Publications

2022

• Melonic Large $N$ Limit of $5$-Index Irreducible Random Tensors
  
  • Carrozza Sylvain
  • Harribey Sabine
  Communications in Mathematical Physics, Springer Verlag, 2022, 390 (3), pp.1219-1270. We demonstrate that random tensors transforming under rank-5 irreducible representations of $\mathrm {O}(N)$ can support melonic large N expansions. Our construction is based on models with sextic (5-simplex) interaction, which generalize previously studied rank-3 models with quartic (tetrahedral) interaction (Benedetti et al. in Commun Math Phys 371:55, 2019. arXiv:1712.00249; Carrozza in JHEP 06:039, 2018. arXiv:1803.02496). Beyond the irreducible character of the representations, our proof relies on recursive bounds derived from a detailed combinatorial analysis of the Feynman graphs. Our results provide further evidence that the melonic limit is a universal feature of irreducible tensor models in arbitrary rank. (10.1007/s00220-021-04299-1)
  DOI : 10.1007/s00220-021-04299-1
• Sextic tensor model in rank 3 at next-to-leading order
  
  • Harribey Sabine
  Journal of High Energy Physics, Springer, 2022, 10, pp.037. We compute the four-loop beta functions of short and long-range multi-scalar models with general sextic interactions and complex fields. We then specialize the beta functions to a U(N)$^{3}$ symmetry and study the renormalization group at next-to-leading order in N and small ϵ. In the short-range case, ϵ is the deviation from the critical dimension while it is the deviation from the critical scaling of the free propagator in the long-range case. This allows us to find the 1/N corrections to the rank-3 sextic tensor model of [1]. In the short-range case, we still find a non-trivial real IR stable fixed point, with a diagonalizable stability matrix. All couplings, except for the so-called wheel coupling, have terms of order ϵ$^{0}$ at leading and next-to-leading order, which makes this fixed point different from the other melonic fixed points found in quartic models. In the long-range case, the corrections to the fixed point are instead not perturbative in ϵ and hence unreliable; we thus find no precursor of the large-N fixed point. (10.1007/JHEP10(2022)037)
  DOI : 10.1007/JHEP10(2022)037
• Bootstrapping line defects with $O(2)$ global symmetry
  
  • Gimenez-Grau Aleix
  • Lauria Edoardo
  • Liendo Pedro
  • van Vliet Philine
  Journal of High Energy Physics, Springer, 2022, 11, pp.018. We use the numerical bootstrap to study conformal line defects with $O(2)$ global symmetry. Our results are very general and capture in particular conformal line defects originating from bulk CFTs with a continuous global symmetry, which can either be preserved or partially broken by the presence of the defect. We begin with an agnostic approach and perform a systematic bootstrap study of correlation functions between two canonical operators on the defect: the displacement and the tilt. We then focus on two interesting theories: a monodromy line defect and a localized magnetic field line defect. To this end, we combine the numerical bootstrap with the $\varepsilon$-expansion, where we complement existing results in the literature with additional calculations. For the monodromy defect our numerical results are consistent with expectations, with known analytic solutions sitting inside our numerical bounds. For the localized magnetic field line defect our plots show a series of intriguing cusps which we explore. (10.1007/JHEP11(2022)018)
  DOI : 10.1007/JHEP11(2022)018
• Celestial holography on Kerr-Schild backgrounds
  
  • Gonzo Riccardo
  • Mcloughlin Tristan
  • Puhm Andrea
  Journal of High Energy Physics, Springer, 2022, 10, pp.073. We explore the celestial holography proposal for non-trivial asymptotically flat backgrounds including the Coulomb field of a static and spinning point charge, their gravitational counterparts described by the Schwarzschild and Kerr metrics, as well as the Aichelburg-Sexl shockwave and spinning shockwave geometries and their electromagnetic cousins. We compute celestial two-point amplitudes on these Kerr-Schild type backgrounds which have the desirable feature, due to the presence of an external source, that they are non-vanishing for general operator positions and are not constrained by the kinematic delta functions of flat space celestial CFT correlators. Of particular interest is the case of shockwave backgrounds where the two-point scattering amplitude of massless scalars can be interpreted as a standard CFT three-point correlator between two massless asymptotic states and a conformal primary shockwave operator. We furthermore show that the boundary on-shell action for general backgrounds becomes the generating functional for tree-level correlation functions in celestial CFT. Finally, we derive (conformal) Faddeev-Kulish dressings for particle-like backgrounds which remove all infrared divergent terms in the two-point functions to all orders in perturbation theory. (10.1007/JHEP10(2022)073)
  DOI : 10.1007/JHEP10(2022)073
• A novel background field approach to the confinement-deconfinement transition
  
  • van Egmond Duifje Maria
  • Reinosa Urko
  • Serreau Julien
  • Tissier Matthieu
  SciPost Physics, SciPost Foundation, 2022, 12 (3), pp.087. We propose a novel approach to the confinement-deconfinement transition in Yang-Mills theories in the context of gauge-fixed calculations. The method is based on a background-field generalisation of the Landau gauge (to which it reduces at vanishing temperature) with a given, center-symmetric background. This is to be contrasted with most implementations of background field methods in gauge theories, where one uses a variable, self-consistent background. Our proposal is a bona fide gauge fixing that can easily be implemented on the lattice and in continuum approaches. The resulting gauge-fixed action explicitly exhibits the center symmetry of the nonzero temperature theory that controls the confinement-deconfinement transition. We show that, in that gauge, the electric susceptibility diverges at a second order transition [e.g., in the SU(2) theory], so that the gluon propagator is a clear probe of the transition. We implement our proposal in the perturbative Curci-Ferrari model, known for its successful description of various infrared aspects of Yang-Mills theories, including the confinement-deconfinement transition. Our one-loop calculation confirms our general expectation for the susceptibility while providing transition temperatures in excellent agreement with the SU(2) and SU(3) lattice values. Finally, the Polyakov loops above the transition show a more moderate rise, in contrast to previous implementations of the Curci-Ferrari model using a self-consistent background, and our SU(3) result agrees quite well with lattice results in the range $[0,2T_c]$. (10.21468/SciPostPhys.12.3.087)
  DOI : 10.21468/SciPostPhys.12.3.087
• Planckian metal at a doping-induced quantum critical point
  
  • Dumitrescu Philipp T.
  • Wentzell Nils
  • Georges Antoine
  • Parcollet Olivier
  Physical Review B, American Physical Society, 2022, 105 (18), pp.L180404. We numerically study a model of interacting spin-<math><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math> electrons with random exchange coupling on a fully connected lattice. This model hosts a quantum critical point separating two distinct metallic phases as a function of doping: a Fermi-liquid phase with a large Fermi-surface volume and a low-doping phase with local moments ordering into a spin glass. We show that this quantum critical point has non-Fermi-liquid properties characterized by <math><mi>T</mi></math>-linear Planckian behavior, <math><mrow><mi>ω</mi><mo>/</mo><mi>T</mi></mrow></math> scaling, and slow spin dynamics of the Sachdev-Ye-Kitaev type. The <math><mrow><mi>ω</mi><mo>/</mo><mi>T</mi></mrow></math> scaling function associated with the electronic self-energy is found to have an intrinsic particle-hole asymmetry, a hallmark of a “skewed” non-Fermi liquid. (10.1103/PhysRevB.105.L180404)
  DOI : 10.1103/PhysRevB.105.L180404
• Precession Caused by Gravitational Waves
  
  • Seraj Ali
  • Oblak Blagoje
  Physical Review Letters, American Physical Society, 2022, 129 (6), pp.061101. We show that gravitational waves cause freely falling gyroscopes to precess relative to fixed distant stars, extending the stationary Lense-Thirring effect. The precession rate decays as the square of the inverse distance to the source and is proportional to a suitable Noether current for dual asymptotic symmetries at null infinity. Integrating the rate over time yields a net rotation—a “gyroscopic memory”—whose angle reproduces the known spin memory effect but also contains an extra contribution due to the generator of gravitational electric-magnetic duality. The angle’s order of magnitude for the first Laser Interferometer Gravitational Wave Observatory signal is estimated to be <math display="inline"><mrow><mi mathvariant="normal">Φ</mi><mo>∼</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>-</mo><mn>35</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>arc</mi><mtext> </mtext><mi>sec</mi></mrow></math> near Earth, but the effect may be substantially larger for supermassive black hole mergers. (10.1103/PhysRevLett.129.061101)
  DOI : 10.1103/PhysRevLett.129.061101
• Femtosecond laser-induced sub-wavelength plasma inside dielectrics. II. Second-harmonic generation
  
  • Ardaneh Kazem
  • Hassan Mostafa
  • Morel Benoît
  • Meyer Rémi
  • Giust Remo
  • Couairon Arnaud
  • Bonnaud Guy
  • Courvoisier François
  Physics of Plasmas, American Institute of Physics, 2022, 29 (7), pp.072716. Second-harmonic emission at a frequency that is twice the laser frequency is an important diagnostic for nonlinear laser–plasma interaction. It is forbidden for centrosymmetric materials such as the bulk of sapphire. The symmetry, however, can be broken by dielectric discontinuities as a result of plasma generation inside a solid dielectric. In the present work, we explore the basic characteristics of experimentally observed second-harmonic emission during focusing a femtosecond Bessel beam inside sapphire. We employ three-dimensional particle-in-cell simulations and the Helmholtz wave equation for theoretical investigations. We analyze how the efficiency of second-harmonic generation and its polarization depend on the plasma parameters. We find that the second-harmonic is generated either due to the coalescence of two-surface electromagnetic waves or nonlinear interaction between the transverse electromagnetic wave and the longitudinal electron plasma wave driven by linear mode conversion. Experimental results agree with the theoretical predictions and confirm the existence of over-critical plasma inside the sapphire that is essential for the resonance of plasma waves or excitation of surface plasmons. (10.1063/5.0090270)
  DOI : 10.1063/5.0090270
• Anomalous mobility edges in one-dimensional quasiperiodic models
  
  • Liu Tong
  • Xia Xu
  • Longhi Stefano
  • Sanchez-Palencia Laurent
  SciPost Physics, SciPost Foundation, 2022, 12 (1), pp.027. Mobility edges, separating localized from extended states, are known to arise in the single-particle energy spectrum of disordered systems in dimension strictly higher than two and certain quasiperiodic models in one dimension. Here we unveil a different class of mobility edges, dubbed anomalous mobility edges, that separate energy intervals where all states are localized from energy intervals where all states are critical in diagonal and off-diagonal quasiperiodic models. We first introduce an exactly solvable quasi-periodic diagonal model and analytically demonstrate the existence of anomalous mobility edges. Moreover, numerical multifractal analysis of the corresponding wave functions confirms the emergence of a finite energy interval where all states are critical. We then extend the sudy to a quasiperiodic off-diagonal Su-Schrieffer-Heeger model and show numerical evidence of anomalous mobility edges. We finally discuss possible experimental realizations of quasi-periodic models hosting anomalous mobility edges. These results shed new light on the localization and critical properties of low-dimensional systems with aperiodic order. (10.21468/SciPostPhys.12.1.027)
  DOI : 10.21468/SciPostPhys.12.1.027
• Relativistic fluids, hydrodynamic frames and their Galilean versus Carrollian avatars
  
  • Petkou Anastasios C.
  • Petropoulos P. Marios
  • Betancour David Rivera
  • Siampos Konstantinos
  Journal of High Energy Physics, Springer, 2022, 09, pp.162. We comprehensively study Galilean and Carrollian hydrodynamics on arbitrary backgrounds, in the presence of a matter/charge conserved current. For this purpose, we follow two distinct and complementary paths. The first is based on local invariance, be it Galilean or Carrollian diffeomorphism invariance, possibly accompanied by Weyl invariance. The second consists in analyzing the relativistic fluid equations at large or small speed of light, after choosing an adapted gauge, Arnowitt-Deser-Misner-Zermelo for the former and Papapetrou-Randers for the latter. Unsurprisingly, the results agree, but the second approach is superior as it effortlessly captures more elaborate situations with multiple degrees of freedom. It furthermore allows to investigate the fate of hydrodynamic-frame invariance in the two limits at hand, and conclude that its breaking (in the Galilean) or its preservation (in the Carrollian) are fragile consequences of the behaviour of transport attributes at large or small c. Both methods do also agree on the doom of Nœtherian currents generated in the relativistic theory by isometries: conserved currents are not always guaranteed in Newton-Cartan or Carroll spacetimes as a consequence of Galilean or Carrollian isometries. Comparison of Galilean and Carrollian fluid equations exhibits a striking but often superficial resemblance, which we comment in relation to black-hole horizon dynamics, awkwardly akin to Navier-Stokes equations. This congruity is authentic in one instance though and turns out then to describe Aristotelian dynamics, which is the last item in our agenda. (10.1007/JHEP09(2022)162)
  DOI : 10.1007/JHEP09(2022)162
• Pion and nucleon relativistic charge four-current distributions
  
  • Chen Yi
  • Lorcé Cédric
  Physical Review D, American Physical Society, 2022, 106 (11), pp.116024. The quantum phase-space approach allows one to define relativistic spatial distributions inside a target with arbitrary spin and arbitrary average momentum. We apply this quasiprobabilistic formalism to the whole charge four-current operator in the case of spin-$0$ and spin-$\frac{1}{2}$ targets, study in detail the frame dependence of the corresponding spatial distributions, and compare our results with those from the light-front formalism. While former works focused on the charge distributions, we extend here the investigations to the current distributions. We clarify the role played by the Wigner rotation and argue that electromagnetic properties are most naturally understood in terms of Sachs form factors, contrary to what the light-front formalism previously suggested. Finally, we illustrate our results using the pion and nucleon electromagnetic form factors extracted from experimental data. (10.1103/PhysRevD.106.116024)
  DOI : 10.1103/PhysRevD.106.116024
• Femtosecond laser-induced sub-wavelength plasma inside dielectrics: I. Field enhancement
  
  • Ardaneh Kazem
  • Meyer Rémi
  • Hassan Mostafa
  • Giust Remo
  • Morel Benoît
  • Couairon Arnaud
  • Bonnaud Guy
  • Courvoisier François
  Physics of Plasmas, American Institute of Physics, 2022, 29 (7), pp.072715. The creation of high energy density ($\geq$ 10$^6$ joules per cm$^3$) over-critical plasmas in a large volume has essential applications in the study of warm dense matter, being present in the hot cores of stars and planets. It was recently shown that femtosecond Bessel beams enable creating over-critical plasmas inside sapphire with subwavelength radius and several tens of micrometers in length. Here, the dependence of field structure and absorption mechanism on the plasma density transverse profile are investigated by performing self-consistent Particle-In-Cell (PIC) simulations. Two limiting cases are considered: one is a homogeneous step-like profile, that can sustain plasmon formation, the second is an inhomogeneous Gaussian profile, where resonance absorption occurs. Comparing experimental absorption measures to analytical predictions allows determining the plasma parameters used in PIC simulations. The PIC simulation results are in good agreement with experimental diagnostics of total absorption, near-field fluence distribution, and far-field radiation pattern. We show that in each case an ambipolar field forms at the plasma surface due to the expansion of the hot electrons and that electron sound waves propagate into the over-critical region. (10.1063/5.0086708)
  DOI : 10.1063/5.0086708
• Fermionic wave functions from neural-network constrained hidden states
  
  • Moreno Javier Robledo
  • Carleo Giuseppe
  • Georges Antoine
  • Stokes James
  Proc.Nat.Acad.Sci., 2022, 119 (32), pp.1-21. We introduce a systematically improvable family of variational wave functions for the simulation of strongly correlated fermionic systems. This family consists of Slater determinants in an augmented Hilbert space involving “hidden” additional fermionic degrees of freedom. These determinants are projected onto the physical Hilbert space through a constraint that is optimized, together with the single-particle orbitals, using a neural network parameterization. This construction draws inspiration from the success of hidden-particle representations but overcomes the limitations associated with the mean-field treatment of the constraint often used in this context. Our construction provides an extremely expressive family of wave functions, which is proved to be universal. We apply this construction to the ground-state properties of the Hubbard model on the square lattice, achieving levels of accuracy that are competitive with those of state-of-the-art variational methods. (10.1073/pnas.2122059119)
  DOI : 10.1073/pnas.2122059119
• Algorithmically Solving the Tadpole Problem
  
  • Bena Iosif
  • Blåbäck Johan
  • Graña Mariana
  • Lüst Severin
  Advances in Applied Clifford Algebras, Springer Verlag, 2022, 32 (1), pp.7. The extensive computer-aided search applied in Bena et al. (The tadpole problem, 2020) to find the minimal charge sourced by the fluxes that stabilize all the (flux-stabilizable) moduli of a smooth K3 $\times $ K3 compactification uses differential evolutionary algorithms supplemented by local searches. We present these algorithms in detail and show that they can also solve our minimization problem for other lattices. Our results support the Tadpole Conjecture: The minimal charge grows linearly with the dimension of the lattice and, for K3 $\times $ K3, this charge is larger than allowed by tadpole cancellation. Even if we are faced with an NP-hard lattice-reduction problem at every step in the minimization process, we find that differential evolution is a good technique for identifying the regions of the landscape where the fluxes with the lowest tadpole can be found. We then design a “Spider Algorithm,” which is very efficient at exploring these regions and producing large numbers of minimal-tadpole configurations. (10.1007/s00006-021-01189-6)
  DOI : 10.1007/s00006-021-01189-6
• Oxygen vacancies at the origin of pinned moments in oxide interfaces: the example of tetragonal CuO/SrTiO$_3$
  
  • Bacq-Labreuil Benjamin
  • Lenz Benjamin
  • Biermann Silke
  Physical Review B, American Physical Society, 2022, 106 (23), pp.235155. Obtaining an accurate theoretical description of the emergent phenomena in oxide heterostructures is a major challenge. Recently, intriguing paramagnetic spin and pinned orbital moments have been discovered by x-ray magnetic circular dichro\"ism measurements at the Cu $L_{2,3}$-edge of a tetragonal CuO/SrTiO$_3$ heterostructure. Using first principles calculations, we propose a scenario that explains both types of moments, based on the formation of oxygen vacancies in the TiO$_2$ interface layer. We show the emergence of a paramagnetic 2D electron gas hosted in the interface CuO layer. It is invisible at the Ti $L_{2,3}$-edge since the valence of the Ti atoms remains unchanged. Strong structural distortions breaking both the local and global fourfold rotation $C_4$ symmetries at the interface lead to the in-plane pinning of the Cu orbital moment close to the vacancy. Our results, and in particular the pinning of the orbital moment, may have implications for other systems, especially monoxide/dioxide interfaces with similar metal-oxygen bond length and weak spin-orbit coupling. (10.1103/PhysRevB.106.235155)
  DOI : 10.1103/PhysRevB.106.235155
• Report of the Topical Group on Top quark physics and heavy flavor production for Snowmass 2021
  
  • Schwienhorst Reinhard
  • Wackeroth Doreen
  • Agashe Kaustubh
  • Alioli Simone
  • Aparisi Javier
  • Bevilacqua Giuseppe
  • Bi Huan-Yu
  • Brock Raymond
  • Camacho Abel Gutierrez
  • Cordero Fernando Febres
  • de Blas Jorge
  • Demina Regina
  • Du Yong
  • Durieux Gauthier
  • Fein Jarrett
  • Franceschini Roberto
  • Fuster Juan
  • Garzelli Maria Vittoria
  • Gavardi Alessandro
  • Gombas Jason
  • Grojean Christoph
  • Gu Jiale
  • Guzzi Marco
  • Hartanto Heribertus Bayu
  • Hoang Andre
  • Holguin Jack
  • Irles Adrian
  • Kidonakis Nikolaos
  • Kim Dojin
  • Kraus Manfred
  • Lepenik Christopher
  • Liss Tony M.
  • Mantani Luca
  • Mantry Sonny
  • Mateu Vicent
  • Melini Davide
  • Michel J.
  • Miralles Victor
  • Lopez Marcos Miralles
  • Llacer Maria Moreno
  • Moch Sven-Olaf
  • Nadolsky Pavel
  • Neumann Tobias
  • Narain Meenakshi
  • Nasufi Jasmina
  • Nowak Kacper
  • Pathak Aditya
  • Peskin Michael
  • Poncelet Rene
  • Procura Massimiliano
  • Reina Laura
  • Rodrigo G.
  • Sathyan Deepak
  • Sawford Sara
  • Simon Frank
  • Spira Michael
  • Stewart Ian
  • Tairafune Seidai
  • Tian Junping
  • Tricoli Alessandro
  • Uwer Peter
  • Vryonidou Eleni
  • Voss Katharina
  • Vos Marcel
  • Worek Malgorzata
  • Xie Keping
  • Yamamoto Hitoshi
  • Yunamine Ryo
  • Yu Zhite
  • Yuan C. -P.
  • Zarnecki Aleksander Filip
  , 2022. This report summarizes the work of the Energy Frontier Topical Group on EW Physics: Heavy flavor and top quark physics (EF03) of the 2021 Community Summer Study (Snowmass). It aims to highlight the physics potential of top-quark studies and heavy-flavor production processes (bottom and charm) at the HL-LHC and possible future hadron and lepton colliders and running scenarios.
• Probabilistic picture for particle number densities in stretched tips of the branching Brownian motion
  
  • Le Anh Dung
  • Mueller Alfred H.
  • Munier Stéphane
  EPL - Europhysics Letters, European Physical Society / EDP Sciences / Società Italiana di Fisica / IOP Publishing, 2022, 140 (5), pp.51003. In the framework of a stochastic picture for the one-dimensional branching Brownian motion, we compute the probability density of the number of particles near the rightmost one at a time $T$, that we take very large, when this extreme particle is conditioned to arrive at a predefined position $x_T$ chosen far ahead of its expected position $m_T$. We recover the previously-conjectured fact that the typical number density of particles a distance $\Delta$ to the left of the lead particle, when both $\Delta$ and $x_T-\Delta-m_T$ are large, is smaller than the mean number density by a factor proportional to $e^{-\zeta\Delta^{2/3}}$, where $\zeta$ is a constant that was so far undetermined. Our picture leads to an expression for the probability density of the particle number, from which a value for $\zeta$ may be inferred. (10.1209/0295-5075/aca699)
  DOI : 10.1209/0295-5075/aca699
• Black holes in dS$_3$
  
  • Emparan Roberto
  • Pedraza Juan F.
  • Svesko Andrew
  • Tomašević Marija
  • Visser Manus R.
  Journal of High Energy Physics, Springer, 2022, 11, pp.073. In three-dimensional de Sitter space classical black holes do not exist, and the Schwarzschild-de Sitter solution instead describes a conical defect with a single cosmological horizon. We argue that the quantum backreaction of conformal fields can generate a black hole horizon, leading to a three-dimensional quantum de Sitter black hole. Its size can be as large as the cosmological horizon in a Nariai-type limit. We show explicitly how these solutions arise using braneworld holography, but also compare to a non-holographic, perturbative analysis of backreaction due to conformally coupled scalar fields in conical de Sitter space. We analyze the thermodynamics of this quantum black hole, revealing it behaves similarly to its classical four-dimensional counterpart, where the generalized entropy replaces the classical Bekenstein-Hawking entropy. We compute entropy deficits due to nucleating the three-dimensional black hole and revisit arguments for a possible matrix model description of dS spacetimes. Finally, we comment on the holographic dual description for dS spacetimes as seen from the braneworld perspective. (10.1007/JHEP11(2022)073)
  DOI : 10.1007/JHEP11(2022)073
• Jet Broadening in Flowing Matter -- Resummation
  
  • Andres Carlota
  • Dominguez Fabio
  • Sadofyev Andrey V.
  • Salgado Carlos A.
  Physical Review D, American Physical Society, 2022, 106 (7), pp.074023. In this work, we obtain the leading corrections to the jet momentum broadening distribution in a QCD medium arising from the transverse flow of the matter. We first derive the single-particle propagator of a highly energetic parton resumming its multiple interactions with the homogeneous flowing matter, explicitly keeping the leading subeikonal flow terms. Then, we use this propagator to obtain the jet broadening distribution and its leading moments. We show that this distribution becomes anisotropic in the presence of transverse flow, since its odd moments are generally non-zero and proportional to the transverse velocity of the medium. Finally, we evaluate several odd moments, which we compare to the corresponding results at first order in opacity, showing that accounting for multiple in-medium scatterings is essential to describe some observables in dense nuclear matter. (10.1103/PhysRevD.106.074023)
  DOI : 10.1103/PhysRevD.106.074023