##
Inauguration de l'INTRIQ (Institut transdisciplinaire d'informatique quantique)

Jeudi 9 novembre 2006

6214 et au Salon Maurice
L'Abbé du Pavillon André-Aisenstadt de l'Université de Montréal
(2920 Chemin de la Tour).

09:30 croissants, café

10:29 Mots de bienvenue, Gilles Brassard & François Lalonde

10:30 Barry Sanders, University of Calgary,
Implementing quantum information

11:15 Michele Mosca, University of Waterloo
Self-testing of quantum circuits

12:00 Lunch

14:00 Chip Elliott, BBN,
Architectures for quantum networks

14:45 John Watrous, University of Waterloo,
Zero-knowledge against quantum attacks

15:45 coffee break

16:15 Charles H. Bennett, IBM Research, Privacy, Publicity, and Permanence of Information

17:15 Première réunion plénière des membres de l'INTRIQ (membres
seulement)

18:15 Réception

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Résumés

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Charles H. Bennett

*
Privacy, Publicity, and Permanence of Information
*

The most private information, exemplified by a quantum eraser
experiment, exists only conditionally and temporarily--after the
experiment is over even God no longer remembers what "happened". Less
private are classical secrets, known only to a few, or information--like
the lost poems of Sappho--that once was public but has been lost over
time. Finally there is information that has been replicated and
propagated so widely as to be infeasible to conceal and unlikely to be
forgotten. Modern information technology has caused an explosion of
such information, with the beneficial side effect of making it harder
for tyrants to rewrite the history of their misdeeds; and it is tempting
to hope that all macroscopic information is permanent, making such
cover-ups impossible in principle. However, by comparing entropy flows
into and out of the Earth with estimates of the planet's storage
capacity, we conclude that most macroscopic information--for example the
pattern of sand grains on an ancient beach--is impermanent, in the sense
of becoming irrecoverable in principle from the Earth, though still
recorded in the Universe.
##
Chip Elliott

*
Architectures for Quantum Networks
*

The beautiful vision of quantum communications
is now almost within reach. Entanglement, teleportation, and
quantum relays have all been demonstrated - but how can
true quantum networking become an engineering reality?
Can we really build a global quantum Internet?
We review recent developments in the DARPA Quantum Network,
and look forward to new architectures for quantum networks that
just might be possible within a few years.
##
Michele Mosca

*
Self-Testing of Quantum Circuits
*

Abstract: I will explain how a quantum circuit together with measurement
apparatuses and EPR sources can be fully verified without any
reference to
some other trusted set of quantum devices. Our main assumption is
that the
physical system we are working with consists of several identifiable
sub-systems, on which we can apply some given gates locally.
To achieve our goal we define the notions of simulation and
equivalence. The
concept of simulation refers to producing the correct probabilities when
measuring physical systems. The notion of equivalence is used to
enable the
efficient testing of the composition of quantum operations. Unlike
simulation, which refers to measured quantities (i.e., probabilities of
outcomes), equivalence relates mathematical objects like states,
subspaces
or gates.
Using these two concepts, we prove that if a system satisfies some
simulation conditions, then it is equivalent to the one it is
supposed to
implement. In addition, with our formalism, we can show that these
statements are robust, and the degree of robustness can be made
explicit.
Finally, we design a test for any quantum circuit whose complexity is
linear
in the number of gates and qubits, and polynomial in the required
precision.
Joint work with Frederic Magniez, Dominic Mayers and Harold Ollivier
##
Barry Sanders

*
Implementing Quantum Information
*

Although quantum information is challenging to implement, we are
fortunate to have several promising technologies, such as coding,
transmitting, processing, and reading quantum information in light,
atomic nuclei, cold atoms, superconductors, and solid state. We will
survey these technologies, weigh up their advantages, and consider
hybridizing quantum information to convert quantum information
between different media so that we can exploit the advantages and
minimize the obstacles.
##
John Watrous

*
Zero-Knowledge Against Quantum Attacks
*

It was an unsolved problem in theoretical quantum cryptography for
several years to formulate a general and cryptographically meaningful
definition of quantum zero-knowledge and to apply the definition to
non-trivial protocols. In this talk I will explain how this problem can
be solved, at least to a significant extent, for what are arguably the
strongest and most natural definitions of quantum zero-knowledge.