Abstract: Two indistinguishable photons can be transformed into a maximally entangled N00N state (N=2) using a simple beamsplitter in the Hong-Ou-Mandel (HOM) configuration. Entangled photons are potential probes of entangled materials, where entanglement can be swapped between the probe and the target. X-rays are an ideal probe of quantum materials, so there is a need for creating entangled x-rays to probe entangled materials.
We propose using the HOM effect to create entangled synchrotron x-rays. The source’s photon degeneracy factor, proportional to brightness, describes how many indistinguishable photons occupy each mode. Fortunately, the APS upgrade increases the likelihood of two photons occupying the same mode from fairly low to quite high, meaning the arrival of a new frontier in degenerate x-ray photons is nearly upon us. We describe a new x-ray interferometer for producing x-ray N00N states and describe some unique diffraction properties of x-ray biphotons that allow for simple discrimination of biphotons from a single-photon background. Future applications to quantum materials will be discussed.
Bio: Professor Durbin has been a member of the Department of Physics & Astronomy at Purdue University for many years and conducted x-ray physics research at the original Advanced Photon Source throughout its entire existence. His interests have included x-ray dynamical diffraction theory, nuclear resonant vibrational spectroscopy on proteins, and x-ray pump/laser probe studies of GaAs, and he is currently interested in developing x-ray quantum optics.