• Quantum Langevin dynamics of a charged particle in a magnetic field: Response function, position–velocity and velocity autocorrelation functions

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    • Keywords


      Quantum Langevin equation; response function; autocorrelation function; cyclotron frequency; memory kernel.

    • Abstract


      We use the quantum Langevin equation as a starting point to study the response function, the position– velocity correlation function and the velocity autocorrelation function of a charged quantum Brownian particle in the presence of a magnetic field and linearly coupled to a heat bath via position coordinate. We study two bath models – the Ohmic bath model and the Drude bath model and make a detailed comparison in various time–temperature regimes. For both bath models, there is a competition between the cyclotron frequency and the viscous damping rate giving rise to a transition from an oscillatory to a monotonic behaviour as the damping rate is increased. In the zero point fluctuation dominated low-temperature regime, non-trivial noise correlations lead to some interesting features in this transition. We study the role of the memory time-scale which comes into play in the Drude modeland study the effect of this additional time-scale. We discuss the experimental implications of our analysis in the context of experiments in cold ions.

    • Author Affiliations



      1. Raman Research Institute, Bengaluru 560 080, India
      2. International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bengaluru 560 089, India
    • Dates

  • Pramana – Journal of Physics | News

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