Mar 09, 2015 (Mon)   13:30 ~                                                                 21

Introduction to 1+1 integrable systems

Junichi Inoguchi

In this talk I would like to explain how to construct CP^1 sigma models via the methods of integrable systems. From mathematical points of view, CP^1 sigma models are formulated as harmonic maps from Riemann surfaces into 

the complex projective line CP^1. In case the domain is CP^1, sigma models are nothing but meromorphic functions. As the next target, we are interested in CP^1 sigma models on tori. in such a case, the field equation is normalised to the so-called sinh-Gordon equation. This normalisation connects with soliton theory and sigma models. Note that the sinh-Gordon equation describe mathematical models of soap bubble.

Mar 16, 2015 (Mon)   13:30 ~                                                                21

Advances in Calculation of Scattering Amplitudes

Filip Blaschke

Recently, there has been remarkable progress in the way 

scattering amplitudes are calculated.  In this talk, I will introduce 

the most basic methods, the helicity-spinor formalism and BCFW recursion,

which are at the ground base of what is now rapidly developing field in 

high energy physics. Even these (now) basic methods can allow to 

calculate tree-level scattering amplitudes of pure gluon processes with 

such an efficiency, previously deemed unimaginable and also to provide 

strong statements about scattering amplitudes, which are totally obscure 

at the level of Feynman diagrams.

Feb 23, 2015 (Mon)   13:30 ~                                                                 R101

Standard Model on a domain-wall brane?

Masato Arai

We propose a 4+1-dimensional action that is a candidate for realising

a standard-model-like effective theory for fields dynamically

localised to a domain-wall brane. Our construction is based in part on

the conjecture that the Dvali-Shifman mechanism for dynamically

localising gauge bosons works correctly in 4+1-d. Assuming this to be

so, we require the gauge symmetry to be SU(5)in the bulk,

spontaneously breaking to SU(3)xSU(2)xU(1) inside the domain wall,

thus dynamically localising the standard model gauge bosons provided

that the SU(5) theory in the bulk exhibits confinement. Localised

gravity is generated via the Randall-Sundrum alternative to

compactification.

Ref: R. Davis, D. George, R. Volkas, Phys. Rev. D77, 124038 (2008)

Nov 6, 2015 (Fri)   16:00 ~                                                              E316/317

Adiabatic Invariance of Oscillons/I-balls

(Authors: M. Kawasaki, F.Takahashi and N. Takeda)

arXiv:1508.01028v1

Speaker:Filip Blaschke

The goal of this talk is to introduce the notion of oscillons and their

significance in physics. Oscillons are long-living, time-dependent

solutions of scalar field theories. Like solitons they are spatially

localised objects, typically spherically symmetric, with most of the

energy concentrated inside certain radius. Within this radius the field

oscillates rapidly (hence the name). Unlike topological solitons or Q-

kinks, their stability (or longevity) is not guaranteed by conservation

of topological or global charges. Instead, it can be shown that if the

mass term in the potential dominates over self-interaction part, the so-

called adiabatic charge is approximately (or in some models exactly)

conserved. It is believed that oscillons may play significant role in

Early Universe cosmology, in particular inflation and baryogenesis, as

these phenomena are govern by real scalar field(s).

Oct 16, 2015 (Fri)   16:00 ~                                                              E316/317

Scattering of Nucleons in the Classical Skyrme Model

(Authors: David Foster, Nicholas S. Manton)

http://arxiv.org/abs/1505.06843

Speaker: Minoru Eto

abstract of the paper

Classically spinning B=1 Skyrmions can be regarded as approximations 

to nucleons with quantised spin. Here, we investigate nucleon-nucleon 

scattering through numerical collisions of spinning Skyrmions. We identify 

the dineutron/diproton and dibaryon short-lived resonance states, and 

also the stable deuteron state. Our simulations lead to predictions for 

the polarisation states occurring in right angle scattering.

Dec 4, 2015 (Fri)   16:00 ~                                                             E316/317

Cohomogeneity one special lagrangian submanifolds

in the cotangent bundle of the sphere

(Authors: K. Hashimoto, T. Sakai)

Tohoku Math. J. 64 No. 1 (2012) 141

Speaker: Masato Arai

Abstract: Special lagrangian submanifolds (SLSs) play an important

role in particle physics, for example, to understand the mirror symmetry in string theory and moduli space in topological solitons in field theory. Nevertheless, no many non-trivial examples are known. In this paper, they develop a way to construct the SLS by using the so-called moment map and apply it to the cotangent bundle over the sphere. I will try to explain their method so that physicist can understand since this paper is of mathematics. After introduction of their method, I will show an example of the SLS

of the cotangent bundle over the sphere.

Nov 20, 2015 (Fri)   16:00 ~                                                             E316/317

A way to discover Maxwell's equations

(Authors: Krzysztof Rebilas)

Speaker: Ryusuke Endo

Historically, the special relativity was found after Maxwell's equations

had been established. Logically, however, we do not need Maxwell's equations as the basis for the special relativity.

(For example, see Mirmin's work "Relativity without light".)

Thus, the alternative history was also possible:

Maxwell's equations were discoverd after the special relativity had been established.

I will introduce a work along this line.

We only assume (1) the static Coulomb's force law and (2) the special relativity, then we can define the electirc field and the magnetic field  

and deduce that those fields satisfy Maxwell's equations.