Sarkar Sumit, Paul Sanku, Vishwakarma Chetan, Kumar Sunil, Verma Gunjan, Sainath M, Rapol Umakant D, Santhanam M S
Department of Physics, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune 411 008, India.
Center for Energy Sciences, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune 411 008, India.
Phys Rev Lett. 2017 Apr 28;118(17):174101. doi: 10.1103/PhysRevLett.118.174101. Epub 2017 Apr 26.
Quantum systems lose coherence upon interaction with the environment and tend towards classical states. Quantum coherence is known to exponentially decay in time so that macroscopic quantum superpositions are generally unsustainable. In this work, slower than exponential decay of coherences is experimentally realized in an atom-optics kicked rotor system subjected to nonstationary Lévy noise in the applied kick sequence. The slower coherence decay manifests in the form of quantum subdiffusion that can be controlled through the Lévy exponent. The experimental results are in good agreement with the analytical estimates and numerical simulations for the mean energy growth and momentum profiles of an atom-optics kicked rotor.
量子系统在与环境相互作用时会失去相干性，并趋向于经典状态。已知量子相干性会随时间呈指数衰减，因此宏观量子叠加通常难以维持。在这项工作中，在应用的踢腿序列中受到非平稳 Lévy 噪声作用的原子光学踢转子系统中，通过实验实现了比相干性指数衰减更慢的情况。较慢的相干性衰减表现为量子亚扩散的形式，其可以通过 Lévy 指数来控制。实验结果与原子光学踢转子的平均能量增长和动量分布的解析估计及数值模拟结果高度吻合。
