# This Week

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

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

No Seminar

On Tuesday at 11:30 in Simpkins Lee Room, Beecroft Building, a seminar in
the Cosmology series:

Boris Bolliet (University of Manchester)

Cosmological constraints from the thermal Sunyaev Zeldovich power spectrum and cluster counts

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

Joseph Conlon (Oxford)

The Swampland, Holography and the Large Volume Scenario

*String compactifications are essential for connecting string theory to low energy particle physics and cosmology. Moduli stabilisation gives rise to effective Lagrangians that capture the low-energy degrees of freedom. Much recent interest has been on swampland consistency conditions on such effective field theories - which low energy Lagrangians can arise from quantum gravity? Furthermore, given that moduli stabilisation scenarios often exist in AdS space, we can also ask: what do swampland conditions mean in the context of AdS/CFT? I describe work on developing a holographic understanding of moduli stabilisation and swampland consistency conditions. I focus in particular on the Large Volume Scenario, which is especially appealing from a holographic perspective as in the large volume limit all its interactions can be expressed solely in terms of the AdS radius, with no free dimensionless parameters.*

**Further information:**
On Tuesday at 15:30 in L4, a seminar in
the Algebraic Geometry series:

Dominic Bunnett (FU Berlin)

Moduli of hypersurfaces in weighted projective space

*The moduli space of smooth hypersurfaces in projective space was constructed by Mumford in the 60’s using his newly developed classical (a.k.a. reductive) Geometric Invariant Theory. I wish to generalise this construction to hypersurfaces in weighted projective space (or more generally orbifold toric varieties). The automorphism group of a toric variety is in general non-reductive and I will use new results in non-reductive GIT, developed by F. Kirwan et al., to construct a moduli space of quasismooth hypersurfaces in certain weighted projective spaces. I will give geometric characterisations of notions of stability arising from non-reductive GIT.*

**Further information:**
On Tuesday at 16:00 in C5, a seminar in
the Twistor Workshop series:

Dhritiman Nandan (Southampton)

Celestial Amplitudes: conformal partial waves and soft theorems

*Massless scattering amplitudes in four-dimensional Minkowski spacetime can be Mellin transformed to correlation functions on the celestial sphere at null infinity called celestial amplitudes. We study various properties of massless four-point scalar and gluon celestial amplitudes such as conformal partial wave decomposition, crossing relations and optical theorem. As a byproduct, we derive the analog of the single and double soft limits for all gluon celestial amplitudes.*

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

Diego Berdeja Suarez

Seiberg-Witten theory

On Thursday at 13:00 in Simpkins Lee Seminar Room, a seminar in
the Dalitz Seminar in Fundamental Physics series:

Markus Ebert (MIT)

Power corrections for fixed-order subtractions

*http:/*

**Further information:**
On Thursday at 16:00 in L6, a seminar in
the Number Theory series:

Michalis Neururer (TU Darmstadt)

Fourier expansions at cusps and the Manin constant of elliptic curves

*I will discuss the arithmetic significance of Fourier expansions of modular forms at cusps. I will talk about joint work with F. Brunault, where we determine the number field generated by Fourier coefficients of newforms at a cusp. Then I will discuss joint work with A. Saha and K. Česnavičius where we find denominator bounds for Fourier expansions at cusps and apply these bounds to a conjecture on the Manin constants of elliptic curves.*

**Further information:**
On Thursday at 16:15 in Simpkins Lee Room, Beecroft Building, a seminar in
the Theoretical Particle Physics series:

Maria Ubiali (DAMTP Cambridge)

Can New Physics hide in the proton PDFs?

*http:/*

**Further information:**
On Friday at 15:30 in Martin Wood Lecture Theatre, a seminar in
the Colloquia Series Seminars series:

Professor Thirumalai Venkatesan (National University of Singapore)

Bridging the divide - academic entrepreneurship