Related Experiment Video
Updated: Sep 20, 2026

Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
Sound attenuation study on the bose-Einstein condensation of magnons in TlCuCl3
E Ya Sherman1, P Lemmens, B Busse
1Institute for Theoretical Physics, Karl-Franzens-University of Graz, A-8010, Graz, Austria.
Abstract:
We investigate experimentally and theoretically sound attenuation in the quantum spin system TlCuCl3 in magnetic fields at low temperatures. Near the point of Bose-Einstein condensation of magnons a sharp peak in the sound attenuation is observed. The peak demonstrates a hysteresis as a function of the magnetic field pointing to a first-order contribution to the transition. The sound damping has a Drude-like form arising as a result of hard-core magnon-magnon collisions. The strength of the coupling between lattice and magnons is estimated from the experimental data. The puzzling relationship between the transition temperature and the concentration of magnons is explained by their "relativistic" dispersion.
Related Concept Videos
Theory of Metallic Conduction
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
Electromagnetic Waves in Matter
Consider the electromagnetic wave passing through a dielectric medium. In such a case, Maxwell's equations get modified. In Ampere's law, ε0 , the dielectric permittivity of free space is replaced with ε, the permittivity of dielectric. Also, the vacuum permeability μ0 is replaced by the permeability of the medium, μ.
Furthermore, the...
Standing Waves in a Cavity
Inductance: Solid Cylindrical Conductor
Given the uniform current distribution, the magnetic field Hx and flux density Bx inside the conductor are...
Oscillations In An LC Circuit
Poisson's And Laplace's Equation

