Thermal Dissipation in Quantum Turbulence

The microscopic mechanism of thermal dissipation in quantum turbulence is numerically studied by solving the coupled system involving the Gross-Pitaevskii equation and the Bogoliubov–de Gennes equation. At low temperatures, the obtained dissipation does not work at scales greater than the vortex core size. However, as the temperature increases, dissipation works at large scales and it affects the vortex dynamics. We successfully obtain the mutual friction coefficients of the vortex in dilute Bose-Einstein condensates dynamics as functions of temperature.

Figure 1

Image of the energy flow in a system of quantum fluid coupled with a heat bath.

Figure 2

(a) An example of the configurations of quantized vortices at $t=0$. (b) Wave number dependence of the Fourier-transformed dissipation term $\gamma (k,t=1)$, which is obtained by performing an ensemble average of 25 initial states.

Figure 3

Configurations of quantized vortices at $t=1$ at $T=0.01T_c$ (a) and $T=0.1T_c$ (b), starting from the configuration shown in Fig. 2a.

Figure 4

Temperature dependence of the coefficients $\alpha$ and ${\alpha }^{\prime }$. Plots represent the numerical results and lines indicate some fitting.