## Wednesday, April 3, 2013

### A Stroll on Strange Spaces

Pizza Seminar Talk:   Tuesday, April 9, 2013, 4:30-5:30 PM, MC 108.
Speaker: Mitsuru Wilson

Like the above ad  promoting a potent Nitro NCG mixture, Noncommutative Geometry (NCG), as created  by  Alain Connes is a potent
mixture of many ideas in mathematics and physics.

One of the grand themes in mathematics, geometry, dates back for thousands  of years. Starting from Euclidean spaces, many elementary shapes such as circles, disks, spheres have been studied until today; all spaces we learn in school are still studied today! Riemann then generalized Euclidean spaces with his foundation of manifolds, which was then used by Einstein for his theory which successfully encodes our knowledge of space-time and gravity.

With all they knew they did not understand quantum mechanics. The geometry is very fuzzy, uncertain, probabilistic and entangled there. Although it was introduced theoretically, this analogy works to explain noncommutative geometry (NCG) very accurately. The celebrated 1943 paper by Gelfand and Naimark proves the anti-equivalence (functors are contravariant) between (the
category of) compact Hausdor spaces X  and (the category of) commutative C* algebras A. In the construction, A is nothing but C(X), the algebra  of continuous functions . This correspondence gives rise to the viewpoint that any C* algebra is the  space of functions C(X) of some noncomutative space X . They are fuzzy spaces in the sense that we cannot directly see them! My goal in  this talk is to present the basic idea of Noncommutative Geometry in as elementary terms as possible and discuss a few canonical and fascinating examples in NCG.

Absolutely no background is necessary!

### First Steps in Quantum Computing

Discovery Cafe Talk: Tuesday, April 9, 5:30-6:30 PM, MC 108.  Pizza to follow immeditaley after!
Speaker: Masoud Khalkhali

Public-key encryption and security of internet communications is based on a certain mathematical hypothesis:factoring a given integer  N is a computationally difficult problem. The best current methods take about
$$O(e^{1.9 (\log N)^{1/3} (\log \log N)^{2/3}})$$
operations. This is almost exponential in log N, the number of digits of N
A quantum computer, running Shor's algorithm, can factor N in
$$O((\log N)^3)$$
steps! This is polynomial in log N, or polynomial time,  and a huge improvement over current methods.

This talk will introduce  mathematics and physics ideas behind quantum computing and Shor's fast factoring quantum computing algorithm.