Le contenu de cette page n’est pas disponible en français. Veuillez nous en excuser.

Video Library

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. 

  

 

Lundi juin 04, 2007

Imperfections in devices are inevitable in practice.  In this talk, we focus on the imperfection of QKD systems in the detectors, namely that the efficiencies of the detectors are not completely identical.  We show some practical attacks that specifically exploit this efficiency mismatch and demonstrate how Eve may obtain some information on the final key if Alice and Bob are unaware of the attack.  Also, we discuss the upper and lower bounds on the secret key rates both with and without the assumption of the efficiency mismatch

Scientific Areas: 

 

Lundi juin 04, 2007

I will introduce Kitaev's suface codes as a block quantum error-correcting code.  Recovery procedures will be described in the case of imperfect syndrome measurements.  More might be covered if time permits.

Scientific Areas: 

 

Dimanche juin 03, 2007
Speaker(s): 

Imagine that Alice and Bob share a quantum state, from which they want to distill something useful like entanglement or secret key. For this they need to communicate classically and they want to do this by one way communication from Alice to Bob. For some states, it might happen that the state is a part of a tripartite state shared with Charlie, which is invariant if Bob's and Charlie's systems are switched. Such a state is called a symmetric extension, and if it exists Alice and Bob have no chance of distilling key or entanglement by one way communication.

Scientific Areas: 

 

Dimanche juin 03, 2007
Speaker(s): 

Traditionally, we use the quantum Fourier transform circuit (QFT) in order to perform quantum phase estimation, which has a number of useful applications.  The QFT circuit for a binary field generally consists controlled-rotation gates which, when removed, yields the lower-depth approximate QFT circuit.  It is known that a logarithmic-depth approximate QFT circuit is sufficient to perform phase estimation with a degree of accuracy negligibly lower than that of the full QFT.

Scientific Areas: 

 

Dimanche juin 03, 2007
Speaker(s): 


"Most of the experimental advances in coherent quantum control in recent years have involved ultrashort pulses and pulse shaping techniques. These pulses have been an excellent source of coherent light with precise phase relationship between the various frequency components. In several recent works we have investigated the possibility of using broadband nonclassical light, generated by down-conversion of narrow-band lasers, for coherent control.

Scientific Areas: 

 

Samedi juin 02, 2007
Speaker(s): 

Proving the additivity of the classical capacity of quantum channels is a major open problem in quantum information.  This problem is related to the multiplicativity of certain norms with respect to the tensor product.  These problems are introduced and some approached to resolving them are discussed.  Several special cases that have been solved are also mentioned.

Scientific Areas: 

 

Samedi juin 02, 2007
Speaker(s): 

Any implementation of  a quantum computer will require the ability to reset qubits to a pure input state, both to start the computation and more importantly to implement fault-tolerant operations.  Even if we cannot reset to a perfectly pure state, heat-bath algorithmic cooling provides a method of purifying mixed states.  By combining the ability to pump entropy out of the system through a controllable interaction with a heat bath and coherent control of the qubits, we are able to cool a subset of the qubits far below the heat bath temperature.

Scientific Areas: 

Pages