Publications

2021

• Rapidity gap distribution in diffractive dissociation: Predictions for future electron-ion colliders
  
  • Le Anh Dung
  Physical Review D, American Physical Society, 2021, 104 (1), pp.014014. We present predictions for the distribution of rapidity gaps in realistic kinematics of future electron-ion colliders, based on numerical solutions of the original Kovchegov-Levin equation and of its next-to-leading extension taking into account the running of the strong coupling. We find that for the rapidities we have considered, the fixed and the running coupling equations lead to different distributions whose general shape is rather insensitive to the chosen prescription in the running coupling case. The obtained distributions for the fixed coupling framework exhibit a shape characteristic of a recently proposed partonic picture of diffractive dissociation already at rapidities accessible at future electron-ion colliders. The modification of this shape in the running coupling case can also be understood qualitatively from that picture. Our results confirm the relevance of measurements of such observables for the microscopic understanding of diffractive dissociation in the framework of quantum chromodynamics. (10.1103/PhysRevD.104.014014)
  DOI : 10.1103/PhysRevD.104.014014
• Renormalized holographic entanglement entropy for quadratic curvature gravity
  
  • Anastasiou Giorgos
  • Araya Ignacio J.
  • Moreno Javier
  • Olea Rodrigo
  • Rivera-Betancour David
  Physical Review D, American Physical Society, 2021, 104 (8), pp.086003. We derive a covariant expression for the renormalized holographic entanglement entropy for conformal field theories (CFTs) dual to quadratic curvature gravity in arbitrary dimensions. This expression is written as the sum of the bare entanglement entropy functional obtained using standard conical defect techniques, and a counterterm defined at the boundary of the extremal surface of the functional. The latter corresponds to the cod-2 self-replicating part of the extrinsic counterterms when evaluated on the replica orbifold. This renormalization method isolates the universal terms of the holographic entanglement entropy functional. We use it to compute the standard <math display="inline"><mi>C</mi></math>-function candidate for CFTs of arbitrary dimension, and the type-B anomaly coefficient <math display="inline"><mi>c</mi></math> for four-dimensional CFTs. (10.1103/PhysRevD.104.086003)
  DOI : 10.1103/PhysRevD.104.086003
• On systematic effects in the numerical solutions of the JIMWLK equation
  
  • Cali Salvatore
  • Cichy Krzysztof
  • Korcyl Piotr
  • Kotko Piotr
  • Kutak Krzysztof
  • Marquet Cyrille
  European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2021, 81 (7), pp.663. In the high energy limit of hadron collisions, the evolution of the gluon density in the longitudinal momentum fraction can be deduced from the Balitsky hierarchy of equations or, equivalently, from the nonlinear Jalilian–Marian–Iancu–McLerran–Weigert–Leonidov–Kovner (JIMWLK) equation. The solutions of the latter can be studied numerically by using its reformulation in terms of a Langevin equation. In this paper, we present a comprehensive study of systematic effects associated with the numerical framework, in particular the ones related to the inclusion of the running coupling. We consider three proposed ways in which the running of the coupling constant can be included: “square root” and “noise” prescriptions and the recent proposal by Hatta and Iancu. We implement them both in position and momentum spaces and we investigate and quantify the differences in the resulting evolved gluon distributions. We find that the systematic differences associated with the implementation technicalities can be of a similar magnitude as differences in running coupling prescriptions in some cases, or much smaller in other cases. (10.1140/epjc/s10052-021-09380-6)
  DOI : 10.1140/epjc/s10052-021-09380-6
• Bounds on multiscalar CFTs in the $\epsilon$ expansion
  
  • Hogervorst Matthijs
  • Toldo Chiara
  Journal of High Energy Physics, Springer, 2021, 04, pp.068. We study fixed points with N scalar fields in 4 − ε dimensions to leading order in ε using a bottom-up approach. We do so by analyzing O(N) invariants of the quartic coupling λ$_{ijkl}$ that describes such CFTs. In particular, we show that λ$_{iijj}$ and $ {\lambda}_{ijkl}^2 $ are restricted to a specific domain, refining a result by Rychkov and Stergiou. We also study averages of one-loop anomalous dimensions of composite operators without gradients. In many cases, we are able to show that the O(N) fixed point maximizes such averages. In the final part of this work, we generalize our results to theories with N complex scalars and to bosonic QED. In particular we show that to leading order in ε, there are no bosonic QED fixed points with N < 183 flavors. (10.1007/JHEP04(2021)068)
  DOI : 10.1007/JHEP04(2021)068
• Spin-orbit coupling in the kagome lattice with flux and time-reversal symmetry
  
  • Titvinidze Irakli
  • Legendre Julian
  • Grothus Maarten
  • Irsigler Bernhard
  • Le Hur Karyn
  • Hofstetter Walter
  Physical Review B, American Physical Society, 2021, 103 (19), pp.195105. We study the topological properties of a spin-orbit coupled tight-binding model with flux on the kagome lattice. The model is time-reversal invariant and realizes a Z2 topological insulator as a result of artificial gauge fields. We develop topological arguments to describe this system showing three inequivalent sites in a unit cell and a flat band in its energy spectrum in addition to the topological dispersive energy bands. We show the stability of the topological phase towards spin-flip processes and different types of on-site potentials. In particular, we also address the situation where on-site energies may differ inside a unit cell. Moreover, a staggered potential on the lattice may realize topological phases for the half-filled situation. Another interesting result is the occurrence of a topological phase for large on-site energies. To describe topological properties of the system we use a numerical approach based on the twisted boundary conditions and we develop a mathematical approach, related to smooth fields. (10.1103/PhysRevB.103.195105)
  DOI : 10.1103/PhysRevB.103.195105
• Probability distribution for the quantum universe
  
  • Kehagias Alex
  • Partouche Hervé
  • Toumbas Nicolaos
  Journal of High Energy Physics, Springer, 2021, 12, pp.165. We determine the inner product on the Hilbert space of wavefunctions of the universe by imposing the Hermiticity of the quantum Hamiltonian in the context of the minisuperspace model. The corresponding quantum probability density reproduces successfully the classical probability distribution in the ħ → 0 limit, for closed universes filled with a perfect fluid of index w. When −1/3 < w ≤ 1, the wavefunction is normalizable and the quantum probability density becomes vanishingly small at the big bang/big crunch singularities, at least at the semiclassical level. Quantum expectation values of physical geometrical quantities, which diverge classically at the singularities, are shown to be finite. (10.1007/JHEP12(2021)165)
  DOI : 10.1007/JHEP12(2021)165
• Relativistic spin sum rules and the role of the pivot
  
  • Lorcé Cédric
  European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2021, 81 (5), pp.413. Spin sum rules depend on the choice of a pivot, i.e. the point about which the angular momentum is defined, usually identified with the center of the nucleon. The latter is however not unique in a relativistic theory and has led to apparently contradictory results in the literature. Using the recently developed phase-space approach, we compute for the first time the contribution associated with the motion of the center of the nucleon, and we derive a general spin sum rule which reduces to established results after appropriate choices for the pivot and the spin component. (10.1140/epjc/s10052-021-09207-4)
  DOI : 10.1140/epjc/s10052-021-09207-4
• Hydrodynamic Diffusion and Its Breakdown near AdS2 Quantum Critical Points
  
  • Arean Daniel
  • Davison Richard A.
  • Goutéraux Blaise
  • Suzuki Kenta
  Physical Review X, American Physical Society, 2021, 11 (3), pp.031024. Hydrodynamics provides a universal description of interacting quantum field theories at sufficiently long times and wavelengths, but breaks down at scales dependent on microscopic details of the theory. In the vicinity of a quantum critical point, it is expected that some aspects of the dynamics are universal and dictated by properties of the critical point. We use gauge-gravity duality to investigate the breakdown of diffusive hydrodynamics in two low-temperature states dual to black holes with <math display="inline"><mrow><msub><mrow><mi>AdS</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math> horizons, which exhibit quantum critical dynamics with an emergent scaling symmetry in time. We find that the breakdown is characterized by a collision between the diffusive pole of the retarded Green’s function with a pole associated to the <math display="inline"><mrow><msub><mrow><mi>AdS</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math> region of the geometry, such that the local equilibration time is set by infrared properties of the theory. The absolute values of the frequency and wave vector at the collision (<math display="inline"><msub><mi>ω</mi><mrow><mi>eq</mi></mrow></msub></math> and <math display="inline"><msub><mi>k</mi><mrow><mi>eq</mi></mrow></msub></math>) provide a natural characterization of all the low-temperature diffusivities <math display="inline"><mi>D</mi></math> of the states via <math display="inline"><mi>D</mi><mo>=</mo><msub><mi>ω</mi><mrow><mi>eq</mi></mrow></msub><mo stretchy="false">/</mo><msubsup><mi>k</mi><mrow><mi>eq</mi></mrow><mn>2</mn></msubsup></math>, where <math display="inline"><msub><mi>ω</mi><mrow><mi>eq</mi></mrow></msub><mo>=</mo><mn>2</mn><mi>π</mi><mi mathvariant="normal">Δ</mi><mi>T</mi></math> is set by the temperature <math display="inline"><mi>T</mi></math> and the scaling dimension <math display="inline"><mi mathvariant="normal">Δ</mi></math> of an operator of the infrared quantum critical theory. We confirm that these relations are also satisfied in a Sachdev-Ye-Kitaev chain model in the limit of strong interactions. Our work paves the way toward a deeper understanding of transport in quantum critical phases. (10.1103/PhysRevX.11.031024)
  DOI : 10.1103/PhysRevX.11.031024
• 3d large $N$ vector models at the boundary
  
  • Di Pietro Lorenzo
  • Lauria Edoardo
  • Niro Pierluigi
  SciPost Physics, SciPost Foundation, 2021, 11 (3), pp.050. We consider a 4d scalar field coupled to large $N$ free or critical $O(N)$ vector models, either bosonic or fermionic, on a 3d boundary. We compute the $\beta$ function of the classically marginal bulk/boundary interaction at the first non-trivial order in the large $N$ expansion and exactly in the coupling. Starting with the free (critical) vector model at weak coupling, we find a fixed point at infinite coupling in which the boundary theory is the critical (free) vector model and the bulk decouples. We show that a strong/weak duality relates one description of the renormalization group flow to another one in which the free and the critical vector models are exchanged. We then consider the theory with an additional Maxwell field in the bulk, which also gives decoupling limits with gauged vector models on the boundary. (10.21468/SciPostPhys.11.3.050)
  DOI : 10.21468/SciPostPhys.11.3.050
• Two-loop corrections to the QCD propagators within the Curci-Ferrari model
  
  • Barrios Nahuel
  • Gracey John A.
  • Peláez Marcela
  • Reinosa Urko
  Physical Review D, American Physical Society, 2021, 104 (9), pp.094019. We evaluate all two-point correlation functions of the Curci-Ferrari (CF) model in four dimensions and in the presence of mass-degenerate fundamental quark flavors, as a natural extension of an earlier investigation in the quenched approximation. In principle, the proper account of chiral symmetry breaking (<math display="inline"><mrow><mi>χ</mi><mi>SB</mi></mrow></math>) and the corresponding dynamical generation of a quark-mass function within the CF model requires one to go beyond perturbation theory [M. Peláez, U. Reinosa, J. Serreau, M. Tissier, and N. Wschebor, Phys. Rev. D 103, 094035 (2021)]. However, it is interesting to assess whether a perturbative description applies to correlation functions that are not directly sensitive to <math display="inline"><mrow><mi>χ</mi><mi>SB</mi></mrow></math>, such as the gluon, ghost and quark dressing functions. We compare our two-loop results for these form factors to QCD lattice data in the two-flavor case for two different values of the pion mass, one that is relatively far from the chiral limit, and one that is closer to the physical value. Our results confirm that the QCD gluon and ghost dressing functions are well described by a perturbative approach within the CF model, as already observed at one-loop order [M. Peláez, M. Tissier, and N. Wschebor, Phys. Rev. D 90, 065031 (2014)]. Our new main result is that the quark dressing function is also well captured by the perturbative approach, but only starting at two-loop order, as also anticipated [M. Peláez, M. Tissier, and N. Wschebor, Phys. Rev. D 90, 065031 (2014)]. The quark-mass function predicted by the CF model at two-loop order is in good agreement with the data if the quarks are not too light but it shows some clear tension with respect to the two-loop CF dressing functions in the close to physical case, as expected. Interestingly, however, we find that there is much less tension between the nonperturbative quark-mass function, as it can be obtained from lattice simulations or from M. Peláez, U. Reinosa, J. Serreau, M. Tissier, and N. Wschebor, Phys. Rev. D 103, 094035 (2021), and the two-loop CF dressing functions, which confirms the perturbative nature of the latter. (10.1103/PhysRevD.104.094019)
  DOI : 10.1103/PhysRevD.104.094019
• Towards bootstrapping RG flows: sine-Gordon in AdS
  
  • Antunes António
  • Costa Miguel S.
  • Penedones João
  • Salgarkar Aaditya
  • van Rees Balt C.
  Journal of High Energy Physics, Springer, 2021, 12, pp.094. The boundary correlation functions for a Quantum Field Theory (QFT) in an Anti-de Sitter (AdS) background can stay conformally covariant even if the bulk theory undergoes a renormalization group (RG) flow. Studying such correlation functions with the numerical conformal bootstrap leads to non-perturbative constraints that must hold along the entire flow. In this paper we carry out this analysis for the sine-Gordon RG flows in AdS$_{2}$, which start with a free (compact) scalar in the UV and end with well-known massive integrable theories that saturate many S-matrix bootstrap bounds. We numerically analyze the correlation functions of both breathers and kinks and provide a detailed comparison with perturbation theory near the UV fixed point. Our bounds are often saturated to one or two orders in perturbation theory, as well as in the flat-space limit, but not necessarily in between. (10.1007/JHEP12(2021)094)
  DOI : 10.1007/JHEP12(2021)094
• The importance of kinematic twists and genuine saturation effects in dijet production at the Electron-Ion Collider
  
  • Boussarie Renaud
  • Mäntysaari Heikki
  • Salazar Farid
  • Schenke Björn
  Journal of High Energy Physics, Springer, 2021, 09, pp.178. We compute the differential yield for quark anti-quark dijet production in high-energy electron-proton and electron-nucleus collisions at small x as a function of the relative momentum P$_{⊥}$ and momentum imbalance k$_{⊥}$ of the dijet system for different photon virtualities Q$^{2}$, and study the elliptic and quadrangular anisotropies in the relative angle between P$_{⊥}$ and k$_{⊥}$. We review and extend the analysis in [1], which compared the results of the Color Glass Condensate (CGC) with those obtained using the transverse momentum dependent (TMD) framework. In particular, we include in our comparison the improved TMD (ITMD) framework, which resums kinematic power corrections of the ratio k$_{⊥}$ over the hard scale Q$_{⊥}$. By comparing ITMD and CGC results we are able to isolate genuine higher saturation contributions in the ratio Q$_{s}$/Q$_{⊥}$ which are resummed only in the CGC. These saturation contributions are in addition to those in the Weizsäcker-Williams gluon TMD that appear in powers of Q$_{s}$/k$_{⊥}$. We provide numerical estimates of these contributions for inclusive dijet production at the future Electron-Ion Collider, and identify kinematic windows where they can become relevant in the measurement of dijet and dihadron azimuthal correlations. We argue that such measurements will allow the detailed experimental study of both kinematic power corrections and genuine gluon saturation effects. (10.1007/JHEP09(2021)178)
  DOI : 10.1007/JHEP09(2021)178
• Étude de l'impact du handicap sur le recrutement et le déroulé de carrière des chercheurs au CNRS
  
  • Jacques Vincent
  • Löfberg Axel
  • Loty Laurent
  • Loubière Karine
  • Lütjens Hinrich
  • Marie Emmanuelle
  • Saracco Ginette
  • Souchay Céline
  • Tricard Simon
  • Weil Dominique
  , 2021.
• A window on infrared QCD with small expansion parameters
  
  • Peláez Marcela
  • Reinosa Urko
  • Serreau Julien
  • Tissier Matthieu
  • Wschebor Nicolás
  Reports on Progress in Physics, IOP Publishing, 2021, 84 (12), pp.124202. Lattice simulations of the QCD correlation functions in the Landau gauge have established two remarkable facts. First, the coupling constant in the gauge sector—defined, e.g., in the Taylor scheme—remains finite and moderate at all scales, suggesting that some kind of perturbative description should be valid down to infrared momenta. Second, the gluon propagator reaches a finite nonzero value at vanishing momentum, corresponding to a gluon screening mass. We review recent studies which aim at describing the long-distance properties of Landau gauge QCD by means of the perturbative Curci–Ferrari model. The latter is the simplest deformation of the Faddeev–Popov Lagrangian in the Landau gauge that includes a gluon screening mass at tree-level. There are, by now, strong evidences that this approach successfully describes many aspects of the infrared QCD dynamics. In particular, several correlation functions were computed at one- and two-loop orders and compared with ab-initio lattice simulations. The typical error is of the order of ten percent for a one-loop calculation and drops to few percents at two loops. We review such calculations in the quenched approximation as well as in the presence of dynamical quarks. In the latter case, the spontaneous breaking of the chiral symmetry requires to go beyond a coupling expansion but can still be described in a controlled approximation scheme in terms of small parameters. We also review applications of the approach to nonzero temperature and chemical potential. (10.1088/1361-6633/ac36b8)
  DOI : 10.1088/1361-6633/ac36b8
• A master exceptional field theory
  
  • Bossard Guillaume
  • Kleinschmidt Axel
  • Sezgin Ergin
  Journal of High Energy Physics, Springer, 2021, 06, pp.185. We construct a pseudo-Lagrangian that is invariant under rigid E$_{11}$ and transforms as a density under E$_{11}$ generalised diffeomorphisms. The gauge-invariance requires the use of a section condition studied in previous work on E$_{11}$ exceptional field theory and the inclusion of constrained fields that transform in an indecomposable E$_{11}$-representation together with the E$_{11}$ coset fields. We show that, in combination with gauge-invariant and E$_{11}$-invariant duality equations, this pseudo-Lagrangian reduces to the bosonic sector of non-linear eleven-dimensional supergravity for one choice of solution to the section condi- tion. For another choice, we reobtain the E$_{8}$ exceptional field theory and conjecture that our pseudo-Lagrangian and duality equations produce all exceptional field theories with maximal supersymmetry in any dimension. We also describe how the theory entails non-linear equations for higher dual fields, including the dual graviton in eleven dimensions. Furthermore, we speculate on the relation to the E$_{10}$ sigma model. (10.1007/JHEP06(2021)185)
  DOI : 10.1007/JHEP06(2021)185
• Low-x improved TMD approach to the lepto- and hadroproduction of a heavy-quark pair
  
  • Altinoluk Tolga
  • Marquet Cyrille
  • Taels Pieter
  Journal of High Energy Physics, Springer, 2021, 06, pp.085. We study the lepto- and hadroproduction of a heavy-quark pair in the ITMD factorization framework for dilute-dense collisions. Due to the presence of a nonzero quark mass and/or nonzero photon virtuality, new contributions appear compared to the cases of photo- and hadroproduction of dijets, for which the ITMD framework was originally derived. These extra terms are sensitive to gluons that are not fully linearly polarized. At small x, those gluons emerge only when all saturation effects are carefully taken into account. Therefore, the resulting contributions are absent in linear small-x frameworks, where gluons are fully linearly polarized. We show, however, that even for large gluon transverse momentum, these contributions are not always negligible, due to the behavior of the off-shell hard factors. (10.1007/JHEP06(2021)085)
  DOI : 10.1007/JHEP06(2021)085
• Universal record statistics for random walks and Lévy flights with a nonzero staying probability
  
  • Majumdar Satya
  • Mounaix Philippe
  • Schehr Gregory
  Journal of Physics A: Mathematical and Theoretical, IOP Publishing, 2021, 54 (31), pp.315002. We compute exactly the statistics of the number of records in a discrete-time random walk model on a line where the walker stays at a given position with a nonzero probability 0  p  1, while with the complementary probability 1 p, it jumps to a new position with a jump length drawn from a continuous and symmetric distribution f 0 (⌘). We have shown that, for arbitrary p, the statistics of records up to step N is completely universal, i.e., independent of f 0 (⌘) for any N. We also compute the connected two-time correlation function C p (m 1 , m 2) of the record-breaking events at times m 1 and m 2 and show it is also universal for all p. Moreover, we demonstrate that C p (m 1 , m 2) < C 0 (m 1 , m 2) for all p > 0, indicating that a nonzero p induces additional anticorrelations between record events. We further show that these anti-correlations lead to a drastic reduction in the fluctuations of the record numbers with increasing p. This is manifest in the Fano factor, i.e. the ratio of the variance and the mean of the record number, which we compute explicitly. We also show that an interesting scaling limit emerges when p ! 1, N ! 1 with the product t = (1 p) N fixed. We compute exactly the associated universal scaling functions for the mean, variance and the Fano factor of the number of records in this scaling limit. (10.1088/1751-8121/ac0a2f)
  DOI : 10.1088/1751-8121/ac0a2f
• The Large Hadron–Electron Collider at the HL-LHC
  
  • Agostini P.
  • Aksakal H.
  • Alekhin S.
  • Allport P.P.
  • Andari N.
  • Andre K.D.J.
  • Angal-Kalinin D.
  • Antusch S.
  • Aperio Bella L.
  • Apolinario L.
  • Apsimon R.
  • Apyan A.
  • Arduini G.
  • Ari V.
  • Armbruster A.
  • Armesto N.
  • Auchmann B.
  • Aulenbacher K.
  • Azuelos G.
  • Backovic S.
  • Bailey I.
  • Bailey S.
  • Balli F.
  • Behera S.
  • Behnke O.
  • Ben-Zvi I.
  • Benedikt M.
  • Bernauer J.
  • Bertolucci S.
  • Biswal S.S.
  • Blümlein J.
  • Bogacz A.
  • Bonvini M.
  • Boonekamp M.
  • Bordry F.
  • Boroun G.R.
  • Bottura L.
  • Bousson S.
  • Bouzas A.O.
  • Bracco C.
  • Bracinik J.
  • Britzger D.
  • Brodsky S.J.
  • Bruni C.
  • Brüning O.
  • Burkhardt H.
  • Cakir O.
  • Calaga R.
  • Caldwell A.
  • Calıskan A.
  • Camarda S.
  • Catalan-Lasheras N.C.
  • Cassou K.
  • Cepila J.
  • Cetinkaya V.
  • Chetvertkova V.
  • Cole B.
  • Coleppa B.
  • Cooper-Sarkar A.
  • Cormier E.
  • Cornell A.S.
  • Corsini R.
  • Cruz-Alaniz E.
  • Currie J.
  • Curtin D.
  • d'Onofrio M.
  • Dainton J.
  • Daly E.
  • Das A.
  • Das S.P.
  • Dassa L.
  • de Blas J.
  • Delle Rose L.
  • Denizli H.
  • Deshpande K.S.
  • Douglas D.
  • Duarte L.
  • Dupraz K.
  • Dutta S.
  • Efremov A.V.
  • Eichhorn R.
  • Eskola K.J.
  • Ferreiro E.G.
  • Fischer O.
  • Flores-Sánchez O.
  • Forte S.
  • Gaddi A.
  • Gao J.
  • Gehrmann T.
  • Gehrmann-de Ridder A.
  • Gerigk F.
  • Gilbert A.
  • Giuli F.
  • Glazov A.
  • Glover N.
  • Godbole R.M.
  • Goddard B.
  • Gonçalves V.
  • Gonzalez-Sprinberg G.A.
  • Goyal A.
  • Grames J.
  • Granados E.
  • Grassellino A.
  • Gunaydin Y.O.
  • Guo Y.C.
  • Guzey V.
  • Gwenlan C.
  • Hammad A.
  • Han C.C.
  • Harland-Lang L.
  • Haug F.
  • Hautmann F.
  • Hayden D.
  • Hessler J.
  • Helenius I.
  • Henry J.
  • Hernandez-Sanchez J.
  • Hesari H.
  • Hobbs T.J.
  • Hod N.
  • Hoffstaetter G.H.
  • Holzer B.
  • Honorato C.G.
  • Hounsell B.
  • Hu N.
  • Hug F.
  • Huss A.
  • Hutton A.
  • Islam R.
  • Iwamoto S.
  • Jana S.
  • Jansova M.
  • Jensen E.
  • Jones T.
  • Jowett J.M.
  • Kaabi W.
  • Kado M.
  • Kalinin D.A.
  • Karadeniz H.
  • Kawaguchi S.
  • Kaya U.
  • Khalek R.A.
  • Khanpour H.
  • Kilic A.
  • Klein M.
  • Klein U.
  • Kluth S.
  • Köksal M.
  • Kocak F.
  • Korostelev M.
  • Kostka P.
  • Krelina M.
  • Kretzschmar J.
  • Kuday S.
  • Kulipanov G.
  • Kumar M.
  • Kuze M.
  • Lappi T.
  • Larios F.
  • Latina A.
  • Laycock P.
  • Lei G.
  • Levitchev E.
  • Levonian S.
  • Levy A.
  • Li R.
  • Li X.
  • Liang H.
  • Litvinenko V.
  • Liu M.
  • Liu T.
  • Liu W.
  • Liu Y.
  • Liuti S.
  • Lobodzinska E.
  • Longuevergne D.
  • Luo X.
  • Ma W.
  • Machado M.
  • Mandal S.
  • Mäntysaari H.
  • Marhauser F.
  • Marquet C.
  • Martens A.
  • Martin R.
  • Marzani S.
  • Mcfayden J.
  • Mcintosh P.
  • Mellado B.
  • Meot F.
  • Milanese A.
  • Milhano J.G.
  • Militsyn B.
  • Mitra M.
  • Moch S.
  • Mohammadi Najafabadi M.
  • Mondal S.
  • Moretti S.
  • Morgan T.
  • Morreale A.
  • Nadolsky P.
  • Navarra F.
  • Nergiz Z.
  • Newman P.
  • Niehues J.
  • Nissen E.A.
  • Nowakowski M.
  • Okada N.
  • Olivier G.
  • Olness F.
  • Olry G.
  • Osborne J.A.
  • Ozansoy A.
  • Pan R.
  • Parker B.
  • Patra M.
  • Paukkunen H.
  • Peinaud Y.
  • Pellegrini D.
  • Perez-Segurana G.
  • Perini D.
  • Perrot L.
  • Pietralla N.
  • Pilicer E.
  • Pire B.
  • Pires J.
  • Placakyte R.
  • Poelker M.
  • Polifka R.
  • Polini A.
  • Poulose P.
  • Pownall G.
  • Pupkov Y.A.
  • Queiroz F.S.
  • Rabbertz K.
  • Radescu V.
  • Rahaman R.
  • Rai S.K.
  • Raicevic N.
  • Ratoff P.
  • Rashed A.
  • Raut D.
  • Raychaudhuri S.
  • Repond J.
  • Rezaeian A.H.
  • Rimmer R.
  • Rinolfi L.
  • Rojo J.
  • Rosado A.
  • Ruan X.
  • Russenschuck S.
  • Sahin M.
  • Salgado C.A.
  • Sampayo O.A.
  • Satendra K.
  • Satyanarayan N.
  • Schenke B.
  • Schirm K.
  • Schopper H.
  • Schott M.
  • Schulte D.
  • Schwanenberger C.
  • Sekine T.
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  • Xiaohao C.
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  • Yaguna C.E.
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  • Yang H.
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  • Yock P.
  • Yue C.X.
  • Zadeh S.G.
  • Zenaiev O.
  • Zhang C.
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  • Zhu G.
  • Zhu S.
  • Zimmermann F.
  • Zomer F.
  • Zurita J.
  • Zurita P.
  J.Phys.G, 2021, 48 (11), pp.110501. The Large Hadron–Electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy-recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High-Luminosity Large Hadron Collider (HL-LHC). The accelerator and interaction region are designed for concurrent electron–proton and proton–proton operations. This report represents an update to the LHeC’s conceptual design report (CDR), published in 2012. It comprises new results on the parton structure of the proton and heavier nuclei, QCD dynamics, and electroweak and top-quark physics. It is shown how the LHeC will open a new chapter of nuclear particle physics by extending the accessible kinematic range of lepton–nucleus scattering by several orders of magnitude. Due to its enhanced luminosity and large energy and the cleanliness of the final hadronic states, the LHeC has a strong Higgs physics programme and its own discovery potential for new physics. Building on the 2012 CDR, this report contains a detailed updated design for the energy-recovery electron linac (ERL), including a new lattice, magnet and superconducting radio-frequency technology, and further components. Challenges of energy recovery are described, and the lower-energy, high-current, three-turn ERL facility, PERLE at Orsay, is presented, which uses the LHeC characteristics serving as a development facility for the design and operation of the LHeC. An updated detector design is presented corresponding to the acceptance, resolution, and calibration goals that arise from the Higgs and parton-density-function physics programmes. This paper also presents novel results for the Future Circular Collider in electron–hadron (FCC-eh) mode, which utilises the same ERL technology to further extend the reach of DIS to even higher centre-of-mass energies. (10.1088/1361-6471/abf3ba)
  DOI : 10.1088/1361-6471/abf3ba
• The Status and Future of Color Transparency and Nuclear Filtering
  
  • Jain P
  • Pire B
  • Ralston J
  , 2022, 2022 (4), pp.578–589.. 40 years after its introduction, the phenomenon of color transparency remains a domain of controversial interpretations of experimental data. We review present evidence for or against its manifestation in various exclusive hard scattering reactions. The nuclear transparency experiments reveal whether short distance processes dominate a scattering amplitude at some given kinematical point. We plead for a new round of nuclear transparency measurements in a variety of experimental setups , including near-forward exclusive reactions related to generalized parton distribution (GPD) physics and near-backward exclusive reactions related to transition distribution amplitudes (TDA) physics.
• The tadpole problem
  
  • Bena Iosif
  • Blåbäck Johan
  • Graña Mariana
  • Lüst Severin
  Journal of High Energy Physics, Springer, 2021, 11, pp.223. We examine the mechanism of moduli stabilization by fluxes in the limit of a large number of moduli. We conjecture that one cannot stabilize all complex-structure moduli in F-theory at a generic point in moduli space (away from singularities) by fluxes that satisfy the bound imposed by the tadpole cancellation condition. More precisely, while the tadpole bound in the limit of a large number of complex-structure moduli goes like 1/4 of the number of moduli, we conjecture that the amount of charge induced by fluxes stabilizing all moduli grows faster than this, and is therefore larger than the allowed amount. Our conjecture is supported by two examples: K3 × K3 compactifications, where by using evolutionary algorithms we find that moduli stabilization needs fluxes whose induced charge is 44% of the number of moduli, and Type IIB compactifications on $ \mathbbm{CP} ^{3}$, where the induced charge of the fluxes needed to stabilize the D7-brane moduli is also 44% of the number of these moduli. Proving our conjecture would rule out de Sitter vacua obtained via antibrane uplift in long warped throats with a hierarchically small supersymmetry breaking scale, which require a large tadpole. (10.1007/JHEP11(2021)223)
  DOI : 10.1007/JHEP11(2021)223
• Efficient second-harmonic generation of a high-energy, femtosecond laser pulse in a lithium triborate crystal
  
  • Aparajit C.
  • Jana Kamalesh
  • Lad Amit
  • Ved Yash
  • Couairon Arnaud
  • Kumar G. Ravindra
  Optics Letters, Optical Society of America - OSA Publishing, 2021, 46 (15), pp.3540. (10.1364/OL.423725)
  DOI : 10.1364/OL.423725
• Flow equations for disordered Floquet systems
  
  • Thomson Steven
  • Magano Duarte
  • Schiro' Marco
  SciPost Physics, SciPost Foundation, 2021, 11 (2), pp.028. In this work, we present a new approach to disordered, periodically driven (Floquet) quantum many-body systems based on flow equations. Specifically, we introduce a continuous unitary flow of Floquet operators in an extended Hilbert space, whose fixed point is both diagonal and time-independent, allowing us to directly obtain the Floquet modes. We first apply this method to a periodically driven Anderson insulator, for which it is exact, and then extend it to driven many-body localized systems within a truncated flow equation ansatz. In particular we compute the emergent Floquet local integrals of motion that characterise a periodically driven many-body localized phase. We demonstrate that the method remains well-controlled in the weakly-interacting regime, and allows us to access larger system sizes than accessible by numerically exact methods, paving the way for studies of two-dimensional driven many-body systems. (10.21468/SciPostPhys.11.2.028)
  DOI : 10.21468/SciPostPhys.11.2.028
• E$_{9}$ exceptional field theory. Part II. The complete dynamics
  
  • Bossard Guillaume
  • Ciceri Franz
  • Inverso Gianluca
  • Kleinschmidt Axel
  • Samtleben Henning
  Journal of High Energy Physics, Springer, 2021, 05, pp.107. We construct the first complete exceptional field theory that is based on an infinite-dimensional symmetry group. E$_{9}$ exceptional field theory provides a unified description of eleven-dimensional and type IIB supergravity covariant under the affine Kac-Moody symmetry of two-dimensional maximal supergravity. We present two equivalent formulations of the dynamics, which both rely on a pseudo-Lagrangian supplemented by a twisted self-duality equation. One formulation involves a minimal set of fields and gauge symmetries, which uniquely determine the entire dynamics. The other formulation extends $ {\mathfrak{e}}_9 $ by half of the Virasoro algebra and makes direct contact with the integrable structure of two-dimensional supergravity. Our results apply directly to other affine Kac-Moody groups, such as the Geroch group of general relativity. (10.1007/JHEP05(2021)107)
  DOI : 10.1007/JHEP05(2021)107
• Remarks on a melonic field theory with cubic interaction
  
  • Benedetti Dario
  • Delporte Nicolas
  Journal of High Energy Physics, Springer, 2021, 04, pp.197. We revisit the Amit-Roginsky (AR) model in the light of recent studies on Sachdev-Ye-Kitaev (SYK) and tensor models, with which it shares some important features. It is a model of N scalar fields transforming in an N-dimensional irreducible representation of SO(3). The most relevant (in renormalization group sense) invariant interaction is cubic in the fields and mediated by a Wigner 3jm symbol. The latter can be viewed as a particular rank-3 tensor coupling, thus highlighting the similarity to the SYK model, in which the tensor coupling is however random and of even rank. As in the SYK and tensor models, in the large-N limit the perturbative expansion is dominated by melonic diagrams. The lack of randomness, and the rapidly growing number of invariants that can be built with n fields, makes the AR model somewhat closer to tensor models. We review the results from the old work of Amit and Roginsky with the hindsight of recent developments, correcting and completing some of their statements, in particular concerning the spectrum of the operator product expansion of two fundamental fields. For 5.74 < d < 6 the fixed-point theory defines a real CFT, while for smaller d complex dimensions appear, after a merging of the lowest dimension with its shadow. We also introduce and study a long-range version of the model, for which the cubic interaction is exactly marginal at large N , and we find a real and unitary CFT for any d < 6, both for real and imaginary coupling constant, up to some critical coupling. (10.1007/JHEP04(2021)197)
  DOI : 10.1007/JHEP04(2021)197
• Localization dynamics from static and mobile impurities
  
  • Bernhardt Ephraim
  • Yang Fan
  • Le Hur Karyn
  Physical Review B, American Physical Society, 2021, 104 (11), pp.115113. We study the superfluid response and localization dynamics from static and mobile impurities. The superfluidity is formed in the rung-Mott phase of a bosonic ladder model producing spin-Meissner currents induced by a <math><mrow><mi mathvariant="double-struck">U</mi><mo>(</mo><mn>1</mn><mo>)</mo></mrow></math> gauge field or a uniform magnetic field. Impurities are described through two-state systems, which act as a two-peak random potential. An impurity sits either at the top or at the bottom of the ladder on each rung equally, producing a telegraph signal. The impurities-matter coupling gives rise to a classical Ising symmetry for static and mobile impurities associated to the inversion symmetry of the two legs of the ladder. From the decoupled rungs limit, we also identify a local <math><msub><mi mathvariant="double-struck">Z</mi><mn>2</mn></msub></math> gauge theory for mobile impurities. The properties of the system are studied from an effective quantum spin model including the possibility of four-body coupling in the limit of a strong interaction between bosons and impurities. Through analytical approaches and numerical exact diagonalization, we study the superfluid currents both in the weakly-coupled and strongly-coupled rungs limits for the bosons. In the weakly-coupled rungs situation, we find a smooth power-law localization whereas the strongly-coupled rungs limit produces a steep localization or insulating phase for various configurations of the two-peak random potential. In the strongly disordered situation, through entanglement and bipartite fluctuation measures, we also identify a many-body localization regime in time after a quench of the system when prepared in a Néel state. (10.1103/PhysRevB.104.115113)
  DOI : 10.1103/PhysRevB.104.115113