Papers

We calculate the magnetic dipole moments of doubly strange hidden-charm pentaquark states with spin-parity $J^P = 1/2^-$ and $3/2^-$ using QCD light-cone sum rules (LCSR), presenting the first systematic LCSR investigation of the electromagnetic multipole structure in the $S = -2$ sector. To assess the model dependence, we employ independent interpolating currents in diquark-diquark-antiquark form, which probe different assumptions about the internal color-spin correlations. For the spin-$3/2$ states, we also compute the electric quadrupole and magnetic octupole moments. The magnetic dipole moments exhibit a considerable spread across currents, ranging from $-2.15\,\mu_N$ to $5.74\,\mu_N$ for spin-$1/2$ pentaquarks and from $-4.25\,\mu_N$ to $-0.43\,\mu_N$ for spin-$3/2$ states, reflecting the sensitivity of magnetic moments to the internal wave function. A quark-level decomposition reveals that the charm quark dominates in most configurations, while strange quarks play a decisive role only in currents favoring axial-vector diquark structures. The electric quadrupole moments lie between $-2.01\times10^{-2}$ fm$^2$ and $5.55\times10^{-2}$ fm$^2$, and the magnetic octupole moments are typically an order of magnitude smaller. The current dependence of the magnetic dipole moments provides a quantitative measure of the theoretical uncertainty arising from the choice of interpolating operator. The pronounced isospin sensitivity of $J^3_\mu(x)$ across all three multipole moments arises from its axial-vector diquark structure, which isolates the light quark from spin averaging and allows the charge asymmetry $e_u/e_d = -2$ to propagate directly into the electromagnetic moments; the ratio $\mu_u/\mu_d = -2.00$ confirms this mechanism exactly. Our predictions offer benchmarks for future experiments and lattice QCD calculations, and may help discriminate among competing structural models.

We study the entanglement of low-energy excited states after a fixed-outcome projective measurement on a spatial interval in a (1+1)-dimensional conformal field theory (CFT). We restrict to post-selected measurement outcomes whose induced boundary condition flows in the infrared to a conformal boundary condition. Such an outcome is represented by a slit carrying that boundary condition, while excited states are introduced by operator insertions in the Euclidean path integral. After mapping the replicated slit geometry to a disk, the excited-state contribution to the post-measurement Rényi entropy is expressed as a normalized boundary-CFT correlation function. We apply this framework to the compact free boson CFT. For the chiral current excitation, the relevant ratios are given by current hafnians. We also study coherent superpositions of $J$ and $\bar J$, and of conjugate compact vertex operators. In the conjugate-vertex case, the ordinary-cylinder second Rényi ratio is independent of the relative phase, whereas the finite-slit post-measurement ratio contains phase-sensitive interference terms. Finally, we describe free-fermion and multi-Slater determinant methods for testing these predictions in the critical XX chain.

In the scattering of two electric charges, the particles acquire a shift in their net boost-like angular momentum, balanced by an opposite field contribution. This electromagnetic scoot effect appears at first order in post-Minkowskian expansion (1PM) order when conservation laws are evaluated on constant-time slices, but disappears at this order on hyperboloidal slices. Here, we extend this analysis to scattering involving both electric and magnetic charges and compare the results with the purely electric case in the context of multiparticle state representations.

We study integrable boundary states of the alternating SU(4) spin chain arising in ABJM theory. Starting from the $KT$-relation, we directly solve the integrability constraints for states with $n$-site translational invariance. For odd and even $n$, these constraints are reduced respectively to state equations and operator equations for the elementary $n$-site block and the matrix $K(u)$. We analyze chiral and achiral cases for $n\leq4$. In the 1-site case we allow general operator-valued integrable pairs with an internal space, while in the remaining cases we focus on $c$-number solutions.

We study a static, spherically symmetric black hole obtained from Einstein gravity coupled to a nonlinear electrodynamics model with a quark–antiquark confinement interaction. The metric extends Reissner–Nordström by a logarithmic correction controlled by $\zeta$, modifying both horizon structure and the near-singularity regime. The Hamilton–Jacobi tunneling method for Dirac fermions yields the Hawking temperature; the $\zeta$-dependent terms suppress the small-horizon divergence and signal a remnant. Quantum-gravitational fluctuations are incorporated through Barrow entropy with deformation index $\Delta$. Within the extended phase space we compute the internal energy, free energy, pressure, heat capacity, isothermal compressibility, and Joule–Thomson coefficient. The heat capacity locates $\Delta$-dependent stability regions; the compressibility stays negative across the domain analysed here, marking a mechanically rigid phase with no van der Waals criticality in this branch. The central result is a quadruple coincidence: the peak Hawking temperature, the heat-capacity divergence, the Joule–Thomson inversion, and the zero of the radial tidal force all sit at one radius $r_\star$ defined by $A''(r_\star)=0$, while the extremal horizon and the angular tidal-force zero coincide via $A'(r_h)=0$. These reduce the full critical-point analysis to two scalar equations on $A(r)$. Geometric tidal accelerations are mapped against the thermodynamic critical curves. Event Horizon Telescope observations of Sgr~A* translate into a constraint $\zeta\lesssim 0.7$ at $Q/M=0.5$, leaving a finite window open. The confinement term induces observable corrections to geodesic deviation.

We give an operator-algebraic and representation-theoretic description of the Hilbert spaces of finite-$N$ bilocal holography. This work is a sequel to the finite-$N$ Hilbert space construction of arXiv:2602.20788 [hep-th]. The central result is the establishment of an invariant dual-pair operator algebra: before imposing the singlet constraint the Fock space carries commuting actions of the color group and of a bilocal Lie algebra, while the projection to the singlet sector selects a single irreducible representation of the invariant Lie algebra, which we call a master algebra. The finite-$N$ trace relations, beginning with the quadratic identities studied here, are shown to become representation-theoretic identities of the selected irreducible representation. We summarize the orthogonal, symplectic and unitary cases, identify the corresponding finite-$N$ constraints, compute the singlet Casimirs, and explain how finite traces and partition functions are obtained through characters of the resulting irreducible representations. This provides a novel, previously unknown mathematical description of the singlet space.

Two-sided octonionic $E_6^L\times E_6^R$ unification carries a nominal second colour $SU(3)_{c'}$ which, gauged, would colour the charged lepton and must be suppressed by hand. We argue no such device is needed: the left-right symmetry acts in spacetime, not internally – in the gravi-weak reading $SU(2)_R$ is the gravitational frame group and the exchange is ordinary parity on the Dirac field; a spacetime operation cannot double the internal colour, so $SU(3)_{c'}=SU(3)_c$, one vector-like colour with a colour-singlet electron. The right sector contributes one colour-blind datum, $\sqrt m$ (values: the exceptional-Jordan trace split, an input; $N_R$ fixes only the colour representation). An anomaly no-go proven here shows every anomaly-free $U(1)$ on visible fermions lies in span$\{Q,B-L\}$, which the $\sqrt m$ pattern does not, in any sign or chirality assignment. The gauged dark-electromagnetic $U(1)_{dem}$ – the mirror electroweak chain's unbroken remnant – therefore carries the parity-mirror of electric charge on the dark sector: the visible fermions are dem-neutral (kinetic mixing the sole portal; no visible fifth force), and $\sqrt m$ enters visible physics only as the spectral label of the Jordan mass operator. The same recognition recovers hypercharge as the consistency relation $Y=Q-T^3_L$, $Q=N/3$, with no right-sector generator. As an application, the spontaneous parity forbids the QCD vacuum angle ($\theta_{QCD}=0$, conditional on the gravi-weak identification), while the flavour rotors have real determinant, so $\arg\det M=0$ at tree level (exact for the Cabibbo rung, texture-contingent in full), coexisting with a nonzero CKM phase. Loop stability – where minimal gauged-$SU(2)_R$ parity solutions fail – is plausibly evaded (no gauged $W_R$) but open, pending the Higgs-bridge matrix elements. We tag throughout what is derived, what is input, and what is open.

Infrared divergences (IRDs) are usually treated as pathologies to be cancelled, regularized, or hidden in dressed asymptotic states. This paper develops a complementary and constructive viewpoint: an IRD is the signature of an itinerant vacuum – a quantum vacuum that wanders continuously through a family of inequivalent states as a classical order parameter evolves. Each value of the order parameter carries its own coherent vacuum, so moving the order parameter means traversing a succession of orthogonal vacua. The IRD is the field-theoretic cost of this wandering, and the $1/f$ noise, gravitational memory, and non-Gaussian fluctuations that emerge from it are its observable classical remnants. The technical core is an exact separation in the real-time closed-time-path (CTP) effective action. The infrared-divergent imaginary part of the influence functional must not be left as a divergent coefficient in a deterministic equation of motion; it is instead converted, by a Hubbard–Stratonovich identity, into a classical stochastic source. This step is an algebraic identity of the generating functional and requires no prior coarse graining or decoherence assumption: the retarded kernel encodes the memory of past vacuum transitions, while the noise kernel encodes the quantum uncertainty of the next one. We apply this construction to four parallel arenas – soft QED, scalar fields in de Sitter space, soft gravitons, and non-equilibrium phase transitions – and show that the same itinerant-vacuum mechanism underlies $1/f$ current noise, the primordial power spectrum, gravitational memory, and order-parameter dynamics. A geometric formulation in terms of a Hilbert-space bundle over the vacuum manifold is outlined as an outlook.

In spread complexity, the growth rate of the average position of a time-evolved state along its Krylov chain recovers the proper radial momentum of an infalling particle in AdS. It is, however, a measure of the first moment only, irrespective of the spread of the wavepacket away from its classical trajectory. The rate of a normalized Krylov-Wigner negativity can be proposed as a diagnostic of the second moment of the boundary state that captures this spreading. Starting with the seed-normalized Krylov-Wigner distribution, that is, the Wigner transform of the descendant cloud with the decaying return amplitude divided out, we obtain an analytic Bessel form in the macroscopic limit and compute its total negativity explicitly. Retaining the Bessel variable all the way through, we find that the negativity goes as $\sinh^{4\Delta}(\pi t/\beta)$. But the raw normalized-state negativity saturates to an $O(1)$ constant, well below the $O(\sqrt{D})$ bound. Using the exact negative binomial statistics of the Krylov chain, the normalized negativity is at late times a fixed power of the second moment of the Krylov wavepacket, $\mathcal{N}(t)\propto[\mathrm{Var}(\hat{N}_{\mathrm{Krylov}})]^{\Delta}$, for every $\Delta>1/2$. The relation linearizes precisely at $\Delta=1$. In this regime via the momentum dictionary of Caputa et al. (arXiv:2410.23334), the rate becomes the product of the proper radial position and momentum, $\mathcal{R}\propto\mathcal{C}\,P_\rho$, which we interpret as the rate of the tidal stretch of nearby geodesics falling into the horizon. We also comment briefly on a speculative direction for future research, in particular the interpretation of the transverse string size operator in terms of the Krylov number operator through the common $\mathrm{SU}(1,1)$ discrete series.

Within the framework of generalised entropic cosmology and its equivalent $f(Q)$ gravity, we construct inflationary scenarios consistent with recent Atacama Cosmology Telescope (ACT) observations combined with Planck-BAO data. We work with $f(Q)$ gravity and use the reconstruction scheme from which one can obtain an arbitrary cosmological evolution consistent with desirable theoretical or observational considerations. Explicit inflationary cosmologies of the above theory, which pass ACT-Data Release 6 (DR6) data combined with Planck and BAO, are obtained. For $f(Q)$ gravity coupled with scalar, we obtain ACT inflation for large classes of $f(Q)$ via the choice of the scalar potentials. The entropic cosmology based on generalised entropy, which includes most of the known entropies like Tsallis, Rényi, Barrow, etc as a particular case, is investigated. The corresponding FRW equations, depending on the parameters of generalised entropy, are presented. Using the correspondence between the generalised entropy and $f(Q)$ gravity, we obtain generalised entropic inflation, which is consistent with the ACT-DR6. At the next step, the entropic gravity coupled with scalar is considered. It is demonstrated how one can obtain ACT-DR6-consistent inflation for such a theory based on any generalised entropy considered in this paper via the choice of scalar potentials. These findings may point towards the correct unifying entropy of the early universe.

We present a framework connecting the algebraic consistency of the Operator Product Expansion (OPE) in Conformal Field Theories to observable signatures in the stochastic gravitational wave background (SGWB). By interpreting the conformal 6j symbols as crossing kernels, we extract the anomalous dimensions $\gamma_{n,J}$ of double-trace operators from the singularities of the crossing equation. Through the AdS/CFT correspondence, these algebraic shifts are holographically reinterpreted as effective mass shifts in the Anti-de Sitter bulk. We identify a critical anomalous dimension, $\gamma_c$, which marks the threshold where the effective mass violates the Breitenlohner-Freedman bound. Upon analytic continuation to de Sitter space ($L_{\text{AdS}} \to iL_{\text{dS}}$), we demonstrate that crossing this threshold ($\gamma < \gamma_c$) forces the dual scaling dimensions into the complex principal series, $\Delta_{\text{dS}} = d/2 \pm i\mu$. This complex dimensionality induces characteristic logarithmic oscillations in the four-point correlators. In the cosmological context, these oscillations manifest as a log-periodic modulation in the SGWB, characterized by a specific spacing $\Delta \ln f = 2\pi/\mu$. Detecting this log-periodic structure with next-generation interferometers such as LISA would directly measure the parameter $\mu$, closing the loop between abstract OPE associativity and observational cosmology.

Quantum states of Neon-20 are generally agreed to lie in rotational-vibrational bands of a cluster of five alpha particles. However, more than one cluster shape has been proposed as dominant at low energy. As relative motion within a cluster is soft in certain directions, we investigate how the low-lying rotational bands of Neon-20 can arise from a circle of clusters connecting favoured shapes: a triangular bipyramid, a square pyramid, and a $D_{2d}$-symmetric distorted tetrahedron – a twisted bow-tie. Motion around the circle extends the Berry pseudo-rotation that connects differently oriented bipyramids.

We study pole-skipping for a scalar field in the JT/AdS$_2$ black-hole background. Previous work established the local mechanism: at a pole-skipping point, a near-horizon recurrence relation becomes degenerate and an additional regular expansion coefficient is left undetermined. We take this local degeneracy as the starting point and track two independent solutions normalized at the AdS boundary, denoted by $R_1$ and $R_2$ for the source and response branches, respectively. Let $\widehat A$ and $\widehat B$ denote the source and response coefficients after their common singular factor is removed, and let $\chi_\mu$ denote the universal ingoing horizon factor. We find \[ \widehat A=0 \Longleftrightarrow \frac{R_2}{\chi_\mu}\in C^\infty, \qquad \widehat B=0 \Longleftrightarrow \frac{R_1}{\chi_\mu}\in C^\infty . \] Thus the source and response zeros correspond separately to horizon smoothness of the two boundary-normalized solutions after the ingoing factor is removed. At integer resonance the local regular solution contains an additional coefficient $a_N$. In the JT/AdS$_2$ model, continuation of the nonresonant ingoing solution fixes $a_N=0$ and thereby selects a unique retarded value at resonance, although unrestricted approaches in parameter space remain path dependent. At the endpoint of the pole-skipping lattice, the response branch is a lowest-weight state of the background $SL(2,\mathbb R)$ symmetry. A static holographic-superconductor example further shows that simultaneous horizon smoothness is insufficient if the two boundary branches are linearly dependent. A two-branch pole-zero intersection therefore requires \[ W[R_1,R_2]\neq0. \] These results distinguish the known local horizon degeneracy from the global relation between boundary branches and the resonant horizon solution space.

In the functional-integral formulation of Euclidean field theory, exact renormalization group (ERG) transformations are realized by functional-integral kernels. Unlike the ERG flow equations that describe infinitesimal ERG transformations, these ERG kernels explicitly depend on the global topology of the configuration space. This paper explores this topology dependence for multiply connected configuration spaces. We show that the ERG kernel is in general given by a weighted sum of kernels on its universal covering space, where the weight factors are determined by a one-dimensional representation of the fundamental group. These weight factors are shown never to be renormalized under the ERG. We also show that these factors can be interpreted as Aharonov-Bohm phases with respect to a background magnetic flux penetrating the infinite-dimensional configuration space. From this viewpoint, a normalization condition for ERG transformations corresponds to a flux-quantization condition, which is equivalent to the level-quantization condition for Wess-Zumino-Witten terms in nonlinear sigma models. Finally, we present an alternative gauge-equivalent form of the ERG flow equation that incorporates this topological information locally.

We construct reversible black hole heat engines in asymptotically flat spacetime using quasi-local gravitational thermodynamics. We enclose a Schwarzschild black hole in a finite spherical cavity and identify the working substance with the holographically dual thermal system on the cavity boundary. The surface pressure and the boundary area define a thermodynamic pressure-volume pair, while all coupling constants of the gravitational theory remain fixed. We derive exact efficiencies for the Carnot, Otto, Diesel, Brayton, and Stirling engines and compare them numerically. The non-Carnot efficiencies probe the quasi-local equations of state of the Schwarzschild black hole. Both the regenerative and non-regenerative Stirling efficiencies on the large black hole branch approach the Carnot value in the high-temperature limit, with regeneration reducing the leading deviation from the Carnot bound.

The equal-charge branch of supersymmetric rotating AdS$_5$ black holes has $Q_1=Q_2=Q_3$. The corresponding microcanonical sector of the $\mathcal{N}=4$ superconformal index is obtained by projecting to equal charges, or equivalently by extracting the constant term in the two charge-difference fugacities. We prove that for the large-$N$ multigraviton sector the projected index factorizes exactly as \[ \mathcal{I}^{\rm eqQ}_\infty(x,p) =\prod_{k\ge1}(1-p^kx^{3k})(1-p^{-k}x^{3k}) \sum_{n\ge0}\mathsf{p}(n)^3x^{6n}, \] where $\mathsf{p}(n)$ is the partition function. This factorization gives, for every spin sector, an explicit onset energy below which the large-$N$ coefficient is zero. Exact $U(3)$ computations show that finite-rank coefficients can nevertheless appear at energies where the large-$N$ coefficient vanishes, including beyond the classical $U(3)$ black-hole bound. We also determine the full line $j=6J_R+6$. In particular, with $j^*(J_R)$ denoting this large-$N$ onset energy, \[ d_3^{\rm eqQ}(87,\tfrac{27}{2})=1, \qquad j^*(\tfrac{27}{2})-87=1554, \] and the first giant-graviton sector already contributes one unit at this point. All coefficients are coefficients of the $(-1)^F$-graded index, not positive degeneracies. The main conclusion is that the high-spin tail survives the exact equal-charge projection.

We show that Holographic Renormalisation (HR) in eight dimensions is encoded in the unique conformal gravity theory that admits an Einstein sector with constant negative curvature. We explicitly relate HR to Topological Regularisation (TR), where the latter prescribes to add the Euler term to the Einstein-Hilbert Lagrangian density, with a precise coefficient so as to ensure that the resulting density is polynomial in the anti de Sitter (AdS) curvature. The polynomial is still asymptotically divergent. We find that the aforementioned, unique conformal gravity action in 8D, reproduces the polynomial, together with extra boundary terms that cancel the divergent terms in the action. We conjecture that, in arbitrary even dimension, HR is equivalent to conformally completing the Einstein-Hilbert action with negative cosmological constant, plus the Euler term with fixed coupling prescribed by TR.

We study axial gravitational perturbations of the neutral regular black hole generated by a non-local, T-duality-inspired zero-point length and the associated gravitational self-energy. In this geometry, the usual point source is replaced by a regular core, and the zero-point length controls the departure from the Schwarzschild limit. We compute the fundamental quasinormal modes and several overtones using high-order WKB–Padé methods, and we verify the dominant mode via direct time-domain evolution. When the zero-point length is turned on, the real parts of the ADM-scaled frequencies increase for the gravitational modes with $\ell=2,3,4$, so the ringdown oscillates faster than in the Schwarzschild limit. The damping rates change more gradually: they initially increase slightly and then decrease near the largest deformation values considered here. This behavior is consistent with the effective potential, whose barrier becomes higher as the deformation parameter increases. We also compute the corresponding excitation factors and find that their magnitudes vary much less strongly than the quasinormal frequencies.

We derive new exact formulae for elliptic genera in two spacetime dimensions with $\mathcal{N}\ge 2$ supercharges, as well as their one- and zero-dimensional counterparts (for Witten indices and matrix-model partition functions). Our results are written as a discrete sum over geometric/combinatorial structures of crystals introduced previously by the authors. The contribution from each crystal may be expressed in terms of the boundary data of a finite substructure of the crystal called the molecules. Our results provide vast generalisations of the celebrated Nekrasov partition function enumerated by the Young diagrams, and uncover new combinatorics underlying the crystal melting. We also analyse the thermodynamic limit of crystals arising from two-dimensional $\mathcal{N}=(0,2)$ theories associated with toric Calabi-Yau fourfolds, where a projection of the Calabi-Yau geometry emerges in the limit.

We develop a top-down counterpart of the minimal proper-time formulation of quantum field theory previously introduced as an effective bottom-up framework. Starting from a deterministic pre-geometric substrate of causally ordered events, we show how coarse-graining over microscopic histories leads, at low energies, to an effective Nambu-like quantum dynamics. The elementary deterministic update is identified with the minimal proper-time step, while the growth of coarse-grained equivalence classes controls both the ultraviolet dissipative correction and the scale dependence of the effective quantization strength, encoded in a running Planck constant. In this way, the proper-time cutoff kernel of the bottom-up formulation acquires a microscopic interpretation as the inverse growth of unresolved deterministic histories. In the infrared limit, the dissipative term vanishes and standard unitary quantum field theory is recovered. The same coarse-grained structure also provides a natural setting for an emergent relativistic spacetime geometry, compatible in the macroscopic limit with Einstein gravity. The resulting picture suggests a common deterministic origin for minimal-scale structure, quantum behavior, and relativistic spacetime.

We unify two independent notions of effective temperature in dynamical thin-shell wormholes: the local acceleration temperature of the throat and the Hawking-like particle-creation temperature governed by the peeling of null rays. The effective acceleration scale, obtained by averaging over both sides of the junction, defines the thermodynamic shell temperature, while peeling functions for each asymptotic universe yield an effective particle-creation temperature. For asymptotically exponential null-ray maps, we derive the generalized Unruh identity that equates these two temperatures. Applied to Schwarzschild-Schwarzschild wormholes, the formalism yields explicit analytical expressions for the Hawking-like spectra, renormalized quantum fluxes, and quasi-horizon limits in both symmetric and asymmetric configurations. The divergence of the shell temperature near the quasi-horizon is shown to mirror the divergence of the local Tolman temperature, both originating from the infinite gravitational blueshift at a horizon. These results provide a unified interpretation of acceleration, particle creation, and temperature in horizonless dynamical spacetimes, extending the conceptual link between the Hawking and Unruh effects beyond stationary black holes.

Swift memory burden (MB) implies that the information stored in a black hole (BH) can modify its classical dynamics when the BH is perturbed. This influences the gravitational waves (GWs) emitted during BH mergers. In this paper, we investigate how the BH memory load is determined by the features of the collapsing source. We show that the memory load can vastly exceed the information content of its progenitor. An extreme example is a BH formed in a two-particle collision, which exhibits maximal MB. We then derive bounds for BHs formed through stellar collapse and examine the impact of swift MB on BH quasinormal modes, quantifying the MB-induced frequency shift of GWs. These findings imply that GW observations probe the fundamental mechanisms of BH information storage as well as their formation history.

Fixed-point (FP) tensor networks provide a discrete spacetime representation of conformal field theories (CFTs), offering a new route toward understanding holographic duality, generalized symmetries, and even quantum gravity. In this work, we construct FP tensors for the 2D compactified boson theory at a generic compactification radius, an archetypal irrational CFT, using boundary (open-string) data with conformal boundary conditions. We show that the resulting tensors reproduce the closed-string spectrum with high accuracy and generate stable renormalization-group (RG) flows under the tensor complex renormalization algorithm. Moreover, we identify a controllable exactly marginal deformation at the level of a single tensor, enabling flows that move continuously along the $c=1$ moduli space. This framework establishes a concrete lattice-level route toward describing a broad class of 2D irrational CFTs.

How do we define a bulk subsystem in quantum gravity? In \cite{Wong:2025kpz}, we argued that such a subsystem must support local holographic degrees of freedom. These are gravitational edge modes, whose entanglement creates a backreaction that fuses together subregions of spacetime. In this work we give a realization of these ideas in topological string theory, building upon \cite{Donnelly:2020teo,Jiang:2020cqo}. In this theory, a subsystem for closed strings consists of open strings ending on entanglement branes, which play the role of a dynamical entangling surface. Local holography is implemented by the geometric transition of these branes. We define a subregion open string algebra and develop a diagrammatics for open string modular flow for arbitrary states and subregion. We check that the entanglement entropy of these open strings reproduces the gravitational entropy of the associated closed string background. Finally, we relate these local transitions to defect holography.

Black hole mimickers, ultracompact horizonless objects, have been proposed as alternatives to black holes in a variety of settings, including extensions of general relativity and scenarios involving matter sectors beyond the Standard Model. Their formation in gravitational collapse of matter requires quantum mechanical tunneling to occur on a length scale of the order of the Schwarzschild radius of the corresponding black hole. We propose a mechanism, based on multichannel enhancement catalyzed by quantum chaotic dynamics, that can dramatically amplify the quantum mechanical transmission across a tunneling barrier. We explore, in particular, how the nucleation of a string theoretic black shell is enhanced via this mechanism. We anticipate similar results to hold for other proposed black hole mimickers.

The perturbative expansion in powers of the coupling of observables in quantum field theory and quantum mechanics is known to yield an asymptotic series. If the original physical system is well-behaved and a finite observable is expected, this can often be calculated via a Borel resummation of the asymptotic series. However, there are cases where a system is well-behaved and the series is not Borel summable. This typically occurs when the physical system has a non-trivial vacuum structure. It has recently been shown that if the perturbative series is carried out under finite path integral limits, one can obtain a convergent series that yields observables even at strong coupling. This was recently used to obtain the energy at strong coupling for the anharmonic oscillator. This is a Borel summable case so the question is whether finite path integral limits work when the series is not Borel summable. To begin answering this question we consider a simple non-Borel summable case: the series stemming from a basic integral where the function has a double-well shape and hence two minima. The integral has an exact analytical expression that the series can be compared to. Under finite integral limits that run from $-L$ to $L$, where $L$ is finite, positive and real, we develop two perturbative series in powers of the coupling: one by expanding the integral about the local maximum at the origin and the other by expanding it about one of the minima. In both cases, we obtain an absolutely convergent series and the series sums to the exact analytical expression of the original integral in the infinite $L$ limit. It is significant that a perturbative expansion about one of the minima reproduces the exact analytical expression because this implies that it captures the full effect of both minima.

We estimate the strength of chaos of probe waves and probe geodesics in different smooth supergravity backgrounds of decreasing supersymmetry and/or increasing length of the AdS throat in the interior. Since BPS spectra are highly degenerate and thus do not display the level repulsion that ordinarily diagnoses chaos, we propose compliance with the Berry random wave hypothesis for probe wavefunctions as a new notion of BPS chaos suited to the supergravity regime. The wave chaos becomes stronger and stronger with less supersymmetry and longer throats (i.e., as we approach black hole solutions). Geodesic motion shows the opposite trend, becoming more and more regular. We explain this dichotomy by the existence of stable periodic orbits inside long throats while the overall measure of KAM tori decreases. Computing the Rényi entropies for the dual CFT states in the weak coupling regime, we show that they do not have such universal behavior.

When calculating the decay width of $H\to b\bar{b}b\bar{b}$ induced by the effective Higgs-gluon-gluon interaction using the optical theorem, the three-loop Feynman diagrams are encountered. Among them, there is an interesting integral family, which involves not only the sectors evaluated to multiple polylogarithms but also those related to an elliptic curve and a K3 surface. We demonstrate how to construct and solve the canonical differential equation for the entire family, which includes mixing between different sectors, by using the recently proposed algorithm in~\cite{e-collaboration:2025frv, Bree:2025tug}. Analytical results for all master integrals in this family up to the first two orders of $\varepsilon$ are given.

We study quantum-gravitational effects on the response of an infalling detector as it crosses the horizon of a near-extremal black hole in the framework of quantum JT gravity. These effects are incorporated via the gravitational dressing needed to define both the infalling trajectory and the local observables probed by the detector in a diffeomorphism-invariant way. In the black hole exterior, a preferred choice of dressing to the Schwarzian mode of JT gravity can be motivated in connection to geometric modular flow. We show how to extend this dressing to the black hole interior, defining local observables that are gravitationally dressed to both boundaries in the thermofield double state. The gravitational dressing connects the near-horizon region to the IR sector of the Schwarzian theory, leading to measurable effects as the horizon is approached. We find that the infalling detector is able to locally determine the location of the horizon and its temperature, violating the equivalence principle, but without encountering a firewall.

Precision studies of radiative return processes at low-energy electron–positron colliders require next-to-next-to-leading order QED predictions retaining full dependence on the electron mass. We present the calculation of planar two-loop four-point Feynman integrals relevant for initial-state radiation contributions to these processes. The calculation presents considerable analytical complexity, due to the presence of a nested square root and of integrals associated with elliptic geometries. We construct differential equations for the Feynman integrals which are polynomial in the dimensional regulator, and are suitable for numerical integration. We demonstrate stable numerical evaluations throughout the physical region relevant for low-energy experiments, despite the presence of large hierarchies of scales. Our results provide essential building blocks for NNLO predictions for radiative return processes.