Theory Seminar
Seminars are at 2pm in Room 179 CP Building unless otherwise indicated.
Quantum Computing with Continuous Variables
NOTE SPECIAL TIME AND LOCATION
ABSTRACT: Quantum fields are fundamental constituents of the physical world. The encoding of quantum information in continuous-variable (CV) quantum fields, a.k.a. qumodes (in lieu of discrete-variable qubits), has enabled multipartite entanglement over millions of qumodes. This scale, unparalleled in any qubit architecture, defines new horizons and paradigms to be explored for quantum computing, quantum communication, and quantum sensing. I will outline our work in CV quantum computing applied to quantum field theory and quantum machine learning aiming at understanding properties of physical systems.
Effective Field Theories for precision beta decays
How are we saved from complete annihilation
IR Phase of Thermal QCD, Non-Analytic Dirac Spectra and Emergent Dimensions
Recent suggestion that SU(3) gauge theories with fundamental quarks generate a phase with IR scale invariant glue leads to interesting consequences materializing in very unusual ways. In this talk I will discuss these developments, including those featured in the Title.
(UV-complete) Emergent Matrix Cosmology
I will review recent results, and list outstanding challenges, of deriving an emergent spacetime from a non-perturbative proposal of String Theory -- namely, the BFSS matrix model. I will show how a metric can be coarse-grained from abstract matrix degrees of freedom, and how one naturally gets a scale-invariant spectrum of primordial perturbations in this model without introducing arbitrary tunable parameters. Furthermore, I will highlight distinct cosmological signatures of this model which have the potential of distinguishing it from other early-universe paradigms.
The Future of High Energy Theory with Quantum Computing
The advent of quantum computation presents the opportunity to solve questions in high energy theory which are inaccessible to classical computation such as real-time evolution and the equation of state at finite density. In order to take advantage of this new resource, a number of theoretical and computational hurdles will need to be addressed. In this talk, I will discuss the state of the art research being performed in HEP and outstanding questions that require our attention going forward, focusing on digitization of lattice gauge theories and extracting physical results that demonstrate practical quantum advantage.
Muon g-2 with overlap valence fermions
The ~4σ discrepancy between the experiment and the data-driven theory prediction of the anomalous magnetic moment of the muon is one of the crucial benchmarks to verify the correctness of the standard model. On the lattice QCD side, the Budapest-Marseille-Wuppertal collaboration (BMWc) has a precise full calculation that favors the experimental prediction. Various independent lattice QCD calculations have been done to verify their findings, especially on well-defined ``window quantities'' which suffer fewer lattice artifacts. I will present our lattice calculation of the leading order (LO) hadronic vacuum polarization (HVP) contribution to the muon anomalous magnetic moment for the connected light and strange quarks in the widely used window t0 = 0.4 fm, t1 = 1.0 fm, ∆ = 0.15 fm, and also in the short distance region. We use the overlap fermions on 4 physical-point ensembles. Two 2+1 flavor RBC/UKQCD ensembles use the domain wall fermion (DWF) and Iwasaki gauge actions at a = 0.084 and 0.114 fm, and two 2+1+1 flavor MILC ensembles use the highly improved staggered quark (HISQ) and Symanzik gauge actions at a = 0.088 and 0.121 fm. They have incorporated infinite volume corrections from 3 additional DWF ensembles at L = 4.8, 6.4, and 9.6 fm and physical pion mass. Eventually, our results on the connected light and strange quarks in the widely used window agree with the BMWc findings and other most recent lattice calculations which deviate from the data-driven theory prediction.
The Status of the Cabibbo Angle Anomaly
A Path to Detecting Self-Interacting Dark Matter using Astrophysical Sub-Structure
Dark matter self interactions can leave distinctive signatures on the properties of satellite galaxies around Milky Way-like hosts. By analyzing a number of Milky Way dwarf galaxies, we were able to place new constraints on models of self-interacting dark matter which interact via a Yukawa potential. The results push the theory into a parameter space with a very specific prediction: self-interactions within satellite galaxies can be either very large (so large that new dynamical effects become important), or very small (so small that such models are usually thought of as collisionless), but not intermediate. Specifically, if self-interactions are large, some dwarfs of the Milky Way must be undergoing a process of gravothermal collapse, and this process has a number of distinct observational predictions which can be searched for in current and upcoming data.