The shape of a magnonic black hole horizon

Abstract

Black holes are extremely dense objects with a gravitational ?eld so strong that nothing, not even light, can escape from it. One of Stephen Hawkings most popular ?ndings is that black holes might, in fact, be not completely black and emit radiation caused by quantum effects at the horizon which is called Hawking radiation. Black holes are for obvious reasons really hard to detect and creating one is out of our reach, so analogue systems are proposed to test the theory of Hawking radiation. One of those analogues is a magnonic black hole system. Magnons are spin-waves in a ferromagnetic material. If a current is induced, the magnons act like particles in a gravitational ?eld. We design a model for different shaped electrical circuits made of magnetic material where we make use of the Laplace equation and corresponding boundary conditions to simulate such a black hole and determine the shape of its horizons. We ?nd that the shape of the magnonic black hole horizon depends on the geometry of the ferromagnetic system and the magnitude of the applied current. The results may be helpful for the experimental design of magnonic black holes.