Synopsis: Doing sums with swirls

Acoustic vortices that interact in a nonlinear medium may be one route to a new kind of robust arithmetic computation.
Synopsis figure

Calculating minds have employed a wide variety of objects to carry out computations, from stones and fingers, to electrons, strands of DNA, and recently quantum states and spintronics. Essentially anything that can represent numbers can be used to do arithmetic, but it helps if the object is robust—that is, the numbers shouldn’t change in the presence of noise or environmental contact (which is what makes quantum computing so difficult). Even better would be a system that goes beyond binary (two-level) logic computations to multilevel logic that might carry more information.

In Physical Review Letters, Régis Marchiano and Jean-Louis Thomas of the Université Pierre et Marie Curie report on their efforts to use vortices as computational elements. Vortices can be screw dislocations in a material, acoustic waves, or swirls in a liquid, but they always possess a topological “charge” related to the phase or winding number (similar to the number of times you would revolve around the axis while climbing a spiral staircase). Such vortices exist in acoustic or optical systems in both linear and nonlinear media, so there are many opportunities for creating and controlling them.

The researchers created vortices in water tanks with arrays of piezoelectric transducers and measured the pressure fields at the end of the tank using a tiny hydrophone. By creating vortices with different acoustic frequencies, and allowing these vortices to mix, they found that the resulting “output” vortex represented the sums and differences of the original topological charges. The vortices are not only resistant to changes in topological charge caused by perturbations but the charge can occur in integer multiples of 2π, rather than only two conventional binary values of 0 and 1. Although a useful computational device is unlikely to emerge from this work soon, it suggests a different way to add and subtract. – David Voss


More Announcements »

Subject Areas

Nonlinear DynamicsInterdisciplinary Physics

Previous Synopsis

Next Synopsis


The pressure is on to ban doping

Read More »

Related Articles

Synopsis: Robust Yet Flexible Clocks
Biological Physics

Synopsis: Robust Yet Flexible Clocks

A theoretical analysis explains why circadian clocks can be robust but also able to adapt to environmental changes.   Read More »

Focus: Evolution Sometimes Slows Things Down
Interdisciplinary Physics

Focus: Evolution Sometimes Slows Things Down

When a strongly cooperative species invades new territory, its spread can slow down or stop, according to a mathematical model, suggesting potential strategies against cancer and insect pests. Read More »

Focus: Explaining the Periodicity of Snow Spikes
Fluid Dynamics

Focus: Explaining the Periodicity of Snow Spikes

A new model explains the fixed periodicity of a rare snow formation that appears at high altitudes. Read More »

More Articles