Publications

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• Classical weight-four L-value ratios as sums of Calabi-Yau invariants

  Philip Candelas, Xenia de la Ossa, Joseph McGovern

  SciPost Phys. 18, 181 (2025) · published 6 June 2025 | Toggle abstract · pdf

  We revisit the series solutions of the attractor equations of 4d $\mathcal{N}=2$ supergravities obtained by Calabi–Yau compactifications previously studied in [P. Candelas et al., J. High Energy Phys. 11, 032 (2021)]. While only convergent for a restricted set of black hole charges, we find that they are summable with Padé resummation providing a suitable method. By specialising these solutions to rank-two attractors, we obtain many conjectural identities of the type discovered in [P. Candelas et al., J. High Energy Phys. 11, 032 (2021)]. These equate ratios of weight-four special L-values with an infinite series whose summands are formed out of genus-0 Gromov–Witten invariants. We also present two new rank-two attractors which belong to moduli spaces each interesting in their own right. Each of these moduli spaces possess two points of maximal unipotent monodromy. One has already been studied by Hosono and Takagi, and we discuss issues stemming from the associated L-function having nonzero rank.

• 2d dualities from 4d

  Jiaqun Jiang, Satoshi Nawata, Jiahao Zheng

  SciPost Phys. 18, 180 (2025) · published 6 June 2025 | Toggle abstract · pdf

  We find new $\mathcal{N}=(2,2)$ and $\mathcal{N}=(0,2)$ dualities through the twisted compactifications of 4d supersymmetric theories on $S^2$. Our findings include dualities for both $\mathcal{N}=(2,2)$ and $\mathcal{N}=(0,2)$ non-Abelian gauge theories, as well as $\mathcal{N}=(0,2)$ Gauge/Landau-Ginzburg duality.

  1 citation

• Lightcone Hamiltonian for Ising field theory I: $T < T_c$

  Andrew Liam Fitzpatrick, Emanuel Katz, Yuan Xin

  SciPost Phys. 18, 179 (2025) · published 5 June 2025 | Toggle abstract · pdf

  We study 2d Ising Field Theory (IFT) in the low-temperature phase in lightcone quantization, and show that integrating out zero modes generates a very compact form for the effective lightcone interaction that depends on the finite volume vacuum expectation value of the $\sigma$ operator. This form is most naturally understood in a conformal basis for the lightcone Hilbert space. We further verify that this simple form reproduces to high accuracy results for the spectra, the $c$-function, and the form-factors from integrability methods for the magnetic deformation of IFT. For generic non-integrable values of parameters we also compute the above observables and compare our numeric results to those of equal-time truncation. In particular, we report on new measurements of various bound-state form-factors as well as the stress-tensor spectral density. We find that the stress tensor spectral density provides additional evidence that certain resonances of IFT are surprisingly narrow, even at generic strong coupling. Explicit example code for constructing the effective Hamiltonian is included in an appendix.

  1 citation

• Quantum transport theory for unconventional magnets: Interplay of altermagnetism and p-wave magnetism with superconductivity

  Tim Kokkeler, Ilya Tokatly, F. Sebastian Bergeret

  SciPost Phys. 18, 178 (2025) · published 5 June 2025 | Toggle abstract · pdf

  We present a quantum transport theory for generic magnetic metals, in which magnetism occurs predominantly due to exchange interactions, such as ferromagnets, antiferromagnets, altermagnets and p-wave magnets. Our theory is valid both for the normal and the superconducting state and is based on the generalization of nonlinear sigma model to such systems. We derive the effective low-energy action for each of these materials, where the symmetries of the corresponding spin space group are used to determine the form of the tensor coefficients appearing in the action. The transport equations, which are obtained as the saddle point equations of this action, describe a wider range of phenomena than the usual quasiclassical equations. In ferromagnets, in addition to the usual exchange field and spin relaxation effects, we identify a spin-dependent renormalization of the diffusion coefficient, and a correction to the Hanle effect. The former provides a description of spin-polarized currents in both the normal and superconducting equal spin-triplet states. In the normal state, our equations provide a complete description of the spin-splitting effect in diffusive systems, recently predicted in ideal clean altermagnets. In the superconducting state, our equations predict a proximity induced magnetization, the appearance of a spontaneous magnetic moment in hybrid superconductor-altermagnet systems. The distribution and polarization direction of this magnetic moment depend on the symmetry of the structure, thus measurements of such polarization reveal the underlying microscopic symmetry of the altermagnet. Finally, for inversion-symmetry-broken antiferromagnets, such as the p-wave magnet, we show that spin-galvanic effects may emerge. This effect is indistinguishable from the spin-galvanic effect induced by spin-orbit coupling in the normal state, but they can be distinguished through the temperature dependence in the superconducting state. Besides these examples, our model applies to arbitrary magnetic systems, providing a complete theory for nonequilibrium transport in diffusive nonconventional magnets at arbitrary temperatures.

  4 citations

• Effect of the Coulomb repulsion and oxygen level on charge distribution and superconductivity in the Emery model for cuprates superconductors

  Louis-Bernard St-Cyr, David Sénéchal

  SciPost Phys. Core 8, 043 (2025) · published 5 June 2025 | Toggle abstract · pdf

  The Emery model (aka the three-band Hubbard model) offers a simplified description of the copper-oxide planes that form the building blocks of high-temperature superconductors. By contrast with the even simpler one-band Hubbard model, it differentiates between copper and oxygen orbitals and thus between oxygen occupation ($n_p$) and copper occupation ($n_d$). Here we demonstrate, using cluster dynamical mean field theory, how the two occupations are related to the on-site Coulomb repulsion $U$ on the copper orbital and to the energy difference $\epsilon_p$ between oxygen and copper orbitals. Since the occupations ($n_p$ and $n_d$) have been estimated from NMR for a few materials (LCO, YBCO and NCCO), this allows us to estimate the value of $U-\epsilon_p$ for these materials, within this model. We compute the density of states for these and the effect of $(U,\epsilon_p)$ on the $n_d$-$n_p$ curve, superconductivity, and antiferromagnetism.

  1 citation

• Universal thermalization dynamics in (1+1)d QFTs

  Richard A. Davison, Luca V. Delacretaz

  SciPost Phys. 18, 177 (2025) · published 4 June 2025 | Toggle abstract · pdf

  We identify the universal mechanism behind the thermalization of (1+1)d QFTs at high and low temperatures. Viewing these theories as CFTs perturbed by relevant or irrelevant deformations, we show that conformal perturbation theory in the thermal state breaks down at late times allowing for the emergence of hydrodynamics. This breakdown occurs universally due to the unsuppressed exchange of stress tensors near the lightcone. Furthermore, for theories with central charge $c→∞$ we solve for the emergent hydrodynamic theory to all orders in the gradient expansion by arguing that all transport parameters appearing in two-point functions have universal expressions in terms of the scaling dimension $\Delta$ of the perturbation. The radius of convergence of the hydrodynamic dispersion relations provides an early time cutoff for hydrodynamics, which agrees with the time scale at which conformal perturbation theory breaks down.

• Cosmological infrared subtractions & infrared-safe computables

  Paolo Benincasa, Francisco Vazão

  SciPost Phys. 18, 176 (2025) · published 4 June 2025 | Toggle abstract · pdf

  Cosmological observables in perturbation theory turn out to be plagued with infrared divergences, which represents both a conceptual and computational challenge. In this paper we present a proof of concept for a systematic procedure to remove these divergences in a large class of scalar cosmological integrals and consistently define an infrared safe computable in perturbation theory. We provide diagrammatic rules which are based on the nestohedra underlying the asymptotic structure of such integrals.

  2 citations

• Cosmology of the companion-axion model: Dark matter, gravitational waves, and primordial black holes

  Zhe Chen, Archil Kobakhidze, Ciaran O'Hare, Zachary S. C. Picker, Giovanni Pierobon

  SciPost Phys. 18, 175 (2025) · published 4 June 2025 | Toggle abstract · pdf

  The companion-axion model introduces a second QCD axion to rescue the Peccei-Quinn solution to the strong-CP problem from the effects of colored gravitational instantons. As in single-axion models, the two axions predicted by the companion-axion model are attractive candidates for dark matter. The model is defined by two free parameters, the scales of the two axions' symmetry breaking, so we can classify production scenarios in terms of the relative sizes of these two scales with respect to the scale of inflation. We study the cosmological production of companion-axion dark matter in order to predict windows of preferred axion masses, and calculate the relative abundances of the two particles. Additionally, we show that the presence of a second axion solves the cosmological domain wall problem automatically in the scenarios in which one or both of the axions are post-inflationary. We also suggest unique cosmological signatures of the companion-axion model, such as the production of a $\sim$10 nHz gravitational wave background, and $\sim 100\,M_\odot$ primordial black holes.

• Vacua, symmetries, and Higgsing of Chern-Simons matter theories

  Fabio Marino, Marcus Sperling

  SciPost Phys. 18, 174 (2025) · published 3 June 2025 | Toggle abstract · pdf

  Three-dimensional supersymmetric Chern–Simons matter (CSM) theories typically preserve $\mathcal{N}=3$ supersymmetry but can exhibit enhanced $\mathcal{N}=4$ supersymmetry under special conditions. A detailed understanding of the moduli space of CSM theories, however, has remained elusive. This paper addresses this gap by systematically analysing the maximal branches of the moduli space of $\mathcal{N}=3$ and $\mathcal{N}=4$ CSM realised via Type IIB brane constructions. Firstly, for $\mathcal{N}=4$ theories with Chern–Simons levels equal $1$, the $SL(2,\mathbb{Z})$ dualisation algorithm is employed to construct dual Lagrangian 3d $\mathcal{N}=4$ theories without CS terms. This allows the full moduli space to be determined using quiver algorithms that compute Higgs and Coulomb branch Hasse diagrams and associated RG flows. Secondly, for $\mathcal{N}=4$ theories with CS-levels greater $1$, where $SL(2,\mathbb{Z})$ dualisation does not yield CS-free Lagrangians, a new prescription is introduced to derive two magnetic quivers, $\mathsf{MQ}_A $ and $\mathsf{MQ}_B$, whose Coulomb branches capture the maximal A and B branches of the original $\mathcal{N}=4$ CSM theory. Applying the decay and fission algorithm to $ \mathsf{MQ}_{A/B}$ then enables the systematic analysis of A/B branch RG flows and their geometric structures. Thirdly, for $\mathcal{N}=3$ CSM theories, one magnetic quiver for each maximal (hyper-Kähler) branch is derived from the brane system. This provides an efficient and comprehensive characterisation of these previously scarcely studied features.

• Higher spin swampland conjecture for massive AdS$_{3}$ gravity

  Rajae Sammani, El Hassan Saidi

  SciPost Phys. 18, 173 (2025) · published 3 June 2025 | Toggle abstract · pdf

  In this paper, we show that a possible version of the swampland weak gravity conjecture for higher spin (HS) massive topological AdS$_{3}$ gravity can be expressed in terms of mass M$_{\mathrm{hs}}$, charge Q$_{\mathrm{hs}}$ and coupling constant ${\large g}_{\mathrm{hs}}$ of 3D gravity coupled to higher spin fields as M$_{\mathrm{hs}}≤ \sqrt{2}$Q$_{\mathrm{hs}}{\large g}_{\mathrm{hs}}M_{\mathrm{Pl}}$. The higher spin charge is given by the $SO(1,2)$ quadratic Casimir Q$_{\mathrm{hs}}^{2}=s\left( s-1\right) $ and the HS coupling constant by ${\large g}_{\mathrm{hs}}^{2}=2/\left( M_{\mathrm{Pl}}^{2}l_{\mathrm{AdS}_{3}}^{2}\right) $ while the mass expressed like $\left( l_{\mathrm{AdS}_{3}}\text{M}_{\mathrm{hs}}\right) ^{2}$ is defined as $\left( 1+\mathrm{\mu }l_{\mathrm{AdS}_{3}}\right) ^{2}s\left( s-1\right) +\left[1-\left( \mathrm{\mu }l_{\mathrm{AdS}_{3}}\right) ^{2}\left( s-1\right) \right]$.

  1 citation