Nuclear Theory·nucl-th

Thursday·March 24, 2022

7 papers—4 primary·3 cross-listed

05
Some Conceptual Aspects of Operator Design for Quantum Simulations of Non-Abelian Lattice Gauge Theories
Anthony Ciavarella🇺🇸 · Natalie Klco🇺🇸 · Martin J. Savage🇺🇸
In the Kogut-Susskind formulation of lattice gauge theories, a set of quantum numbers resides at the ends of each link to characterize the vertex-local gauge field. We discuss the role of these quantum numbers in propagating correlations and supporting entanglement that ensures each vertex remains gauge invariant, despite time evolution induced by operators with (only) partial access to each vertex Hilbert space. Applied to recent proposals for eliminating vertex-local Hilbert spaces in quantum simulation, we describe how the required entanglement is generated via delocalization of the time evolution operator with nearest-neighbor controls. These hybridizations, organized with qudits or qubits, exchange classical operator preprocessing for reductions in quantum resource requirements that extend throughout the lattice volume.
↳ quant-phhep-lathep-phnucl-th32 citations
06
Composition of low-lying $J = \frac{3}{2}^{\pm} Δ$ -baryons
Langtian Liu🇨🇳 · Chen Chen🇨🇳 · Ya Lu🇨🇳 · Craig D. Roberts🇨🇳 · Jorge Segovia🇨🇳
A Poincaré-covariant quark+diquark Faddeev equation is used to develop insights into the structure of the four lightest $(I, J^{P} = \frac{3}{2}, \frac{3}{2}^{\pm})$ baryon multiplets. Whilst these systems can contain isovector-axialvector and isovector-vector diquarks, one may neglect the latter and still arrive at a reliable description. The $(\frac{3}{2}, \frac{3}{2}^{+})$ states are the simpler systems, with features that bear some resemblance to quark model pictures, \emph{e.g}., their most prominent rest-frame orbital angular momentum component is $S$ -wave and the $Δ (1600) \frac{3}{2}^{+}$ may reasonably be viewed as a radial excitation of the $Δ (1232) \frac{3}{2}^{+}$ . The $(\frac{3}{2}, \frac{3}{2}^{-})$ states are more complex: the $Δ (1940) \frac{3}{2}^{-}$ expresses little of the character of a radial excitation of the $Δ (1700) \frac{3}{2}^{-}$ ; and whilst the rest-frame wave function of the latter is predominantly $P$ -wave, the leading piece in the $Δ (1940) \frac{3}{2}^{-}$ wave function is $S$ -wave, in conflict with quark model expectations. Experiments that can test these predictions, such as large momentum transfer resonance electroexcitation, may shed light on the nature of emergent hadron mass.
↳ hep-phhep-exhep-latnucl-ex+1PRD(2022)·33 citations
07
Neutrinoless Double-Beta Decay: A Roadmap for Matching Theory to Experiment
Vincenzo Cirigliano🇺🇸 · Zohreh Davoudi🇺🇸 · Wouter Dekens🇺🇸 · Jordy de Vries🇳🇱 · Jonathan Engel🇺🇸 · Xu Feng🇨🇳 · Julia Gehrlein🇺🇸 · Michael L. Graesser🇺🇸 · Lukáš Gráf🇺🇸 · Heiko Hergert🇺🇸 · Luchang Jin🇺🇸 · Emanuele Mereghetti🇺🇸 and 7 other authors
The observation of neutrino oscillations and hence non-zero neutrino masses provided a milestone in the search for physics beyond the Standard Model. But even though we now know that neutrinos are massive, the nature of neutrino masses, i.e., whether they are Dirac or Majorana, remains an open question. A smoking-gun signature of Majorana neutrinos is the observation of neutrinoless double-beta decay, a process that violates the lepton-number conservation of the Standard Model. This white paper focuses on the theoretical aspects of the neutrinoless double-beta decay program and lays out a roadmap for future developments. The roadmap is a multi-scale path starting from high-energy models of neutrinoless double-beta decay all the way to the low-energy nuclear many-body problem that needs to be solved to supplement measurements of the decay rate. The path goes through a systematic effective-field-theory description of the underlying processes at various scales and needs to be supplemented by lattice quantum chromodynamics input. The white paper also discusses the interplay between neutrinoless double-beta decay, experiments at the Large Hadron Collider and results from astrophysics and cosmology in probing simplified models of lepton-number violation at the TeV scale, and the generation of the matter-antimatter asymmetry via leptogenesis. This white paper is prepared for the topical groups TF11 (Theory of Neutrino Physics), TF05 (Lattice Gauge Theory), RF04 (Baryon and Lepton Number Violating Processes), NF03 (Beyond the Standard Model) and NF05 (Neutrino Properties) within the Theory Frontier, Rare Processes and Precision Frontier, and Neutrino Physics Frontier of the U.S. Community Study on the Future of Particle Physics (Snowmass 2021).
↳ hep-phhep-exhep-latnucl-ex+196 citations

Affiliations

first authorsco-authorsvia INSPIRE

Some Conceptual Aspects of Operator Design for Quantum Simulations of Non-Abelian Lattice Gauge Theories

Composition of low-lying J=23​±Δ-baryons

Neutrinoless Double-Beta Decay: A Roadmap for Matching Theory to Experiment

Affiliations

Composition of low-lying $J = \frac{3}{2}^{\pm} Δ$ -baryons