Quantum processes in an electromagnetic wave field

A. I. Nikishov, V. I. Ritus

В. Ч. Жуковский, I. Kherrmann

Eliade N. Stefanescu

Alessandro Ciattoni, Claudio Conti

We provide a quantum description of X waves by considering two different kinds of quantum states of the electromagnetic field whose field amplitude expectation value coincides with a propagation-invariant solution of the Maxwell equation. The difference between the two states is of pure quantum mechanical origin since they are internally entangled and disentangled and can be generated by different linear or nonlinear processes.

Li Wang, Fengxue Zhou, Pidong Hu +2 more

By using two orthogonal coupling standing-wave fields, we propose a scheme for a two-dimensional electromagnetically induced cross-grating (EICG) in a four-level tripod-type atomic system. Based on the electromagnetically induced transparency, the probe field will be diffracted and form the two-dimensional EICG through the interaction of the two coupling standing-wave fields. It is shown that the first-order diffraction intensity of the two-dimensional EICG depends observably on the detuning of the probe field and the Rabi frequencies of the two coupling standing-wave fields. The results may be used to develop novel photonic devices for use in quantum information processing, quantum networking and optical imaging.

Antonino Di Piazza, Kenan Qu

When an electron is accelerated, it emits radiation. In the relativistic quantum realm the elementary radiation process is the emission of a single photon, a process known as nonlinear Compton scattering in the case of an electron moving in the presence of a strong electromagnetic wave. This process is typically described within the Furry picture, where the electromagnetic wave is described as a classical background field and the electron-positron field is quantized in the presence of that background field. Equivalently one can quantize the electron-positron field in the vacuum but then the photon emission process is described as a transition from an initial state to a final state both featuring, apart from the electron (the initial state) and the electron and the photon (the final state), the same coherent state of photons appropriately related to the electromagnetic wave. Here, we consider a more general situation where the initial and the final state feature the same squeezed coherent state. Then, we specialize to the case where the coherent state corresponds to a plane-wave field and the mostly populated modes of the coherent state are also squeezed. We show that, when quantum fluctuations induced by the squeezing in the coherent field are negligible, a condition well satisfied at available squeezing levels, the squeezing effects effectively reduce to a frequency modulation of the plane-wave field corresponding to the coherent state. By means of numerical examples we show that at already available squeezing levels the emission spectrum of nonlinear Compton scattering and the total photon yield can be altered significantly. Analytical explanations of the main numerical results are also provided.