Olivier Pfister’s research focuses on experimental quantum optics and quantum information. The quantum nature of light (the existence of photons) is a fascinating subject which has turned into a mature experimental field since its inception in the eighties. The research by Pfister’s group, “Quantum Fields and Quantum Information” (QFQI), aims at blazing new trails into the realm of quantum information. In particular, QFQI and their theory collaborators, Nicolas Menicucci and Steven Flammia at the University of Sydney, discovered a new, highly scalable experimental paradigm for the implementation of quantum computing: building a quantum register out of the multitude of resonant fields (“Qmodes”) of a single optical cavity. The QFQI group and collaborators have achieved the preliminary step of “quantum computing over the optical frequency comb” (or “over the rainbow”...) by demonstrating, in the lab, the quantum correlations necessary for quantum computing, known as cluster-state entanglement, in 15 sets of 4 entangled modes, thereby establishing parallel entanglement within a record-size 60-Qmode register. Work is now underway toward the creation of even larger cluster entangled states and their use for nontrivial quantum processing.

In addition to this NSF-funded work on continuous-variable entanglement, QFQI has also established an NSF-funded collaboration with the group of Dr. Sae Woo Nam at NIST, and with Prof. Aaron Miller at Albion College, toward the construction of a photon-number-resolved detector system which has been completed and installed in the QFQI lab. Using this unique machine, we seek to attack the study of quantum fields from their purely particle aspect, as an epitome of the complementarity principle first put forth by Niels Bohr. On the theoretical side, we are striving to understand the deep connections between the multipartite entanglement of continuous variables with that of discrete ones.

Last but not least, in collaboration with Drs. Jonathan Habif and Saikat Guha at Raytheon-BBN, we are participating in fundamental studies of quantum information theory and their experimental applications to quantum imaging, under the umbrella of the DARPA "InPho" (Information in a Photon) program. The goal is to ascertain the quantity of information that can be carried by a single photon and to experimentally demonstrate such concepts.