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PACS numbers: 03.65.−w, 05.40.−a, 37.10.Vz, 45.50.−j
Abstract:
“The noise is the signal” [R. Landauer, Nature (London) 392, 658 (1998)] emphasizes the rich information
content encoded in fluctuations. This paper assesses the dynamical role of fluctuations of a quantum system driven
far from equilibrium, with laser-aligned molecules as a physical realization. Time evolutions of the expectation
value and the uncertainty of a standard observable are computed quantum mechanically and classically. We
demonstrate the intricate dynamics of the uncertainty that are strikingly independent of those of the expectation
value, and their exceptional sensitivity to quantum properties of the system. In general, detecting the time
evolution of the fluctuations of a given observable provides information on the dynamics of correlations in a
quantum system.
