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Delocalization of phonons and energy spectrum in disordered nonlinear systems

Akaberian, M ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1103/PhysRevB.101.220301
  3. Publisher: American Physical Society , 2020
  4. Abstract:
  5. We study phonon delocalization in disordered media in the presence of nonlinearity. By considering the Fermi-Pasta-Ulam β-model, we show that regardless of whether the initial state of the linear system is localized or not, the final state will be an extended mode after turning on the nonlinear term. We report on the results of an extensive dynamical simulation of a disordered nonlinear system, which show that, independent of the initial mode frequency, in the final state the energy spectrum is excited according to the Kolmogorov spectrum E(ω)∼ω-5/3. Finally, we show that disorder will not cause delocalization of intrinsic localized modes. © 2020 American Physical Society
  6. Keywords:
  7. Computational complexity ; Linear systems ; Nonlinear systems ; Phonons ; Spectroscopy ; Delocalizations ; Disordered media ; Dynamical simulation ; Energy spectra ; Intrinsic localized mode ; Kolmogorov spectrum ; Mode frequencies ; Nonlinear terms ; Excited states
  8. Source: Physical Review B ; Volume 101, Issue 22 , 2020
  9. URL: https://journals.aps.org/prb/abstract/10.1103/PhysRevB.101.220301