Papers

It is a problem of great importance in quantum gravity whether quantum effects lead to nontrivial structure near black hole horizons, and if their interiors are emergent features of a large $N$ limit. We show that the strongly chaotic nature of black holes, captured by random matrix statistics of their spectrum, makes it so that a suitably gravitationally dressed infalling observer takes an infinite amount of proper time to reach the horizon. This makes the black hole interior operationally inaccessible to any outside observer, marking a sharp breakdown of the large $N$ causal structure of black holes in quantum gravity. To model the experience of an infalling observer, we study the response of an infalling particle detector coupled to a matter field in a 2d quantum black hole background, finding a peak in the detector's excitation probability as it enters an infinitely long non-perturbative journey close to the black hole horizon.

In this paper, we classify the type IIB uplifts of the $\mathcal{N}=4$ $D=4$ pure $\text{SO}(4)$-gauged supergravity admitting a dS$_4$ solution. As for their AdS cousins, the internal geometries of these uplifts consist of two $S^2$ fibred over a Riemann surface $\Sigma$, and are classified by pairs of harmonic functions $h_{1,\,2}$ on $\Sigma$, providing a new family of de Sitter solutions in type IIB. Choosing specific functions $h_{1,\,2}$ on $\Sigma = \mathbb{R} \times I$, we perform an S-fold quotient of the internal space along its non-compact direction. This S-folding allows us to evade the assumptions of the Maldacena-Nunez no-go theorem and provides a classical de Sitter solution of type IIB supergravity with finite and non-vanishing four-dimensional effective Newton constant.

Within the entropic gravity paradigm introduced by Verlinde, one assumes that the microscopic degrees of freedom residing on the holographic screen obey the equipartition law of energy. Nevertheless, implications of statistical mechanics suggest that this energy sharing can acquire corrections that depend on temperature. Taking such modifications into account leads to altered gravitational field equations when derived from thermodynamic considerations. We solve the resulting modified Einstein equations in the case of a static, spherically symmetric spacetime and determine the general structure of the metric components. Our findings indicate that if the temperature correction function behaves as $f(T)\propto T^{2}$, the corresponding spacetime geometry reduces to the flat Minkowski metric. Therefore, to obtain small deviations from flatness, it is necessary to consider slight departures from this purely quadratic temperature dependence. Such deviations can be interpreted as encoding additional gravitational effects, potentially associated with matter contributions that are not entirely described by the holographic screen. As a result of these effects, the effective gravitational potential acquires a logarithmic correction, which can give rise to deviations from Newtonian gravity. This aspect is especially significant in the regime of very weak gravitational fields, where these corrections may affect particle motion and could carry implications for both astrophysical and cosmological contexts.

We study an ultrarelativistic fluid with no conserved particle number in a planar slab geometry bounded by two parallel, thermally conducting plates held at fixed (possibly different) temperatures. The fluid-wall interaction is described within kinetic theory by modeling the fluid as self-interacting radiation: a gas of bosons emitted and absorbed by the walls according to black-body laws, while mutual collisions enforce local equilibration. From this microscopic setup we derive effective boundary conditions for the hydrodynamic fields, finding that the walls behave as modified absorbing boundaries (and not as thermostats). In particular, the fluid temperature at the boundary does not generally coincide with the wall temperature. We prove that the resulting initial-boundary-value problem is well posed. When the plates are held at different temperatures, the system develops a uniform steady flow from the hotter to the colder wall, with energy density equal to the arithmetic mean of the corresponding black-body energy densities in the limit of a small temperature difference.

We revisit the classical definition of a null string in a D-dimensional Minkowski target space and distinguish a consistent partially-gauged Carrollian sigma-model from the null string theory. The Isberg-Lindström-Sundborg-Theodoridis (ILST) action gauges worldsheet diffeomorphisms and the common Weyl rescaling, but not the independent relative rescaling of the temporal and spatial representatives of the intrinsic Carrollian structure, Carroll-Weyl scaling. A physical string theory requires every local change of worldsheet representative to be gauged, therefore, the Carroll-Weyl symmetry should be gauged in a null string theory. In the minimal realization, the corresponding gauging is obstructed at finite tension, whereas at zero tension it yields an additional first-class constraint and the associated identification of physical configurations along its gauge orbits. The description of the null worldsheet as a congruence of null geodesics provides a complementary target-space interpretation of gauging of the Carroll-Weyl scaling. Our analysis thus provides the supplementary requirements that turns the ILST theory into the null string theory.

We develop a cluster-algebraic description of symbol alphabets for chiral stress-tensor form factors in planar $\mathcal N=4$ super-Yang–Mills theory. Motivated by unfolding the three-point $C_2$ quiver, we propose a periodic framework for $n$-point form-factor alphabets based on folding a $\mathrm{Gr}(4,2n)$ quiver with two periods of frozen nodes. At four points, the folding leads to the $\widetilde{\mathrm{VI}}$ cluster algebra, which has infinitely many cluster variables. Tropical truncation selects a finite set of rational coordinates and four physical limit rays. The $A_1^{(1)}$ mutation sequences approaching these rays generate the four square roots and the corresponding algebraic-letter spaces. Within the resulting finite set of rational candidates, antipodal closure excludes precisely eight additional letters. On the parity-preserving surface, the antipodal map is realized, after a further folding, by two commuting mutations followed by a relabelling. Furthermore, we find an alternative quiver within the same mutation class that becomes self-antipodal after parity folding, mirroring the antipodal self-duality of the four-point MHV form factor. Its double- and triple-collinear boundaries reproduce, respectively, the $C_2$ algebra of the three-point form factor and the $A_3$ algebra of the six-point amplitude; after folding the latter to $C_2$, the antipodal map exchanges the two $C_2$ boundaries.

Loday's derived product is revisited in the setting of Q-manifolds, i.e., supermanifolds equipped with an odd vector field that `squares to zero'. We interpret the Grassmann odd product as a standard product upon shifting the grading, which implies the existence of a derived (noncommutative) associative $\mathbb{Z}_2$-graded algebra associated with any Q-manifold. We apply Connes' cyclic cohomology to the derived associative algebra, giving a new cohomology on Q-manifolds distinct from the standard cohomology: we refer to this as the derived cyclic cohomology of a Q-manifold. The derived cyclic cocycles are interpreted as classically BRST-invariant functionals within the BV–BFV–BRST formalism or generalised Ruelle–Sullivan currents when applied to regular foliations via their foliation Lie algebroids.

Using the language of q-opers, we propose an algebro-geometric description of the duality between Bethe Ansatz equations for quantum XXZ spin chains and many-body trigonometric Ruijsenaars-Schneider/Macdonald systems for classical groups. Upon this duality, the energy level sets of the classical B/C/D-type Hamiltonians are found to be in bijection with the set of solutions of the XXZ Bethe Ansatz equations of type A, albeit with open boundary conditions. This dictionary generalizes previous results in which a GL(N) XXZ spin chain with twisted periodic boundary conditions was dual to an N-body Ruijsenaars-Schneider system. Our construction implements a $\mathbb{Z}/2\mathbb{Z}$ folding both at the level of the (GL(N),q)-oper data as well as at the level of the N-body trigonometric Ruijsenaars-Schneider model. The nonreduced BC-type systems appear in our analysis as well.

We study how finite-$N$ invariant theory organizes the non-perturbative structure of matrix models. For a model of four traceless Hermitian $2\times 2$ matrices, the Hironaka decomposition realizes the gauge-invariant configuration space as an eight-sheeted branched cover of the space of primary invariants. We show that ramification points of this cover naturally generate additional saddle points when the action depends only on the primaries. For an explicit rank-two saddle, we compute its action, one-loop normalization and Picard–Lefschetz connection to the perturbative vacuum. The same saddle controls the leading Borel singularity and large-order growth of perturbation theory, while its first fluctuation correction reproduces the first subleading large-order correction with no fitted parameters. Our results provide a concrete link between finite-$N$ invariant geometry and resurgence in matrix models.

Open-closed-open triality relates two distinct open string descriptions through a common closed string theory. In this paper, we develop an open-closed-open triality for protected half-BPS three-point functions in four-dimensional $\mathcal{N}=4$ super Yang-Mills theory. Starting from determinant insertions representing giant gravitons, we formulate a V-type open-string Gaussian three-matrix model and, through a color-flavor transformation, derive an F-type open-string model of three bifundamental matrices forming a triangular quiver. Its closed quiver walks include oriented cubic cycles, a feature absent from the bipartite two-point case. We test the correspondence by deriving exact finite-$N$ single-giant polynomials, recovering the known F-type large-$N$ saddles, and proving the equivalence of the V- and F-type character expansions via an explicit bijection of their combinatorial data. At the closed string corner, connected three-matrix contractions determine three-colored integer Strebel surfaces. We argue that the corresponding target-space construction is naturally described by a barycentrically subdivided Belyi map or a colored Hurwitz constellation.

We derive the scalar propagator in a thermal medium under global rotation without restricting the spacetime points to a common comoving trajectory. The resulting propagator retains an explicit dependence on the radial coordinates, reflecting the lack of translational invariance in the transverse plane, and therefore cannot in general be formulated solely in momentum space. We show that the usual free Feynman propagator is exactly recovered in the nonrotating limit, providing a first consistency check of the formulation. As a nontrivial test, we apply the propagator to the interacting $\lambda\phi^4$ theory at finite temperature and rotation. The one-loop scalar self-energy obtained within the Matsubara formalism correctly separates into vacuum and medium contributions and reproduces the standard finite-temperature result when $\Omega\to0$. We subsequently construct the effective potential including screening effects through ring resummation and, for $\Omega/T\ll1$, evaluate the rotational corrections up to $\mathcal{O}(\Omega^4)$. Within this model, the resulting effective potential exhibits the expected thermal restoration of the spontaneously broken $\mathbb{Z}_2$ symmetry, while global rotation favors symmetry restoration and enhances this effect as the transverse size of the system increases. These results provide complementary consistency checks of the rotating scalar propagator and highlight the need to retain its explicit position-space structure in more general perturbative calculations.

We study circular geodesics of neutral test particles in the static charged solution of Scalar–Tensor–Vector Gravity (STVG), and we use the twin kilohertz quasiperiodic oscillations (QPOs) of twelve accreting compact objects to bound its parameters. Starting from the effective potential we obtain closed forms for the specific energy, the specific angular momentum and the Keplerian angular velocity, and from these the radial and vertical epicyclic frequencies. The horizon, photon sphere, shadow radius and innermost stable circular orbit are given in closed form as well, and each one reduces to the RN and Schwarzschild value in the appropriate limit. Null geodesics are integrated numerically and show how the enhanced coupling widens the capture cross section while leaving the logarithmic divergence of the deflection angle at the photon sphere intact. Within the RP model we then run Metropolis–Hastings MCMC simulations on the QPO pairs of eight neutron stars and four microquasars, comparing the Schwarzschild spacetime, the RN spacetime, STVG with vanishing charge and the full STVG solution. The best fits are obtained mainly for the charged solutions in the neutron star sample, while all four models describe the black hole sample equally well. We show that the orbital dynamics depends on the mass $M$, the coupling $\alpha$ and the charge $Q$ only through the two combinations $\Meff=(1+\alpha)M$ and $\Qeff^{2}=(1+\alpha)(\alpha M^{2}+Q^{2})$, which accounts for the multimodal posteriors found in the neutron star sample and sets a model-independent limit on what QPO timing alone can measure. The astrophysical implications of these bounds, in particular for inferred masses above the Tolman–Oppenheimer–Volkoff limit, are discussed in detail.

We prove a finite-$G\hslash$ singularity theorem for semiclassical spacetimes with compact Cauchy slices. Let a compact Cauchy slice be divided by a compact surface into regions $B$ and $C$. Suppose that $B$ is conditionally hyperentropic, $H_{\max,\mathrm{gen}}^\varepsilon(BC|C)>0$, that the future-inward null boundary from the dividing surface toward $B$ is a discrete max lightsheet, and that $C$ is robustly quantum trapped. Assuming discrete max-focusing and a regular semiclassical endpoint for a closing lightsheet, the future Cauchy development of $B$ contains an incomplete null generator. This parallels entropy singularity theorems in which hyperentropy is combined with the existence of an inward lightsheet, while robust quantum trapping supplies the additional finite-$G\hslash$ local obstruction needed here. In a closed Friedmann universe, the theorem excludes a controlled semiclassical bounce when a contracting hemisphere lies on such a lightsheet and contains more independent information than its boundary can support.

String T-duality, through its correspondence with path-integral duality, endows the low-energy propagator with a zero-point length $l_0=2\pi\sqrt{\alpha'}$ that softens the short-distance behavior of gravitational fields. Motivated by the regular black-hole construction obtained from the corresponding smeared source, we formulate a T-duality-inspired Alcubierre geometry by identifying the warp profile with the complementary cumulative mass fraction of that source. For the effective one-scale choice $f(r_s)=1-r_s^3/(r_s^2+l^2)^{3/2}$, with $l^2=R^2+l_0^2$, the metric is $C^2$ at the bubble center and smooth elsewhere, while the energy density, its volume integral, and the York expansion are available in closed form. In particular, $E=-(15\pi/1024)v_s^2 l$ in geometric units and $|\rho_E|$ is bounded by a constant times $v_s^2/l^2$. Within this one-scale family, the model therefore removes the divergence associated with the profile-contraction limit $R\to 0$ at fixed velocity, because $l$ cannot fall below $l_0$. This should not be confused with a regularization of the conventional Alcubierre thin-wall limit at fixed macroscopic bubble radius, in which an independent wall thickness is taken to zero. We emphasize, however, that the construction is an effective ansatz rather than a derivation from string-corrected field equations: $R$ is a macroscopic profile scale, the choice $l^2=R^2+l_0^2$ is an interpolation, and the classical $l_0\to 0$ limit remains a smooth thick-walled profile rather than the distributional Alcubierre top hat. Exotic matter remains necessary, and neither semiclassical stability nor a modified quantum energy inequality is claimed without an explicit renormalized stress-tensor calculation.

The problem of the effective excitations of a gauge theory in the nonperturbative regime remains not completely understood. Using the Refined Gribov-Zwanziger (RGZ) theory as effective model for pure gauge Yang-Mills theories, we revisit the quasiparticle (quadratic) excitations of the theory. A novel interpretation of such quasiparticles is proposed, in the case of real mass poles, taking into account the manifest ${\cal PT}-$symmetry of the RGZ Lagrangian.

Fukui and Kawakami showed that the trigonometric Haldane–Shastry (HS) spin chain can be deformed by introducing twisted boundary conditions. In this work we revisit the resulting twisted HS chains, which we call Fukui–Kawakami (FK) chains. We analyse their spectra in dependence of the twist parameter, utilising a direct connection with the (untwisted) HS chain. This allows us to explain why part of the spectrum can be described by Fukui and Kawakami's twisted Bethe equations, and can be constructed from Yangian highest weight states. These states can be labelled by combinatorial data called `motifs', as in the HS chain, which cover some of the (deformed) descendants. We furthermore show that there are other descendants which do not follow from these Bethe equations, but whose energy can be described as a sum of two single-particle energies, suggesting additional hidden symmetries. We then focus on the special case of antiperiodic boundary conditions, and show that this chain coincides with the `minimally polarised' long-range model recently introduced by Basu-Mallick, Finkel, and González-López. Remarkably, this connection implies that the antiperiodic chain has a hidden $\mathfrak{gl}(1|1)$-symmetry, which we use to relate the HS motifs to their `supersymmetric' $\mathfrak{gl}(1|1)$ counterparts.

This paper describes classical soliton scattering in the 2+1d integrable chiral model, related to the Bogomolny monopole equation and self-dual Yang-Mills, as a case study for higher-dimensional integrable scattering. Extended line solitons exhibit nontrivial scattering with lump solitons and with other line solitons, and $N \to N$ interactions can be factorised into a series of $2 \to 2$ interactions. Scattering between parallel line solitons in 3d is related to lump soliton scattering in 2d, allowing for direct comparison with results in 1+1d integrable field theories.

An analog of the standard renormalization procedure may be useful for four-derivative theories, and we illustrate it with the four-derivative scalar field theory in the $m\to0$ limit. The renormalization scale $\mu$ appears in momentum-dependent logarithms associated with both UV and IR divergences. At one loop, the on-shell scattering amplitude satisfies an analog Callan–Symanzik equation involving the analog beta functions. These functions are determined from the combined UV and IR pole parts of the 1PI functions.

The superselection-rule approach to ghost theories is extended to theories with a nonreal spectrum containing a complex-conjugate pair of poles on the physical sheet. The two excitations are labeled by their respective complex masses, $M$ and $M^*$, and the superselection sectors are labeled by $n$, the difference between the numbers of $M$ and $M^*$ excitations. The corresponding generalized ghost parity $Q$ assigns a phase $e^{in\alpha}$ to each sector. Under $Q$ superselection, nonvanishing norms occur only in the $n=0$ sector, and the physical state condition $Q^{2}|s\rangle=|s\rangle$ projects onto this sector. For a $MM^*$ pair carrying real total energy and momentum, we define a swap operation $R$. The $R$-eigenstates are entangled pairs, and an $R$ superselection rule ensures positive probabilities. We discuss how the optical theorem describes physical cuts through these entangled pairs.

The mathematically elegant and promising idea of supersymmetry faces severe challenges as its conventional weak-scale realizations are increasingly constrained by the lack of experimental evidence of superpartners. However, we point out that the prediction of new (seemingly non-existing) supersymmetric particles is not a necessity: if we slightly relax our expectations from the supersymmetric models, generators $Q^a_\alpha$ of $N$-extended supersymmetry can be readily interpreted as carrying a quantum number of the internal gauge group, thus connecting particles with different gauge properties. In this view, operators $Q^a_\alpha$ remain “square roots” of translations, but do not by themselves generate symmetries of the model. They merely represent transformations that mathematically relate bosonic and fermionic fields; it is only the gauge-invariant combinations of the form $\sum_a \{Q^a_\alpha, \bar Q_{a\beta}\}$ that correspond to spacetime momenta and thus represent symmetries of the model. With this conceptual modification, the simplest Yang-Mills supersymmetric model no longer connects vector bosons with hypothetical gauginos, but with far less exotic chiral fermions, e.g.\ with left-handed leptons. Further adding an $SU(2)$ doublet of Higgs scalars no longer introduces Higgsinos, but a fermion that naturally corresponds to the right-handed lepton, with the familiar Yukawa term showing up as a mathematical necessity. Despite giving up the requirement that operators $Q^a_\alpha$ alone generate symmetries of the action, this approach to supersymmetry is strikingly mathematically similar to standard SUSY, raising hopes that many of the favorable properties of standard supersymmetry can be retained, while potentially reconciling the idea of supersymmetry with experimental data. The approach is still quite restrictive: the relative coefficients of such models are strongly determined.

We construct a new family of exact rotating solutions of four-dimensional Einstein–Maxwell theory with negative cosmological constant describing regular spinning AdS black holes and smooth solitons. The geometries are free of curvature singularities and admit open regions of parameter space without closed timelike curves, while supersymmetric limits correspond to causally regular horizonless configurations. A remarkable feature of these solutions is the existence of at least two codimension-one conformal boundaries. The first is Minkowski spacetime, where the expectation value of the energy–momentum tensor describes a finite spinning disk of strongly coupled conformal plasma whose edge rotates at the speed of light. The second boundary is a rotating black-hole geometry with vanishing energy–momentum tensor but non-vanishing Cotton tensor, defining a holographic theory in which the dual graviton is fixed at the boundary. We show that the energy density associated with the dual graviton exactly reproduces that of the plasma after a suitable analytic continuation and the identification of the holographic energy scale with the Lorentz factor of the rotating fluid, providing evidence for a boundary-boundary duality. Indeed, electromagnetic duality exchanges the electric and magnetic currents between the boundary supporting the graviton and that supporting the dual graviton thus providing a generalized mirror symmetry between these boundary theories. Hence, the Lorentz factor is identified with the electromagnetic dual of the renormalization scale. In an appropriate limit, the solutions reduce to the planar Reissner–Nordström–AdS black hole, whereas the supersymmetric solitons have no regular static limit.

We develop an analytical treatment of the emergent cosmological dynamics induced by local polynomial interactions in a deparametrised group field theory model, moving beyond the usual non-interacting approximation. For a single field mode with quartic and sextic couplings we obtain a closed-form generalised Friedmann equation within a controlled Gaussian regime. The dynamics preserves the quantum bounce while generating effective dark matter and dark energy contributions as collective quantum-geometric phenomena, providing the first derivation of both components from a single model. Matching the resulting dark-energy-to-dark-matter density ratio to observations places concrete phenomenological constraints on the fundamental theory, linking the cosmic coincidence problem directly to the underlying quantum gravity dynamics. Our results extend to arbitrary even polynomial interactions, establishing a systematic dictionary between microscopic interaction orders and effective equations of state.

We derive new nonperturbative inequalities on the cusp anomalous dimensions of conformal line defects. We impose reflection positivity, locality, and conformal invariance on a pair of cusps forming an “eye” geometry, deriving a novel condition on the cusp anomalous dimension which we refer to as conformal concavity. The resulting constraint is much stronger than the known angular concavity, and our derivation applies also to cusps involving distinct line defects. Remarkably, it directly links the smooth and fusion limits, yielding bounds on defect-changing operator dimensions, Casimir energies, and subleading fusion data. We thus uncover a new quantitative bridge between aspects of the local operator data and the fusion rules of line operators in conformal field theories.

We determine the gauge-invariant identity, mass scale and ultraviolet stability of the dark matter candidate arising from \(G(2)\to SU(3)_C\) in the exceptional \(G(2)\!-\!E_6\!-\!E_7\) construction. The broken \(G(2)\) sector contains odd \(1^{+-}\) and \(0^{--}\) channels, whereas the scalar \(0^{++}\sim X\bar X\) state is even and unprotected. For \(m_X\simeq5.7\times10^{13}\,\mathrm{GeV}\), weak-binding reference masses are \(M_{2X}\simeq1.14\times10^{14}\,\mathrm{GeV}\) and \(M_{3X}\simeq1.71\times10^{14}\,\mathrm{GeV}\), while the exact pole masses remain nonperturbative. Gauge-invariant Fröhlich–Morchio–Strocchi (FMS) operators, Hall–Post bounds, \(Y\)-junction arguments and the pure-\(SU(3)\) glue spectrum favor \(1^{+-}\) in their controlled regimes without excluding a deeply bound \(0^{--}\) state. We then test whether this dark grading survives the full chiral exceptional embedding. An on-shell analysis finds no independent purely dark odd operator through dimension seven: the first nonvanishing basis appears at dimension nine. So the minimal one-copy exceptional embedding does not provide an exact ultraviolet dark \(G\)-parity. Moving the dark Higgs from the common \(\mathbf{1463}_H\) parent to a separated \(\mathbf{1539}_H\) removes the scalar-parent obstruction and the relevant dimension-nine exceptional parents vanish on the selected pure-dark component in the undressed limit. A genuinely gauged or geometric \(\mathbb Z_{2,D}\) would therefore leave a bosonic parity after dark Higgsing. Its extension to the mirror-free theory nevertheless fails because the required \(G(2)\) conjugation also conjugates color, \(\mathbf3_C\leftrightarrow\bar{\mathbf3}_C\). The remaining obstruction to exact dark matter stability is therefore ultraviolet and chiral, rather than low-energy or purely scalar.

Euclidean wormholes can break the axion shift symmetry, and when this symmetry is broken, a periodic potential is created for the axion, and the curvature of this potential at a minimum point can give the axion mass. In this work, we take seriously the assumption that the mere existence of a wormhole does not mean that the axion mass is uniquely determined, and that more information is needed to determine it. We first show that since for a Giddings–Strominger wormhole with symmetry \(O(4)\), the gravitational Pontryagin density is zero, the dynamical Chern–Simons interaction can affect quantum effects, including the determinant phase and fermionic selection rules, without changing the classical wormhole action. We also conclude that in a fixed \(\alpha\) sector, the axion can have a specific mass, but this mass depends on the baby-universe state and is not a universal value. Then, for the mixed case of \(\alpha\) sectors that give a distribution of conditional masses, we show that the lower edge of the averaged spectral measure is determined by the essential infimum of the conditional mass squared over the $\alpha$ distribution. Finally, we conclude that even if almost all individual sectors are massive and the mean mass squared is also non-zero, if the support of the measure accumulates at the symmetric point \(\alpha=0\), the averaged spectral measure will be gapless. To clarify the discussion, we consider a clear example of this situation, which can be a Gaussian baby-universe state, and show that in it the spectral threshold starts at zero and there is no isolated massive pole. Therefore, predicting the mass and cosmology of a gravi-axion from a wormhole without specifying the baby-universe state is not a unique, state-independent prediction.

We study four-dimensional axion wormholes in the Lorentzian mini-superspace path integral using dual scalar and three-form flux formulations. We analyze this duality for generic metric boundary conditions and real lapse integration contour, and show that it holds on any background, including complex ones. With the Dirichlet condition on the metric, the fixed-flux path integral is evaluated exactly. In the Euclidean regime, saddle geometries organize into same-side and cross-throat segments of the Giddings-Strominger (GS) wormhole, depending on whether the two boundaries lie on the same or opposite sides of the throat. A Picard-Lefschetz analysis in the covering plane of lapse reveals that the cross-throat saddle has vanishing intersection number, and therefore does not contribute. In the asymptotically flat limit, it corresponds to the imaginary wormhole that saturates the imaginary distance bound (IDB). The same conclusion follows independently on the scalar side of the duality, and is confirmed by the exact amplitude. Replacing the Dirichlet condition with a one-parameter Neumann condition, the cross-throat saddle that leads to the imaginary wormholes remains irrelevant for the physical lift of the contour. This purely imaginary parameter characterizing the Neumann condition interpolates continuously between the half- and complete-wormhole geometries. Convergence of the sum over fixed-charge sectors imposes a corresponding interpolating bound not only on the imaginary part of the boundary axion but also on the parameter characterizing the Neumann boundary condition. An independent analysis based on the KSW criterion reproduces exactly the same bound, emphasizing its compatibility with the IDB.

Understanding real-time string dynamics in three spatial dimensions is essential for connecting quantum simulations of lattice gauge theories (LGTs) to the physical dimensionality of QED and QCD, where transverse fluctuations and competing local processes proliferate. We present the first real-time simulations of string breaking in $3+1$D lattice quantum electrodynamics. Using tree tensor networks, we simulate the quench dynamics of electric flux strings in a $3\!+\!1$D U(1) LGT with dynamical matter. At strong coupling, the string breaks resonantly at a sharp resonance condition of mass and gauge couplings, converting electric energy into matter–antimatter pairs that screen the static charges. Off resonance, we classify all competing channels—pair production, string deformations and extensions, and flux loops—whose multiplicity, extensive for pair production and flux loops, depletes the string sector even far from resonance. A channel-resolved perturbation theory quantitatively reproduces these dynamics and their Fourier spectrum. Our results establish diagnostics and benchmarks for upcoming quantum simulators of higher-dimensional LGTs.

In this work, we constructed a new metric describing a rotating cosmological black hole with electric and magnetic charges in the presence of quintessence dark energy, where the cosmological constant and quintessence are associated with external matter. Starting from a Schwarzschild-type metric and considering all energy contributions in the function $f(r)$, we introduced rotation through the Newman–Janis algorithm using a unique and general complexification rule, avoiding possible ambiguities. Assuming that the metric satisfies the Einstein field equations with matter, we calculate the event horizon condition, the total stress–energy tensor $T_{\mu\nu}$, and the Kretschmann and Ricci scalars. We also analyze the influence of the cosmological constant $\Lambda$ and quintessence parameter $\alpha$ on the event horizon and ergosphere. In the limit $\alpha \rightarrow 0$, the scalar curvature differs from the vacuum result, $R \neq -4\Lambda$, while the singularity region remains unchanged. Finally, we investigate the angular and rotational velocities of a test particle, as well as the energy conditions, through the energy density and pressures required for the existence of this black hole solution.

We study the growth of massive $SO(9)$ super-representations in type II and type I string theories. We do this first directly by finding an empirical formula that specifies which representations appear at any level, and then compute the multiplicities from a refined partition function evaluated over finite fields up to level 501 for individual representations, and level 226 for all representations. We then derive asymptotic formulae for the growth of any representation, which are constructed by integrating about the peaks of the refined partition function. Using a Rademacher sum we can find very accurate approximations for the multiplicities of the representations. Unlike the superstring partition function, which only receives contributions from the odd Rademacher terms, the multiplicities for any representation have contributions from both even and odd terms. Finally, we apply the same techniques to the ordinary representations, where a simplified refined partition function allows for better computational speed and simpler expressions for the asymptotic approximations.

We study the SCFT/VOA correspondence for the $(A_2,D_{3n-2})$ Argyres–Douglas theories with $n\geq2$. From the matching of the central charges and the equality of the Schur index with the vacuum supercharacter to all orders, we propose that the associated VOA is the logarithmic doublet algebra $\mathcal A(4n-2)$ of Feigin, Feigin, and Tipunin. For $n=2$, this correspondence was studied in detail by Buican and Nishinaka, and our proposal extends it to $n\geq3$. Using the Nahm sum expression for the vacuum supercharacter, we further propose a family of 3d $\mathcal N=2$ abelian Chern–Simons matter theories that flow to the 3d $\mathcal N=4$ SCFTs obtained by the R-twisted circle reduction, generalizing the $n=2$ construction. We determine the monopole superpotential and show that the Coulomb branch is $\mathbb C^2/\mathbb Z_2$ for every $n$. The superconformal index provides quantitative evidence for the proposed infrared fixed points, including the expected enhancement to $\mathcal N=4$ supersymmetry and the Higgs and Coulomb branch structure.