# This Week

Here is a selection of seminars that might be of interest to string theorists in Oxford:

On Monday, May 22, at 12:45 in L3, a seminar in
the String Theory series:

Guy F. de Teramond (University of Costa Rica)

Nonperturbative approach to hadron physics from superconformal algebraic structures and their light-front holographic embedding

*Understanding the structure of hadrons in terms of their fundamental constituents requires an understanding of QCD at large distances, a vastly complex and unsolved dynamical problem. I will discuss in this talk a new approach to hadron structure based on superconformal quantum mechanics in the light-front and its holographic embedding in a higher dimensional gravity theory. This approach captures essential aspects of the confinement dynamics which are not apparent from the QCD Lagrangian, such as the emergence of a mass scale and confinement, the occurrence of a zero mode: the pion, universal Regge trajectories for mesons and baryons and precise connections between the light meson and nucleon spectra. This effective semiclassical approach to relativistic bound-state equations in QCD can be extended to heavy-light hadrons where heavy quark masses break the conformal invariance but the underlying dynamical supersymmetry holds.*

**Further information:**
On Monday, May 22, at 14:00 in Dennis Sciama Lecture Theatre, a seminar in
the Astrophysics Colloquia series:

Prof. Chris Done (Durham University)

How to connect observations of accreting black holes with MRI simulations

On Monday, May 22, at 14:15 in L4, a seminar in
the Geometry and Analysis series:

Simon Salamon (Kings College London)

Kahler configurations of points

*I shall discuss Zauner's conjecture about the existence of n^2 mutually equidistant points in complex projective space CP^{n-1} with its standard Fubini-Study metric. This is the so-called SIC-POVM problem, and is related to properties of the moment mapping that embeds CP^{n-1} into the Lie algebra su(n). In the case n=3, there is an obvious 1-parameter family of such sets of 9 points under the action of SU(3) and we shall sketch a proof that there are no others. This is joint work with Lane Hughston.*

**Further information:**
On Tuesday, May 23, at 11:30 in Bipac Seminar Room, DWB, a seminar in
the Cosmology series:

Joe Silk (Oxford / IAP / Johns Hopkins)

(Tentatively) Lunar Radio Array

On Tuesday, May 23, at 12:00 in L4, a seminar in
the Quantum Field Theory series:

Arthur Lipstein (Durham University)

From 4d Ambitwistor Strings to On Shell Diagrams and Back

On Tuesday, May 23, at 14:00 in DWB Fisher Room, a seminar in
the Holography series:

Misha Shifman (U. Minnesota)

Critical soliton vortex in 4D YM as a �Little String�

On Tuesday, May 23, at 15:45 in L4, a seminar in
the Algebraic and Symplectic Geometry series:

Tom Begley (Cambridge)

On Short Time Existence of Lagrangian Mean Curvature Flow

*The goal of this talk will be to give an overview of recent work, joint with Kim Moore, on a short time existence problem in Lagrangian mean curvature flow. More specifically, we consider a compact initial Lagrangian submanifold with a finite number of singularities, each asymptotic to a pair of transversely intersecting planes. We show it is possible to construct a smooth Lagrangian mean curvature flow, existing for positive times, that attains the singular Lagrangian as its initial condition in a suitable weak sense. The construction uses a family of smooth solutions whose initial conditions approximate the singular Lagrangian. In order to appeal to compactness theorems and produce the desired solution, it is necessary to first establish uniform curvature estimates on the approximating family. As time allows I hope to focus in particular on the proof of these estimates, and their role in the proof of the main theorem.*

**Further information:**
On Thursday, May 25, at 12:45 in L6, a seminar in
the Strings Junior series:

Hadleigh Frost

Quantum cohomology

*Poincaré, thinking of the 3-body problem, conjectured that a Hamiltonian flow on the annulus which twists the edges in opposite directions has at least two fixed points. Arnold conjectured that a Hamiltonian flow on compact X has at least as many fixed points as the sum of the Betti numbers -- in response, people like Gromov and Floer introduced tools involving spaces of curves in X which remind us of strings, CFT, etc. Witten noticed the connection. Fukaya and Ono used this to prove the conjecture, though their paper has been controversial at times. We ignore all of this and discuss one or two examples instead.*

**Further information:**
On Thursday, May 25, at 13:00 in Dalitz Institute, a seminar in
the Dalitz Seminar in Fundamental Physics series:

Tevong You (Cambridge)

Implications of Decoupled New Physics (click for slides)

On Thursday, May 25, at 16:00 in L6, a seminar in
the Number Theory series:

Holly Krieger (Cambridge)

Reduction of dynatomic curves

*Dynatomic curves parametrize n-periodic orbits of a one-parameter family of polynomial dynamical systems. These curves lack the structure of their arithmetic-geometric analogues (modular curves of level n) but can be studied dynamically. Morton and Silverman conjectured a dynamical analogue of the uniform boundedness conjecture (theorems of Mazur, Merel), asserting uniform bounds for the number of rational periodic points for such a family. I will discuss recent work towards the function field version of their conjecture, including results on the reduction mod p of dynatomic curves for the quadratic polynomial family z^2+c.*

**Further information:**
On Thursday, May 25, at 16:15 in Dennis Sciama Lecture Theatre, a seminar in
the Theoretical Particle Physics series:

Shin'ichiro Ando (University of Amsterdam)

The high energy neutrino sky

On Friday at 14:00 in Dennis Sciama Lecture Theatre, a seminar in
the Theoretical Physics Colloquia series:

Herbert Spohn (MA@TUM)

Nonlinear fluctuating hydrodynamics and time-correlations for one-dimensional systems

On Friday at 15:30 in Martin Wood Lecture Theatre, Clarendon Laboratory, Parks Road, Oxford, a seminar in
the Colloquia Series Seminars series:

Professor Myles Padgett, Kelvin Chair of Natural Philosophy and Vice Principal (Research) (University of Glasgow)

Ghost Imaging with Quantum Light