Cerenkov Radiation in Presence of Squeezed Electromagnetic Vacuum
Peter A. Meleshenko, Hang Thi Nguyen, Vladimir A. Gorlov +2 more
In this work we investigate the Cerenkov radiation in the case of motion of a charged particle on a background of the squeezed electromagnetic vacuum. Using the quantum approach (time dependent perturbation theory) we obtain the explicit expression for the Cerenkov radiated power. The analysis of the obtained expression shows that in contrast to the \classical case (where the Cerenkov radiation is a spontaneous process) the Cerenkov radiation in the squeezed vacuum has an induced character. The expression for radiated power contains two terms, namely the flrst term corresponds to radiation power, while the second one corresponds to absorption power. 1. INTRODUCTION Cerenkov efiect (1) have a long history but it remains relevant in relation to the difierent areas of application of such a phenomena (the wide list of publication on this subject takes place, see, e.g., (2{4) and related references). The expression for the radiated power was obtained by solving the equations of classical electrodynamics in the medium. A large number of studies have been devoted to other aspects of the Cerenkov efiect. They concern the extension to the case of magnetic media, a detailed analysis of radiation in crystals, the role of boundaries, etc. The classical theory of spontaneous Cerenkov efiect is fairly accurate, however the quantum analysis gives a more complete understanding of the phenomenon. Moreover, the quantum approach is most useful when considering the motion of a charged particle in a dielectric medium in the external electromagnetic wave. The radiation in this case has an induced nature and quantum approach gives a better understanding of the physical nature of phenomena. Creation of powerful sources of electromagnetic radiation initiated extensive research in the area of particle-fleld interaction. The squeezed states of light (5) play an important role in such researches. These states generalize the well-known class of coherent states and are characterized by the fact that the uncertainty of one of the canonical variables of the electromagnetic fleld is less than in a conventional coherent state. The squeezed states are important in such areas as optical communication, interferometry, nonlinear optics, the detection of gravitational waves, etc. It should also be noted that the squeezed states are objects of purely quantum nature. So the description of the motion of a charged particle on a background of the squeezed vacuum can be performed using the quantum fleld theory only. This problem is of great practical interest (new sources of electromagnetic radiation such as free-electron lasers and Cerenkov lasers). In this work we investigate the Cerenkov radiation in the case of motion of a charged particle on a background of the squeezed electromagnetic vacuum. Due to \purely quantum nature of the squeezed vacuum we use the quantum approach, namely the time dependent perturbation theory.
•Jan 1, 2015•0 citations