Text Size
Facebook Twitter More...

A new experiment that tests the limit of how large an object can be before it ceases to behave quantum mechanically has been proposed by physicists in the UK and India. The measurement involves trapping a nanocrystal with light and then measuring its position to see if its behaviour violates the Leggett-Garg inequality – which is a test of the quantum nature of a system. While the team is keen to have their proposal tested in the lab, not all physicists believe that it could be implemented.


A crucial important feature of quantum mechanics is Heisenberg’s uncertainty principle. Whereas in classical mechanics, both the position and momentum of an object can be determined at arbitrarily high precision at the same time, the principle states that it is impossible to measure both position and momentum in quantum mechanics beyond a certain degree of accuracy. Furthermore, the more you know about one measurement, the more uncertain the other becomes.


The proposed experiment tests how large an object can be before the rules of quantum measurement do not apply. Sougato Bose of University College London and colleagues at the Bose Institute and the SN Bose National Centre for Basic Sciences in Kolkata studied the behaviour of a quantum linear harmonic oscillator, which bears a strong resemblance to its classical counterpart.  “The uncertainties in position and momentum are both as low as they can get,” explains Bose.

To read more, click here.

Category: Science