John Howell

Universitiy of Rochester

“Wonderful World of Weak Values”

Weak values were originally introduced by Aharanov, Albert and Vaidman for understanding the arrow of time in quantum mechanics.  Weak values have recently proved useful in amplifying very small effects.  I will introduce the ideas of weak values and discuss some of our recent experimental results in which we were able to observe a deflection of a laser beam of less than 1 picoradian (equivalent to measuring a deflection of the width of a hair at the distance of the moon).  Perhaps more interestingly, the noise properties are simply remarkable in leading to a suppression of technical noise and a tremendous amplification of the signal to noise ratio for standard beam deflection techniques.  We have also shown that a phase amplification in the interferometer can lead to measurement of the phase at the standard quantum limit while only observing the dark port of an interferometer.