论文标题
正常的密度和移动超流体的惯性矩
Normal density and moment of inertia of a moving superfluid
论文作者
论文摘要
在这项工作中，研究了正常的密度$ρ_n$和移动超流动的惯性矩。我们发现，即使在零温度下，移动的超流体也存在有限的正常密度。当超级流体的速度达到声音速度时，正常密度变为总质量密度$ρ$，这表明系统损失了超流体。同时，Landau的临界速度也变为零。非零正常密度的存在归因于横向上的超流动和密度波动之间的耦合。通过Josephson的关系，还计算了超级流体密度$ρ_s$，并且身份$ρ_s+ρ_n=ρ$保持。此外，我们发现有限的正常密度还会导致被环捕获的运动超流体中的量化惯性矩。通过测量环陷阱中移动的超氟的角动量，可以在零温度下的正常密度和惯性矩进行实验验证。
In this work, the normal density $ρ_n$ 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 $ρ$, 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 $ρ_s$ is also calculated and the identity $ρ_s+ρ_n=ρ$ 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.
