1. Normal density and moment of inertia of a moving superfluid
- Author
-
Gang Chen, Yi-Cai Zhang, and Shu-Wei Song
- Subjects
Physics ,Condensed Matter::Quantum Gases ,Work (thermodynamics) ,Angular momentum ,Condensed matter physics ,Condensed Matter::Other ,FOS: Physical sciences ,Moment of inertia ,Condensed Matter Physics ,Coupling (probability) ,Critical ionization velocity ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,010305 fluids & plasmas ,law.invention ,Superfluidity ,Transverse plane ,law ,Quantum Gases (cond-mat.quant-gas) ,0103 physical sciences ,Condensed Matter - Quantum Gases ,010306 general physics ,Bose–Einstein condensate - Abstract
In this work, the normal density $\rho_n$ and moment of inertia of a moving superfluid are investigated. We find that, even at zero temperature, there exists a finite normal density for the moving superfluid. When the velocity of superfluid reaches sound velocity, the normal density becomes total mass density $\rho$, which indicates that the system losses superfluidity. At the same time, the Landau's critical velocity also becomes zero. The existence of the non-zero normal density is attributed to the coupling between the motion of superflow and density fluctuation in transverse directions. With Josephson relation, the superfluid density $\rho_s$ is also calculated and the identity $\rho_s+\rho_n=\rho$ holds. Further more, we find that the finite normal density also results in a quantized moment of inertia in a moving superfluid trapped by a ring. The normal density and moment of inertia at zero temperature could be verified experimentally by measuring the angular momentum of a moving superfluid in a ring trap., Comment: 6 pages
- Published
- 2020
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