Centre de Physique Théorique

Publications

2024

  • Non-geometric BPS branes on T-folds
    • Bianchi Massimo
    • Bossard Guillaume
    Journal of High Energy Physics, Springer, 2024, 02, pp.162. We give a detailed (microscopic) description of the geometric and non-geometric fundamental branes and their bound states in Type II superstring compactifications preserving N=6 supersymmetry. We consider general boundary states that couple to the twisted sector and compute the relevant annulus amplitudes. We check consistency of the construction by relating the transverse channel, corresponding to closed-string tree-level exchange, with the direct open-string loop channel. Focussing on the Type IIA frame, we show that D0-D4 have the expected tension for a geometric brane, while the non-geometric D2-D6 boundary states have a tension equal to $1/\sqrt{K}$ the one of a geometric brane for the $\mathbb{Z}_K$ orbifold. This is consistent with Fricke T-duality of the N=6 model. (10.1007/JHEP02(2024)162)
    DOI : 10.1007/JHEP02(2024)162
  • Spin-orbit correlations in the nucleon in the large-$N_{c}$ limit
    • Kim June-Young
    • Won Ho-Yeon
    • Kim Hyun-Chul
    • Weiss Christian
    Physical Review D, American Physical Society, 2024, 110 (5), pp.054026. We study the twist-3 spin-orbit correlations of quarks described by the nucleon matrix elements of the parity-odd rank-2 tensor QCD operator (the parity-odd partner of the QCD energy-momentum tensor). Our treatment is based on the effective dynamics emerging from the spontaneous breaking of chiral symmetry and the mean-field picture of the nucleon in the large-$N_c$ limit. The twist-3 QCD operators are converted to effective operators, in which the QCD interactions are replaced by spin-flavor-dependent chiral interactions of the quarks with the pion field. We compute the nucleon matrix elements of the twist-3 effective operators and discuss the role of the chiral interactions in the spin-orbit correlations. We derive the first-quantized representation in the mean-field picture and develop a quantum-mechanical interpretation. The chiral interactions give rise to new spin-orbit couplings and qualitatively change the correlations compared to the quark model picture. We also derive the twist-3 matrix elements in the topological soliton picture where the quarks are integrated out (skyrmion). The methods used here can be extended to other QCD operators describing higher-twist nucleon structure and generalized parton distributions. (10.1103/PhysRevD.110.054026)
    DOI : 10.1103/PhysRevD.110.054026
  • Aspects of higher spin symmetry in flat space
    • Pekar Simon Alexandre
    Riv.Nuovo Cim., 2024, 47 (1), pp.1-90. We review some aspects of higher spin symmetry, in (Anti-)de Sitter and flat space–times, aiming at closing the gap between the constantly curved and flat cases. On (Anti-)de Sitter space, non-Abelian higher spin algebras are at the core of the construction of interacting theories of higher spin gravity. By considering a suitable contraction of these algebras, we show that similar considerations can apply to Minkowski space–time. We identify a unique candidate to the role of higher spin symmetry in flat space that can also be built as a quotient of the universal enveloping algebra of the isometries of the vacuum, as in the (Anti-)de Sitter case. We then show how to recover the free dynamics from the gauging of the resulting algebra at the linear level. Finally, we show how to realise this gauge algebra as a subset of the global symmetries of a Carrollian conformal scalar field theory living on the null infinity of Minkowski space–time. This theory emerges as the limit of vanishing speed of light of a free massless relativistic scalar. The identification of the same higher spin algebra that rules the dynamics in the bulk of space–time within the global symmetries of this boundary theory paves the way to a flat counterpart of higher spin holography. (10.1007/s40766-024-00051-2)
    DOI : 10.1007/s40766-024-00051-2
  • Borel summability of the $\frac 1N$-expansion in quartic $\text{O}(N)$-vector models
    • Ferdinand Léonard
    • Gurau Razvan
    • Perez-Sanchez Carlos I.
    • Vignes-Tourneret Fabien
    Annales Henri Poincaré, Springer Verlag, 2024, 25 (3), pp.2037-2064. We consider a quartic O(N)-vector model. Using the Loop Vertex Expansion, we prove the Borel summability in 1/N along the real axis of the partition function and of the connected correlations of the model. The Borel summability holds uniformly in the coupling constant, as long as the latter belongs to a cardioid like domain of the complex plane, avoiding the negative real axis. (10.1007/s00023-023-01350-w)
    DOI : 10.1007/s00023-023-01350-w
  • Spin-orbit entanglement in the Color Glass Condensate
    • Bhattacharya Shohini
    • Boussarie Renaud
    • Hatta Yoshitaka
    Physics Letters B, Elsevier, 2024, 859, pp.139134. We compute the spin-orbit correlations of quarks and gluons at small-$x$ and show that the helicity and the orbital angular momentum of individual partons are strongly anti-aligned even in unpolarized or spinless hadrons and nuclei. Combined with the fact that gluons in the Color Glass Condensate are linearly polarized, our finding indicates that the helicity and the orbital angular momentum of single gluons are maximally entangled in a quantum mechanical sense. (10.1016/j.physletb.2024.139134)
    DOI : 10.1016/j.physletb.2024.139134
  • Hydrodynamics and instabilities of relativistic superfluids at finite superflow
    • Areán Daniel
    • Goutéraux Blaise
    • Mefford Eric
    • Sottovia Filippo
    Journal of High Energy Physics, Springer, 2024, 05, pp.272. We study the linear response of relativistic superfluids with a non-zero superfluid velocity. For sufficiently large superflow, an instability develops via the crossing of a pole of the retarded Green's functions to the upper half complex frequency plane. We show that this is caused by a local thermodynamic instability, i.e. when an eigenvalue of the static susceptibility matrix (the second derivatives of the free energy) diverges and changes sign. The onset of the instability occurs when $\partial_{\zeta}(n_s\zeta)=0$, with $\zeta$ the norm of the superfluid velocity and $n_s$ the superfluid density. The Landau instability for non-relativistic superfluids such as Helium 4 also coincides with the non-relativistic version of this criterion. We then turn to gauge/gravity duality and show that this thermodynamic instability criterion applies equally well to strongly-coupled superfluids. In passing, we compute holographically a number of transport coefficients parametrizing deviations out-of-equilibrium in the hydrodynamic regime and demonstrate that the gapless quasinormal modes of the dual planar black hole match those predicted by superfluid hydrodynamics. (10.1007/JHEP05(2024)272)
    DOI : 10.1007/JHEP05(2024)272
  • Exact Numerical Solution of the Fully Connected Classical and Quantum Heisenberg Spin Glass
    • Kavokine Nikita
    • Müller Markus
    • Georges Antoine
    • Parcollet Olivier
    Physical Review Letters, American Physical Society, 2024, 133 (1), pp.016501. We present the mean field solution of the quantum and classical Heisenberg spin glasses, using the combination of a high precision numerical solution of the Parisi full replica symmetry breaking equations and a continuous time quantum Monte Carlo algorithm. We characterize the spin glass order and its low-energy excitations down to zero temperature. The Heisenberg spin glass has a rougher energy landscape than its Ising analog, and exhibits a very slow temperature evolution of its dynamical properties. We extend our analysis to the doped, metallic Heisenberg spin glass, which displays unexpectedly slow spin dynamics, reflecting the proximity to the melting quantum critical point and its associated Sachdev-Ye-Kitaev Planckian dynamics. (10.1103/PhysRevLett.133.016501)
    DOI : 10.1103/PhysRevLett.133.016501
  • Consistent truncation of eleven-dimensional supergravity on $S^8\times S^1$
    • Bossard Guillaume
    • Ciceri Franz
    • Inverso Gianluca
    • Kleinschmidt Axel
    Journal of High Energy Physics, Springer, 2024, 01, pp.045. Eleven-dimensional supergravity on $S^8\times S^1$ is conjectured to be dual to the M-theory matrix model. We prove that the dynamics of a subset of fluctuations around this background is consistently described by D=2 SO(9) gauged maximal supergravity. We provide the full non-linear uplift formulae for all bosonic fields. We also present a further truncation to the SO(3)$\times$SO(6) invariant sector and discuss its relation to the BMN matrix model at finite temperature. The construction relies on the framework of generalised Scherk-Schwarz reductions, established for E$_9$ exceptional field theory in a companion paper. As a by-product, we severely constrain the most general gauge deformations in D=2 admitting an uplift to higher dimensions. (10.1007/JHEP01(2024)045)
    DOI : 10.1007/JHEP01(2024)045
  • Non-collinear magnetism driven by a hidden multipolar order in PrO2
    • Khmelevskyi Sergii
    • Pourovskii Leonid V
    Communications Physics, Nature Research, 2024, 7, pp.12. Standard microscopic approach to magnetic orders is based on assuming a Heisenberg form for inter-atomic exchange interactions. These interactions are considered as the driving force for the ordering transition with magnetic moments serving as the primary order parameter. Any higher-rank multipoles appearing simultaneously with such magnetic order are typically treated as auxiliary order parameters rather than a principal cause of the transition. In this study, we show that these traditional assumptions are violated in the case of PrO 2. Evaluating a full set of Pr-Pr superexchange interactions from a first-principles many-body technique we find that its unusual non-collinear 2k magnetic structure stems from high-rank multipolar interactions, and that the corresponding contribution of the Heisenberg interactions is negligible. The observed magnetic order in PrO 2 is thus auxiliary to high-rank "hidden" multipoles. Within this picture we consistently account for previously unexplained experimental observations like the magnitude of exchange splitting and the evolution of magnetic structure in external field. Our findings challenge the standard paradigm of observable magnetic moments being the driving force for magnetic transitions. (10.1038/s42005-023-01503-7)
    DOI : 10.1038/s42005-023-01503-7
  • Interplay of superexchange and vibronic effects in the hidden order of Ba<sub>2</sub>MgReO<sub>6</sub> from first principles
    • Fiore Mosca Dario
    • Franchini Cesare
    • Pourovskii Leonid V
    Physical Review B, American Physical Society, 2024, 110 (20), pp.L201101. The origin of the "hidden" quadrupolar and unconventional magnetic low-temperature orders observed in the spin-orbit double perovskite Ba<sub>2</sub>MgReO<sub>6</sub> defies explanation through standard experimental and theoretical techniques. Here we address this problem by deriving and solving an ab initio low-temperature effective Hamiltonian including inter-site electronic exchange and vibronic (electron-lattice) couplings between J<sub>eff</sub> = 3/2 Jahn-Teller-active Rhenium states. Our findings disclose the nature of these elusive states, attributing it to intertwined exchange and electron-lattice couplings, thus diverging from the conventional dichotomy of purely electronic or lattice driving mechanisms. Our results indicate the resilience of the quadrupolar hidden order under pressure, yet its rapid suppression under uniaxial strain suggests that external or lattice-induced distortions play a pivotal role in determining the relative stability of competing phases in Ba2MgReO6 and similar d 1 double perovskites. (10.1103/PhysRevB.110.L201101)
    DOI : 10.1103/PhysRevB.110.L201101
  • In-medium gluon radiation spectrum with all-order resummation of multiple scatterings in longitudinally evolving media
    • Andres Carlota
    • Apolinário Liliana
    • Dominguez Fabio
    • Martinez Marcos Gonzalez
    Journal of High Energy Physics, Springer, 2024, 11, pp.025. Over the past years, there has been a sustained effort to systematically enhance our understanding of medium-induced emissions occurring in the quark-gluon plasma, driven by the ultimate goal of advancing our comprehension of jet quenching phenomena. To ensure meaningful comparisons between these new calculations and experimental data, it becomes crucial to model the interplay between the radiation process and the evolution of the medium parameters, typically described by a hydrodynamical simulation. This step presents particular challenges when dealing with calculations involving the resummation of multiple scatterings, which have been shown to be necessary for achieving an accurate description of the in-medium emission process. In this paper, we extend our numerical calculations of the fully-resummed gluon spectrum to account for longitudinally expanding media. This new implementation allows us to quantitatively assess the accuracy of previously proposed scaling laws that establish a correspondence between an expanding medium and a "static equivalent". Additionally, we show that such scaling laws yield significantly improved results when the static reference case is replaced by an expanding medium with the temperature following a simple power-law decay. Such correspondence will enable the application of numerical calculations of medium-induced energy loss in realistic evolving media for a broader range of phenomenological studies. (10.1007/JHEP11(2024)025)
    DOI : 10.1007/JHEP11(2024)025
  • One-dimensional Carrollian fluids I: Carroll-Galilei duality
    • Athanasiou Nikolaos
    • Petropoulos P. Marios
    • Schulz Simon
    • Taujanskas Grigalius
    Journal of High Energy Physics, Springer, 2024, 11, pp.012. Galilean and Carrollian algebras acting on two-dimensional Newton-Cartan and Carrollian manifolds are isomorphic. A consequence of this property is a duality correspondence between one-dimensional Galilean and Carrollian fluids. We describe the dynamics of these systems as they emerge from the relevant limits of Lorentzian hydrodynamics, and explore the advertised duality relationship. This interchanges longitudinal and transverse directions with respect to the flow velocity, and permutes equilibrium and out-of-equilibrium observables, unveiling specific features of Carrollian physics. We investigate the action of local hydrodynamic-frame transformations in the Galilean and Carrollian configurations, i.e. dual Galilean and Carrollian local boosts, and comment on their potential breaking. Emphasis is laid on the additional geometric elements that are necessary to attain complete systems of hydrodynamic equations in Newton-Cartan and Carroll spacetimes. Our analysis is conducted in general Cartan frames as well as in more explicit coordinates, specifically suited to Galilean or Carrollian use. (10.1007/JHEP11(2024)012)
    DOI : 10.1007/JHEP11(2024)012
  • Horizon causality from holographic scattering in asymptotically dS$_3$
    • Franken Victor
    • Mori Takato
    Journal of High Energy Physics, Springer, 2024, 12, pp.199. In the AdS/CFT correspondence, direct scattering in the bulk may not have a local boundary analog. A nonlocal implementation on the boundary requires $O(1/G_N)$ mutual information. This statement is formalized by the connected wedge theorem, which can be proven using general relativity within AdS$_3$ but also by applying quantum information theory on the boundary, suggesting that the theorem applies to any holographic duality. We examine scattering within the static patch of asymptotically dS$_3$ spacetime, which is conjectured to be described by a quantum theory on the stretched horizon in static patch holography. We prove that causality on the horizon should be induced from null infinities $\mathcal{I}^{\pm}$ to maintain consistency with the theorem. Specifically, signals propagating in the static patch are associated with local operators at $\mathcal{I}^{\pm}$. Our results suggest a novel connection between static patch holography and the dS/CFT correspondence. (10.1007/JHEP12(2024)199)
    DOI : 10.1007/JHEP12(2024)199
  • States, symmetries and correlators of $T\bar{T}$ and $ J\bar{T} $ symmetric orbifolds
    • Chakraborty Soumangsu
    • Georgescu Silvia
    • Guica Monica
    SciPost Physics, SciPost Foundation, 2024, 16 (1), pp.011. We derive various properties of symmetric product orbifolds of $T\bar{T}$ and $J\bar{T}$ - deformed CFTs from a field-theoretical perspective. First, we generalise the known formula for the torus partition function of a symmetric orbifold theory in terms of the one of the seed to non-conformal two-dimensional QFTs; specialising this to seed $T\bar{T}$ and $J\bar{T}$ - deformed CFTs reproduces previous results in the literature. Second, we show that the single-trace $T\bar{T}$ and $J\bar{T}$ deformations preserve the Virasoro and Kac-Moody symmetries of the undeformed symmetric product orbifold CFT, including their fractional counterparts, as well as the KdV charges. Finally, we discuss correlation functions in these theories. By extending a previously-proposed basis of operators for $J\bar{T}$ - deformed CFTs to the single-trace case, we explicitly compute the correlation functions of both untwisted and twisted-sector operators and compare them to an appropriate set of holographic correlators. Our derivations are based mainly on Hilbert space techniques and completely avoid the use of conformal invariance, which is not present in these models. (10.21468/SciPostPhys.16.1.011)
    DOI : 10.21468/SciPostPhys.16.1.011
  • Perturbative results of matrix elements of the axial current and their relation with the axial anomaly
    • Castelli Ignacio
    • Freese Adam
    • Lorcé Cédric
    • Metz Andreas
    • Pasquini Barbara
    • Rodini Simone
    Physics Letters B, Elsevier, 2024, 857, pp.138999. In the Standard Model of particle physics, the axial current is not conserved, due both to fermion masses and to the axial anomaly. Using perturbative quantum chromodynamics, we calculate matrix elements of the local and non-local axial current for a gluon target, clarifying their connection with the axial anomaly. In so doing, we also reconsider classic results obtained in the context of the nucleon spin sum rule as well as recent results for off-forward kinematics. An important role is played by the infrared regulator, for which we put a special emphasis on the nonzero quark mass. We highlight cancellations that take place between contributions from the axial anomaly and the quark mass, and we elaborate on the relation of those cancellations with the conservation of angular momentum. (10.1016/j.physletb.2024.138999)
    DOI : 10.1016/j.physletb.2024.138999
  • Weak Superfluidity in Twisted Optical Potentials
    • Johnstone Dean
    • Mishra Shanya
    • Zhu Zhaoxuan
    • Yao Hepeng
    • Sanchez-Palencia Laurent
    Physical Review Research, American Physical Society, 2024, 6 (4), pp.L042066. A controlled twist between different underlying lattices allows one to interpolate, under a unified framework, across ordered and (quasi-)disordered matter while drastically changing quantum transport properties. Here, we use quantum Monte Carlo simulations to determine the unique phase diagrams of strongly-correlated ultracold bosons in twisted optical potentials. We show that at commensurate twisting angles, spectral gaps govern the formation of insulating patterns, separated by thin superfluid domains. The latter form weak superfluids, which are very sensitive to thermal fluctuations, but can be stabilized under appropriate parameter control. In contrast, slightly changing the twisting angle to a incommensurate value destroys most spectral gaps, leaving behind a prominent Bose glass phase. Our results are directly applicable to current generation experiments that quantum simulate moiré physics. (10.48550/arXiv.2406.12963)
    DOI : 10.48550/arXiv.2406.12963
  • Distributional Celestial Amplitudes
    • Pano Yorgo
    • Borji Majdouline
    Journal of High Energy Physics, Springer, 2024, 07, pp.120. Scattering amplitudes are tempered distributions, which are defined through their action on functions in the Schwartz space $S(\mathbb{R})$ by duality. For massless particles, their conformal properties become manifest when considering their Mellin transform. Therefore we need to mathematically well-define the Mellin transform of distributions in the dual space $S'(\mathbb{R}^+)$. In this paper, we investigate this problem by characterizing the Mellin transform of the Schwartz space $S(\mathbb{R}^+)$. This allows us to rigorously define the Mellin transform of tempered distributions through a Parseval-type relation. Massless celestial amplitudes are then properly defined by taking the Mellin transform of elements in the topological dual of the Schwartz space $S(\mathbb{R}^+)$. We conclude the paper with applications to tree-level graviton celestial amplitudes. (10.1007/JHEP07(2024)120)
    DOI : 10.1007/JHEP07(2024)120
  • Spinodal slowing down and scaling in a holographic model
    • Caddeo Alessio
    • Henriksson Oscar
    • Hoyos Carlos
    • Sanchez-Garitaonandia Mikel
    Journal of High Energy Physics, Springer, 2024, 08, pp.091. The dynamics of first-order phase transitions in strongly coupled systems are relevant in a variety of systems, from heavy ion collisions to the early universe. Holographic theories can be used to model these systems, with fluctuations usually suppressed. In this case the system can come close to a spinodal point where theory and experiments indicate that the the behaviour should be similar to a critical point of a second-order phase transition. We study this question using a simple holographic model and confirm that there is critical slowing down and scaling behaviour close to the spinodal point, with precise quantitative estimates. In addition, we determine the start of the scaling regime for the breakdown of quasistatic evolution when the temperature of a thermal bath is slowly decreased across the transition. We also extend the analysis to the dynamics of second-order phase transitions and strong crossovers. (10.1007/JHEP08(2024)091)
    DOI : 10.1007/JHEP08(2024)091
  • Bounds on photon scattering
    • Häring Kelian
    • Hebbar Aditya
    • Karateev Denis
    • Meineri Marco
    • Penedones João
    Journal of High Energy Physics, Springer, 2024, 2410, pp.103. We study 2-to-2 scattering amplitudes of massless spin one particles in $d=4$ space-time dimensions, like real world photons. We define a set of non-perturbative observables (Wilson coefficients) which describe these amplitudes at low energies. We use full non-linear unitarity to construct various novel numerical bounds on these observables. For completeness, we also rederive some bounds using positivity only. We discover and explain why some of these Wilson coefficients cannot be bounded. (10.1007/JHEP10(2024)103)
    DOI : 10.1007/JHEP10(2024)103
  • Searching for a new light gauge boson with axial couplings in muon beam dump experiments
    • Fayet Pierre
    • Olea-Romacho María Olalla
    Journal of High Energy Physics, Springer, 2024, 2024 (07), pp.223. We present a formalism for new $U(1)$ interactions involving weak hypercharge, baryon, and lepton numbers, and a possible axial symmetry generator $F_A$ in the presence of a second Brout-Englert-Higgs doublet. The resulting $U$ boson, after mixing with the $Z$, interpolates between a generalised dark photon, a dark $Z$, and an axially coupled gauge boson. We especially focus on the axial couplings originating from $F_A$ or from mixing with the $Z$, determined by the scalar sector via parameters like $\tan\beta$ and the v.e.v. of an extra dark singlet. We explore the distinctive features of axially coupled interactions, especially in the ultrarelativistic limit, where the $U$ boson behaves much as an axion-like particle, with enhanced interactions to quarks and leptons. This enhancement is particularly relevant for future muon beam dump experiments, since the muon mass considerably increases the effective coupling, proportional to $2m_\mu/m_U$, compared to analogous experiments with electrons. We also analyse the shape of the expected beam dump exclusion or discovery regions, influenced by $U$ boson interactions and the experiment geometry. Different situations are considered, limited in particular by cases for which the $U$ decays before reaching the detector, or has too small couplings to produce detectable events. We also compare to vectorially coupled bosons and axion-like pseudoscalars, highlighting the importance of understanding the parameter space for future experiment design and optimisation. (10.1007/JHEP07(2024)223)
    DOI : 10.1007/JHEP07(2024)223
  • On the Quantum Bousso Bound in de Sitter JT gravity
    • Franken Victor
    • Rondeau François
    Journal of High Energy Physics, Springer, 2024, 03, pp.178. We prove the validity of the Strominger-Thompson quantum Bousso bound in the infinite class of conformal vacua of de Sitter space in semiclassical JT gravity. The Bousso-Fisher-Leichenauer-Wall quantum Bousso bound follows from an analogous derivation, requiring only initial quantum non-expansion. In this process, we show that the quantity ${2\pi k^{\mu}k^{\nu}<:T_{\mu\nu}:>-S"-\frac{6}{c}(S')^2}$ vanishes in any vacuum state, entailing a stronger version of Wall's quantum null energy condition. We derive an entropy formula in the presence of a generic class of two reflecting boundaries, in order to apply our argument to the half reduction model of de Sitter JT gravity. (10.1007/JHEP03(2024)178)
    DOI : 10.1007/JHEP03(2024)178
  • Orientation Memory of Magnetic Dipoles
    • Oblak Blagoje
    • Seraj Ali
    Physical Review D, American Physical Society, 2024, 109 (4), pp.044037. We study the precession caused by electromagnetic radiation on a magnetic dipole located far from the source. As we show, this entails a net rotation of the dipole in the plane orthogonal to the direction of wave propagation, providing an electromagnetic analogue of gyroscopic gravitational memory. Like its gravitational cousin, the precession rate falls off with the square of the distance to the source, and is related to electric-magnetic duality and optical helicity on the celestial sphere. We use a multipolar expansion to compute the memory effect due to localized sources such as moving point charges, and highlight its occurrence in setups that break parity symmetry. (10.1103/PhysRevD.109.044037)
    DOI : 10.1103/PhysRevD.109.044037
  • Mechanical structure of the nucleon and the baryon octet
    • Won Ho-Yeon
    • Kim Hyun-Chul
    • Kim June-Young
    Journal of High Energy Physics, Springer, 2024, 05, pp.173. In this study, we investigate the flavor-decomposed gravitational form factors(GFFs) of the nucleon and the baryon octet in a mean-field approach based on the large $N_{c}$ limit of QCD. Our central focus lies on illuminating the distinctive role played by the separate quarks in this context. We first scrutinize the behavior of the gravitational form factors in the large $N_c$ limit, tracing the relations governed by spin-flavor symmetry within the framework of flavor SU(3). The results are compared with those in flavor SU(2). Additionally, we quantitatively assess the fraction of light-front momentum carried by individual quark flavors within the nucleon. Notably, we unravel variations arising from the mass distribution, as evidenced through the non-conserved form factor of the nucleon, known as the cosmological constant-term $\bar{c}(q^2)$. Venturing further, we explore not only the decomposition of the total angular momentum into the orbital angular momentum and intrinsic spin, but also its flavor decomposition. Furthermore, we delve into the intricate interplay between the $D$-term and $\bar{c}$ form factors, discerning their collaborative impact on the stabilization of the nucleon system. Alongside this, we undertake an analysis, questioning the assumption of "large $N_{c}$ blindness'' concerning $D^{u-d} \sim 0$. Our examination concludes that such an assumption finds justification predominantly within the framework of flavor SU(3) symmetry. Using the spin-flavor symmetry, the baryon octet GFFs can be easily obtained, and various sum rules between the baryon octet GFFs are discussed. Finally, we introduce the generalized electromagnetic form factors, where the flavor structure of the electromagnetic current is induced into the GFFs. Similar to the electromagnetic form factors, we find that these newly introduced form factors possess the $U$-spin symmetry. (10.1007/JHEP05(2024)173)
    DOI : 10.1007/JHEP05(2024)173
  • Dynamic critical exponent in quantum long-range models
    • Benedetti Dario
    • Gurau Razvan
    • Lettera Davide
    Physical Review B, American Physical Society, 2024, 110 (10), pp.104102. Quantum long-range models at zero temperature can be described by fractional Lifshitz field theories, that is, anisotropic models whose actions are short-range in time and long-range in space. In this paper we study the renormalization of fractional Lifshitz field theories with weakly relevant cubic or quartic self-interactions. Their nontrivial infrared fixed points exhibit Lifshitz scale invariance, and we compute the lowest-order corrections to the dynamic critical exponent. (10.1103/PhysRevB.110.104102)
    DOI : 10.1103/PhysRevB.110.104102
  • Impact of hole-doping on the thermoelectric properties of pyrite FeS2
    • Mukherjee Anustup
    • Subedi Alaska
    Solid State Communications, Elsevier, 2024, 406, pp.116194. We present a comprehensive first-principles analysis of the thermoelectric transport properties of hole-doped pyrite FeS$_2$ that includes electron-phonon interactions. This work was motivated by the observed variations in the magnitude of thermopower reported in previous experimental and theoretical studies of hole-doped FeS$_2$ systems. Our calculations reveal that hole-doped FeS$_2$ exhibits large positive room-temperature thermopower across all doping levels, with a room-temperature thermopower of 608 $μ$V/K at a low hole-doping concentration of 10$^{19}$ cm$^{-3}$. This promising thermopower finding prompted a comprehensive investigation of other key thermoelectric parameters governing the thermoelectric figure of merit $ZT$. The calculated electrical conductivity is modest and remains below 10$^5$ S/m at room-temperature for all doping levels, limiting the achievable power factor. Furthermore, the thermal conductivity is found to be phonon driven, with a high room-temperature lattice thermal conductivity of 40.5 W/mK. Consequently, the calculated $ZT$ remains below 0.1, suggesting that hole-doped FeS$_2$ may not a viable candidate for effective thermoelectric applications despite its promising thermopower. (10.1016/j.ssc.2025.116194)
    DOI : 10.1016/j.ssc.2025.116194