# Measuring the time a tunnelling atom spends in the barrier

arXiv
Ramos, R.Spierings, D.Racicot, I.Steinberg, A.M. Centre for Quantum Information and Quantum Control
Institute for Optical Sciences,
Department of Physics,

MaRS Centre,
There have been a number of experiments confirming this, and even a recent one claiming that tunnelling may take no time at all. There have also been efforts to identify another timescale, which would better describe how long a given particle spends in the barrier region. Here we present a direct measurement of such a time, studying Bose-condensed $^{87}$Rb atoms tunnelling through a 1.3-${\mu}$m thick optical barrier. By localizing a pseudo-magnetic field inside the barrier, we use the spin precession of the atoms as a clock to measure the time it takes them to cross the classically forbidden region.