Boston Chapter of the IEEE Photonics Society

Abstract:  Consider a single photon in a completely unknown polarization state.  Any attempt to measure the state might change it; so an unknown state cannot be conveyed faithfully from one place to another just by measuring it and communicating the result.  However, if the sender and receiver share, as a resource, an entangled pair of particles, they can use this pair, together with ordinary communication, to teleport a photon’s state.  The state then arrives at the receiver’s location—embodied in a different photon—without ever having passed through the intervening environment, an environment that might have caused disturbances in the photon if it had been transmitted directly.  In this talk I describe the process of teleportation and its realization in experiments.  I also discuss a potential application to quantum cryptography, in which teleportation is used to extend the range over which a cryptographic key can be shared.

Biography:  William K. Wootters is the Barclay Jermain Professor of Natural Philosophy at Williams College.  His degrees are from Stanford (BS, 1973) and the University of Texas at Austin (PhD, 1980), both in physics.  Prof. Wootters’ research is in the field of quantum information theory, the study of information stored or processed in objects such as electrons and photons that exhibit quantum mechanical behavior.  He is one of the authors of the 1993 paper pointing out the theoretical possibility of quantum teleportation, and his recent work analyzes quantum measurements performed on spatially distributed systems.  Prof. Wootters is the 2007 recipient of the American Physical Society’s Prize for a Faculty Member for Research at an Undergraduate Institution.