Papers

Complex extremal surfaces naturally arise in holographic observables associated with timelike subregions in AdS/CFT and with holographic observables in dS/CFT, but their integration contours are generally ambiguous. In this work, we propose a method for constructing complex bulk metrics from families of complex extremal surfaces, thereby generating candidate complex geometries relevant to the gravitational path integral. This construction provides a concrete realization of how complex bulk geometry may emerge from timelike entanglement, extending the familiar idea that spacetime geometry is encoded in quantum entanglement. We use the Kontsevich–Segal–Witten (KSW) criterion as a strong consistency condition to constrain the corresponding contours. The same framework also explains why spacelike entanglement naturally selects a real Lorentzian section. In several AdS and dS examples, the KSW condition uniquely determines the admissible contour within the class considered. We also identify configurations for which the resulting complex geometry violates the KSW bound near the asymptotic boundary, revealing both the scope and the limitations of the construction. These results highlight KSW admissibility as a useful organizing principle for complex saddles in real-time holography.

Flavor-current correlators are studied in strongly-coupled dense (holographic) matter, at finite quark chemical potential $\mu_q$ and finite isospin asymmetry. The non-Abelian hydrodynamic description of the charged currents is derived in the presence of an isospin chemical potential $\mu_3$. The two-point correlators of charged currents are then computed holographically at finite quark and isospin chemical potentials. In the near-extremal hydrodynamic regime, $\omega, k, T, \mu_3 \ll \mu \equiv \sqrt{\mu_q^2+\mu_3^2}$, relevant for cold strongly coupled matter, the IR properties of the correlators are studied. It is shown that in this regime, the correlators agree with the non-Abelian hydrodynamic predictions. Therefore, the traditional regime of validity of standard hydrodynamics extends beyond $\omega, k \ll T \ll \mu$ to the so-called extended hydrodynamic regime $T\ll \omega, k \ll \mu$. The holographic product formula is applied to the present non-Abelian system, and is used to propose an extended hydrodynamic approximation capturing both hydrodynamic-like poles and the leading effect of AdS$_2$ poles, by resumming the low-$\omega$ logarithms. The results are verified through a detailed numerical analysis of the exact correlators and quasi-normal mode spectrum.

We study three definitions of large deviation in many-body quantum dynamics: (i) via the full distribution of an extensive observable, (ii) via the distribution of measurement outcomes (from a continuous monitoring of the observable) over a time interval $t \le t_{\max}$, and (iii) via the distribution of expectation values over $t \le t_{\max}$. In generic systems without conservation laws, the large deviation function (i) reaches its longtime limit at $t \sim \mathcal{O}(1)$, independently of system size $N$. (ii) and (iii) reach their longtime limit at $t \sim e^{ N}$ and $t \sim \exp(e^{N})$, respectively. Before that, there is a sharp frontier between the explored and unexplored outcomes/expectation values; their distribution equals the longtime limit truncated at values that drift with $t_{\max}$. We propose that the evolution of these values with $t_{\max}$ provides a measure of quantum complexity.

We propose several general necessary conditions for quantum many-body system in one dimension respecting U(1) symmetry to be gapped. We show that the ground-state expectation value of topologically trivial twisting operators must approach unity in the thermodynamic limit with a certain finite-size scaling. Equivalently, its violation can indicate gaplessness of U(1)-symmetric Hamiltonians. The topological triviality of such a twisting operator enables us to derive infinitely many other gaplessness indicators by static structure factor to any order in real experiments, which are impossible to obtain by earlier topologically nontrivial twisting operators. We also apply analytic and numerical calculations to test the efficiency and consistency of our results.

The vacuum persistence probability, encoded in the imaginary part of the in-out effective action, is a basic measure of vacuum instability and particle production. However, its evaluation may appear prescription-dependent: the Bogoliubov prescription and the Green's function prescription can yield different expressions. We show that this apparent ambiguity arises because the Green's function prescription omits the nontrivial contribution from the endpoint vacuum wavefunctionals, which should be present in the complete in-out amplitude. Including this contribution accomplishes the boundary completion of the Green's function prescription. The ambiguity is thereby resolved, and the complete result agrees with the Bogoliubov expression.

We investigate how, in a highly constrained system such as a four-dimensional diffeomorphism-invariant theory with vanishing bulk Hamiltonian and non-trivial interactions between the metric and additional degrees of freedom, transient excited states–called Glauber-Sudarshan states–can be constructed over supersymmetric minima. These states are generically non-supersymmetric and, although they are not minima of any potential, they admit positive-energy metric configurations that effectively mimic four-dimensional quasi-de Sitter backgrounds. We analyze how such states differ from conventional coherent states by studying their time evolution both in the canonical formalism–via boundary Hamiltonians–and in the in-in path-integral framework through Schwinger-Keldysh contours. We also examine the consistency of the construction across three complementary descriptions: the 1PI effective action, the Wilsonian (or exact renormalization group) effective action, and the Picard-Lefschetz (Lefschetz-thimble) decomposition of the Schwinger-Keldysh path integral, which provides the trans-series organization of the theory. In the presence of gauge-fixing and ghost sectors, we show that the dynamics of these transient configurations are governed by a nontrivial bootstrap relation that simultaneously constrains their behavior near supersymmetric Minkowski vacua and along quasi-de Sitter-like trajectories. Finally, we examine the Wheeler-DeWitt equation, the notion of time in the presence of transient excited states, and the emergence of the bulk Schrodinger equation. We further show that these states admit a natural structural interpretation analogous to the vertex operators that arise in the two-dimensional world-sheet formulation of string theory.

Recent advances in multidimensional modeling of core-collapse supernovae (CCSNe) have enabled detailed predictions of high-frequency gravitational-wave (GW) signals, offering a new probe of extreme matter and gravity. A proto-neutron star (PNS) emits quasi-continuous GWs through the excitation of its characteristic oscillation modes. State-of-the-art CCSN simulations show that these oscillations, in particular $g$- and $f$-modes, dominate the GW spectrum, with frequencies rising from a few hundred hertz to the kilohertz (kHz) range as the PNS compactness increases in the post-bounce phase. Therefore, the temporal evolution of these GW frequencies, if detected, would provide a direct and quantitative tracer of the PNS internal structure and the surrounding explosive dynamics. In addition to such standard GW emission mechanism, fully general relativistic (GR) simulations have revealed additional GW sources linked to more exotic physical processes. In highly massive progenitors, continuous mass accretion drives rapid PNS contraction and early black-hole (BH) formation, producing strong kHz GW emission that abruptly ceases when the PNS core is swallowed by the BH horizon. Similarly, a strong first-order quantum chromodynamics (QCD) phase transition can induce a secondary collapse and rebound of the nascent quark core, generating powerful, millisecond-duration GW bursts with frequencies exceeding $\sim$2 kHz. Alternative theories of gravity, such as scalar-tensor frameworks, predict spontaneous scalarization that can trigger multiple collapses of the PNS, yielding analogous high-frequency and broadband GW signals. The combined analysis of these GW signals, together with their detection by next-generation GW detectors, offers a promising multi-messenger pathway to identify smoking-gun signatures of new physics beyond the standard model of the CCSN GW mechanism and general relativity.

We investigate the quantum Mpemba effect in a holographic superfluid, in which states with stronger initial symmetry breaking relax faster toward the symmetry-restored equilibrium. We demonstrate its emergence by identifying the shifted free energy computed from the energy flux into the black hole horizon as monotonic distance measure. By decomposing the nonlinear bulk dynamics based on quasinormal modes, we reveal that the anomalous relaxation is governed by a dynamical competition in which the slowest-decaying mode is suppressed while the second mode is amplified. These findings provide a holographic perspective on the quantum Mpemba effect in nonequilibrium relaxation involving strongly coupled degrees of freedom.

We derive which-path decoherence for matter-wave interferometry that arises from tracing out the gravitons of linearized quantum gravity. Because the gravitons are driven linearly by the matter source, the branch-dependent evolution can be solved exactly, and the reduced coherence is given by the characteristic function of the initial graviton state, evaluated at the difference of the branch-induced field displacements. In vacuum, the decoherence exponent equals half the mean number of gravitons radiated by the difference source. For a smooth Gaussian trajectory, it reduces to $\Gamma_{\rm vac}=(8/15)\,Gm^2d^4/(\hbar c^5\tau^4)$, ranging from $10^{-89}$ to $10^{-61}$ across representative matter-wave platforms. For a general squeezed graviton vacuum, we obtain an exact expression in which squeezing either suppresses or enhances the vacuum response, depending on the squeezing phase. For the strongly squeezed state produced by inflation, this expression reduces to $\Gamma_{\rm inf}=(\pi/20)\,\Omega_{\rm inf}(md^2H_0/\hbar)^2$ and reaches at most $\sim10^{-27}$ for optimistic parameters. Hence, the which-path decoherence induced by radiative gravitons is therefore negligible in current matter-wave interferometers.

The tilted dipole cosmology extends the standard model by incorporating a preferred spatial direction and separate bulk velocities for matter and radiation, offering a potential explanation for observed large-scale bulk flows and the CMB dipole. We conduct a comprehensive analysis of this anisotropic framework using Big Bang Nucleosynthesis (BBN) and Gravitational Baryogenesis (GB) to impose stringent constraints on the radiation tilt parameter $\beta_r$, which quantifies the magnitude of the radiation bulk flow. By deriving the modified expansion rate $H(T)$ and its impact on light element abundances, we find that the combined $2\sigma$ BBN limits from primordial helium-4 and deuterium are $|\beta_r| \lesssim 0.03$ for maximal shear (tightest bound) and $|\beta_r| \lesssim 0.2$ for minimal shear (weakest bound). These bounds are consistent with, but tighter than, those inferred from the effective neutrino species count $|\Delta N_{\mathrm{eff}}| \lesssim 0.4$. Importantly, both bounds are upper limits; $\beta_r = 0$ is always allowed by the BBN constraints. The lithium-7 problem persists, as the $\beta_r$ values required to resolve it are excluded by helium-4 data. Furthermore, GB – operating at decoupling temperatures $T_D \gtrsim 10^{12}$ GeV under the scaling $\beta_r \propto T$ – yields far more severe constraints, limiting $|\beta_r^{\mathrm{BBN}}| \lesssim 10^{-8}$ for such high-scale baryogenesis scenarios.

Noncommutative and nonassociative geometry has attracted much attention in both mathematics and physics communities. A prominent example is a stringy $R$-space over an underlying manifold, which exhibits both noncommutative and nonassociative structures and is known to be locally nongeometric. However, previous studies have mainly described $R$-space through algebraic relations of local string position coordinates, instead of a precise global geometric definition. In this paper, we propose a rigorous and systematic mathematical formulation of nongeometric $R$-space within the framework of descent theory. The central idea is to regard nongeometric $R$-space as carrying only local data of a quasitriangular quasi-Hopf algebra on each local coordinate domain of the underlying manifold, which are then glued coherently together to produce a global geometric object. We show that the appropriate global structure is not an ordinary space or a globally defined algebra, but a bicategory-valued stack. This provides a global and geometric definition of $R$-space while still preserving its locally nongeometric intrinsic character.

We study gauge-field production in a post-recombination magnetogenesis scenario driven by an ultralight pseudoscalar dark matter field $\phi$ coupled to electromagnetism. Previous analytical work has shown that a homogeneous oscillating $\phi$ background can excite gauge field modes through tachyonic and narrow-band resonance channels. Here we follow the coupled evolution of the homogeneous $\phi$ mode and gauge field modes of both helicities in an expanding background. Our numerical work confirms the results for the spectra of produced gauge particles obtained in the previous approximate analytical treatments. In addition, our study allows us to determine when back-reaction shuts off the resonance. We find that for parameter values for which the tachyonic instability band is open, back-reaction does not shut off the resonance until a fraction ${\cal{F}}$ of order one of the initial dark matter energy density has been transferred to photons, and this happens on a time scale which is short compared to the Hubble time. In the parameter range in which only the narrow resonance band is open, ${\cal{F}}$ eventually reaches order one, but the time when this happens increases as the effective coupling constant decreases, and therefore ${\cal{F}}$ may remain negligible until the present time.

Three-form fluxes generate a potential for the complex structure moduli in type IIB string compactifications on Calabi-Yau threefolds. In the large complex structure patch, the potential consists of a perturbative contribution and a convergent series of instanton corrections. We present examples of vacua near the boundary of large complex structure, where the minimum of the potential is essentially determined by the perturbative contribution and the first instanton correction, while the effect of all higher instantons is negligible. This phenomenon occurs when fluxes are such that the magnitude of the perturbative potential in certain directions in moduli space is of the same size as the first instanton contribution. Analysing an ensemble of flux vacua, we find that this phenomenon is statistically quite common. We also discover more subtle phenomena where instanton terms affect the multiplicity of the solutions and induce monodromy shifts.

The equilibrium thermodynamics of boosted Schwarzschild black holes is worked out in a concise way and shown to agree with expectations from relativistic thermodynamics.

We argue that the back-reaction of inhomogeneities, when combined with a pure cosmological constant, produces an effective dark energy whose equation of state can evolve with time. Our analytical computation agrees with recent numerical simulations, which have shown that the back-reaction of inhomogeneities can impact dark energy around the present time. Here, its equation of state is derived from an average version of the Friedmann equations, for which the average is taken over a fixed volume of matter particles (not necessarily global). When treating the inhomogeneities as small perturbations around a homogeneous background, dark energy acquires a time dependence which reduces to a boundary term, at least at quadratic order in the scalar modes of the perturbations. Thus, it becomes negligible for a global average. On the other hand, when treating instead the spatial derivatives of the inhomogeneities perturbatively in a gradient expansion, dark energy gets the same time dependence, which no longer reduces to a boundary term. This time dependence can be significant even for a global average or when the constant spatial curvature induced by the inhomogeneities is negligible. It also keeps the same sign around the present time, thus causing dark energy to remain either always phantom or never phantom, not allowing for any crossing from one type of behaviour to the other.

We study the one-dimensional linear-potential system as an affine extension of the conformal triangle formed by the free particle, harmonic oscillator (HO) and inverted harmonic oscillator (IHO). Unlike these homogeneous quadratic Hamiltonians in the $sl(2,\mathbb R)$ sector, the linear-potential Hamiltonian involves the Heisenberg ideal of the Schrödinger algebra. Its direct relation to the free particle is a regular accelerated-frame transformation, developed here at the levels of the classical action, canonical transformation, wave-function intertwiner and propagator; its HO and IHO realizations instead arise through singular displaced-oscillator limits. The Airy energy eigenstates follow from a cubic-phase transform of free-particle momentum eigenstates, from condensation of highly excited harmonic-oscillator levels, and from the limit of a subdominant parabolic-cylinder scattering branch of the inverted oscillator. We also develop a planar extension in homogeneous crossed electric and magnetic fields, where uniform acceleration generates the electric interaction, while uniform rotation produces the Landau coupling and the centrifugal inverted-oscillator term; the guiding-center dynamics yields the Hall drift.

In arXiv:2306.01837, it was conjectured that one can engineer a large class of quantum field theory states for which the modular flow on a spacelike slice is "instantaneously local." Here we show that on null slices, such flows are highly constrained; ultraviolet universality essentially requires null-local modular flow to be unique. Concretely, we study massless Klein-Gordon theory in Minkowski spacetime, and construct, for any sufficiently regular future-directed vector field on the past null boundary of a causal diamond, a state that has this vector field as its instantaneous modular flow. We then show by explicit computation that no two distinct states in this class can be realized in the same local Hilbert space. Using a more abstract argument, we also show that in the vacuum sector of the theory, the only null-local modular flow in a causal diamond is provided by the vacuum state itself. We also comment on the construction of null-local modular flow for massive scalars, free Maxwell fields, free gravitons, and in curved backgrounds.

In these proceedings, we provide a summary of our recent advancements in determining the mass of the lightest gluelump using hyperasymptotic expansions in Quantum Chromodynamics (QCD) \cite{Ayala2025}. This paper details our methodology, our precise determination of leading renormalon normalization constants, and our extraction of the gluelump mass from two independent physical systems, yielding a final combined, renormalization-group-invariant and scheme-independent result of $\Lambda_{B}^{\rm PV} = 2.44(7) r_0^{-1}$.

In this work we study whether nonlinear models of quantum mechanics can avoid detection by strong measurements, if the nonlinear effects only exist as high frequency modes. A potential physical process which could hide such modes would be amplitude level time averaging over fundamentally indistinguishable times. To that end, we have defined a temporal indistinguishability postulate which describes the averaging process, and handcrafted a nonlinear toy model well suited to avoid detection. We have demonstrated that even in such an ideal setup, tabletop weak postselected measurements can still detect nonlinear behavior and put constraints on nonlinear high frequency modes of evolution, even at frequencies beyond fundamental minimal temporal resolution.

Unitary $k$-designs provide a resource-efficient framework for emulating Haar randomness up to the $k$-th order. Quench-based protocols have recently been shown to generate such designs, but achieving this typically requires multiple Hamiltonian realizations, even when using temporal ensembles. Here, we show that no independent Hamiltonians are required: a single chaotic Hamiltonian is sufficient to generate approximate unitary $k$-designs, even when that Hamiltonian is spatially local. We introduce a two-Pauli-kick (2PK) protocol, in which unitary evolution under a fixed Hamiltonian is interspersed with two Pauli operator insertions (kicks). We find that the resulting frame potential approaches the Haar value at long times, with deviations suppressed by the inverse Hilbert-space dimension. We verify this for single realizations of Gaussian random matrices, the Majorana and Spin Sachdev-Ye-Kitaev models, and deterministic local quantum spin chains. Remarkably, in deterministic spin systems, the 2PK protocol generates approximate unitary designs in regimes where quench-based protocols are either inapplicable or fail to converge. Furthermore, our protocol provides a finite-temperature extension of the frame potential and establishes an analytic bound in terms of the equilibrium partition function. We discuss a holographic perspective on this mechanism.

The $\mathrm{SL}(2,\mathbb{Z})$ electromagnetic duality of 4d Maxwell theory induces theory-generating operations on 3d theories with $U(1)$ global symmetry. For theories with $U(1)^n$ symmetry, this structure generalizes to $\mathrm{Sp}(2n,\mathbb{Z})$. Focusing on the $U(1)^2$ case, we formulate the bulk $\mathrm{Sp}(4,\mathbb{Z})$ action and derive the corresponding boundary operations. We identify an intrinsically two-component element of order five, which generalizes the order-three $ST$ element of the single-$U(1)$ theory. Although its fifth power acts trivially in the bulk, the corresponding boundary operation closes only up to a decoupled $U(1)_1$ invertible phase, suggesting a mixed duality-gravitational anomaly. We realize the resulting theory-generating web for Abelian Chern-Simons theories within the $K$-matrix formalism and apply it to bilayer fractional quantum Hall systems. Recasting the Haldane–Halperin hierarchy construction as a sequence of $\mathrm{SL}(2,\mathbb{Z})$ operations, we generalize it to systems with charge $U(1)_c$ and pseudospin $U(1)_s$ symmetries. The resulting bilayer hierarchies contain branches terminating in an interlayer-correlated bosonic $(221)$ daughter sector, yielding candidate Abelian states at the even-denominator equal-layer fillings $3/8+3/8$ and $5/12+5/12$. Integral changes of anyon basis establish the equivalence of these states to their corresponding Abelian composite-fermion descriptions. We further discuss the spin-charge constraints that arise when the electromagnetic background field is treated as a spin-$c$ connection.

Previous studies of poly-instantons in type IIB Calabi-Yau orientifolds found that these effects arise when Euclidean D3-branes wrap rigid cycles with a Wilson line. In this work, we extend this result through a general analysis of instanton zero modes, revealing the existence of new poly-instanton effects for rigid cycles with a deformation, provided that O3-planes are localised on the worldvolume of the Euclidean D3-brane. We provide concrete Calabi-Yau examples with explicit orientifold involution and brane setup. One of them is particularly well suited for realising axion hilltop quintessence. In particular, the double exponential suppression of poly-instanton effects allows to reproduce the observed vacuum energy for natural values of the underlying parameters.

Generalized Toric Polygons (GTPs) extend the geometric realization of $5d$ superconformal field theories beyond toric Calabi-Yau 3-folds to general $(p,q)$ 5-brane webs ending on 7-branes. We take significant steps towards the generalization of brane tilings for GTPs, or equivalently, the corresponding quiver theories. We focus on GTPs connected to ordinary toric diagrams by polytope mutations. Parallel 5-brane legs of a $(p,q)$ web define $\mathcal{N}=2$ fractional branes bounded by the corresponding parallel zig-zag paths in the brane tiling obtained by treating the GTP as an ordinary toric diagram. We propose that terminating multiple 5-branes on a common 7-brane, the defining feature of GTPs, translates into bringing these zig-zag paths together, thereby shrinking the corresponding $\mathcal{N}=2$ fractional branes to zero size in a process we call $\mathcal{N}=2$ strip condensation. We show that strip condensation follows from mirror symmetry when the coefficients in the Newton polynomial are tuned to the GTP point. We further support this proposal through several non-trivial consistency checks. In particular, it correctly reproduces the expected number of gauge groups, given equivalently by that of the mutation-related toric diagram or by the number of $T$-cones in a tessellation of the GTP. We verify this for all examples previously considered in the literature, as well as for a new infinite family of GTPs with arbitrarily large $T$-cones. Strip condensation drives the corresponding gauge groups to infinite coupling. Confinement then yields quivers that coincide with those of the mutation-related toric diagrams up to vector pairs and adjoint fields, suggesting that GTP quivers are related to those of the corresponding toric diagrams by relevant deformations, extending to GTPs the known correspondence between polytope mutations and relevant deformations.

At asymptotic limits of moduli spaces of quantum gravity vacua, we argue that the masses of the lightest particle towers are eigenfunctions of the moduli-space Laplacian. The associated eigenvalues are quantized by the Emergent String Conjecture and determine the exponential decay rates of axionic directions in these limits. We also connect the quantization of Laplacian eigenvalues to the spectrum of instantons for the theory. We support our claims with diverse examples that preserve between 4 and 32 supercharges.

The field equations of Conformal Gravity (CG) are constructed from fourth-order derivatives of the metric. While the second-order field equations of General Relativity (GR) reduce to a second-order Poisson equation in the weak-field limit, those of CG yield a fourth-order one. Despite this, works by Tanhayi, Fathi, and Takook [Mod. Phys. Lett. A 26, 2403 (2011)], Payandeh and Fathi [Int. J. Th. Phys. 51, 2227 (2012)], and Fathi, Olivares, and Villanueva [Galaxies 9, 43 (2021)] use second-order Poisson equations to generate purported solutions to CG in a weak-field limit. We demonstrate that these solutions are erroneous due to the use of second-order Poisson equations instead of appropriate fourth-order ones. We also point out other inconsistencies in the derivations of these metrics, such as the assertion that known CG (electro)vacuum solutions describe the interiors of matter distributions.

The gauge symmetry breaking $SU(2) \to U(1) \to Z_2 \to 1$ successively produces monopoles, strings and domain walls bounded by strings (WBS), with the elementary monopole carrying a $U(1)$ magnetic flux twice as large as the elementary string. The elementary strings and subsequently WBS emit gravitational waves, and during their decay, the WBS yield a network of composite strings that carry the same $U(1)$ flux as the monopoles. Depending on the cosmological evolution, we provide the gravitational wave spectra generated by the elementary strings and WBS, in combination with the composite strings which are either effectively stable, quasistable, or metastable. These three scenarios are also realized in the symmetry breaking chain $SU(3) \to SO(3) \to Z_2 \to 1$. Both $SU(2)$ and $SU(3)$ have appeared in the literature as flavor gauge symmetries.

Dark Energy (DE) and Dark Matter (DM) are among the greatest mysteries in particle physics and cosmology, since their origins remain unclear. It is intriguing to consider whether both may originate from a purely gravitational sector. We propose that they arise from degrees of freedom associated with the partners of the Brans-Dicke boson in No-Scale Gravity, a fundamental scale-invariant gravitational theory in which the Planck scale is illusional. We consider the Brans-Dicke boson, together with two scalar fields, to form a vector multiplet under an $O(3)$ symmetry, whose angular directions in the Einstein frame are identified with DM and DE. Small explicit breaking of $O(3)$ generates their masses and interaction, and we show that the resulting model reproduces the required background cosmological evolution and present-day abundances, with the lighter field providing a dynamical DE component at late times. Although the DE field remains canonical, the interacting cosmology exhibits an effective phantom-like evolution at late times, of the type suggested by DESI in combination with other cosmological probes, without introducing a fundamental phantom degree of freedom. The model provides a first-principles realization of interacting DE, in which DM, DE, and their coupling emerge from the symmetry structure of the underlying gravitational theory.

We resolve Gauss' law in the maximal Abelian gauge supplemented by the Coulomb gauge for the Abelian gauge field and derive the gauge-fixed Hamiltonian of QCD.

It is an old idea that higher-dimensional super-gravity (SuGra) is put on-shell just by imposing Bianchi identities on super-field strengths over super-spacetimes subject to super-torsion constraints. We give a modernized, rigorous account and review recent developments, pointing out how this perspective lends itself to the construction of infrared completions of SuGra by electromagnetic flux quantization in differential nonabelian cohomology theories $\mathcal{A}_{\mathrm{dff}}$ lifting the coefficient $L_\infty$-algebra $\mathfrak{l}\mathcal{A}$ of the super-Bianchi identities. After surveying necessary background, we highlight: (1.) our recent proof that solutions of 11D SuGra are equivalent to the $\mathfrak{l}S^4$-Bianchi identities on super $C$-field flux over super-torsion-free 11D super-spacetimes, (2.) how from this the nonlinearly self-dual gauge sector on 6D M5-brane worldvolumes is equivalent to the $\mathfrak{l}_{S^4}S^7$-Bianchi identity on super $B$-field flux, (3.) and the recent complete discussion of superspace dimensional reduction of this situation to 10D IIA SuGra via $\mathfrak{l}\mathrm{Cyc}(S^4)$-Bianchi identities on super NS/RR-flux, together with its extension to further reduction to 9 SuGra via $\mathfrak{l}\mathrm{Tor}(S^4)$-Bianchis on the corresponding super-fluxes. We close by indicating how this implies consistent infrared completions of 11D SuGra by $C$-field flux quantization in 4-Cohomotopy, of 10D IIA SuGra by NS/RR-field flux-quantization in a form of twisted unstable K-theory, and of M5-brane worldvolumes by $B$-field flux-quantization in twisted (twistorial) relative Cohomotopy. The latter admits geometric engineering of experimentally relevant topological quantum orders.

We study the twisted dimensional reduction of 4d $\mathcal{N}=2$ Argyres–Douglas theories via the 3d/3d correspondence, focussing on $(A_1, A_{2n})$ theories realised as the class-$\mathcal{S}$ theory $T[\mathcal{C}]$ for a curve $\mathcal{C}$ with one irregular puncture. We argue the resulting 3d $\mathcal{N}=4$ rank-0 superconformal field theory (SCFT) arises as the IR fixed point of a Dimofte–Gaiotto–Gukov (DGG) abelian Chern–Simons-matter (ACSM) theory $T[M_3^{(k)}]$ for the lens space $M_3^{(k)}=L(2n+3,2k)$, obtained by fibering $\mathcal{C}$ over the circle with twist $k \in \mathbb{Z}_{2n+3}^\times$. The triangulation of $M_3^{(k)}$, derived from the 4d BPS spectrum, determines the ACSM theory including its superpotential. $T[M_3^{(k)}]$ flows to the expected SCFT when the monopole superpotential is near-maximal in a precise sense, while the maximal superpotential gives $T_A[M_3^{(k)}]$, which flows directly to a non-unitary TQFT, the topological $A$-twist of the SCFT. Geometrically, the SCFT and TQFT points are related by shifting conical singularities between edges of the triangulation, and we propose a correspondence between singular edges and SCFT points predicting when the SCFT is a unitary TQFT. The TQFTs from $M_3^{(k)}$ can support 2d vertex operator algebras (VOAs) on their holomorphic boundary, including the Schur-sector VOA of the 4d SCFT for $k=1$. For $n=k=1$, our construction reproduces the minimal 3d $\mathcal{N}=4$ SCFT of Gang and Yamazaki from $L(5,2)$, where $T_A[M_3^{(k)}]$ is the Yang–Lee TQFT supporting $M(2,5)$ on its boundary. We check our proposals in detail, reconstructing the modular structure of the IR TQFTs from partition functions on Seifert manifolds, and matching phases to determine VOA central charges $c_{\text{2d}} \bmod 8$ from the ACSM data, including the gravitational Chern–Simons level.