterizes expectation values, the entire ensemble of stochastic trajectories goes beyond simple linear observables, keeping a more attentive description of the entire dynamics. Here we go beyond the Lindblad dynamics and study the probability distribution of the expectation value of a given observable over the possible quantum trajectories. The measurements are applied to the entire system, having the effect of projecting the system into a product state. We develop an analytical tool to evaluate this probability distribution at any time t. We illustrate our approach by analyzing two paradigmatic examples: a single qubit subjected to magnetization measurements, and a free hopping particle subjected to position measurements.
2024
26
2
1
14
023041
10.1088/1367-2630/ad1f0a
https://arxiv.org/abs/2305.04108
Lami, Guglielmo; Santini, Alessandro; Collura, Mario
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/138953
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