Dr. Ryan Abbott, MIT

Normalizing Flows for Lattice QCD

Normalizing flows have recently arisen as a potential tool for accelerating lattice field theory calculations. In this talk I will give an overview of how normalizing flows have been applied to field theories, in particular focusing on recent progress applying normalizing flows to lattice QCD as well as current efforts to scale flow models towards modern lattice field theory calculations.

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Dr. John Sous, Yale University

Bipolaronic high transition-temperature superconductivity

A model for phonon-mediated high-Tc superconductivity based on superfluidity of light bipolarons is presented. I present numerically exact results obtained using a sign-problem-free quantum Monte Carlo approach for bipolaron binding energies, masses and radii for both Holstein (density-coupled) and Peierls/Su-Schrieffer-Heeger (bond-modulated) models of electron-phonon coupling, with and without both short- and long-range Coulomb interactions. The bond-modulated mechanism is shown to give rise to small-size, yet light-mass bipolarons, which condense at temperatures that generically and significantly exceed typical upper bounds on Tc of phonon-mediated superconductivity based on Migdal-Eliashberg theory. Using a semi-classical instanton approach, an upper bound on Tc for the bond bipolaronic superconductivity is shown to parametrically exceed the upper based on Holstein bipolaron superconductivity.

Masato Nagatsuka, KEK, the High Energy Accelerator Research Organization, Japan

Search for bound state formation in DD* and BB* channels using lattice QCD with a relativistic heavy quark action

A color-singlet combination of two heavy quarks and two light antiquarks is an attractive object in search for exotic hadrons. In particular, the doubly charmed tetraquark has been observed by LHCb and the doubly bottomed tetraquark is expected to have a deeply bound state. In this seminar, we address a scenario that the BB* channel has a shallow bound state based on our latest lattice simulations to explore the phase shifts of DD and BB* scattering. For this purpose, 2+1 flavor PACS-CS gauge ensembles with pion masses 295, 411 and 569 MeV are utilized and a relativistic heavy quark action is adopted for the charm and bottom quarks.

Prof. Ronald Garcia Ruiz, MIT

Radioactive Molecules are Dying to Reveal New Physics

Rapid progress in the experimental control and interrogation of molecules is enabling new opportunities for investigating the fundamental laws of our universe. In particular, molecules containing heavy, octupole-deformed nuclei, such as radium, offer enhanced sensitivity for measuring yet-to-be-discovered parity and time-reversal violating nuclear properties. In this colloquium, I will present recent highlights and perspectives from laser spectroscopy experiments on these species, as well as discuss the relevance of these experiments in addressing open problems in nuclear and particle physics.