Heisenberg's uncertainty principle posits that there is a fundamental limit to the precision with which so-called complementary variables, such as position and momentum, can be measured. That is, the more accurately the speed and direction (and thus the momentum) of a quantum particle are known, the less certain we can be about its position. Remarkably, this intrinsic limitation can be relaxed when measurements extract periodic functions of position and momentum with a characteristic length and momentum scale, respectively. Simply put, the uncertainty in either variable can be 'spread out' in broad comb-like structures, where each tooth is still relatively sharp, thus enabling precise measurements in a limited range.
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