Electromagnetic black holes with controllable composite right/left-handed transmission lines.

Given that the Hawking radiation from celestial black holes is extremely weak and thus difficult to be practically detected, a series of analogue black holes have been constructed to observe the relevant analogue Hawking radiations in the laboratory. Based on the critical behavior of group velocity of the microwave signal propagating along a controllable composite right/left-handed transmission line, in this paper, we theoretically demonstrate that an electromagnetic black hole (EBH) can be constructed in the relevant co-moving coordinate system, i.e., in the velocity space, the horizon of such an analogous black hole could be generated, when the electromagnetic wave propagation group velocity equals to the propagation velocity of the voltage solitary wave. The corresponding Hawking radiation temperature of such an EBH and the particle production outside its horizon are calculated specifically for the typical circuit parameters. The results indicate that the Hawking radiation temperature of such an EBH can be enhanced as [Formula: see text] mK, and thus it should be detected by using the current ultra-low temperature technique, at least theoretically.