A team of researchers claims to have created the world's fastest spinning man-made object. They were able to levitate and spin a microscopic sphere at speeds of up to 600 million revolutions per minute.
This spin speed is half a million times faster than a domestic washing machine and more than a thousand times faster than a dental drill. The work by the University of St Andrews scientists is published in Nature Communications.
Although there is much international research exploring what happens at the boundary between classical physics and quantum physics, most of this experimental work uses atoms or molecules. The St Andrews team aimed to understand what happened for larger objects containing a million million atoms or more.
To do this they manufactured a microscopic sphere of calcium carbonate only four millionths of a metre in diameter. The team then used the miniscule forces of laser light to hold the sphere with the radiation pressure of light - rather like levitating a beach ball with a jet of water.
They exploited the property of polarisation of the laser light that changed as the light passed through the levitating sphere, exerting a small twist or torque.
Placing the sphere in vacuum largely removed the drag due to any gas environment, allowing the team to achieve the very high rotation rates.
In addition to the rotation, the team observed a "compression" of the excursions or "wobble" of the particle in all three dimensions, which can be understood as a "cooling" of the motion.
Essentially the particle behaved like the world's smallest gyroscope, stabilising its motion around the axis of rotation. The rotation rate is so fast that the angular acceleration at the sphere surface is one billion times that of gravity on the Earth surface”
Dr Yoshihiko Arita of the university's School of Physics and Astronomy said: "This is an exciting, thought-provoking experiment that pushes the boundary of our understanding of rotating bodies.