Title: TBA

Abstract: TBA

Gauge theories describe the fundamental interactions, but their complexity makes questions involving real-time dynamics beyond the reach of classical computation. Quantum computers open a new path by naturally representing quantum fields and evolving them in real time thus circumventing for example the sign problem that limits classical Monte Carlo methods. In this talk, we will discuss the challenges and recent progress in encoding and simulating Gauge theories on fault-tolerant quantum computers.

The neutron lifetime is a precision observable of the Standard Model probing the CKM matrix element |Vud| and beyond the Standard Model physics. For nuclear beta decay, in the region of small electron velocity or the limit of large nuclear charge Z, a Fermi function is used to account for enhanced perturbative effects. In this talk, I will present the derivation of the quantum field theoretic analog of the Fermi function valid for neutron beta decay in which neither of the aforementioned limits apply. This QFT analog is related to renormalization group effects of objects occurring in the context of a factorization formula valid in the limit of small electron mass. I will introduce this factorization formula and present results through two-loop order. The main phenomenological results are two-loop input to the long-distance corrections to neutron beta decay and an accompanying calculation of |Vud|.

High temperatures are typically thought to increase disorder. Here we examine this idea in Quantum Field Theory in 2+1 dimensions. For this sake we explore a novel class of tractable models, consisting of nearly-mean-field scalars interacting with critical scalars. We identify UV-complete, local, unitary models in this class and show that symmetry breaking $\mathbb{Z}_2 \to \emptyset$ occurs at any temperature in some regions of the phase diagram. This phenomenon, previously observed in models with fractional dimensions, or in the strict planar limits, or with non-local interactions, is now exhibited in a local, unitary 2+1 dimensional model with a finite number of fields.

The pattern in the Standard Model (SM) charges can be traced to an ambiguity in the gauge group of the SM. The easiest way to resolve this ambiguity would be to discover a particle with electric charge that is an integer multiple of e/6 (beyond +/- e, 0). The discovery of such fractionally charged particles would also challenge and potentially rule out many minimal unification models. In this talk I will review the connection between the `global structure' of the SM and the charges particles can have, then explore the phenomenology of fractionally charged particles, focusing on the constraints provided by current searches at the Large Hadron Collider (LHC). By reinterpreting existing results, we assess the bounds on various fractionally charged representations, uncovering scenarios where collider limits are unexpectedly weak or entirely absent.

 

I will summarize the discussions at the recent plenary workshop at KEK and give an update of recent lattice calculations.

We explore the prospects of very heavy millicharged particles as candidates for some or all of dark matter (DM). Constraints on their properties like charge, dipole moment and mass are obtained by translating the current limits set by state-of-the-art nuclear recoil experiments like XENONnT and LZ. We contrast the extracted limits with those coming from astrophysical considerations, such as the decoupling of DM from regular matter during the recombination epoch and the suitability of the dynamical environments in the galactic halo for these heavy and charged beyond the Standard Model particles to remain lodged-in and available for future detections. 

Thanks! 

The parton distribution functions (PDFs) are crucial to the understanding of the internal structure of hadrons, and their precise determination is necessary for searches of BSM physics in collider experiments. Directly accessing PDFs in Lattice QCD calculations is impossible due to the Euclidean space-time geometry. The moments of PDFs are defined in terms of local operators that can be computed in Lattice QCD, but suffer from power divergent mixing beyond a certain order due to the hypercubic symmetry of the lattice. Recently, a method was proposed [1] to use gradient flow in order to circumvent this mixing and access moments of PDFs of any order. In this talk, I will summarize this method, and present preliminary results on moments of the unpolarized isovector PDF of the pion using four stabilized Wilson fermion ensembles generated by the OpenLat [2] initiative.

[1] A. Shindler 2311.18704

[2] https://openlat1.gitlab.io

 ``Axion Stars: Mass Functions and Constraints''

The QCD axion and axion-like particles, as leading dark matter candidates, can also have interesting implications for dark matter substructures if the Peccei-Quinn symmetry is broken after inflation. In such a scenario, axion perturbations on small scales will lead to the formation of axion miniclusters at matter-radiation equality, and subsequently the formation of axion stars. Such compact objects open new windows for indirect searches for axions. We compute the axion star mass function based on recent axion minicluster studies and Bose star simulations. Applying this mass function, we find post-inflation axion-like particles with masses 1.8×10^−21 eV<ma<3.3×10^−17 eV are constrained by the lack of dynamical heating of stars in ultrafaint dwarfs. We also find that current microlensing surveys are insensitive to QCD axion stars. While we focus on the gravitational detectability of axion stars, our result can be directly applied to other interesting signatures of axion stars, e.g. their decay to photons, that require as input the abundance, mass, and density distribution of axion stars.