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Nonmonotonic diffusion rates in an atom-optics Lévy kicked rotor
Sanku Paul1, Sumit Sarkar2, Chetan Vishwakarma2
1Max-Planck-Institut für Physik Komplexer Systeme, Nöthnitzer Straße 38, 01187-Dresden, Germany.
Physical Review. E
|January 23, 2020
Summary
Quantum diffusion in chaotic systems shows nonmonotonic behavior with Lévy noise, unlike monotonic behavior with standard noise. Optimal diffusion rates were found experimentally and analytically in the atom-optics Lévy kicked rotor.
Area of Science:
- Quantum chaos
- Atom optics
- Condensed matter physics
Background:
- Chaotic Hamiltonian systems, like the kicked rotor, are crucial for understanding transport and localization.
- Decoherence and noise typically cause localized quantum states to decay, increasing quantum diffusion monotonically.
Purpose of the Study:
- Investigate the quantum diffusion dynamics of the atom-optics Lévy kicked rotor.
- Explore the nonmonotonic behavior of quantum diffusion with varying Lévy distribution parameters.
- Determine optimal diffusion rates experimentally and analytically.
Main Methods:
- Utilized an ultracold cloud of rubidium atoms in a pulsed optical lattice for experimental realization.
- Employed analytical methods to derive parameters for optimal diffusion.
- Performed numerical simulations to validate results.
Main Results:
- Observed nonmonotonic quantum diffusion in the Lévy kicked rotor, contrasting with monotonic diffusion in standard noise models.
- Experimentally identified optimal diffusion rates.
- Analytical results showed good agreement with experimental and numerical findings.
Conclusions:
- The nonmonotonic quantum diffusion is a distinct quantum effect.
- This nonmonotonicity disappears in the classical limit, highlighting quantum phenomena in chaotic systems.
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