In two places at once: Strange world of quantum mechanics shown to work in visible world for first time
The mind-bending laws of quantum mechanics, where tiny atoms and molecules can effectively be in two places at once, have been applied to a visible object for the first time. A U.S team managed to create a quantum state in an object billions of times larger than any previously tested.
Andrew Cleland from the University of California and his team used a tiny metal paddle, which is inclined to vibrate when a current passes through it.
They cooled it to a thousandth of a degree above absolute zero. This is very close to its quantum mechanical ‘ground state’, which is when no more energy can be removed.
The team then transmitted just one quantum of electrical energy from a specially devised electric circuit to the paddle.
They were able to show the resonating paddle was in a quantum state, between one and zero quanta of energy. This meant it was effectively moving and standing still at the same time.
The paddle was effectively a real-life version of ‘Schrodinger’s cat’ – a famous thought experiment devised by the physicist Erwin Schrodinger.
He described a situation where a cat is placed inside a steel chamber alongside a vial of acid and a small amount of radioactive substance. If one atom of this decays during a test period this will break the vial and kill the cat.
Schrodinger said according to quantum law the cat was alive and dead in a super-position of states while the chamber was closed.
The state of the cat is only decided when the chamber is opened and the cat is observed. So it is the observation or measurement itself that affects the outcome.
This is the nub of the paradoxes that occur in the quantum state – the world of the very very small.
But the latest experiment is important as it proved that the principles of quantum mechanics can apply to everyday objects as well as atomic-scale particles’This is an important validation of quantum theory, as well as a significant step forward for nanomechanics research,’ Professor Cleland told the journal Nature.
So why don’t we see much larger objects like buses moving and standing still at the same time?
Professor Cleland says the larger an object, the easier it is for outside forces to disrupt its quantum state.
‘The environment is this huge, complex thing,’ he said.
‘It’s that interaction with this incredibly complex system that makes the quantum coherence vanish.’
For more information visit Nature’s website