A. I. Golov

Quantum and quasiclassical types of superfluid turbulence

By injecting negative ions in superfluid 4He in the zero-temperature limit (T<or=0.5 K), we have generated tangles of quantized vortex line with negligible large-scale flow. For this quantum regime of superfluid turbulence, the vortex line length L was found to decay at late time t as L proportional to t{-1}, the prefactor being independent of the initial value of L. The corresponding effective kinematic viscosity is 0.1 kappa, where kappa is the circulation quantum. At T>0.7 K, a jet of ions generates quasiclassical tangles identical to those produced by mechanical means.

Quantum turbulence in a propagating superfluid vortex front

We present experimental, numerical, and theoretical studies of a vortex front propagating into a region of vortex-free flow of rotating superfluid 3He-B. We show that the nature of the front changes from laminar through quasiclassical turbulent to quantum turbulent with decreasing temperature. Our experiment provides the first direct measurement of the dissipation rate in turbulent vortex dynamics of 3He-B and demonstrates that the dissipation becomes mutual-friction independent with decreasing temperature, and it is strongly suppressed when the Kelvin-wave cascade on vortex lines is predicted to be involved in the turbulent energy transfer to smaller length scales.

Magnetocaloric effect in pyrochlore antiferromagnet Gd 2Ti 2O 7

An adiabatic demagnetization process is studied in

Excimers He2* as Tracers of Quantum Turbulence in 4He in the T=0 Limit

{\mathrm{Gd}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}

Sharp and Stable Metal Tips for Helium Ionization at mK Temperatures

, a geometrically frustrated antiferromagnet on a pyrochlore lattice. In contrast to conventional paramagnetic salts, this compound can exhibit a temperature decrease by a factor of 10 in the temperature range below the Curie-Weiss constant. The most efficient cooling is observed in the field interval between 120 and

A new type of excimer atom: electron + ionized helium cluster

60\phantom{\rule{0.3em}{0ex}}\mathrm{kOe}

Dynamics of quantum turbulence of different spectra

corresponding to a crossover between saturated and spin-liquid phases. This phenomenon indicates that a considerable part of the magnetic entropy survives in the strongly correlated state. According to the theoretical model, this entropy is associated with a macroscopic number of local modes remaining gapless until the saturation field. Monte Carlo simulations on a classical spin model demonstrate good agreement with the experiment. The cooling power of the process is experimentally estimated with a view to possible technical applications. The results for

Spectroscopic study of injected electrons in solid helium

{\mathrm{Gd}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}

Reconnections of Quantized Vortex Rings in Superfluid 4He at Very Low Temperatures

are compared to those for

A compact rotating dilution refrigerator

{\mathrm{Gd}}_{3}{\mathrm{Ga}}_{5}{\mathrm{O}}_{12}