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ISSN Печать: 0040-2508
ISSN Онлайн: 1943-6009
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AN ANALOG TO THE SECOND ORDER PHASE TRANSITION IN A QUASI-OPTICAL MICROWAVE CAVITY RESONATOR
Краткое описание
An analog to the second-order phase transition has been discovered and studied in volumetric microwave resonant structures of spherical (cylindrical) geometry that contain inhomogeneous inserts in the form of a metal sphere (disk). The transition occurs between the states where the sphere (disk) is located either symmetrically or non-symmetrically with respect to the structure's side walls. For each of these states, eigen-oscillation spectra are measured in the 8-mm waveband, and the data are used to estimate correlation factors between the interline frequency intervals. As has been found, integrable (i.e., symmetric) spherical or cylindrical resonant structures with an inner sphere (disk) show correlation factors close to zero, whereas non-integrable structures where the inner sphere (disk) is placed asymmetrically demonstrate correlation factors C(1) > 0.2 in absolute value. A transition between such states may occur within a narrow range of the structure's eccentricity. The distributions of the inter-line intervals have been studied in dependence on the mean separation between the eigenfrequencies. In the case of integrable systems these dependences are given by the Poisson function, while in non-integrable systems they tend to the Wigner distribution which is characteristic of the states demonstrating spectral line repulsion and appearance of quantum chaos. Thus, it has been established that a change in the microwave cavity's symmetry can lead to appearance of effects analogous to a second-order phase transition, whereby the resonant structure becomes non-integrable and demonstrates a 'quantum chaotic' behavior.