Fri, 31 May 2013
14:00
L2

Geometric Unity

Eric Weinstein
(Oxford)
Abstract

A program for Geometric Unity is presented to argue that the seemingly baroque features of the standard model of particle physics are in fact inexorable and geometrically natural when generalizations of the Yang-Mills and Dirac theories are unified with one of general relativity.

Mon, 20 May 2013

12:00 - 13:00
L3

The Riemann Zeta Function and the Berry-Keating Hamiltonian

Philip Candelas
(Oxford)
Abstract
It is an old idea that the imaginary part of the nontrivial Riemann zeros s =-1/2 + iE might be related to the eigenvalues of a hermitean operator H, and so to a quantum mechanical system. Such a system has been proposed by Berry and Keating; it is a harmonic oscillator with the "wrong" signatureH=1/2(xp + px). The difficulty and interest in implementing this proposal is the need to find suitable boundary conditions, or a self adjoint extension for H, since the classical phase space orbits are hyperbolae rather than circles. I will review interesting observations of Mark Srednicki relating the ground state wave functions of the Berry Keating hamiltonian and the conventional harmonic oscillator hamiltonian to the zeta function.
Thu, 23 May 2013
16:00
Martin Wood Lecture

Geometric Unity

Eric Weinstein
(Oxford)
Abstract

A program for Geometric Unity is presented to argue that the seemingly baroque features of the standard model of particle physics are in fact inexorable and geometrically natural when generalizations of the Yang-Mills and Dirac theories are unified with one of general relativity.

Tue, 21 May 2013
17:00
L2

Spectral presheaves as generalised (Gelfand) spectra

Anreas Doering
(Oxford)
Abstract

The spectral presheaf of a nonabelian von Neumann algebra or C*-algebra

was introduced as a generalised phase space for a quantum system in the

so-called topos approach to quantum theory. Here, it will be shown that

the spectral presheaf has many features of a spectrum of a

noncommutative operator algebra (and that it can be defined for other

classes of algebras as well). The main idea is that the spectrum of a

nonabelian algebra may not be a set, but a presheaf or sheaf over the

base category of abelian subalgebras. In general, the spectral presheaf

has no points, i.e., no global sections. I will show that there is a

contravariant functor from unital C*-algebras to their spectral

presheaves, and that a C*-algebra is determined up to Jordan

*-isomorphisms by its spectral presheaf in many cases. Moreover, time

evolution of a quantum system can be described in terms of flows on the

spectral presheaf, and commutators show up in a natural way. I will

indicate how combining the Jordan and Lie algebra structures may lead to

a full reconstruction of nonabelian C*- or von Neumann algebra from its

spectral presheaf.

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