Cooperative spontaneous emission of N atoms: Many-body eigenstates, the effect of virtual Lamb shift processes, and analogy with radiation of N classical oscillators
Cooperative spontaneous emission of N atoms: Many-body eigenstates, the effect of virtual Lamb shift processes, and analogy with radiation of N classical oscillators
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DOI：
10.1103/physreva.81.053821
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发表时间：
2010-05
影响因子：
2.9
通讯作者：
A. Svidzinsky;Juntao Chang;M. Scully
中科院分区：
文献类型：
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作者：
A. Svidzinsky;Juntao Chang;M. Scully
我们考虑一个光子的集体发射从$N$两能级原子云（一个激发态，$N\ensuremath{-}1$基态）。对于稠密云，问题被简化为寻找一个积分方程的特征函数和特征值。我们讨论了球对称原子云的这个多原子问题的精确解析解。一些本征态的衰减速度比单原子的衰减速度快得多，而另一些本征态的衰减速度非常慢。我们表明，虚拟过程对快速衰减状态的演化产生很小的影响。然而，它们将长时间动力学从指数衰减转变为幂律行为，可以在实验中观察到。对于捕获态，虚拟过程更为重要，产生额外的衰减通道，导致其他捕获态的缓慢衰减。我们还证明了弱激发原子系综自发发射的量子力学处理类似于经典谐振子的发射。
We consider collective emission of a single photon from a cloud of $N$ two-level atoms (one excited, $N\ensuremath{-}1$ ground state). For a dense cloud the problem is reduced to finding eigenfunctions and eigenvalues of an integral equation. We discuss an exact analytical solution of this many-atom problem for a spherically symmetric atomic cloud. Some eigenstates decay much faster then the single atom decay rate, while the others undergo very slow decay. We show that virtual processes yield a small effect on the evolution of rapidly decaying states. However, they change the long time dynamics from exponential decay into a power-law behavior which can be observed experimentally. For trapped states virtual processes are much more important yielding additional decay channels which results in a slow decay of the otherwise trapped states. We also show that quantum mechanical treatment of spontaneous emission of weakly excited atomic ensemble is analogous to emission of $N$ classical harmonic oscillators.