2013/11/19 by Лев П. Питаевский, Pitaevskii, Lev P. · 1 citation
Physics and Astronomy · #Quantum, superfluid, helium dynamics #Cold Atom Physics and Bose-Einstein Condensates #Atomic and Subatomic Physics Research
paper · pdf · doi:10.48550/arxiv.1311.4693
I study vortex ring oscillations in a superfluid, trapped in an elongated\ntrap, under the conditions of the Local Density Approximation. On the basis of\nthe Hamiltonian formalism I develop a hydrodynamic theory, which is valid for\nan arbitrary superfluid and depends only on the equation of state. The problem\nis reduced to an ordinary differential equation for the ring radius. The cases\nof the dilute BEC and the Fermi gas at unitarity are investigated in detail.\nSimple analytical equations for the periods of small oscillations are obtained\nand the equations of non-linear dynamics are solved in quadratures. The results\nagree with available numerical calculations. Experimental possibilities to\ncheck the predictions are discussed.\n