What could be the smallest force that can be applied to an object? For now, scientists have measured a force of 42 yoctonewtons, the smallest force measured so far.
A yoctonewton is one-septillionth, or 10 of a Newton.
Using a combination of lasers and a unique optical trapping system that provides a cloud of ultra-cold atoms, the force has been detected by researchers at Berkeley Lab and University of California (UC) Berkeley.
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If you want to confirm the existence of gravitational waves, — space-time ripples Measurements of force and motion at the quantum levels bump against a barrier imposed by the Heisenberg uncertainty principle — when the measurement itself perturbs the measuring device, a phenomenon known as “quantum back-action”.
This barrier of least possible measurement is called the Standard Quantum Limit (SQL).
A wide array of strategies have been deployed to minimise quantum back-action and get ever closer to the SQL, but the best of these techniques fell short by six to eight orders of magnitude.
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“We measured force with a sensitivity that is the closest ever to the SQL,” said lead author Sydney Schreppler.
The findings appeared in the journal Science .