Since 2002 Perimeter Institute has been recording seminars, conference talks, and public outreach events using video cameras installed in our lecture theatres. Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities. Recordings of events in these areas are all available On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA). PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.
We present an entanglement verification method for systems with underlying qubit-mode structure, which does not require full knowledge of the bi-partite density matrix. It is applied to a quantum key distribution experiment with coherent signal states and one of two different detection schemes: For heterodyne detection, it is possible to detect entanglement even in the presence of loss and noise whereas for Stokes operator measurements, entanglement verification fails.
We present an information-theoretically secure protocol for the
transmission of a quantum state between an anonymous sender and an
anonymous receiver. The anonymity is perfect and so is the privacy
of the message. No assumption is made on the number of honest
participants and this leads to a protocol in which a single participant can cause an abort. Unless the receiver is corrupt, the quantum state is never destroyed; thus the state is either transferred to the receiver or it remains in the hands of the sender.
For most variations of Quantum finite automata (QFA), it is an open question to characterize the language recognition power of these machines. We extend several techniques used to obtain lower bounds on Kondacs and Watrous' 1-way Quantum Finite Automata to the case of Nayak's Generalized Quantum Finite Automata (GQFA). A consequence of these results is that the class of languages recognized by GQFAs is not closed under union.