Publications

2024

• Holographic scattering and non-minimal RT surfaces
  
  • Caminiti Jacqueline
  • Friedman-Shaw Batia
  • May Alex
  • Myers Robert C
  • Papadoulaki Olga
  Journal of High Energy Physics, Springer, 2024, 10, pp.119. In the AdS/CFT correspondence, the causal structure of the bulk AdS spacetime is tied to entanglement in the dual CFT. This relationship is captured by the connected wedge theorem, which states that a bulk scattering process implies the existence of $O(1/G_N)$ entanglement between associated boundary subregions. In this paper, we study the connected wedge theorem in two asymptotically AdS$_{2+1}$ spacetimes: the conical defect and BTZ black hole geometries. In these settings, we find that bulk scattering processes require not just large entanglement, but also additional restrictions related to candidate RT surfaces which are non-minimal. We argue these extra relationships imply a certain CFT entanglement structure involving internal degrees of freedom. Because bulk scattering relies on sub-AdS scale physics, this supports the idea that sub-AdS scale locality emerges from internal degrees of freedom. While the new restriction that we identify on non-minimal surfaces is stronger than the initial statement of the connected wedge theorem, we find that it is necessary but still not sufficient to imply bulk scattering in mixed states. (10.1007/JHEP10(2024)119)
  DOI : 10.1007/JHEP10(2024)119
• Properties of the Ammann–Beenker Tiling and its Square Periodic Approximants
  
  • Jagannathan Anuradha
  • Duneau Michel
  Israel Journal of Chemistry, Wiley-VCH Verlag, 2024, 64 (10-11). Our understanding of physical properties of quasicrystals owes a great deal to studies of tight-binding models constructed on quasiperiodic tilings. Among the large number of possible quasiperiodic structures, two dimensional tilings are of particular importance – in their own right, but also for information regarding properties of three dimensional systems. We provide here a users manual for those wishing to construct and study physical properties of the 8-fold Ammann–Beenker quasicrystal, a good starting point for investigations of two dimensional quasiperiodic systems. This tiling has a relatively straightforward construction. Thus, geometrical properties such as the type and number of local environments can be readily found by simple analytical computations. Transformations of sites under discrete scale changes – called inflations and deflations – are easier to establish compared to the celebrated Penrose tiling, for example. We have aimed to describe the methodology with a minimum of technicalities but in sufficient detail so as to enable non-specialists to generate quasiperiodic tilings and periodic approximants, with or without disorder. The discussion of properties includes some relations not previously published, and examples with figures. (10.1002/ijch.202300119)
  DOI : 10.1002/ijch.202300119
• Flavor structure of the energy-momentum tensor form factors of the proton
  
  • Won Ho-Yeon
  • Kim Hyun-Chul
  • Kim June-Young
  Physics Letters B, Elsevier, 2024, 850, pp.138489. The energy-momentum tensor form factors furnish information on the mechanics of the proton. It is essential to compute the generalized isovector-vector form factors to examine the flavor structure of the energy-momentum tensor form factors. The flavor-decomposed form factors reveal the internal structure of the proton. The up quark dominates over the down quark for the mass and spin of the proton, whereas the down quark takes over the up quark for the D-term form factor. We investigate for the first time the isovector <math altimg="si1.svg"><mover accent="true"><mrow><mi>c</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo stretchy="false">(</mo><mi>t</mi><mo stretchy="false">)</mo></math> form factor of the proton and its physical implications. The flavor-decomposed <math altimg="si1.svg"><mover accent="true"><mrow><mi>c</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo stretchy="false">(</mo><mi>t</mi><mo stretchy="false">)</mo></math> form factors of the proton unveil how the up-quark contribution is exactly canceled by the down-quark contribution inside a proton within the framework of the pion mean-field approach. While the proton <math altimg="si1.svg"><mover accent="true"><mrow><mi>c</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo stretchy="false">(</mo><mi>t</mi><mo stretchy="false">)</mo></math> form factor does not contribute to the proton mass, its flavor structure sheds light on how the strong force fields due to the <math altimg="si1.svg"><mover accent="true"><mrow><mi>c</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo stretchy="false">(</mo><mi>t</mi><mo stretchy="false">)</mo></math> form factor characterize the stability of the proton. (10.1016/j.physletb.2024.138489)
  DOI : 10.1016/j.physletb.2024.138489
• Center-symmetric Landau gauge: Further signatures of confinement
  
  • van Egmond Duifje Maria
  • Reinosa Urko
  Physical Review D, American Physical Society, 2024, 109 (3), pp.036002. In a recent article [1], we have identified new signatures for the Yang-Mills deconfinement transition, based on the finite-temperature longitudinal or (chromo-)electric gluon propagator as computed in the center-symmetric Landau gauge. Here, we generalize these considerations into a systematic study of the center symmetry identities obeyed by the correlation functions in this gauge. Any violation of these constraints signals the breaking of center symmetry and can thus serve as a probe for the deconfinement transition. (10.1103/PhysRevD.109.036002)
  DOI : 10.1103/PhysRevD.109.036002
• Majorana fermions and quantum information with fractional topology and disorder
  
  • Bernhardt Ephraim
  • Cheung Brian Chung Hang
  • Le Hur Karyn
  Physical Review Research, American Physical Society, 2024, 6 (2), pp.023221. The quest to identify and observe Majorana fermions in physics and condensed-matter systems remains an important challenge. Here, we introduce a qubit (spin-1/2) from the occurrence of two delocalized zero-energy Majorana fermions in a model of two spins-1/2 on the Bloch sphere within the fractional one-half topological state. We address specific protocols in time with circularly polarized light and the protection of this spin-1/2 state related to quantum information protocols. We also show how disorder can play a positive and important role allowing singlet-triplet transitions and resulting in an additional elongated region for the fractional phase, demonstrating the potential of this platform related to applications in topologically protected quantum information. (10.1103/PhysRevResearch.6.023221)
  DOI : 10.1103/PhysRevResearch.6.023221
• Seeing Beauty in the Quark-Gluon Plasma with Energy Correlators
  
  • Andres Carlota
  • Dominguez Fabio
  • Holguin Jack
  • Marquet Cyrille
  • Moult Ian
  Physical Review D, American Physical Society, 2024, 110 (3), pp.L031503. Heavy quarks created in heavy-ion collisions serve as an excellent probe of the produced quark-gluon plasma (QGP). The radiation pattern of jets formed from heavy quarks as they traverse the QGP exhibits a particularly interesting structure due to the interplay of two competing effects: the suppression of small-angle radiation, also known as the ``dead-cone'' effect, and the enhancement of emitted gluons by medium-induced radiation. In this Letter, we propose a new observable, based on the energy correlator approach to jet substructure, which will allow us to disentangle the two scales associated to these two phenomena and to determine under which conditions the dead-cone is filled by medium-induced radiation. Combined with the forthcoming high-statistics measurements of heavy-flavor jets, this work provides a novel tool to unravel the dynamics of the QGP. (10.1103/PhysRevD.110.L031503)
  DOI : 10.1103/PhysRevD.110.L031503
• Spectroscopy and topological properties of a Haldane light system
  
  • Legendre Julian
  • Le Hur Karyn
  Physical Review A, American Physical Society, 2024, 109 (2), pp.L021701. We present a method to probe the topological properties of a circuit quantum electrodynamics (cQED) array described through a Haldane model on the honeycomb lattice. We develop the theory of microwave light propagating in a local probe or a microscope (a one-dimensional transmission line) capacitively coupled to the topological cQED lattice model. Interestingly, we show that even if the microwave light has no transverse polarization, the measured reflection coefficient, resolved in frequency through the resonance, allows us to reveal the geometrical properties and topological phase transition associated to the model. This spectroscopy tool developed for cQED lattice models reveals the same topological information as circularly polarized light, locally within the Brillouin zone of the honeycomb lattice. Furthermore, our findings hold significance for topological magnon systems and are a priori applicable to all Chern insulators, presenting an intriguing opportunity for their adaptation to other systems with different particle statistics. (10.1103/PhysRevA.109.L021701)
  DOI : 10.1103/PhysRevA.109.L021701
• Transverse momentum dependent factorization for SIDIS at next-to-leading power
  
  • Rodini Simone
  • Vladimirov Alexey
  Physical Review D, American Physical Society, 2024, 110 (3), pp.034009. The semi-inclusive deep-inelastic scattering (SIDIS) is the golden process for investigating the nucleon's transverse momentum-dependent (TMD) structure. We present the complete expression for SIDIS structure functions in the TMD factorization formalism at the next-to-leading power. All perturbative elements of the factorization theorem -- coefficient functions and evolution kernels -- are presented at one-loop accuracy. We found several differences with earlier derivations, which are due to accounting for nontrivial kinematics of the quark-gluon interference terms. As a side result, we present the definition and evolution of twist-three TMD fragmentation functions, including the leading-order evolution kernel. (10.1103/PhysRevD.110.034009)
  DOI : 10.1103/PhysRevD.110.034009
• Anisotropic Quantum Hall Droplets
  
  • Oblak Blagoje
  • Lapierre Bastien
  • Moosavi Per
  • Stéphan Jean-Marie
  • Estienne Benoit
  Phys.Rev.X, 2024, 14 (1), pp.011030. We study two-dimensional (2D) anisotropic droplets of non-interacting electrons in the lowest Landau level, confined by trapping potentials whose level curves have an arbitrary shape at large distances. Using semiclassical methods, we show that energy eigenstates are localized on equipotentials of the trap, with angle-dependent local widths and heights. We exploit this one-particle insight to deduce explicit formulas for many-body observables in the thermodynamic limit. For instance, the droplet's density falls off at the boundary with an angle-dependent width inherited from that of the underlying wave functions, while the many-body current is localized on the edge, to which it is tangent. Correlations along the edge are long-ranged, in accordance with the system's low-energy edge modes which are described by a free chiral conformal field theory in terms of the angle variable of the trapping potential. These results are likely to be observable in solid-state systems or quantum simulators of 2D electron gases with a high degree of control on the confining potential. (10.1103/PhysRevX.14.011030)
  DOI : 10.1103/PhysRevX.14.011030
• Hybrid light-matter states in topological superconductors coupled to cavity photons
  
  • Dmytruk Olesia
  • Schirò Marco
  Physical Review B, American Physical Society, 2024, 110 (7), pp.075416. We consider a one-dimensional topological superconductor hosting Majorana bound states at its ends coupled to a single mode cavity. In the strong light-matter coupling regime, electronic and photonic degrees of freedom hybridize resulting in the formation of polaritons. We find the polariton spectrum by calculating the cavity photon spectral function of the coupled electron-photon system. In the topological phase the lower in energy polariton modes are formed by the bulk-Majorana transitions coupled to cavity photons and are also sensitive to the Majorana parity. In the trivial phase the lower polariton modes emerge due to the coupling of the bulk-bulk transitions across the gap to photons. Our work demonstrates the formation of polaritons in topological superconductors coupled to photons that contain information on the features of the Majorana bound states. (10.1103/PhysRevB.110.075416)
  DOI : 10.1103/PhysRevB.110.075416
• Spectroscopic signatures and origin of hidden order in Ba₂MgReO₂
  
  • Soh Jian-Rui
  • Merkel Maximilian E
  • Pourovskii Leonid V
  • Živković Ivica
  • Malanyuk Oleg
  • Pásztorová Jana
  • Francoual Sonia
  • Hirai Daigorou
  • Urru Andrea
  • Tolj Davor
  • Fiore Mosca Dario
  • Yazyev Oleg V
  • Spaldin Nicola A
  • Ederer Claude
  • Rønnow Henrik M
  Nature Communications, Nature Publishing Group, 2024, 15 (1), pp.10383. Clarifying the underlying mechanisms that govern ordering transitions in condensed matter systems is crucial for comprehending emergent properties and phenomena. While transitions are often classified as electronically driven or lattice-driven, we present a departure from this conventional picture in the case of the double perovskite Ba₂MgReO₂ . Leveraging resonant and nonresonant elastic x-ray scattering techniques, we unveil the simultaneous ordering of structural distortions and charge quadrupoles at a critical temperature of T_q ~33 K. Using a variety of complementary first-principles-based computational techniques, we demonstrate that, while electronic interactions drive the ordering at T_q, it is ultimately the lattice distortions that dictate the specific ground state that emerges. Our findings highlight the crucial interplay between electronic and lattice degrees of freedom, providing a unified framework to understand and predict unconventional emergent phenomena in quantum materials. (10.1038/s41467-024-53893-z)
  DOI : 10.1038/s41467-024-53893-z