Papers

In this paper, we investigate background-hierarchy bounds in Type~3 of New General Relativity (NGR). These bounds arise when the contribution associated with the evolution of the background spacetime exceeds that of the kinetic term in the perturbed Lagrangian. Type~3 of NGR has two free parameters and is described in a pure-tetrad formulation while preserving diffeomorphism invariance and spatial rotations. We first review Type~3 and identify preferable gauge choices for metric-affine gauge theories of gravity with Weitzenböck connection, including NGR, from the viewpoint of symmetry in both Dirac–Bergmann analysis and linear perturbation theory. We then revisit the perturbative analysis of Type~3 and show that the propagating modes are correctly identified even when the perturbed Lagrangian is not written solely in terms of gauge-invariant variables. Finally, we derive the background-hierarchy bounds for the scalar, transverse-vector, and tensor modes around a flat FLRW background, and identify the region of parameter space in which the linear perturbation theory of Type~3 remains viable for cosmological applications.

We study the separable master equations for the electromagnetic and gravitational perturbations in five-dimensional Myers-Perry black holes. In the static limit, while the master equation for the electric polarization of the Maxwell field reduces to that of a massless scalar field, the magnetic polarization and gravitational perturbation yield Heun equations for both its angular and radial components. Remarkably, these Heun equations fall into a special class that admits exact analytic solutions in terms of hypergeometric functions. We reconstruct the gauge field using master fields and study its asymptotic behavior. When expanding the result in the basis of modified spherical harmonics, we find modes with higher angular momentum arise in response to the excitation of sources with lower angular momentum. The static tidal Love tensor that characterizes such mixing structure of the response can be computed iteratively. We also discuss the possible near zone approximation of the master equations for the magnetic polarization.

The super Macdonald polynomials indexed by the super partitions form a basis of the level zero super Fock module (combinatorial representation) of the quantum toroidal algebra $\mathcal{U}_{q,t}(\widehat{\widehat{\mathfrak{gl}}}_{1|1})$. The action of the super charges of $\mathcal{U}_{q,t}(\widehat{\widehat{\mathfrak{gl}}}_{1|1})$ implies the Pieri rule of the super Macdonald polynomials. We can express the Pieri rule in terms of differential operators in the power sums $p_k$ and the fermionic power sums $\pi_k$, which leads to the operators on the Fock space of a free boson and a free fermion. From the Pieri rule we compute the supersymmetric Hamiltonians given by the anti-commutator of the super charges and recover the results previously obtained in the literature. It is remarkable that we have to deal with a shifted quantum toroidal algebra.

We revisit the reconstruction of a free quantum field in 4-dimensional Lorentzian Anti-de-Sitter (AdS$_4$) spacetime in terms of primary operators in the boundary 3d CFT (CFT$_3$). We show that the positive and negative energy subspaces of solutions to the Klein-Gordon equation in AdS can be spanned with bulk-to-boundary propagators with appropriate time orderings. As a result, free scalar fields on a codimension-1 bulk hypersurface $\Sigma_{\tau}$ can be expressed in terms of operators integrated over boundary regions in the past or future of $\Sigma_{\tau}$ with kernels given by time-ordered or anti-time-ordered propagators. We present various equivalent representations for the bulk field in terms of either CFT primaries or their shadows. We show from both a representation theoretic perspective and by direct computation of various flat space limits that our construction is the AdS analog of the canonical quantization of a free scalar in flat space. Depending on the choice of $\Delta$ and the location of the boundary insertions one obtains a decomposition of the scalar in either a plane wave basis ($\Delta \rightarrow \infty$) or a Carrollian basis (fixed $\Delta$). Finally, we show that the free scalar in AdS$_4$ can be alternatively decomposed in terms of wavefunctions associated with principal series representations of dimension $\delta = 1 + i\lambda$ of an $\mathfrak{so}(3,1)$ subalgebra of the AdS$_4$ isometry algebra. We demonstrate that the latter become, in the limit of large AdS radius and for fixed $\delta$, scalar conformal primary wavefunctions in flat space.

We study the evolution of the interior of an evaporating black hole in a simple model of Jackiw-Teitelboim (JT) gravity with an end-of-the-world (EoW) brane, where evaporation is modeled by entangling the brane's internal states with an auxiliary radiation system. To probe the black hole interior, we consider a geodesic length extracted from a boundary-to-brane two-point function and interpret its renormalised value as a measure of subsystem complexity. Our computation, based on quenched disorder averaging, includes non-perturbative gravitational effects from both spacetime wormholes and replica wormholes, encoding ensemble averaging over the dual random Hamiltonian and brane-state couplings. Unlike non-evaporating black holes, for which complexity first grows linearly and then plateaus at late times $\sim{\cal O}(e^{S_{\rm BH}})$, we find that complexity evolution of the black hole subsystem in the evaporating case differs drastically, depending nontrivially on the dimension of the emitted radiation Hilbert space. It grows linearly at early times, reaches a maximum shortly before the Page-time crossover $\sim{\cal O}({S_{\rm BH}})$, and then decays exponentially. We further show that the relative fluctuations of the interior length remain small before the Page time but become of order one and eventually large at later times: this signals a loss of self-averaging, with the ensemble-averaged complexity dominated by rare configurations rather than by typical realisations.

In this paper we consider IR divergences in a 3d toy model field theory for 4d holographic cosmology, and we analyze them by introducing a mass term in a way that preserves a certain form of the generalized conformal structure. This allows us to compute 2- and 3-point functions at 2-loops and study their IR structure below the mass scale, from which we argue for a possible IR finiteness beyond perturbation theory, consistent with lattice results. In the holographically dual 4d cosmology, this corresponds to UV finiteness, i.e., the absence of cosmological singularities. The 3d IR field theory methods could be extended beyond this specific application.

Starting from a general analysis of obstruction classes, we develop the investigation of obstructions associated with the bundle structure of the hyperbolic Clifford algebra. By taking into account particularities arising from the Whitney sum, it is shown that, unlike classical tangent bundle cases, the hyperbolic frame bundle admits lifting without any topological obstruction. This leads to the possibility of always defining spinor structures in hyperbolic Clifford bundles.

We develop a general framework for interpreting the thermodynamic descriptions of Kerr-anti de Sitter black holes (KadS). These descriptions satisfy a first law and respect the homogeneity required by scaling properties. Additionally, they are subject to restrictions from semiclassical arguments. We show that temperature and angular velocity are kinematic quantities tied to a reference frame, identified through the Euclidean formalism. However, the pressure-volume contribution is a dynamical term that requires a gauge fixing of the potential mass and volume. It is established that the observer associated with a given thermodynamic description is directly encoded in the Killing vector that generates the horizon. We demonstrate that the quantum statistical relation restricts the infinite family of KadS descriptions to a subclass that reduces to Schwarzschild-adS and Kerr thermodynamics in the limits of vanishing cosmological constant and angular momentum. Furthermore, we establish the uniqueness of both the description associated with a frame co-rotating with infinity, and the description whose thermodynamic and geometric volumes coincide. Thus, our framework provides a coherent interpretation of the variety of KadS thermodynamics, reconciling geometric and quantum-statistical considerations.

We study a class of four-dimensional $\mathcal{N}=2$ SU($N$) gauge theories with two massless hypermultiplets in the rank-two antisymmetric representation and $0\leq N_f\leq 4$ fundamental flavors. These theories are superconformal for $N_f=4$ and asymptotically free otherwise. Supersymmetric localization on the four-sphere applies in both cases and leads to matrix-model representations for a broad class of protected observables. Within this framework, we compute the free energy and the expectation value of the $\frac{1}{2}$-BPS circular Wilson loop in the large-$N$ limit. For any $N_f$, we show that the infinite series of non-planar corrections at large 't Hooft coupling $\lambda$ can be resummed in terms of an effective coupling $\widetilde{\lambda}$. In the non-conformal window ($0\leq N_f<4$), this provides a first example in which localization leads to explicit results in the planar limit at strong 't Hooft coupling. In the superconformal case ($N_f=4$), the large-$N$ expansion in $\widetilde{\lambda}$ suggests a refined AdS/CFT dictionary in which $\widetilde{\lambda}$, rather than $\lambda$, plays the role of the bulk string coupling.

We investigate Krylov complexity in a simple quantum mechanical model describing a black hole coupled to its radiation. The model is constructed as a simplified “mini-BMN" matrix system inspired by a recent proposal of Maldacena. Our aim is not to reproduce the full dynamics of the BMN matrix model, but rather to isolate a tractable setting in which the information-theoretic behaviour of a radiating black hole can be studied explicitly. We analyze both the early- and late-time behaviour of Krylov complexity and the associated Krylov entropy. At early times, perturbative and numerical analyses reveal the expected growth characteristic of chaotic quantum dynamics. At late times, however, the dynamics saturates to a plateau, consistent with equilibration between the black hole and its radiation and with general expectations from finite-entropy quantum systems. We argue that this plateau behaviour admits a semiclassical interpretation in terms of Euclidean instanton contributions in an effective path-integral. The toy model studied here offers a controlled framework in which these features can be investigated analytically and numerically.

Recently, an atomic classification scheme of 5d SCFTs has been proposed, relying on the identification of indecomposable building blocks that can be fused together to produce large classes of 5d SCFTs. These novel SCFTs are known as bifundamental 5d conformal matter theories, and their fusion produces linear generalized quivers. We generalize such picture employing M-theory geometric engineering to construct trinions and tetraon 5d SCFTs with flavor symmetry of type D. They correspond to non-linear generalized quivers displaying novel patterns of instantonic symmetry enhancement, and their fusion produces singular geometries that often are non-toric non-complete intersections. Finally, within our setup, we rule out trinions and tetraons of type E.

We study the dynamical excitation of quasinormal modes (QNMs) during the plunge of a particle into a Schwarzschild black hole, building on the framework of Phys. Rev. D 113 (2026) 2, 024048 (Paper I). Investigating the high-frequency behavior of Leaver's QNM solutions, we obtain a more accurate and general prescription for their propagation. We confirm the existence of a new "characteristic radius" for QNM excitation, the bounce radius $r_*=0$, in agreement with recent literature. To its right, the QNM signal scatters off this point before reaching the observer; to its left, it propagates directly on the light-cone. Applying the formalism of Paper I to inspiralling particles, and using this refined prescription, we obtain a QNM signal that accurately reproduces the oscillatory component of the waveform after the bounce crossing, yielding an essentially complete first-principles description of the waveform from shortly after the signal peak. The dynamical QNM signal undergoes a transition as the particle crosses the bounce radius: from a quasi-resonant regime, where successive overtones are driven in counter-phase and interfere destructively, to a free-oscillator one, where they are in phase and the QNM sum converges rapidly. These results provide a clear physical interpretation of the collective QNM behavior during the plunge, and a firm theoretical foundation for accurate ringdown modelling.

We show analytically that the convergence of the QNM expansion of the retarded Green's function of the Schwarzschild spacetime is set by a singularity in the complex time plane. The singularity has a simple geometric origin: it is an example of a `bouncing singularity' in the language of AdS/CFT literature, caused by a null geodesic which bounces from the black hole singularity. Our work explains why the QNM convergence region at real times is bounded by null ray which scatters from the gravitational potential at a seemingly unremarkable point ($r_* = 0$ in the conventions of previous work) – this ray is the same distance from the origin as the bouncing singularity in the relevant complex plane. The same set of singularities are responsible for an annular region of convergence for the Matsubara mode sum which describes the early time behaviour of the Schwarzschild Green's function for perturbations close to the horizon.

We consider Scherk-Schwarz compactifications of M-theory (toroidal compactifications with a non-trivial spin structure) in various dimensions and find isolated critical points of the potential on the moduli space. We demonstrate this by identifying the unbroken duality group and finding isolated points on the moduli spaces which are fixed by elements of the unbroken duality group. We work out concrete examples involving compactifications down to $d=8,6, 5$ and $4$ spacetime dimensions. We also conjecture a duality covariant anomaly cancellation condition for M-theory on $T^n$ orbifolded by discrete $\mathbb Z_N$ symmetries acting as phases on the charge lattice. This anomaly cancellation condition generalizes the level matching requirement for perturbative string orbifolds.

Monodromy defects describe a dynamical termination of topological symmetry operators, and are sourced by a localized background magnetic flux. We study their properties in gapped SPT phases and, by inflow, in gapless theories with an anomalous symmetry. The background flux acts as a source for the anomaly, impacting the definition of the monodromy defect, which can only be defined as a domain wall between the symmetry generator and a topological order induced by the anomaly. The topological dressing has several consequences, such as the presence of protected chiral edge modes on the defect's worldvolume, and the adiabatic pumping of gapless degrees of freedom bound to the localized flux. We verify our predictions in several examples, focusing on monodromy defects for anomalous chiral symmetries, both in the continuum and on the lattice.

We study the timelike and null geodesic structure of a static, spherically symmetric black hole sourced by a Kalb–Ramond (KR) field coupled to nonlinear electrodynamics (NED). The geometry is characterized by the mass $M$, the magnetic monopole charge $q$, and the Lorentz-violating parameters $(\gamma,\lambda)$. Closed-form expressions are derived for the effective potential, as well as the specific energy and angular momentum of massive particles on circular orbits. We further analyze the photon sphere, black hole shadow, and the Lyapunov exponent associated with unstable null circular geodesics. The latter determines the eikonal quasinormal-mode frequencies through $\omega_{\rm eik}=(\ell+1/2)\,\Omega_c-i(n+1/2)\,|\lambda_L|$. The shadow radius is compared with the Event Horizon Telescope (EHT) observations of M87$^\ast$ and Sgr~A$^\ast$, allowing us to identify the viable region in the $(q,\gamma)$ parameter space. Finally, we compute the Hawking temperature, horizon area, and the Gray–Visser sparsity parameter. We demonstrate that the combined effects of the KR field and magnetic monopole charge increase the sparsity parameter from the Schwarzschild value $16\pi^3 \simeq 496$ to nearly $1.7\times10^3$. This indicates a significantly sparser Hawking cascade compared to the Schwarzschild case, while the photon ring remains consistent with the EHT $1\sigma$ observational bounds across most of the physically allowed parameter range.

We derive an analytic inverse map from the renormalized covariant interval entropy to a symmetry-reduced stationary bulk metric. The main result applies to stationary homogeneous asymptotically AdS$_3$ geometries with a radial lapse, an independent spatial warp factor, and a stationary shift. On a smooth HRT branch, the interval entropy \(S_{\ren}(\Delta t,\Delta x)\) is an on-shell Hamilton–Jacobi functional. Its endpoint derivatives determine two conserved charges, and the ratio \(\kappa=E/J\) organizes the extremal curves into one-parameter families with varying bulk turning points. For each fixed \(\kappa\), the length and endpoint-separation data give three Volterra equations with the standard Abel square-root kernel. Their inverse kernels reconstruct the radial coordinate and the metric functions \(f,h,v\). We also state the local consistency conditions and the agreement required when two local reconstructions of the same smooth HRT family cover an overlapping radial interval. The construction is verified in pure AdS, rotating BTZ, a static warped geometry, and an Einstein–scalar black brane, and extended to higher-dimensional strips when the transverse area density is fixed by symmetry.

We observe and elaborate on a structural similarity between the categorization of monotone and fortuitous BPS operators in supersymmetric theories and gauge invariant quark operators in $SU(N_c)$ QCD. Our designation of fortuity does not rely on supersymmetry and instead uses the BRST cohomology. We argue that within this designation, baryon states are fortuitous while meson states are monotone. We illustrate that in the Veneziano limit of large number of flavors and colors, this designation displays features resembling the fortuitous vs. monotone categorization of BPS operators, e.g., an exponential vs. polynomial dichotomy in the counting of operators. We explore these ideas explicitly in a toy qubit model of quarks. We further investigate the stabilizer Rényi entropy of meson and baryon states as a proxy for the complexity of classical simulation for these states. We show that all mesons display power law complexity and present evidence that typical baryons display super-exponential complexity in the Veneziano limit.

Inflaton decay inevitably emits gravitons through bremsstrahlung during reheating. We show that the soft part of this emission amplitude, fixed by Weinberg's soft-graviton theorem, becomes an irreducible stochastic gravitational-wave (GW) background after accounting for cosmological evolution. The theorem fixes the infrared branch of the spectrum, $\Omega_{\rm GW}\propto f$, independently of the microscopic operator responsible for inflaton decay, while the normalization is controlled by the hard inflaton decay rate and by a phase-space factor. We carry this out for inflaton $n$-body decays, including the phase-space integrals, finding that the maximum of the spectrum scales as $2/n$ relative to the $n=2$ case. The signal can reach $\Omega_{\rm GW}h^2\sim \mathcal O(10^{-17})$ at frequencies above the GHz scale. This predicts a stochastic graviton floor from perturbative reheating: a larger signal would require either other processes beyond perturbative bremsstrahlung or inflationary scenarios beyond conventional single-field slow roll.

We study the Kaluza–Klein descent of non-invertible higher-form symmetry defects from eleven-dimensional Supergravity to Type IIA Supergravity. Starting from the eleven-dimensional construction of non-invertible Supergravity defects, we show that the full defect, including its auxiliary topological sector, admits a pushforward along the M-theory circle in the zero-mode Supergravity regime. The seven-dimensional Chern–Simons-like auxiliary theory descends to a six-dimensional \(BF\)-type sector. We also show that the compactification of the eleven-dimensional Bianchi sector splits into an invertible \(H_{[3]}\)-sector and a twisted non-invertible \(\widetilde F_{[4]}\)-sector, controlled by \(d\widetilde F_{[4]}+H_{[3]}\wedge F_{[2]}=0\). The resulting Type IIA defect algebra contains both an invertible Picard subgroup and non-invertible \(BF\)-dressed defects, with charged probes identified through the standard M-theory/Type IIA brane dictionary.

We construct a BRST-exact quartet mechanism in $SU(3)$ Yang-Mills theory in the Landau gauge. The quartet sector is cohomologically trivial in the standard vacuum, ensuring equivalence to pure Yang-Mills theory, and its transformation rules carry both commutator and anticommutator structures, enlarging the field content from eight to nine degrees of freedom. The quartet prepotential is oriented by an auxiliary adjoint field $\mathcal N_3$ of mass dimension two (the Cartan spurion) through a BRST-exact term, and the spurion sector is closed by a perfect-square potential $\lambda_1\mathrm{Tr}[(\mathcal N_3-\mu^2T^3)^2]$, whose seed $\mu^2T^3$ is the unique external scale of the model. As an algebraic quantum field with covariant BRST law $s\mathcal N_3=ig[\mathcal N_3,c]$, $\mathcal N_3$ keeps the counterterm space finite by power counting. The coupled classical field equations admit an exact stationary solution $\langle\mathcal N_3\rangle=\mu^2_{\mathrm{eff}}T^3$, around which the gauge fields acquire a mass matrix proportional to $d^{3ab}$ only, reproducing the $i$-particle propagator structure of earlier replica models without explicit breaking terms: a massless $(1,2)$ sector and complex-conjugate poles in the $(4,5)$, $(6,7)$ and diagonalized $(3,8)$ sectors. To respect the BRST doublet theorem, we separate background generation from observable cohomology. Introducing a background-equivariant covariant Cartan frame, we show that the filtered $i$-particle bilinear is the lowest component of an all-orders off-shell BRST cocycle. At one loop, its two-point function admits a Kallen-Lehmann representation with a real positive threshold and positive spectral density, despite the complex poles of the elementary propagators. The fully quantized action provides a consistent starting point for algebraic renormalization.

We find solutions to consistent truncations of supergravity where some real scalars are analytically extended to imaginary values, ensuring the metric remains real-valued. Among the solutions there are Lorentzian traversable wormholes connecting two asymptotically Anti-de Sitter spacetimes and flows that have a real metric also when uplifted to ten or eleven dimensions. We argue that the holographic duals are pseudo-Hermitian and $PT$-symmetric theories. Wormhole solutions also admit an interpretation as the low-energy theory of two stacks of branes and antibranes after tachyon condensation. The wormhole is then dual to an entangled state of two copies of the theory that lives on a stack of branes. We present some evidence by computing the mutual information between the theories at each boundary and by identifying the Goldstone bosons associated to the breaking of the two copies of Poincaré symmetry to their diagonal subgroup.

A reason is discussed (may be not the only one) for why we do not see any superposition of macroscopic states in the real world. Under the general assumption that quantum macrostates are statistical ensembles of microstates, it is shown that any superposition of macrostates is reduced in a very short time by the unitary dynamics of the ordinary Schrödinger equation, deducing the Born rule without having to postulate it. In more detail, the macroscopic and microscopic degrees of freedom are decoupled in the Schrödinger equation, yielding an effective stochastic equation for the macroscopic variables, with the ensemble average of the microscopic amplitudes that acts as a self-generated internal white noise. The stochastic equation is shown to be a reducing Itô equation if some general causality conditions are met, predicting a very quick collapse of any macroscopic superposition upon formation, with probabilities which satisfy the Born rule. In the context of the von Neumann measurement scheme, the relevance of the result is discussed as a simple dynamical solution of the measurement problem.

We consider the bulk $\phi^3$ deformation of the free boundary conformal field theory in the $\epsilon$ expansion. We determine the leading corrections to the scaling dimensions of boundary fundamental operators and some boundary operator expansion coefficients. Our procedure combines the conformal multiplet recombination with the boundary crossing symmetry. The results cover both the single field case and the multi-field case with $S_{N+1}$ global symmetry, which are associated with the Yang-Lee model and the $(N+1)$-state Potts model respectively. These semi-infinite models describe branched polymers, percolation, and spanning forest at a surface. We generalize these results to some higher derivative theories. In addition, we study the $\phi^{2n+1}$ theories with $n>1$, but only obtain some boundary operator expansion coefficients.

We study the Sudakov form factor and the four-point scattering amplitude on the Coulomb branch of planar $\mathcal{N}=4$ SYM as functions of the Coulomb-branch parameters and kinematic invariants. This setup provides a controlled probe of the interpolation between on- and off-shell regimes of infrared-sensitive quantities in gauge theories. We identify a novel scaling limit in which both observables exhibit double-logarithmic behavior governed by a walking anomalous dimension. As the mass scales are varied, this walking anomalous dimension interpolates between the cusp anomalous dimension of the on-shell regime and the octagon anomalous dimension of the off-shell regime. Based on the explicit two-loop result and the expected all-order structure, we propose an all-loop form for the walking anomalous dimension both for the form factor and for the four-point scattering amplitude. These all-loop expressions depend on new, presently unknown functions of the 't Hooft coupling.

We analytically prove the linear radial stability of non-Abelian black holes with quartic self-interactions. The background, constructed from the Wu-Yang magnetic monopole ansatz, is an exact black-hole solution carrying a non-Abelian magnetic charge $Q_{\rm NA}^2$ controlled by a single coupling parameter $\chi$, and admits two distinct branches. The odd sector is always stable, while in the even sector the effective potential is positive for branch~I and negative for branch~II, establishing stability and potential instability, respectively. The potential instability of branch~II is consistent with its connection to the perturbatively unstable Einstein-Yang-Mills Reissner-Nordström solution. Branch~I remains linearly stable throughout the physical domain of $\chi$ where the solutions are regular and free of naked singularities. The stability of branch~I is further confirmed through a numerical computation of the quasinormal mode spectrum using Leaver's continued fraction method and time-domain evolution supplemented with Prony method, showing no unstable modes. Our results prove the existence of the first linearly stable asymptotically flat hairy black holes in four dimensions with a minimally coupled non-Abelian Proca self-interaction.

A systematic study of chiral effects is presented using an Effective Field Theory framework. By integrating out a massive Dirac fermion at finite temperature in presence of vector and axial background fields, the currents and their anomalies are computed from the path-integral. Chiral effects previously considered separately naturally arise in a unified computation, including new mass corrections. The link between each anomalous transport effect and the anomalies is clearly established, beyond the identification of their coefficients. In particular, we can appreciate how these effects are sourced by the anomalous nature of the theory even in configurations where the anomaly itself vanishes. The consistent and covariant anomalies are both encapsulated in master formulae for the currents which result from a careful treatment of the regularisation. It is finally found that, at finite temperature, the physical currents cannot be inferred simply from the Chern-Simons terms whose divergence reproduce the chiral anomalies.

Double parton scattering provides a sensitive probe of multiparton correlations inside hadrons. In this work we present a numerical study of unintegrated double parton distribution functions constructed from non-factorized collinear DPDFs. As input we use the GS09 DPDFs and evolve them to unequal scales with a numerical double DGLAP evolution framework, which is validated through the corresponding momentum and valence-number sum rules. We investigate MRW-inspired prescriptions for generating transverse momentum dependence in the double parton case. In particular, we study the double LO-MRW approach (DLO-MRW) in the perturbative region, the double modified KMRW approach (DMKMRW), the double virtuality ordered MRW (DVO-MRW) model, and a normalization-matched version of the latter. The DMKMRW, DVO-MRW, and matched DVO-MRW prescriptions can be applied directly to the full collinear DPDF, including its nonhomogeneous component, and avoid the piecewise treatment required in the conventional LO-MRW construction. We analyze the normalization, transverse momentum dependence, flavor dependence, and sensitivity to longitudinal DPDF correlations of the resulting distributions. The DMKMRW model is normalization preserving by construction, while the DVO-MRW model shows nontrivial normalization deviations that are removed in the matched version. Non-factorized effects are strongly channel-dependent. In DMKMRW, they enter mainly through longitudinal DPDF correlations, whereas in the LO-MRW and virtuality-ordered models, they also modify the transverse momentum shape. The largest deviations occur near the double parton kinematic boundary and in channels affected by valence-number and quark-antiquark correlations.

Wegner's $\mathbb{Z}_2$ gauge model is the earliest formulation of pure lattice gauge theory and predicts the topological nature of the confinement-deconfinement transition. In three dimensions ($D=3$), the equilibrium critical behavior of the model is understood in terms of geometrically defined objects, namely loop excitations and Fortuin-Kasteleyn (FK) clusters. This work investigates the critical quench dynamics of this model from a geometric perspective, following quenches from both a high-temperature percolation phase and the zero-temperature ground state. Using time-dependent finite-size scaling analysis, we find that the critical non-equilibrium relaxation of the percolation order parameter is governed by a dynamical exponent $z_{\rm p} \simeq 2.6$, consistent with that associated with the energy density, $z_{\rm c}$. Importantly, the value of $z_{\rm p}$ is robust with respect to the initial quench condition and the choice of geometrical objects. Furthermore, we provide a detailed characterization of the kinetics of different geometrical objects during the evolution from the percolation phase. Notably, we observe that the quench dynamics obeys dynamic scaling in terms of a growing lengthscale, $\xi_{\rm p}(t) \sim t^{1/z_{\rm p}}$, despite the absence of a local order parameter.

According to the formulation of the charged large $D$ membrane paradigm, an arbitrary dynamic black hole solution to a theory of gravity with a $U(1)$ gauge field is dual to the dynamics of a membrane in a non-gravitational background. This membrane is endowed with a stress-energy tensor and a charge current, whose conservation equations govern its dynamics. In this work, we demonstrate that the dynamics of these membrane configurations (at the leading nontrivial order in $1/D$) can be mapped to a relativistic charged fluid, establishing a correspondence for asymptotically flat black holes with a particular class of fluid systems. Unlike the standard AdS/Hydrodynamics correspondence, this dual fluid does not reside on an asymptotic boundary, but is localised strictly on the non-gravitational membrane worldvolume. By evaluating the system in both the Eckart and Landau frames, we systematically extract the out-of-equilibrium transport coefficients. We find that the fluid is governed by a negative effective thermal conductivity and a negative heat capacity. This mechanism provides a hydrodynamic interpretation of thermodynamic stability, effectively translating the previously established quasinormal mode damping of the large-$D$ Reissner-Nordström geometry into the language of fluid dynamics.