Charles Bamber (NRC)

The first direct measurement of the quantum wavefunction
 
Central to quantum theory, the wavefunction is a complex distribution
associated with a quantum system. Despite its fundamental role, it is
typically introduced as an abstract element of the theory with no
explicit definition. Rather, physicists come to a working
understanding of it through its use to calculate measurement outcome
probabilities through the Born Rule. Tomographic methods can
reconstruct the wavefunction from measured probabilities. In contrast,
I present a method to directly measure the wavefunction so that its
real and imaginary components appear on our measurement apparatus. I
will describe an experimental example by directly measuring the
transverse spatial wavefunction of a single photon. This method gives
the wavefunction a plain and general meaning in terms of a specific
set of operations in the lab. A classical interpretation of this
experiment suggests that the technique developed may have novel
applications in optical imaging.