A trapped Bose-Einstein condensed atomic gas containing a quantized vortex is predicted to exhibit precession after a sudden rotation of the confining potential. The equations describing the motion of the condensate are derived and the effects of superfluidity explicitly pointed out. The dependence of the precession frequency on the relevant parameters of the problem is discussed. The proposed gyroscope is well suited to explore rotational effects at the level of single quanta of circulation.
A trapped Bose-Einstein condensed atomic gas containing a quantized vortex is predicted to exhibit precession after a sudden rotation of the confining potential. The equations describing the motion of the condensate are derived and the effects of superfluidity explicitly pointed out. The dependence of the precession frequency on the relevant parameters of the problem is discussed. The proposed gyroscope is well suited to explore rotational effects at the level of single quanta of circulation.
The gyroscopic motion of a trapped Bose gas containing a vortex is studied. We model the system as a classical top, as a superposition of coherent hydrodynamic states, by solution of the Bogoliubov equations, and by integration of the time-dependent Gross-Pitaevskii equation. The frequency spectrum of Bogoliubov excitations, including quantum frequency shifts, is calculated and the quantal precession frequency is found to be consistent with experimental results, though a small discrepancy exists. The superfluid precession is found to be well described by the classical and hydrodynamic models. However the frequency shifts and helical oscillations associated with vortex bending and twisting require a quantal treatment. In gyroscopic precession, the vortex excitation modes m = ±1 are the dominant features giving a vortex kink or bend, while the m = +2 is found to be the dominant Kelvin wave associated with vortex twisting. Superfluid atomic gyroscopes 2 1.
The gyroscopic motion of a trapped Bose gas containing a vortex is studied. We model the system as a classical top, as a superposition of coherent hydrodynamic states, by solution of the Bogoliubov equations, and by integration of the time-dependent Gross–Pitaevskii equation. The frequency spectrum of Bogoliubov excitations, including quantum frequency shifts, is calculated and the quantal precession frequency is found to be consistent with experimental results, although a small discrepancy does exist. The superfluid precession is found to be well described by the classical and hydrodynamic models. However, the frequency shifts and helical oscillations associated with vortex bending and twisting require a quantal treatment. In gyroscopic precession, the Kelvin modes m = ±1 are the dominant features giving a vortex kink or bend, while the m = +2 mode is found to be the dominant Kelvin wave associated with vortex twisting.
We have observed a three-dimensional gyroscopic effect associated with a vortex in a dilute Bose-Einstein condensed gas. A condensate with a vortex possesses a single quantum of circulation, and this causes the plane of oscillation of the scissors mode to precess around the vortex line. We have measured the precession rate of the scissors oscillation. From this we deduced the angular momentum associated with the vortex line and found a value close to Planck's over 2pi per particle, as predicted for a superfluid.
Abstract This chapter is devoted to discussing some key superfluid properties exhibited by dilute Bose gases confined in external traps. Key issues concern the behaviour of the critical velocity and the applicability of Landau’s criterion for superfluidity, the moment of inertia and its quenching caused by the irrotationality of the superfluid motion, the scissors mode, and the expansion of a rotating superfluid cloud. Rotational effects at high angular velocities, with the appearance of quantized vortices and vortex lattices, are also considered. The chapter also discusses the consequences for vortices on the collective oscillations of the trapped gas, the stability and the precession of vortex lines, and the nature of the superfluid flow in toroidal traps.
With high precision and sensitivity, quantum gyroscope has become a research hotspot of inertial technology in recent years. Because the Bose-Einstein Condensate (BEC) in atomic gas has more condensate atoms, atomic gas is pure and thin, and there is no friction in atoms, the matter–wave gyroscopy with counter-rotating vortex superpositions has great potential of higher sensitivity, higher precision, and miniaturization. The basic mechanism and sensitivity of the matter– wave gyroscopy with counter-rotating vortex superpositions were analyzed, and the interaction between superposition of vortex beams and BEC atomic gases were studied, it is Stimulated Raman Adiabatic Passage (STIRAP). In the study, the outstanding issue that the gyroscopy is difficult to obtain stable vortices with high order orbital angular momentum was clarified by theoretical derivation on the base of Gross-Pitaevskii equation which is the basic equation in BEC. For solving the above problems, the scheme which is easy to achieve based on Sombrero potential trap was proposed.
By applying a position-dependent detuning to a spin-orbit-coupled Hamiltonian with equal Rashba and Dresselhaus coupling, we exploit the behavior of the angular momentum of a harmonically trapped Bose-Einstein condensed atomic gas and discuss the distinctive role of its canonical and spin components. By developing the formalism of spinor hydrodynamics, we predict the precession of the dipole oscillation caused by the synthetic rotational field, in analogy with the precession of the Foucault pendulum, the excitation of the scissors mode, following the sudden switching off of the detuning, and the occurrence of Hall-like effects. When the detuning exceeds a critical value, we observe a transition from a vortex free, rigidly rotating quantum gas to a gas containing vortices with negative circulation which results in a significant reduction of the total angular momentum.