Simulation of sympathetic cooling an optically levitated magnetic nanoparticle via coupling to a cold atomic gas

Abstract

A proposal for cooling the translational motion of optically levitated magnetic nanoparticles is presented. The theoretical cooling scheme involves the sympathetic cooling of a ferromagnetic YIG nanosphere with a spin-polarized atomic gas. The particle–atom cloud coupling is mediated through the magnetic dipole–dipole interaction. When the particle and atom oscillations are small compared to their separation, the interaction potential becomes dominantly linear, which allows the particle to exchange energy with the N atoms. While the atoms are continuously Doppler cooled, energy is able to be removed from the nanoparticle’s motion as it exchanges energy with the atoms. The rate at which energy is removed from the nanoparticle’s motion was studied for three species of atoms (Dy, Cr, Rb) by simulating the full N + 1 equations of motion and was found to depend on system parameters with scalings that are consistent with a simplified model. The nanoparticle’s damping rate due to sympathetic cooling is competitive with and has the potential to exceed commonly employed cooling methods.

Giant enhancement of vacuum friction in spinning YIG nanospheres

“…Vacuum radiation and friction results beyond the dipole approximation will be discussed in future work. The following analysis is based on the experimentally accessible parameters from [3,40,41].…”

A levitated atom-nanosphere hybrid quantum system

“…Sympathetic cooling of the centre-of-mass motion by elastic collisions with a cold gas is another route towards creating cold trapped nanoparticles [14]. These methods have been very successful in creating both ultra-cold atoms and molecules that cannot be laser-cooled [15], with temperatures recently reaching 200 nK.…”

“…These methods have been very successful in creating both ultra-cold atoms and molecules that cannot be laser-cooled [15], with temperatures recently reaching 200 nK. Sympathetic cooling via the coupling of the thermal motion of cold atoms to a levitated nanosphere with a mediating cavity light field has also been proposed [16] while more recently sympathetic cooling of YIG nanosphere via an ultra-cold spin-polarized gas has been proposed [14]. Lastly sympathetic cooling mediated by the Coulomb interaction between co-trapped nanospheres in Paul traps and magnetic [17][18][19] and by optical binding have been realized [20].…”

Accelerated Magnonic Motional Cooling with Deep Reinforcement Learning

“…Tripartite opto-magno-mechanical cooling.− Now, we show that the proposed scheme can be extended effectively to more complex systems, for example a higher-order tripartite opto-magno-mechanical system, where we intend to cool the motional mode through non-trivial three-mode interactions. For this, we consider a system comprising a levitated YIG sphere in a harmonic trap [39][40][41], along with a driven WGM optical microresonator placed along the x-direction with a magnetostrictive rod (MR) attached to it, as depicted in Fig. 1(c), which will be used as the RL-environment in Fig.…”