[Seminar] "Solitons, Gravity, Gravitating Solitons and Holography" by Dr. Sven Bjarke Gudnason

This talk will take as a starting point the Skyrmions as baryons in large-N QCD. It is further assumed that at high density, the sextic term in derivatives becomes dominant at some large density. This assumption is based on the observation that the term behaves like a perfect fluid, which is welcome for nuclear matter at large density – an environment suitable for the studies of neutron stars. With very large masses and compact radii, neutron stars become the closes known stable objects to the critical line of gravitational collapse. With some phenomenological motivation in mind, we consider the possibilities of finding exact analytic solutions to a system which is approximated by the sextic derivative term and a potential; this system is called the BPS-Skyrme model. We find a condition for when the gravitating soliton equations can be solved exactly and deduce the phenomenological implications. We furthermore find that this system has the peculiarity of not having stable black holes, meaning that the soliton cannot become scalar hair of a black hole. This is somewhat surprising, because the Skyrme soliton with a fourth-order derivative term can become stable black hole hair. We write down a class of models with higher-order derivative terms and find 2 new models that can sustain stable hair and 2 new that cannot.

Finally, we consider the problem of the classical binding energies of the Skyrmions, which are far too large compared to nuclei and explain a solution to this problem based on holography. Interestingly the solution from holography relates the baryon to the instanton of a 5-dimensional theory and the moduli of the instanton become massive modes in the Skyrmion. These modes in addition to the zero modes of the Skyrmion are expected to describe the spectra of nuclei.

QG group meeting: Integrability and the quantum inverse scattering method

QG group meeting
Speaker: Blaithin Power
Title: Integrability and the quantum inverse scattering method

Conformal Bootstrap lecture series

Conformal bootstrap lecture series organized by Aryeh Fortinsky

Conformal Bootstrap lecture series

Conformal bootstrap lecture series organized by Aryeh Fortinsky

Conformal Bootstrap lecture series

Conformal bootstrap lecture series organized by Aryeh Fortinsky

Conformal Bootstrap lecture series

Conformal bootstrap lecture series organized by Aryeh Fortinsky

Conformal Bootstrap lecture series

Conformal bootstrap lecture series organized by Aryeh Fortinsky

Conformal Bootstrap lecture series

Conformal bootstrap lecture series organized by Aryeh Fortinsky.

[Lecture] "Massless higher spins and cosmology" by Prof. Ergin Sezgin

We present a Freedman-Robertson-Walker solution of higher spin theory in four dimesions. It is obtained by employing a holomorphic factorization in noncommutative twistor space and gauge functions. We interpret the FRW solution in the context of inflationary cosmology. In interpreting the solution in terms of Fronsdal-type fields in spacetime, a field-dependent higher spin transformation is required, which is implemented at leading order. We also observe that the factorization method provides a convenient framework for setting up a perturbation theory around the exact solutions, and we propose that the nonlinear completion of particle excitations over FRW requires black hole-like states.

[Lecture] "Self-Duality and Chiral Higher Spin Theories" by Dr. Dmitry Ponomarev

In this talk I will review recent results revealing the connection between chiral higher spin theories and self-duality as well as discuss consequences of this connection.