论文标题
与经典辐射和辐射反应有关的量子辐射和耗散
Quantum Radiation and Dissipation in Relation to Classical Radiation and Radiation Reaction
论文作者
论文摘要
这项工作继续研究了从原子场相互作用的辐射现象的研究，从而将量子辐射的早期研究从固定原子的内部自由度（由谐波振荡器模型）扩展到了经典辐射的发射。通过假设原子与最初处于连贯状态的量子标量场相互作用，我们表明了原子内部动力学的随机分量是如何源于该场的真空波动引起的，从而导致量子辐射的发射，从而导致其反应诱导内部动力学中的量子消散。我们还展示了确定性均值场如何驱动内部经典均值分量发射经典辐射并接收经典辐射反应。这两个组件在统计上都是不同的，并且完全解耦。可以清楚地看出，该场真空波动的影响与量子辐射反应的效果相匹配，而不是与民间传播的那样，而不是经典的辐射反应。与原子内部动力学的量子分量始终平衡的量子分量相反，经典成分的弛豫动力学在很大程度上取决于平均场的晚期行为。对于定义磁场相干状态的参数的值，如果平均场保持周期性，则原子的内部动力学将显得经典且周期性。如果平均场随时间减少，则原子内部动力学的经典成分将消失，但是量子分量将遵守并动态平衡。这也解释了为什么未观察到来自固定原子的量子辐射，而远距离的探针只能看到经典的辐射。因此，我们的分析描绘了从量子场中的真空波动到经典辐射和辐射反应开始的连续景观。
This work continues the investigation of radiation phenomena from atom-field interactions, extending our earlier study of quantum radiation from a stationary atom's internal degree of freedom, modeled by a harmonic oscillator, to the emittance of classical radiation. By assuming that the atom interacts with a quantum scalar field initially in a coherent state, we show how a stochastic component of the internal dynamics of the atom arises from the vacuum fluctuations of the field, resulting in the emittance of quantum radiation, whose reaction induces quantum dissipation in the internal dynamics. We also show how the deterministic mean field drives the internal classical mean component to emit classical radiation and receive classical radiation reaction. Both components are statistically distinct and fully decoupled. It is clearly seen that the effects of the vacuum fluctuations of the field are matched with those of quantum radiation reaction, not with classical radiation reaction, as the folklore goes. In contrast to the quantum component of the atom's internal dynamics, which always equilibrates, the relaxation dynamics of the classical component largely depends on the late-time behavior of the mean field. For the values of the parameters defining the coherent state of the field much greater than unity, if the mean field remains periodic, then the internal dynamics of the atom will appear classical and periodic. If the mean field diminishes with time, then the classical component of the atom's internal dynamics subsides but the quantum component will abide and dynamically equilibrate. This also explains why quantum radiation from a stationary atom is not observed, and a probe located far away only sees classical radiation. Our analysis therefore paints a continuum landscape starting from vacuum fluctuations in the quantum field to classical radiation and radiation reaction.
