Abstract
Phase singularities of wave-front-like screw dislocations or vortices possess a well-defined quantity that can only take integer value: the topological charge. In the nonlinear regime, it has been demonstrated that optical or acoustical vortices interact and the topological charge follows a conservation law. Here this facility is used in nonlinear parametric interaction of two vortices shifted in frequency to perform sums and subtractions of the topological charge. Thus, we experimentally demonstrate a new technique to perform wave computation in the group of integer . When the two vortices have commensurable frequencies, different combinations give the same frequencies but different tolopological charges may occur. We show that an energy criterion can be used to predict the outcome. A corollary is that a modulation of amplitude of the vortices switches from one result to the other.
- Received 14 February 2008
DOI:https://doi.org/10.1103/PhysRevLett.101.064301
©2008 American Physical Society
Synopsis
Doing sums with swirls
Published 11 August 2008
Acoustic vortices that interact in a nonlinear medium may be one route to a new kind of robust arithmetic computation.
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