Contact Info
Combinatorics & Optimization
University of Waterloo
Waterloo, Ontario
Canada N2L 3G1
Phone: 519-888-4567, ext 33038
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Friday, September 29, 2017 3:30 PM EDT
Title: The quantum and private capacities of quantum channels, and the solution in the low-noise regime
| Speaker: | Debbie Leung |
| Affiliation: | University of Waterloo |
| Room: | MC 5501 |
Abstract:
We first summarize background on the quantum capacity of a quantum channel, and explain why we know very little about this fundamental quantity, even for the qubit depolarizing channel (the quantum analogue of the binary symmetric channel) despite 20 years of effort by the community.
Thursday, September 28, 2017 3:30 PM EDT
Title: Quantum Walks and State Transfer
| Speaker: | Christopher van Bommel |
| Affiliation: | University of Waterloo |
| Room: | MC 6486 |
Abstract:
Quantum walks are the quantum analogues of classical random walks and can be used to model quantum computations. If a quantum walker starts at a vertex of a graph and after some length of time, has probability 1 of being found at a different vertex, we say there is perfect state transfer between the two vertices.
Thursday, September 28, 2017 3:30 PM EDT
Title: The 1,2,3-Conjecture and a related problem for bipartite graphs
| Speaker: | Kasper Lyngsie |
| Affiliation: | University of Waterloo |
| Room: | MC 5479 |
Abstract:
Friday, September 22, 2017 3:30 PM EDT
Title: Symmetric group characters as symmetric functions
| Speaker: | Mike Zabrocki |
| Affiliation: | York University |
| Room: | MC 5501 |
Abstract:
The irreducible polynomial representations have Schur polynomials as characters. Similarly there is an in-homogeneous basis of symmetric functions that we call the "irreducible character basis" which are characters of irreducible symmetric group modules when the symmetric group is represented as the subgroup of permutation matrices.
Friday, September 15, 2017 3:30 PM EDT
Title: Periodic Vertices in Graphs
| Speaker | Chris Godsil |
| Affiliation: | University of Waterloo |
| Room: | MC 5501 |
Abstract:
If $X$ is a graph with adjacency matrix $A$, then any question about the continuous quantum walk on $X$ is a question about the entries of the unitary matrices \[U(t) = \exp(itA)\]
Two pertinent questions are:
Thursday, September 14, 2017 3:30 PM EDT
Title: Using eigenvalues to bound the independence number of a graph
| Speaker: | John Sinkovic |
| Affiliation: | University of Waterloo |
| Location: | MC 6486 |
Abstract:
Finding a maximum independent set (or clique) in an arbitrary graph has been shown to be NP-hard. As any independent set gives a lower bound on the independence number, determining an upper bound is usually more useful.
Thursday, September 14, 2017 3:30 PM EDT
Title: Geometric drawings of graphs (Part I)
| Speaker: | Alan Arroyo |
| Affiliation: | University of Waterloo |
| Room: | MC 5479 |
Abstract:
This is the first of two talks about drawings of graphs that arise from geometry.
Part I: Understanding rectilinear drawings.