Irish physicists’ research into synchronisation explains how crowds work

17 Dec 2021

Image: © agsandrew/

Trinity College Dublin researchers proved that even large groups of clocks can be synchronised, which could have wider practical impacts in everything from ICT to crowd control.

A group of physicists from Trinity College Dublin (TCD) has made a discovery that explains how synchronisation occurs in large groups of individual ‘oscillators’.

From elephants stampeding to crowds cheering, researchers have established the science behind synchronisation and why even inanimate objects like clocks tend to tick together when in close proximity.

The physicists’ work has been published in the Physical Review Research journal. The research process involved creating equations based on the behaviour of clocks. While it is known that synchronisation can occur in clocks by physically connecting them when one ticks faster than another, it is thanks to TCD’s physicists we now know that this can be replicated even in large groups of clocks.

According to Dr Paul Eastham, Naughton associate professor in physics at Trinity, “The equations we have developed describe an assembly of laser-like devices – acting as our ‘oscillating clocks’ – and they essentially unlock the secret to synchronisation.

“These same equations describe many other kinds of oscillators, however, showing that synchronisation is more readily achieved in many systems than was previously thought.”

Eastham added that the research into clocks could potentially be applied to other areas of life where synchronisation occurs.

“Many things that exhibit repetitive behaviour can be considered clocks, from flashing fireflies and applauding crowds to electrical circuits, metronomes and lasers,” he said. “Independently, they will oscillate at slightly different rates. But when they are formed into an assembly, their mutual influences can overcome that variation.”

The new discovery has potential practical applications for the tech industry, too, including the development of new types of computer technology that use light signals to process information.

In 2016, Eastham co-led a team of researchers that discovered a new form of light. That research was published in the online journal Science Advances.

The research project was supported by the Irish Research Council. It involved the Trinity Centre for High Performance Computing, which has been supported by Science Foundation Ireland.

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Blathnaid O’Dea is Careers reporter at Silicon Republic