SEMINAR SERIES ON
STRING PHENOMENOLOGY
SEMINAR SERIES ON
STRING PHENOMENOLOGY
Schedule: Spring Term 2025-26
The seminars are taking place on Zoom every second Tuesday at 11 am (all times in US Eastern Time Zone).
The Seminar Series on String Phenomenology is currently in session!
Feb 24, 2026:
11:00: "Complexity of Effective Field Theories in the Quantum Gravity Landscape", David Prieto, Utrecht University
11:30: "The Cosmological Constant and Dark Dimensions from Non-Supersymmetric Strings", Marco Serra, University of Liverpool
David Prieto
Title: Complexity of Effective Field Theories in the Quantum Gravity Landscape
Abstract: In this talk, we present a recently developed mathematical framework, known as tameness, as a unifying finiteness principle for physical theories. After outlining the core ideas of this formalism, we show how tameness can be used to quantify the amount of information required to specify an EFT. We illustrate the framework with explicit examples in which the resulting notion of complexity is finite, most notably Seiberg-Witten theory. We then conjecture that any EFT admitting a consistent ultraviolet completion in quantum gravity must exhibit finite complexity in this sense, and we discuss the consequences of this conjecture for the swampland program.
Marco Serra
Title: The Cosmological Constant and Dark Dimensions from Non-Supersymmetric Strings
Abstract: We present a string theory construction in which the particle physics contributions to the one-loop vacuum energy exactly cancel, whilst the gravitational contributions are suppressed in the size of one or two large extra dimensions. This provides an ultraviolet realisation of the Dark Dimension and Supersymmetric Large Extra Dimensions scenarios, with, moreover, an explanation as to why the Standard Model contributions to the vacuum energy cancel without the need of eV mass-splittings. Gravity propagates in micron sized dark dimension(s), whilst the visible and hidden sectors are supported on D-branes. Supersymmetry is broken in the dark dimension(s) à la Scherk-Schwarz, whereas supersymmetry is broken at the string scale, à la Brane Supersymmetry Breaking, in the D-branes sector, without inducing tadpoles. Vacuum energy from the visible sector is cancelled by the vacuum energy of the hidden sector branes. We also discuss moduli stabilization in this set-up, finding that the interplay between the Scherk-Schwarz one-loop contribution and non-perturbative effects can fix the size of the dark dimension(s) to be exponentially large in the inverse string-coupling, leading to an exponentially small total vacuum energy, with all moduli stabilised in a dS saddle. Based on 2512.20570.