Anomalous Doppler effect in two-component Bose-Einstein condensates

Abstract

We show that two-component Bose-Einstein condensed mixtures, in presence of a persistent current, exhibit a non trivial Doppler shift of the sound velocities. The peculiarity is due to the inter-species interaction and the possibility of generating a counter-flow persistent current. Analytic predictions are derived by using superfluid hydrodynamics. While the existence of anomalous Doppler shifts at finite temperature has been discussed a long time ago in the case of superfluid Helium-4, an experimental verification of the effect is still missing. For this reason, we also propose a protocol for the measurement of the Doppler shifts, based on the density-density response function. The dynamical protocol is simulated by means of coupled Gross-Pitaevskii equations.

References in corpus (9)

• Minimally destructive, Doppler measurement of a quantized, superfluid flow
• Observation of Massless and Massive Collective Excitations with Faraday Patterns in a Two-Component Superfluid
• Spin-Dipole Oscillation and Polarizability of a Binary Bose-Einstein Condensate near the Miscible-Immiscible Phase Transition
• Observation of Two Sound Modes in a Binary Superfluid Gas
• Sound, superfluidity and layer compressibility in a ring dipolar supersolid
• Hydrodynamic modes of partially condensed Bose mixtures
• Spin and Density Modes in a Binary Fluid of Light
• Anomalous Doppler effect in superfluid and supersolid atomic gases
• Dynamics of Supersolid state: normal fluid, superfluid, and supersolid velocities