Experimental evolution of active Brownian grains driven by quantum effects in superfluid helium

Abstract

Complex structures, consisting of a large number of interacting subsystems, have the ability to self-organize and evolve, when the scattering of energy coming from the outside ensures the maintenance of stationary ordered structures with an entropy less than the equilibrium entropy. One of the fundamental problems here is the role of quantum phenomena in the evolution of macroscopic objects. We provide experimental evidence for the active Brownian motion and evolution of structures driven by quantum effects for micron-sized grains levitating in superfluid helium. The active Brownian motion of grains was induced by quantum turbulence during the absorption of laser irradiation by grains. The intensity of Brownian motion associated with quantum vortices increased by 6–7 orders of magnitude compared to the values from the Einstein formula. We observed the grain structures in a state far from thermodynamic equilibrium and their evolution to more complex organized structures with lower entropy due to the quantum mechanism of exceedingly high entropy loss in superfluid helium.

Motion of a self-propelled particle with rotational inertia

“…If o/n fr c 1, there is an equality of temperatures: T hx 2 i eff /T hXi eff C 1, and the active particle dynamics can be classified as hot Brownian motion. [85][86][87] However, at a lower intensity of rotational fluctuations, the T hx 2 i eff /T hXi eff ratio is in the range from p(1 + o/n fr ) 2 /4(1 + (p/4) 0.5 o/n fr ) 2 to 1 due to the non-Maxwellian velocity distribution. 67 We note that the above results refer to the case of a free selfpropelled particle in a homogeneous environment.…”

“…If ω / ν fr ≫ 1, there is an equality of temperatures: T 〈 x 2〉 eff / T 〈 X 〉 eff ≃ 1, and the active particle dynamics can be classified as hot Brownian motion. 85–87 However, at a lower intensity of rotational fluctuations, the T 〈 x 2〉 eff / T 〈 X 〉 eff ratio is in the range from π(1 + ω / ν fr ) 2 /4(1 + (π/4) 0.5 ω / ν fr ) 2 to 1 due to the non-Maxwellian velocity distribution. 67…”

Active Brownian motion of strongly coupled charged grains driven by laser radiation in plasma

“…The systems of active Brownian grains can be considered open systems, in which there is an exchange of energy and matter with the environment. Open systems are called dissipative structures if the scattering of energy coming from outside maintains a stationary ordered structure with an entropy less than the equilibrium structure 7 , 8 . A change (increase) in the flow of entropy into the environment in dissipative structures can lead to their self-organization and evolution 8 – 11 .…”

The Optimal Axis-Symmetrical Plasma Potential Distribution for Plasma Mass Separation

“…Recently, a whole research area devoted to plasma systems of active particles has emerged. These are both plasma systems with micron-sized macroscopic particles immersed in them [ 1 , 2 , 3 , 4 ] and more traditional plasma systems without a dust component [ 5 , 6 ]. Such plasma formations are open particle systems in which, due to specially selected external conditions, it is possible to transform chaotic thermal motion into directed flows of active particles.…”