Publications

Order by: publication date number of citations

• Beyond braid statistics: Constructing a lattice model for anyons with exchange statistics intrinsic to one dimension

  Sebastian Nagies, Botao Wang, Adam C. Knapp, André Eckardt, Nathan L. Harshman

  SciPost Phys. 16, 086 (2024) · published 26 March 2024 | Toggle abstract · pdf

  Anyons obeying fractional exchange statistics arise naturally in two dimensions: Hard-core two-body constraints make the configuration space of particles not simply-connected. The braid group describes how topologically-inequivalent exchange paths can be associated to non-trivial geometric phases for abelian anyons. Braid-anyon exchange statistics can also be found in one dimension (1D), but this requires broken Galilean invariance to distinguish different ways for two anyons to exchange. However, recently it was shown that an alternative form of exchange statistics can occur in 1D because hard-core three-body constraints also make the configuration space not simply-connected. Instead of the braid group, the topology of exchange paths and their associated non-trivial geometric phases are described by the traid group. In this article we propose a first concrete model realizing this alternative form of anyonic exchange statistics. Starting from a bosonic lattice model that implements the desired geometric phases with number-dependent Peierls phases, we then define anyonic operators so that the kinetic energy term in the Hamiltonian becomes local and quadratic with respect to them. The ground-state of this traid-anyon-Hubbard model exhibits several indications of exchange statistics intermediate between bosons and fermions, as well as signs of emergent approximate Haldane exclusion statistics. The continuum limit results in a Galilean invariant Hamiltonian with eigenstates that correspond to previously constructed continuum wave functions for traid anyons. This provides not only an a-posteriori justification of our lattice model, but also shows that our construction serves as an intuitive approach to traid anyons, i.e. anyons intrinsic to 1D.

• Newton mechanics, Galilean relativity, and special relativity in $\alpha$-deformed binary operation setting

  Won S. Chung, Mahouton N. Hounkonnou

  SciPost Phys. Proc. 14, 024 (2023) · published 23 November 2023 | Toggle abstract · pdf

  We define new velocity and acceleration having dimension of $(Length)^{\alpha}/(Time)$ and $(Length)^{\alpha}/(Time)^2,$ respectively, based on the fractional addition rule. We discuss the formulation of fractional Newton mechanics, Galilean relativity and special relativity in the same setting. We show the conservation of the fractional energy, characterize the Lorentz transformation and group, and derive the expressions of the energy and momentum. The two body decay is discussed as a concrete illustration.

• Analytical results for a coagulation/decoagulation model on an inhomogeneous lattice

  Nicolas Crampé

  SciPost Phys. 2, 006 (2017) · published 24 February 2017 | Toggle abstract · pdf

  We show that an inhomogeneous coagulation/decoagulation model can be mapped to a quadratic fermionic model via a Jordan-Wigner transformation. The spectrum for this inhomogeneous model is computed exactly and the spectral gap is described for some examples. We construct our inhomogeneous model from two different homogeneous models joined by one special bond (impurity). The homogeneous models we started with are the coagulation/decoagulation models studied previously using the Jordan-Wigner transformation.

• Generalisation of affine Lie algebras on compact real manifolds

  Rutwig Campoamor-Stursberg, Marc de Montigny, Michel Rausch de Traubenberg

  SciPost Phys. Proc. 14, 022 (2023) · published 23 November 2023 | Toggle abstract · pdf

  We report on recent work concerning a new type of generalised Kac-Moody algebras based on the spaces of differentiable mappings from compact manifolds or homogeneous spaces onto compact Lie groups.

• NLO finite system size corrections to $2\to2$ scattering in $\phi^4$ theory using newly derived sum of sinc functions

  Jean F. Du Plessis, William A. Horowitz

  SciPost Phys. Proc. 15, 002 (2024) · published 2 April 2024 | Toggle abstract · pdf

  Previously an equation of state for the relativistic hydrodynamics encountered in heavy-ion collisions at the LHC and RHIC has been calculated using lattice gauge theory methods. This leads to a prediction of very low viscosity, due to the calculated trace anomaly. Finite system corrections to this trace anomaly could challenge this calculation, since the lattice calculation was done in an effectively infinite system. In order to verify this trace anomaly it is sensible to add phenomenologically relevant finite system corrections. We investigate massive $\phi^4$ theory with periodic boundary conditions on $n$ of the 3 spatial dimensions. $2\to2$ NLO scattering is then computed. Using a newly derived formula for an arbitrary dimensional sum of sinc functions, we show that the NLO finite size corrections preserve unitarity.

• Photon-photon fusion and tau g-2 measurement in ATLAS

  Agnieszka Ogrodnik

  SciPost Phys. Proc. 15, 003 (2024) · published 2 April 2024 | Toggle abstract · pdf

  Relativistic heavy-ion beams at the LHC are accompanied by a large flux of equivalent photons. New measurements of exclusive dilepton production (electron, muon, and tau pairs) performed by the ATLAS experiment are discussed. We present the photon-induced production of tau pairs and constraints on the tau lepton's anomalous magnetic dipole moment. In addition, measurements of photon-induced electron and muon pair production are presented, which provide strong constraints on the nuclear photon flux and its dependence on the impact parameter and photon energy. Forward neutrons are utilised to provide an experimental handle on the impact parameter range sampled in the events.

• A pitfall in applying non-anticommuting $γ_5$ in $q\overline{q} \rightarrow ZH$ amplitudes

  Taushif Ahmed

  SciPost Phys. Proc. 7, 008 (2022) · published 20 June 2022 | Toggle abstract · pdf

  In computing the two-loop QCD corrections to a class of Feynman diagrams for the process $q\overline{q} \rightarrow ZH$ in Higgs effective field theory, we discover a striking phenomenon. We find the need for an additional local composite operator in the renormalised Lagrangian while employing a non-anticommuting $\gamma_5$ in dimensional regularisation. The computation using anticommuting $\gamma_5$, however, does not require any such amendment.

• On the modeling of $t\bar{t}W^\pm$ signatures at the LHC

  Manfred Kraus

  SciPost Phys. Proc. 7, 010 (2022) · published 20 June 2022 | Toggle abstract · pdf

  We discuss our recent progress on improving the theoretical description of the $pp\to t\bar{t}W^\pm$ process with particular focus on fiducial signatures that include top-quark decays. We employ a wide range of techniques from parton shower matching, narrow width approximation to full off-shell computations to assess the importance of the different modeling approaches.

• The diagrammatic coaction and cuts of the double box

  Einan Gardi, Aris Ioannou

  SciPost Phys. Proc. 7, 012 (2022) · published 20 June 2022 | Toggle abstract · pdf

  The diagrammatic coaction encodes the analytic structure of Feynman integrals by mapping any given Feynman diagram into a tensor product of diagrams defined by contractions and cuts of the original diagram. Feynman integrals evaluate to generalized hypergeometric functions in dimensional regularization. Establishing the coaction on this type of functions has helped formulating and checking the diagrammatic coaction of certain two-loop integrals. In this talk we study its application on the fully massless double box diagram. We make use of differential equation techniques, which, together with the properties of homology and cohomology theory of the resulting hypergeometric functions, allow us to formulate the coaction on a range of cuts of the double box in closed form.

• IR-Improved Amplitude-Based Resummation in Quantum Field Theory: New Results and New Issues

  B.F.L. Ward, S. Jadach, W. Placzek, M. Skrzypek, Z. Was, S. A. Yost

  SciPost Phys. Proc. 7, 015 (2022) · published 20 June 2022 | Toggle abstract · pdf

  With the advancement of strategies for the precision physics programs for the HL-LHC, FCC-ee, FCC-hh, ILC, CLIC, CEPC, and CPPC, the need for proper control of the attendant theoretical precision tags is manifest. We discuss the role that amplitude-based resummation may play in this regard with examples from the LHC, the proposed new colliders and quantum gravity.