Giant enhancement of vacuum friction in spinning YIG nanospheres

Abstract

Experimental observations of vacuum radiation and vacuum frictional torque are challenging due to their vanishingly small effects in practical systems. For example, a nanosphere rotating at $1\,\mathrm{GHz}$ in free space slows down due to friction from vacuum fluctuations with a stopping time around the age of the Universe. Here, we show that a spinning yttrium iron garnet (YIG) nanosphere near aluminum or YIG slabs generates vacuum radiation with radiation power eight orders of magnitude larger than other metallic or dielectric spinning nanospheres. We achieve this giant enhancement by exploiting the large near-field magnetic local density of states in YIG systems, which occurs in the low-frequency GHz regime comparable to the rotation frequency. Furthermore, we propose a realistic experimental setup for observing the effects of this large vacuum radiation and frictional torque under experimentally accessible conditions.

Keywords

• vacuum fluctuations
• vacuum radiation
• vacuum frictional torque
• fluctuational electrodynamics
• yttrium iron garnet
• magnon polariton resonance