The Schwinger model, which describes lattice quantum electrodynamics in $1+1$ space-time dimensions, provides a valuable framework to investigate fundamental aspects of quantum field theory, and a stepping stone toward non-Abelian gauge theories. Specifically, it enables the study of physically relevant dynamical processes, such as the nonperturbative particle-antiparticle pair production, known as the Schwinger effect. In this work, we analyze the quantum computational resource requirements associated with simulating the Schwinger effect under two distinct scenarios: (1) a quench process, where the initial state is a simple product state of a non-interacting theory and then interactions are turned on at time $t=0$, and (2) a splitting (or scattering) process where two Gaussian states, peaked at given initial momenta, are shot away from (or toward) each other. We explore different physical regimes in which the Schwinger effect is expected to be observable. These regimes are characterized by initial momenta and coupling strengths, as well as simulation parameters such as lattice size and electric-field cutoffs. Leveraging known rigorous bounds for electric-field cutoffs, we find that a reliable simulation of the Schwinger effect is provably possible at high cutoff scales. Furthermore, we provide optimized circuit implementations of both the second-order Trotter formula and an interaction-picture algorithm based on the Dyson series to implement the time evolution. Our detailed resource estimates show the regimes in which the interaction-picture approach outperforms the Trotter approach, and vice versa. The improved theoretical error bounds, optimized quantum circuit designs, and explicitly compiled subroutines developed in this study are broadly applicable to simulations of other lattice models in high-energy physics and beyond.

We investigate the strong decays of the recently observed hidden-charm pentaquarks $P_{\psi }^N(4312)$, $P_{\psi }^N(4440)$, and $P_{\psi }^N(4457)$, as well as $P_{\psi s}^{\mathrm{\Lambda }}(4338)$ and $P_{\psi s}^{\mathrm{\Lambda }}(4459)$, within the molecular framework using the effective Lagrangian approach. We construct the effective Lagrangians describing the S-wave couplings between these pentaquarks and their constituent hadrons, namely ${\mathrm{\Sigma }}_c{\overline{D}}^{(*)}$ and ${\mathrm{\Xi }}_c{\overline{D}}^{(*)}$, and determine the coupling constants via the residues of the scattering $T$-matrix at the bound-state poles. Our results show that the decay widths are sensitive to the cutoff parameters in the form factors, whereas the branching fractions exhibit only weak dependence. Using $P_{\psi }^N(4312)$ to calibrate the cutoff range, we further explore the spin assignments of $P_{\psi }^N(4440)$ and $P_{\psi }^N(4457)$. Our calculations favor the assignment where the lower-mass state $P_{\psi }^N(4440)$ carries higher spin $J=3/2$ and the higher-mass state $P_{\psi }^N(4457)$ carries lower spin $J=1/2$. In addition, the experimental widths of $P_{\psi s}^{\mathrm{\Lambda }}(4338)$ and $P_{\psi s}^{\mathrm{\Lambda }}(4459)$ can both be well reproduced under the molecular interpretation. We look forward to future experimental analyses with more accumulated data to clarify whether the lineshape of $P_{\psi s}^{\mathrm{\Lambda }}(4459)$ contains contributions from both spin-$1/2$ and spin-$3/2$ states.

We present HAPS-pPDF1.0, a new global determination of the helicity-dependent parton distribution functions (PDFs) of the proton, based on inclusive deep-inelastic scattering (DIS) and semi-inclusive DIS (SIDIS) data within a consistent next-to-leading order (NLO) QCD framework. In addition to existing measurements, we incorporate simulated pseudodata for the future Electron-Ion Collider (EIC), considering two beam-energy configurations, $E_e\times E_p=5\times 41{\mathrm{GeV}}^2$ and $18\times 275{\mathrm{GeV}}^2$, corresponding to an extended kinematic reach down to $x\sim {10}^{-5}$. We focus on longitudinal double-spin asymmetries $A_1^h$ for charge-separated pion and kaon production in SIDIS off a longitudinally polarized proton target. These projected measurements significantly improve the flavor separation of sea-quark polarized PDFs ($\mathrm{\Delta }\overline{u}$, $\mathrm{\Delta }\overline{d}$, $\mathrm{\Delta }s$) and reduce the uncertainties on both quark and gluon helicity distributions, with the largest impact at small $x$. Polarized PDFs are extracted using a neural-network parametrization and a Monte Carlo replica methodology to propagate experimental uncertainties, while theoretical constraints such as positivity are imposed during the fit. We demonstrate that the inclusion of EIC pseudodata leads to a substantially more precise determination of polarized PDFs, with the largest impact in the small-$x$ region. The resulting polarized PDF sets are provided in the LHAPDF format.

We present the first study of jet substructure modifications during the bottom-up evolution that describes the early stages of heavy-ion collisions. To this end, we study the bremsstrahlung radiation rate of soft gluons from a hard parton propagating through out-of-equilibrium QCD matter. The gluon spectrum is computed within the improved opacity expansion, which accounts for both multiple soft and single hard momentum exchanges between the hard probe and the medium. The background evolution is obtained from effective kinetic theory simulations that determine the jet quenching parameter, which in turn controls the radiation rate. We compute the radiation rate for initially underoccupied and overoccupied systems, as well as for an expanding system undergoing hydrodynamization, which typically represents the initial stages of heavy-ion collisions. The results for these dynamical backgrounds are compared to static and thermally matched scenarios, allowing to gauge the importance of bulk expansion in the evolution of the jet cascade. Our findings show that the early stages of the bulk matter evolution in heavy-ion collisions leave a sizable imprint on the radiation pattern inside jets. These results establish a basis for incorporating preequilibrium dynamics into realistic descriptions of jet quenching and hard-probe evolution.

Since the discovery of the $T_{cc}$ double-charm tetraquark by LHCb collaboration, the field of theoretical research on heavy quarks has advanced rapidly, with increasing interest in exploring the light quark sector. In this work, the quark delocalization color screening model, together with the resonating group method, is employed to systematically investigate the double-strangeness tetraquark system. Both meson-meson and diquark-antidiquark configurations are considered. The interactions between hadron pairs with different quantum numbers are studied, and possible bound-state and resonancelike solutions are examined. In the single-channel estimations, two weakly bound solutions, ${\overline{K}}^{*}\overline{K}$ and ${\overline{K}}^{*}{\overline{K}}^{*}$, are obtained in the $I(J^P)=0(1^{+})$ sector. After channel coupling between the two configurations is included, a deeply bound coupled-channel solution with the same quantum numbers and a mass of approximately 1310 MeV is found. In addition, the real-scaling stabilization analysis indicates a resonancelike structure in the $I(J^P)=0(1^{+})$ $ss\overline{n}\overline{n}$ system, with an estimated mass of around 1783 MeV and a width of approximately 5.6 MeV.

In the operator product expansion (OPE) of hard scattering amplitudes, the twist-3 operators describe local colored Lorentz forces acting on a quark, thereby providing a measure of the strength of the gluon fields. Its value is directly accessible from the nucleon twist-3 polarized $g_2$-parton distribution function. In the semiclassical (instanton-based) QCD vacuum models, the leading nonperturbative contribution stems from correlated instanton-antiinstanton pairs, or molecules. We analyze the magnitude of the color force on a struck quark in light hadrons (pion and nucleon), in the context of the instanton liquid model (ILM). We derive explicitly the pertinent form factors associated with the color Lorentz force and show that they are intimately related to the pertinent hadronic gravitational and transversity form factors. Using the ILM enhanced by molecules, we detail the ensuing colored force distribution in the transverse plane for the luminal pions and nucleons. The results for the nucleons are in good agreement with those recently reported from a lattice collaboration.

Using a sample of $(2712.4\pm 14.3)\times {10}^6\psi (3686)$ events collected with the BESIII detector, we perform a search for the isospin-violating decays ${\chi }_{cJ}\to \mathrm{\Lambda }\overline{\mathrm{\Sigma }}{}^0+\mathrm{c}.\mathrm{c}.(J=0,1,2)$ and ${\eta }_c\to \mathrm{\Lambda }\overline{\mathrm{\Sigma }}{}^0+\mathrm{c}.\mathrm{c}$. No significant signal for ${\chi }_{cJ}$ or ${\eta }_c$ is observed in the $\mathrm{\Lambda }\overline{\mathrm{\Sigma }}{}^0$ invariant mass distribution. The upper limits on the branching fractions at the 90% confidence level are set to be $\mathcal{B}({\chi }_{c0}\to \mathrm{\Lambda }\overline{\mathrm{\Sigma }}{}^0+\mathrm{c}.\mathrm{c}.)<1.5\times {10}^{-6}$, $\mathcal{B}({\chi }_{c1}\to \mathrm{\Lambda }\overline{\mathrm{\Sigma }}{}^0+\mathrm{c}.\mathrm{c}.)<1.6\times {10}^{-6}$, $\mathcal{B}({\chi }_{c2}\to \mathrm{\Lambda }\overline{\mathrm{\Sigma }}{}^0+\mathrm{c}.\mathrm{c}.)<1.7\times {10}^{-6}$, and $\mathcal{B}({\eta }_c\to \mathrm{\Lambda }\overline{\mathrm{\Sigma }}{}^0+\mathrm{c}.\mathrm{c}.)<6.2\times {10}^{-5}$ for the first time.

Based on $(2.712\pm 0.014)\times {10}^9\psi (3686)$ events collected with the BESIII detector, the decays ${\chi }_{cJ}\to p\overline{p}{K}_S^0{K}_S^0$ ($J=0$, 1, 2) are observed for the first time with statistical significances exceeding $5\sigma$. The measured branching fractions are $\mathcal{B}({\chi }_{c0}\to p\overline{p}{K}_S^0{K}_S^0)=(7.25\pm 0.28\pm 0.35)\times {10}^{-5}$, $\mathcal{B}({\chi }_{c1}\to p\overline{p}{K}_S^0{K}_S^0)=(1.33\pm 0.12\pm 0.07)\times {10}^{-5}$, and $\mathcal{B}({\chi }_{c2}\to p\overline{p}{K}_S^0{K}_S^0)=(2.51\pm 0.16\pm 0.12)\times {10}^{-5}$, where the first uncertainties are statistical and the second systematic. In addition, no significant structures are observed in the $p\overline{p}$, $p{K}_S^0$, and $\overline{p}{K}_S^0$ mass spectra.

We study the natural scheme-independent quantity obtained from the three-sphere partition function of a ($2+1$)-dimensional quantum field theory by removing all local counterterm ambiguities. At conformal fixed points this quantity equals the standard $F$-theorem invariant. Conformal perturbation theory shows that it locally decreases at $O(g^2)$ under any relevant scalar deformation of a three-dimensional Conformal Field Theory. However, an exact analysis of the free massive scalar on $S^3$ shows that this sphere-free-energy interpolant is not monotone along the full renormalization-group flow: it dips below its infrared value and then returns to it. Thus the natural counterterm-subtracted quantity built from sphere thermodynamics is not, by itself, a monotone $F$-function. We trace the obstruction to the second-order differential operator required to eliminate the local ambiguities.

Chaplygin gas and other k-essence models exhibit emergent geometry, with perturbations propagating on an acoustic metric disformally related to the Einstein-frame metric. For superluminal sound speed, we identify the disformal metric as the “causal frame,” since choosing a finite causal-frame lapse yields hyperbolic equations of motion for fields propagating in either frame. We show that, with a phantom Chaplygin gas, the Einstein-frame lapse is forced to pass smoothly through zero and change sign, while the causal-frame lapse remains positive. As a result, Einstein-frame degrees of freedom (including the scale factor) undergo spontaneous time reversal, while the Chaplygin gas evolves monotonically, enforcing a robust nonsingular bounce even in the presence of additional matter canonically coupled to the Einstein frame.

The ratio between the $B_c^{+}\to J/\psi {\tau }^{+}{\nu }_{\tau }$ and $B_c^{+}\to J/\psi {\mu }^{+}{\nu }_{\mu }$ branching fractions is measured using a data sample of proton-proton collisions collected by CMS at a center-of-mass energy of $13\mathrm{TeV}$ in the years 2016–2018 and corresponding to an integrated luminosity of $138{\mathrm{fb}}^{-1}$. The $J/\psi$ meson is identified through its $J/\psi \to {\mu }^{+}{\mu }^{-}$ decay and the tau lepton is reconstructed in the hadronic three-prong final state. The measured ratio of branching fractions in this tau decay mode, ${\mathcal{R}}_{J/\psi }^{\mathrm{had}}=1.04_{-0.44}^{+0.50}$, is combined with the previous analysis based on the ${\tau }^{+}\to {\mu }^{+}{\nu }_{\mu }{\overline{\nu }}_{\tau }$ leptonic decay channel, leading to ${\mathcal{R}}_{J/\psi }=0.49\pm 0.26$. As this result is consistent with the standard model prediction of $0.258\pm 0.004$, no evidence of lepton flavor universality violation is found.

We argue that Hopf-algebra deformations of symmetries—as encountered in noncommutative models of quantum spacetime—carry an intrinsic content of operator entanglement that is enforced by the coproduct-defined notion of composite generators. As a minimal and exactly solvable example, we analyze the $U_q(\mathfrak{su}(2))$ quantum group and a two-qubit realization obtained from the coproduct of a $q$-deformed single-spin Hamiltonian. Although the deformation is invisible on a single qubit, it resurfaces in the two-qubit sector through the non-cocommutative coproduct, yielding a family of intrinsically nonlocal unitaries. We compute their operator entanglement in closed form and show that, for Haar-uniform product inputs, their entangling power is fully determined by the latter. This provides a concrete mechanism by which noncommutative symmetries enforce a baseline of entanglement at the algebraic level, with implications for information dynamics in quantum-spacetime settings and quantum information processing.

We introduce the Krylov distribution $\mathcal{D}(\xi )$, a static Krylov-space diagnostic that characterizes how inverse-energy response is organized in Hilbert space. The central object is the resolvent-dressed state $(H-\xi {)}^{-1}|{\psi }_0⟩$, whose decomposition in the Krylov basis generated from a reference state defines a normalized distribution over Krylov levels. Unlike conventional spectral functions, which resolve response solely along the energy axis, the Krylov distribution captures how the resolvent explores the dynamically accessible subspace as the spectral parameter $\xi$ is varied. Using asymptotic analysis, exact results in solvable models, and numerical studies of an interacting spin chain, we identify three universal regimes: saturation outside the spectral support, extensive growth within continuous spectra, and sublinear or logarithmic scaling near spectral edges and quantum critical points. We further show that fidelity susceptibility and the quantum geometric tensor admit natural decompositions in terms of Krylov-resolved resolvent amplitudes.

We introduce a three-dimensional quantum field theory with an infinite-dimensional symmetry, realized explicitly through a centrally extended affine graded Lie algebra. This symmetry is a direct three-dimensional generalization of the chiral symmetry in the Wess-Zumino-Witten model. Upon performing radial quantization, we construct the Fock space of the theory and, via a three-dimensional analog of the state-operator correspondence, we demonstrate that the algebra of local operators is endowed with the structure of a raviolo vertex algebra. Accordingly, this setup provides a framework for extending the methods of two-dimensional conformal field theory to three dimensions, and we expect it to lay the groundwork for exact methods in three-dimensional quantum field theory.

We study a massless Dirac field subjected to two alternative boundary conditions on two parallel thin walls, in $d+1$ dimensions. The two configurations correspond to the system being even or odd under reflection about the midplane between the two walls, and lead to qualitatively different behaviors. The even (symmetric) configuration produces an attractive Casimir force, whereas the odd (antisymmetric) one yields repulsion, in agreement with a general theorem linking parity to the sign of the fermionic Casimir effect. We complement this result by studying two phenomena associated with the vacuum fluctuations responsible for the Casimir interaction, both of which are also sensitive to parity: the correlation between currents concentrated on the walls, and the induced bulk current under the influence of an external electric field. For the latter we show that, in $2+1$ dimensions, an induced transverse (Hall-like) current arises, whose spatial profile inherits the symmetry of the confining potential.

We present a new family of multicentered rotating black hole solutions in 5D vacuum Einstein gravity, providing explicit examples of cohomogeneity-three spacetimes. It is well known that, in the presence of two commuting Killing vector fields, the theory reduces to 3D gravity coupled to an $SL(3,\mathbb{R})$ nonlinear sigma model with five scalar fields. We show that the scalar fields of the extremal Myers-Perry solution can be expressed in terms of two harmonic functions on 3D flat space, and that promoting these functions to include multiple sources yields explicit multicentered extremal Myers-Perry black holes located at arbitrary positions. Each center forms a smooth $S^3$ Killing horizon, provided that the rotation parameters satisfy $|j_i|<1/2$. We further demonstrate that all curvature singularities are hidden behind the horizons and that no closed timelike curves arise on or outside the horizons. The solutions are asymptotically locally Minkowski in the sense that constant-time hypersurfaces are asymptotically locally Euclidean. As a concrete example, we consider a binary configuration, examine its rod structure, and demonstrate the absence of conical singularities between the two black holes, indicating that they are supported by an intermediate bubble region separating them.

We study the backreaction of quantum fields in the Boulware vacuum state on the Schwarzschild geometry, using the Riegert-Mottola-Vaulin renormalized stress-energy tensor derived from the conformal anomaly. An order-reduction procedure is applied to first order, paying special attention to the conservation of the resulting stress-energy tensor. The results obtained in these different situations are compared between them, and also to recent works in the literature using other approximations for the renormalized stress-energy tensor.

In the presence of a background magnetic field, axions or axionlike particles (ALPs) can be resonantly converted to photons when their mass is nearly equal to the effective photon mass. In this paper, we propose a novel method to constrain the parameter space of ALPs by investigating the resulting imprints of axion-photon conversion in the cosmic microwave background (CMB) observations. We show that a helical magnetic field existing prior to the CMB epoch can generate an excess population of photons carrying net circular polarization due to the axion-photon conversion mechanism. Consequently, current measurements of the angular power spectrum of circular polarization ($V$ mode) in the CMB can be used to constrain the parameter space of ALP mass and its coupling to photons. In the optimistic scenario of a maximally helical magnetic field with strength $\sim \mathrm{nG}$, we find that CLASS observations at 40 GHz provide the most stringent upper limits to date, on the previously unconstrained regions of axion-photon coupling corresponding to ALP masses in the range ${10}^{-10}-{10}^{-8}\mathrm{eV}$.

According to the perturbed Friedmann model, the difference between Hubble constant measurements in two rest frames, at leading order in velocity, is determined solely by the relative motion of the observers and remains unaffected by the peculiar velocities of the sources. This implies that, when averaging over a sufficiently large and distant set of sources where local nonlinear inhomogeneities are diminished, such a difference should vanish, so that the Hubble flow is statistically uniform, as predicted by the cosmological principle—a core assumption of the standard cosmological paradigm. In previous works, distance measurement compilations, e.g., the CosmicFlows-3 catalog, were used for this purpose, as it comprises a large number ($\sim {10}^4$) of sources of different types. Due to the increasing amount of precise luminosity distance measurements of Type Ia Supenovae (SNe) in the last few years, in this work we investigate whether we can confirm the uniformity of the Hubble flow with low-$z$ SN distances only. By means of the $\mathrm{Pantheon}+$ and SH0ES compilation, we find that the results align well with previous works based on the CF3 catalog, and are in good agreement with the expected Hubble variance in the standard model across cosmic scales of 20–150 Mpc. Notably, the Hubble constant difference $\mathrm{\Delta }{H}_0\approx 0$ is observed at around 85 Mpc. Despite the smaller sample size ($\sim {10}^2$ versus $\sim {10}^4$) relative to CF3 at those scales, our analysis show that the $\mathrm{Pantheon}+$ and SH0ES dataset supports the standard model paradigm, which indicates that the Hubble flow becomes statistically uniform at around 70–100 Mpc, which is compatible with independent determinations of the homogeneity scale based on galaxy number counts.

We present constraints on the normal branch of the Dvali-Gabadadze-Porrati (nDGP) braneworld gravity model from the abundance of massive galaxy clusters. On scales below the nDGP crossover scale $r_{\mathrm{c}}$, the nDGP model features an effective gravitylike fifth force that alters the growth of structure, leading to an enhancement of the halo mass function (HMF) on cluster scales. The enhanced cluster abundance allows for constraints on the nDGP model using cluster samples. We employ the South Pole Telescope (SPT) cluster sample, selected through the thermal Sunyaev-Zel’dovich effect with the SPT and with mass calibration using weak-lensing data from the Dark Energy Survey (DES) and the Hubble Space Telescope (HST). The cluster sample contains 1,005 clusters with redshifts $0.25<z<1.78$, which are confirmed with the multicomponent matched filter algorithm using optical and near-infrared data. Weak-lensing data from DES and HST enable a robust mass measurement of the cluster sample. We use DES Year 3 data for 688 clusters with redshifts $z<0.95$, and HST data for 39 clusters with redshifts $0.6<z<1.7$. We account for the enhancement in the HMF through a semi-analytic correction factor to the standard cosmology HMF derived from the spherical collapse model in the nDGP model. We then further calibrate this model using $N$-body simulations. In addition, for the first time, we analyze the primary CMB temperature and polarization anisotropy measurements from Planck PR4 within the nDGP model. We obtain a competitive constraint from the joint analysis of the SPT cluster abundance with the Planck PR4 data, and report an upper bound of $1/\sqrt{H_0{r}_{\mathrm{c}}}<1.41$ at 95% when assuming a cosmology with massive neutrinos.