title: Transfer of angular momentum to matter from acoustical vortices in free space.
abstract: An experimental demonstration of the mechanical transfer of orbital angular momentum to matter from acoustical vortices in free field is presented. Vortices with topological charges l=+/-1 and l=+/-2 were generated and a torsion pendulum was used to study the angular momentum transfer to hanging disks of several sizes. This allowed us to make a comparative study of the effective acoustical torque in terms of topological charge of the vortex, the disk radius, and its position along the main propagation axis. A theoretical discussion of the generated sound fields is also provided.
authors.affiliation: Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 Mexico D.F., Mexico.
authors.forename: Karen
authors.initials: K
authors.lastname: Volke-Sepúlveda
authors.forename: Arturo O
authors.initials: AO
authors.lastname: Santillán
authors.forename: Ricardo R
authors.initials: RR
authors.lastname: Boullosa