Publications

2021

• Collisional transport and poloidal asymmetry distribution of impurities in tokamak plasmas, with application to WEST
  
  • Maget P
  • Manas P
  • Dumont R
  • Artaud J-F
  • Bourdelle C
  • Colas L
  • Goniche M
  • Garbet X
  • Frank J
  • Agullo O
  • Nicolas T
  • Lütjens H
  , 2021. We report in this contribution on the development of an analytic model for a selfconsistent determination of the poloidal asymmetry, collisional flux and steady state profile of heavy impurities [1]. The model is compared with nonlinear axisymmetric simulations with the XTOR code [2, 3, 4], and with computations using the drift-kinetic code NEO [5]. An application to Tungsten peaking in the WEST tokamak under Ion Cyclotron Resonance Heating (ICRH) exemplifies the complex balance between accumulation and expulsion forces at play.
• Hubbard model on the Bethe lattice via variational uniform tree states: Metal-insulator transition and a Fermi liquid
  
  • Lunts Peter
  • Georges Antoine
  • Stoudenmire E. Miles
  • Fishman Matthew
  Physical Review Research, American Physical Society, 2021, 3 (2), pp.023054. We numerically solve the Hubbard model on the Bethe lattice with finite coordination number z = 3, and determine its zero-temperature phase diagram. For this purpose, we introduce and develop the "variational uniform tree state" (VUTS) algorithm, a tensor-network algorithm which generalizes the variational uniform matrix product state algorithm to tree tensor networks. Our results reveal an antiferromagnetic insulating phase and a paramagnetic metallic phase, separated by a first-order doping-driven metal-insulator transition. We show that the metallic state is a Fermi liquid with coherent quasiparticle excitations for all values of the interaction strength U , and we obtain the finite quasiparticle weight Z from the single-particle occupation function of a generalized "momentum" variable. We find that Z decreases with increasing U , ultimately saturating to a nonzero, doping-dependent value. Our work demonstrates that tensor-network calculations on tree lattices, and the VUTS algorithm in particular, are a platform for obtaining controlled results for phenomena absent in one dimension, such as Fermi liquids, while avoiding computational difficulties associated with tensor networks in two dimensions. We envision that future studies could observe non-Fermi liquids, interaction-driven metal-insulator transitions, and doped spin liquids using this platform. (10.1103/PhysRevResearch.3.023054)
  DOI : 10.1103/PhysRevResearch.3.023054
• Charged current electroproduction of a charmed meson at an electron-ion collider
  
  • Pire B.
  • Szymanowski L.
  • Wagner J.
  , 2021. We calculate the amplitude for exclusive electroweak production of a pseudoscalar D_s or a vector D^*_s charmed strange meson on an unpolarized nucleon, through a charged current, in leading order in alpha_s. We work in the framework of the collinear QCD approach where generalized gluon distributions factorize from perturbatively calculable coefficient functions. We include both O(m_c) terms in the coefficient functions and O(M_D) mass term contributions in the heavy meson distribution amplitudes. We show that this process may be accessed at future electron-ion colliders.
• Accessing quark GPDs in diffractive events at an electron-ion collider
  
  • Cosyn W.
  • Pire B.
  • Szymanowski L.
  , 2022, 8, pp.159. We discuss two collider processes which combine a diffractively produced rho meson separated by a large rapidity gap from a hard exclusive scattering of a Pomeron on a nucleon, giving rise to a lepton pair or to a second meson. These two processes probe the nucleon quark content described by generalized parton distributions in a very specific way.
• NLO collinear factorization of large mass diphoton photoproduction amplitude
  
  • Grocholski Oskar
  • Pire Bernard
  • Sznajder Paweł
  • Szymanowski Lech
  • Wagner Jakub
  , 2022, 8, pp.078. We calculate large mass diphoton exclusive photoproduction in the framework of collinear QCD factorization at next to leading order in {\alpha}s and at leading twist. Collinear divergences of the coefficient function are absorbed by the evolution of the generalized parton distributions (GPDs). This result enlarges the existing factorization proofs to 2 -> 3 processes, opening new reactions to a trustable extraction of GPDs.
• Exclusive electro-weak production of a charmed meson at high energy
  
  • Pire B.
  • Szymanowski L.
  • Wagner J.
  , 2022, 8, pp.150. Exclusive electro-weak processes have peculiar features which make them complementary to usually discussed deeply virtual electroproduction processes such as deep virtual Compton scattering or meson production (and the corresponding crossed reactions). They allow in particular single charmed meson production, which we study in two different contexts : electroproduction at an electron ion collider and neutrino-production at a medium energy neutrino facility. We rely on the QCD collinear factorization framework where generalized parton distributions allow physicists to perform a nucleon tomography.
• What do DVCS data tell us about TCS observables?
  
  • Grocholski O.
  • Moutarde H.
  • Pire B.
  • Sznajder P.
  • Wagner J.
  , 2022, 8, pp.070. Deeply virtual Compton scattering (DVCS) and timelike Compton scattering (TCS) leading twist amplitudes are intimately related thanks to their analytic properties as a function of Q^2. We exploit this feature to use Compton form factors previously extracted from available DVCS data and derive data-driven predictions for TCS observables to be measured in near future experiments. Our results quantitatively illustrate the complementarity of DVCS and TCS experiments.
• Diffractive dissociation in future electron-ion colliders
  
  • Le Anh Dung
  , 2022, 8, pp.168. We study diffractive scattering cross sections, focusing on the rapidity gap distribution in realistic kinematics at future electron-ion colliders. Our study consists in numerical solutions of the QCD evolution equations in both fixed and running coupling frameworks. The fixed and the running coupling equations are shown to lead to different shapes for the rapidity gap distribution. The obtained distribution when the coupling is fixed exhibits a shape characteristic of a recently developed model for diffractive dissociation, which indicates the relevance of the study of that diffractive observable for the partonic-level understanding of diffraction. (10.21468/SciPostPhysProc.8.168)
  DOI : 10.21468/SciPostPhysProc.8.168
• A spectator-model way to transverse-momentum-dependent gluon distribution functions
  
  • Bacchetta Alessandro
  • Celiberto Francesco Giovanni
  • Radici Marco
  • Taels Pieter
  , 2022, 8, pp.040. We present exploratory analyses of the 3D gluon content of the proton via a study of unpolarized and polarized gluon TMDs at twist-2, calculated in a spectator model for the parent nucleon. Our approach embodies a flexible parametrization for the spectator-mass function, suited to describe both moderate and small-$x$ effects. All these studies can serve as a useful guidance in the investigation of the gluon dynamics inside nucleons and nuclei, which constitutes one of the major goals of new-generation colliding machines, as the EIC, the HL-LHC, NICA, and the FPF. (10.21468/SciPostPhysProc.8.040)
  DOI : 10.21468/SciPostPhysProc.8.040
• Flavoured warped axion
  
  • Bonnefoy Quentin
  • Cox Peter
  • Dudas Emilian
  • Gherghetta Tony
  • Nguyen Minh D.
  Journal of High Energy Physics, Springer, 2021, 2021 (4), pp.84. We consider a 5D extension of the DFSZ axion model that addresses both the axion quality and fermion mass hierarchy problems, and predicts flavour-dependent, off-diagonal axion-fermion couplings. The axion is part of a 5D complex scalar field charged under a U(1) PQ symmetry that is spontaneously broken in the bulk, and is insensitive to explicit PQ breaking on the UV boundary. Bulk Standard Model fermions interact with two Higgs doublets that can be localized on the UV boundary or propagate in the bulk to explain the fermion masses and mixings. When the Higgs doublets are localized on the UV boundary, they induce flavour diagonal couplings between the fermions and the axion. However, when the Higgs doublets propagate in the bulk, the overlap of the axion and fermion profiles generates flavour off-diagonal couplings. The effective scale of these off-diagonal couplings in both the quark and lepton sectors can be as small as 10 11 GeV, and therefore will be probed in future precision flavour experiments. (10.1007/JHEP04(2021)084)
  DOI : 10.1007/JHEP04(2021)084
• Spatial locality of electronic correlations in LiFeAs
  
  • Kim Minjae
  • Miao Hu
  • Choi Sangkook
  • Zingl Manuel
  • Georges Antoine
  • Kotliar Gabriel
  Physical Review B, American Physical Society, 2021, 103 (15), pp.155107. (10.1103/PhysRevB.103.155107)
  DOI : 10.1103/PhysRevB.103.155107
• Hidden order and multipolar exchange striction in a correlated f -electron system
  
  • Pourovskii Leonid V
  • Khmelevskyi Sergii
  Proceedings of the National Academy of Sciences of the United States of America, National Academy of Sciences, 2021, 118 (14), pp.e2025317118. (10.1073/pnas.2025317118)
  DOI : 10.1073/pnas.2025317118
• Analytical solution for time-integrals in diagrammatic expansions: application to real-frequency diagrammatic Monte Carlo
  
  • Vucicevic J.
  • Stipsic P.
  • Ferrero M.
  Physical Review Research, American Physical Society, 2021, 3 (2), pp.023082. The past years have seen a revived interest in the diagrammatic Monte Carlo (DiagMC) methods for interacting fermions on a lattice. A promising recent development allows one to now circumvent the analytical continuation of dynamic observables in DiagMC calculations within the Matsubara formalism. This is made possible by symbolic algebra algorithms, which can be used to analytically solve the internal Matsubara frequency summations of Feynman diagrams. In this paper, we take a different approach and show that it yields improved results. We present a closed-form analytical solution of imaginary-time integrals that appear in the time-domain formulation of Feynman diagrams. We implement and test a DiagMC algorithm based on this analytical solution and show that it has numerous significant advantages. Most importantly, the algorithm is general enough for any kind of single-time correlation function series, involving any single-particle vertex insertions. Therefore, it readily allows for the use of action-shifted schemes, aimed at improving the convergence properties of the series. By performing a frequency-resolved action-shift tuning, we are able to further improve the method and converge the self-energy in a non-trivial regime, with only 3-4 perturbation orders. Finally, we identify time integrals of the same general form in many commonly used Monte Carlo algorithms and therefore expect a broader usage of our analytical solution. (10.1103/PhysRevResearch.3.023082)
  DOI : 10.1103/PhysRevResearch.3.023082
• Interplay between multipolar spin interactions, Jahn-Teller effect, and electronic correlation in a J_eff = 3/2 insulator
  
  • Fiore Mosca Dario
  • Pourovskii Leonid V
  • Kim Beom Hyun
  • Liu Peitao
  • Sanna Samuele
  • Boscherini Federico
  • Khmelevskyi Sergii
  • Franchini Cesare
  Physical Review B, American Physical Society, 2021, 103 (10), pp.104401. In this work we study the complex entanglement between spin interactions, electron correlation and Janh-Teller structural instabilities in the 5d 1 J ef f = 3 2 spin-orbit coupled double perovskite Ba2NaOsO6 using first principles approaches. By combining non-collinear magnetic calculations with multipolar pseudospin Hamiltonian analysis and many-body techniques we elucidate the origin of the observed quadrupolar canted antifferomagnetic. We show that the non-collinear magnetic order originates from Jahn-Teller distortions due to the cooperation of Heisenberg exchange, quadrupolar spin-spin terms and both dipolar and multipolar Dzyaloshinskii-Moriya interactions. We find a strong competition between ferromagnetic and antiferromagnetic canted and collinear quadrupolar magnetic phases: the transition from one magnetic order to another can be controlled by the strength of the electronic correlation (U) and by the degree of Jahn-Teller distortions. (10.1103/PhysRevB.103.104401)
  DOI : 10.1103/PhysRevB.103.104401
• Tracking the Footprints of Spin Fluctuations: A Multi-Method, Multi-Messenger Study of the Two-Dimensional Hubbard Model
  
  • Schäfer Thomas
  • Wentzell Nils
  • Šimkovic Fedor
  • He Yuan-Yao
  • Hille Cornelia
  • Klett Marcel
  • Eckhardt Christian J.
  • Eckhardt Christian
  • Arzhang Behnam
  • Harkov Viktor
  • Le Régent François-Marie
  • Kirsch Alfred
  • Wang Yan
  • Kim Aaram
  • Kozik Evgeny
  • Stepanov Evgeny
  • Kauch Anna
  • Andergassen Sabine
  • Hansmann Philipp
  • Rohe Daniel
  • Vilk Yuri
  • Leblanc James P. f.
  • Zhang Shiwei
  • Tremblay A.-M. s.
  • Ferrero M.
  • Parcollet Olivier
  • Georges Antoine
  Physical Review X, American Physical Society, 2021, 11 (1), pp.011058. The Hubbard model represents the fundamental model for interacting quantum systems and electronic correlations. Using the two-dimensional half-filled Hubbard model at weak coupling as testing grounds, we perform a comparative study of a comprehensive set of state of the art quantum many-body methods. Upon cooling into its insulating antiferromagnetic ground-state, the model hosts a rich sequence of distinct physical regimes with crossovers between a high-temperature incoherent regime, an intermediate temperature metallic regime and a low-temperature insulating regime with a pseudogap created by antiferromagnetic fluctuations. We assess the ability of each method to properly address these physical regimes and crossovers through the computation of several observables probing both quasiparticle properties and magnetic correlations, with two numerically exact methods (diagrammatic and determinantal quantum Monte Carlo) serving as a benchmark. By combining computational results and analytical insights, we elucidate the nature and role of spin fluctuations in each of these regimes and explain, in particular, how quasiparticles can coexist with increasingly long-range antiferromagnetic correlations in the metallic regime. We also critically discuss whether imaginary time methods are able to capture the non-Fermi liquid singularities of this fully nested system. (10.1103/PhysRevX.11.011058)
  DOI : 10.1103/PhysRevX.11.011058
• Strongly Interacting Bosons in a Two-Dimensional Quasicrystal Lattice
  
  • Gautier Ronan
  • Yao Hepeng
  • Sanchez-Palencia Laurent
  Physical Review Letters, American Physical Society, 2021, 126 (11). (10.1103/PhysRevLett.126.110401)
  DOI : 10.1103/PhysRevLett.126.110401
• The tri-fundamental quartic model
  
  • Benedetti Dario
  • Gurau Razvan
  • Harribey Sabine
  Physical Review D, American Physical Society, 2021. We consider a multi-scalar field theory with either short-range or long-range free action and with quartic interactions that are invariant under $O(N_1)\times O(N_2) \times O(N_3)$ transformations, of which the scalar fields form a tri-fundamental representation. We study the renormalization group fixed points at two loops at finite $N$ and in various large-$N$ scaling limits for small $\epsilon$, the latter being either the deviation from the critical dimension or from the critical scaling of the free propagator. In particular, for the homogeneous case $N_i = N$ for $i=1,2,3$, we study the subleading corrections to previously known fixed points. In the short-range model, for $\epsilon N^2\gg 1$, we find complex fixed points with non-zero tetrahedral coupling, that at leading order reproduce the results of arXiv:1707.03866 ; the main novelty at next-to-leading order is that the critical exponents acquire a real part, thus allowing a correct identification of some fixed points as IR stable. In the long-range model, for $\epsilon N \ll 1 $, we find again complex fixed points with non-zero tetrahedral coupling, that at leading order reproduce the line of stable fixed points of arXiv:1903.03578; at next-to-leading order, this is reduced to a discrete set of stable fixed points. One difference between the short-range and long-range cases is that, in the former the critical exponents are purely imaginary at leading-order and gain a real part at next-to-leading order, while for the latter the situation is reversed. (10.1103/PhysRevD.103.046018)
  DOI : 10.1103/PhysRevD.103.046018
• Trifundamental quartic model
  
  • Benedetti Dario
  • Gurau Razvan
  • Harribey Sabine
  Physical Review D, American Physical Society, 2021, 103 (4), pp.046018. (10.1103/PhysRevD.103.046018)
  DOI : 10.1103/PhysRevD.103.046018
• J eff = 3 2 metallic phase and unconventional superconductivity in GaTa 4 Se 8
  
  • Jeong Min Yong
  • Chang Seo Hyoung
  • Lee Hyeong Jun
  • Sim Jae-Hoon
  • Lee Kyeong Jun
  • Janod Etienne
  • Cario Laurent
  • Said Ayman
  • Bi Wenli
  • Werner Philipp
  • Go Ara
  • Kim Jungho
  • Han Myung Joon
  Physical Review B, American Physical Society, 2021, 103 (8). (10.1103/PhysRevB.103.L081112)
  DOI : 10.1103/PhysRevB.103.L081112
• Postfilament supercontinuum on 100 m path in air
  
  • Kosareva Olga
  • Panov Nikolay
  • Shipilo Daniil
  • Mokrousova Daria
  • Nikolaeva Irina
  • Mitina Ekaterina
  • Koribut Andrew
  • Reutov Aleksei
  • Rizaev Georgy
  • Couairon Arnaud
  • Houard Aurélien
  • Skryabin Dmitry
  • Saletsky Alexander
  • Savelev Andrei
  • Seleznev Leonid
  • Ionin Andrey
  • Chin See Leang
  Optics Letters, Optical Society of America - OSA Publishing, 2021, 46 (5), pp.1125. Pulses at 744 nm with 90 fs duration, 6 mJ energy, and a weakly divergent wavefront propagate for more than 100 m and generate a filament followed by an unprecedently long high intensity (≥1TW/cm2) light channel. Over a 20 m long sub-section of this channel, the pulse energy is transferred continuously to the infrared wing, forming spectral humps that extend up to 850 nm. From 3D+time carrier-resolved simulations of 100 m pulse propagation, we show that spectral humps indicate the formation of a train of femtosecond pulses appearing at a predictable position in the propagation path. (10.1364/OL.416224)
  DOI : 10.1364/OL.416224
• Stability of ablation flows in inertial confinement fusion: optimal linear perturbations
  
  • Varillon Grégoire
  • Couairon Arnaud
  • Clarisse Jean-Marie
  , 2021.
• Stability of ablation flows in inertial confinement fusion: non-modal effects
  
  • Varillon G
  • Clarisse J.-M
  • Couairon A.
  Physical Review E, American Physical Society (APS), 2021, 103 (2). Fast transient growth of hydrodynamic perturbations due to non-modal effects is shown to be possible in an ablation flow relevant to inertial confinement fusion (ICF). Likely to arise in capsule ablators with material inhomogeneities, such growths appear to be too fast to be detected by existing measurement techniques, cannot be predicted by any of the methods previously used for studying hydrodynamic instabilities in ICF, yet could cause early transitions to nonlinear regimes. These findings call for reconsidering the stability of ICF flows within the framework of non-modal stability theory. (10.1103/PhysRevE.103.023211)
  DOI : 10.1103/PhysRevE.103.023211
• $U$ boson interpolating between a generalized dark photon or dark $Z$ , an axial boson, and an axionlike particle
  
  • Fayet Pierre
  Physical Review D, American Physical Society, 2021, 103 (3), pp.035034. A light boson U from an extra U(1) interpolates between a generalized dark photon coupled to Q, B, and Li (or B-L), plus possibly dark matter, a dark Z coupled to the Z current, and one axially coupled to quarks and leptons. We identify the corresponding U(1)F symmetries, with F=γYY+γBB+γLiLi+γAFA+γF′F′+γdFd, Fd acting in a dark sector and F′ on possible semi-inert Brout-Englert-Higgs (BEH) doublets uncoupled to quarks and leptons. The U current is obtained from the U(1)F and Z currents, with a mixing determined by the spin-0 BEH fields. The charge QU of chiral quarks and leptons is a combination of Q, B, Li, and T3L with the axial FA. It involves in general isovector and isoscalar axial terms, in the presence of two BEH doublets. A longitudinal U with axial couplings has enhanced interactions and behaves much as an axionlike particle. Its axial couplings gA, usually restricted to ≲ 2×10-7 mU(MeV), lead to effective pseudoscalar ones gP=gA×2mq,l/mU=21/4GF1/2mq,l A±. A± is proportional to an invisibility parameter r=cosθA induced by a singlet v.e.v., possibly large and allowing the U to be very weakly interacting. This allows for a very small gauge coupling, expressed with two doublets and a singlet as g′′/4≃2×10-6 mU(MeV) r/sin2β. We discuss phenomenological implications for meson decays, neutrino interactions, atomic-physics parity violation, naturally suppressed π0→γU decays, etc. The U boson fits within the grand unification framework, in symbiosis with a SU(4)es electrostrong symmetry broken at the grand unification scale, with QU depending on Q, B-L, FA, and T3A through three parameters γY, γA, and η. (10.1103/PhysRevD.103.035034)
  DOI : 10.1103/PhysRevD.103.035034
• Moiré heterostructures as a condensed-matter quantum simulator
  
  • Kennes Dante
  • Claassen Martin
  • Xian Lede
  • Georges Antoine
  • Millis Andrew
  • Hone James
  • Dean Cory
  • Basov D.
  • Pasupathy Abhay
  • Rubio Angel
  Nature Physics, Nature Publishing Group [2005-....], 2021, 17 (2), pp.155-163. Twisted van der Waals heterostructures have latterly received prominent attention for their many remarkable experimental properties and the promise that they hold for realizing elusive states of matter in the laboratory. We propose that these systems can, in fact, be used as a robust quantum simulation platform that enables the study of strongly correlated physics and topology in quantum materials. Among the features that make these materials a versatile toolbox are the tunability of their properties through readily accessible external parameters such as gating, straining, packing and twist angle; the feasibility to realize and control a large number of fundamental many-body quantum models relevant in the field of condensed-matter physics; and finally, the availability of experimental readout protocols that directly map their rich phase diagrams in and out of equilibrium. This general framework makes it possible to robustly realize and functionalize new phases of matter in a modular fashion, thus broadening the landscape of accessible physics and holding promise for future technological applications. (10.1038/s41567-020-01154-3)
  DOI : 10.1038/s41567-020-01154-3
• Ultrasound evidence for a two-component superconducting order parameter in Sr2RuO4
  
  • Benhabib S.
  • Lupien C.
  • Paul I.
  • Berges L.
  • Dion M.
  • Nardone Marc
  • Zitouni Abdelaziz
  • Mao Z.
  • Maeno Y.
  • Georges A.
  • Taillefer L.
  • Proust C.
  Nature Physics, Nature Publishing Group [2005-....], 2021. (10.1038/s41567-020-1033-3)
  DOI : 10.1038/s41567-020-1033-3