Point-like defects in a quantum fluid behave like magnetic monopoles

Phys.org September 12, 2012 by Lisa Zyga

Experimental set-up showing the injection of a polariton fluid and the formation of half-solitons, which act like magnetic monopoles. Image credit: R. Hivet, et al. ©2012 Macmillan Publishers Limited (Phys.org)—No one has ever definitively observed a magnetic monopole, the hypothetical fundamental particle that has only a north or south magnetic pole, but not both like normal magnets do. However, scientists have observed a few types of monopole analogues – objects sometimes described as “quasiparticles” that behave like magnetic monopoles but don’t meet all the requirements to be one – such as excitations in spin-ice crystals and in one-dimensional magnetic nanowires. Now in a new study, scientists have observed a new type of monopole analogue in the form of tiny defects that arise in quantum states of matter called Bose-Einstein condensates (BECs). The discovery could help scientists better understand the fundamental nature of magnetism and may also lead to novel devices such as magnetronic circuits.