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Nonexponential decoherence and momentum subdiffusion in a quantum lévy kicked rotator.
1Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom.
Physical Review Letters
|August 7, 2007
Summary
We found a new decoherence regime in quantum systems subjected to Lévy noise. This regime prevents systems from reaching the classical limit, showing observable quantum subdiffusion.
Area of Science:
- Quantum physics
- Atomic physics
- Statistical mechanics
Background:
- The quantum kicked rotator models cold atoms in pulsed optical fields.
- Understanding decoherence is crucial for quantum system dynamics.
- Noise with power-law tail waiting-time distributions (Lévy noise) presents unique challenges.
Purpose of the Study:
- To investigate decoherence in the quantum kicked rotator under Lévy noise.
- To identify and characterize novel decoherence regimes.
- To explore the impact of Lévy noise on quantum dynamics and localization.
Main Methods:
- Simulating the quantum kicked rotator model.
- Introducing Lévy noise with variable exponent power-law tail waiting-time distributions.
- Analyzing decoherence, dynamical localization, and momentum diffusion.
Main Results:
- Demonstrated a regime of nonexponential decoherence.
- Showed that the decoherence rate is ill-defined in this regime.
- Found that dynamical localization is never fully destroyed, preventing the system from reaching the classical limit.
- Observed quantum subdiffusion of momentum.
Conclusions:
- Lévy noise introduces a unique decoherence regime in quantum systems.
- Quantum systems under this noise may not reach the classical limit.
- Quantum subdiffusion of momentum is a predictable and potentially observable phenomenon.
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