The Heisenberg uncertainty principle, introduced by German physicist Werner Heisenberg in 1927, puts forward the concept of a certain fuzziness in physics. It says that if one characteristic of a quantum particle can be predicted with precision, a paired characteristic becomes less certain.
Position and momentum are the most often-mentioned of these pairs, known as non-commuting variables. Being able to ascertain where a quantum particle is makes it harder to judge its movement, and vice versa.
That fuzziness makes it more difficult to take accurate measurements of weaker signals in physics – in everything from the LIGO gravitational wave detector to the atomic clocks that underpin systems like GPS.
Now researchers led by a team from Shanxi University in China think they've found a fundamental workaround, and it involves looking backward into the past, as well as ahead into the future.
"We experimentally demonstrate simultaneous estimation of non-commuting variables beyond the Heisenberg uncertainty bound and verify the results using weak measurement," write the researchers in a preprint version of their paper, which has yet to be peer-reviewed.
Rather than making a prediction of the future to take a measurement, the researchers wanted to test an alternative approach: taking a measurement using data from both before and after the point to be measured.
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