Dynamics of fluctuations in a quantum system

Abstract

"\textit{The noise is the signal}"[R. Landauer, Nature \textbf{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.

arXiv comment6 pages, 2 figures

References in corpus (23)

• Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
• Cold bosonic atoms in optical lattices
• Single-Atom Resolved Fluorescence Imaging of an Atomic Mott Insulator
• Light-cone-like spreading of correlations in a quantum many-body system
• Probing the Superfluid to Mott Insulator Transition at the Single Atom Level
• Probing many-body states of ultra-cold atoms via noise correlations
• Observation of mesoscopic crystalline structures in a two-dimensional Rydberg gas
• Quantum wave packet revivals
• Spatial quantum noise interferometry in expanding ultracold atom clouds
• Microscopic observation of magnon bound states and their dynamics
• Probing Pair-Correlated Fermionic Atoms through Correlations in Atom Shot Noise
• Spatial coherence and density correlations of trapped Bose gases
• X-ray diffraction from isolated and strongly aligned gas-phase molecules with a free-electron laser
• Persistent currents in normal metal rings
• Quantum Shot Noise
• Reduced density matrices and coherence of trapped interacting bosons
• Impulsive Laser Induced Alignment of Molecules Dissolved in Helium Nanodroplets
• Non-equilibrium dynamics of an unstable quantum pendulum
• Controlling the sense of molecular rotation: classical vs quantum analysis
• Computational studies of x-ray scattering from three-dimensionally-aligned asymmetric-top molecules
• A theory of intense-field dynamic alignment and high harmonic generation from coherently rotating molecules and interpretation of intense-field ultrafast pump-probe experiments
• Harnessing nuclear spin polarization fluctuations in a semiconductor nanowire
• Theory of x-ray absorption by laser-aligned symmetric-top molecules

Cited by in corpus (4)

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• Solvable Model of a Mixture of Bose-Einstein Condensates
• Attractive Bose-Einstein condensates in anharmonic traps: Accurate numerical treatment and the intriguing physics of the variance
• Uncertainty product of an out-of-equilibrium Bose-Einstein condensate