High Energy Physics (Theory)
Can Euclidean lattice quantum field theory be analytically continued into Minkowski space?
B.P.Kosyakov, E.Yu.Popov and M. A. Vronsky
In this paper, we attempt to test whether Euclidean
lattice quantum field theory can be analytically continued into Minkowski space via the inverse Wick rotation. Our discussion indicates that such an analytical continuation is impossible without first taking the
lattice theory to the continuum limit. The obstacle is that discretization of spacetime converts local
quantum field theory into a theory with a nonlocal form factor, for which the Wick rotation is infeasible.
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High Energy Physics (Theory) · Cross-listed from quant-ph
Generalized Catability of Relativistic Quantum States Measurement in a Unified Lie-Algebraic Foldy-Wouthuysen (FW) Framework
Abdelmalek Bouzenada and Rami Ahmad El-Nabulsi
In this work, a unified Lie-algebraic formulation of catability is constructed for relativistic
quantum systems with arbitrary
spin within this framework. In this case, the analysis starts with constructing catability as a quantitative measure for superposed coherent states, where coherence structure and
quantum interference properties are studied using algebraic representations in this framework. Also, a generalized Foldy-Wouthuysen transformation is formulated within a Lie algebraic framework, delivering a systematic procedure for block-diagonalization of relativistic
Hamiltonians and separation of positive- and negative-energy components in this framework. Within this formalism, a phase-sensitive catability operator is introduced to study phase correlations and coherence effects in the relativistic
quantum dynamics framework. The approach is applied to Dirac
spin-$1/2$ particles, where relativistic fermionic catability is analyzed in relation to spinorial structures and
symmetry generators framework. The formalism is extended through a unified
geometric and Lie-algebraic treatment, establishing a consistent description of catability in a relativistic
quantum mechanics framework. In this context, the generalized framework is constructed for arbitrary
spin-$s$ fields, enabling investigation of higher-
spin relativistic
quantum states within the same algebraic structure framework. In this context, the obtained results show a generalized theoretical platform for investigating relativistic
quantum coherence, superposition effects, and algebraic
symmetries in the framework of fermionic and bosonic systems.
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High Energy Physics (Theory)
Beyond Algebraic Superstring Compactification: Part II
Tristan Hübsch
The most impressively prolific exploration of superstring models (aiming for our physical reality) has been focused on worldsheet-supersymmetric gauged linear sigma models and the closely associated complex-algebraic toric geometry. Mirror duality relates this to the inherently real
symplectic geometry of Calabi-Yau factors in spacetime, implying a need for a more general, heterotic framework of analysis. In turn, a closer look at possible deformations even amongst the complex-algebraic complete intersections and toric geometry models themselves indicates an a priori non-algebraic type of generalization that however perfectly aligns with requirements of mirror duality.
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High Energy Physics (Theory)
Real-Time Quantum Dynamics on the Fuzzy Sphere: Chaos and Entanglement
S. Kürkcüoğlu and B. Özcan
We study the real time
quantum dynamics of a
matrix model consisting two bosonic fields on the fuzzy sphere using the Gaussian state approximation. Starting from the
Hamiltonian formulation and using Wick's
theorem, we derive a closed set of coupled nonlinear differential equations governing the time
evolution of the one- and two-point correlation functions. Thermal equation of state is found by maximizing the von Neumann
entropy over Gaussian states and solving algebraic self-consistency equation(s) leading to a complete determination of the
symplectic spectrum of the covariance
matrix. We identify near thermal initial conditions and use them to solve the equations of motion and employ our findings to probe chaos by calculating the largest Lyapunov exponent at various temperatures. Our results demonstrate that the latter tends to zero at a finite temperature indicating that the
quantum dynamics respect the Maldacena,Shenker,Stanford bound across all temperatures, while approaching toward the classically chaotic regime at high temperatures. Finally, we examine the
entanglement dynamics of the model in real-time by considering a sequence of bipartitions of the
Hilbert space and computing the
entanglement entropy and clearly exhibit the fast scrambling features that emerge in due detail.
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High Energy Physics (Theory)
Quantum graviton scattering with definite helicities in the null surface formulation
Carlos Kozameh and Gerardo Depaola
We develop a helicity-resolved description of
quantum graviton scattering in the Null Surface Formulation (NSF) of
gravity. Dynamical data are Bondi shear modes at null infinity ($\mathscr{I}$), and the metric is reconstructed from the cut function. Matching between $\mathscr{I}^+$ and $\mathscr{I}^-$ yields $Z_{\text{total}} = Z_{\text{cut}} + Z_{\text{cone}}$, where $Z_{\text{cut}}$ contains free shear data and $Z_{\text{cone}}$ is the nonlinear cone source solution–analogous to the scalar retarded-advanced relation with on-shell free-data differences. Using second-order NSF equations for $Z_2$ and $\Omega_2$, we derive the second-order Bondi shear and outgoing operators $\delta a_{2,\pm}^{\text{out}}$. Written via on-shell phase-space data at $\mathscr{I}$, their kernels contain
spin-weighted angular Green functions and 3D momentum constraints, with energy fixed by positive frequency. The quadratic cone source decomposes into normal-ordered sectors, allowing
matrix elements to select distinct operator components. We obtain the $(2 \to 1)$ tail amplitude and $(2 \to 2)$ four-graviton
matrix elements. The tail amplitude is generated by the two-annihilation sector, selecting helicities via the NSF kernels'
spin-weight structure. For four-point scattering, products of two outgoing operators reconstruct spatial momentum conservation; 4D conservation is recovered by imposing the positive-energy on-shell Poincaré sector. This reproduces standard tree-level amplitudes, with Mandelstam poles arising from angular Green functions and helicity projections. This yields an intrinsically on-shell formulation of graviton scattering without off-shell bulk propagators, with celestial sphere spectral-angular distributions as natural observables.
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High Energy Physics (Theory)
The Conformal Grassmannian: A Symplectic Bi-Grassmannian for $CFT_ 4$ Correlators
Aswini Bala, Sachin Jain and Dhruva K.S
We introduce a formalism for conformal field theory in four dimensions: a
symplectic bi-Grassmannian representation of CFT$_4$ Wightman correlators. Working in Klein space with off-shell spinor-helicity variables, we show that correlators of $\Delta = 2$ scalars and symmetric-traceless conserved currents are encoded by integrals over a pair of $n$-planes in a $2n$-dimensional
symplectic vector space. These planes are constrained to be mutually symplectically orthogonal and aligned with the external kinematics. Conformal invariance, momentum conservation, and little-group covariance all follow geometrically from this structure. We derive all two- and three-point functions involving scalars,
fermions, conserved currents, and stress tensors. As a non-trivial test, we show that the construction reproduces the full set of independent conformally invariant structures of $\langle JJJ\rangle$ and $\langle TTT\rangle$ in CFT$_4$. The resulting expressions are considerably more compact than their momentum-space counterparts. They also make manifest the double copy between Yang–Mills $\langle JJJ \rangle$ and Einstein-
gravity $\langle TTT \rangle$. We further present a helicity-basis reformulation that makes the GL(1,R) and SL(2,R) weights of individual helicity components explicit. This basis also provides a natural starting point for a twistor-space formulation of the correlators.
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High Energy Physics (Theory)
$G_2$ flux compactifications
Aravind Aikot, Zheng Miao, George Tringas et al. (+1 more)
We derive the three-dimensional $\mathcal{N}=1$ effective theories obtained by compactifying all five ten-dimensional string theories on generic seven-dimensional
manifolds with $G_2$ structure. The resulting flux compactifications are worked out explicitly, including the full
moduli dependence of the scalar potential, kinetic terms, axionic sectors, gauge fields, Stückelberg couplings, and the allowed
geometric and form-flux data. Our results extend previous analyses by incorporating fields and fluxes that are generically present in $G_2$ reductions, and provide a unified framework for comparing type IIA, type IIB, type I and heterotic compactifications to three dimensions. In particular, the effective theories organize naturally in terms of the real superpotential formulation of three-dimensional $\mathcal{N}=1$ supergravity, making the relation between fluxes, torsion, Chern–Simons data, and
moduli potentials manifest.
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All authors Aravind Aikot, Zheng Miao, George Tringas, Timm Wrase
High Energy Physics (Theory)
Sharpened Dynamical Cobordism
Andriana Makridou and Alejandro Javier Puga Gómez
We propose a sharpened version of Dynamical Cobordism, where the physical structure $\xi$ of the theory in question determines an allowed range $R^\xi$ for the critical exponent $\delta$. We interpret a singularity with $\delta \in R^\xi$ as a true transition-to-nothing, i.e., a configuration ending spacetime, while a singularity with $\delta \notin R^\xi$ indicates some obstruction to such a transition, i.e., the presence of a non-trivial cobordism global charge, which is incompatible with a theory of
quantum gravity. In the spirit of the original Cobordism
Conjecture, this apparent inconsistency of the theory can be alleviated via the modification of the structure, for instance by introducing new degrees of freedom and associated defects. Inspired by the Gubser criterion for good singularities, we propose a way to determine $R^\xi$. As a proof-of-concept we show explicitly how the introduction of a higher-form gauge field changes the allowed range of $\delta$ compared to an EFT with only scalars. We test this sharpened version of Dynamical Cobordism against several examples, such as massive IIA string theory, where it is notably compatible with the presence of O8-planes; the Janis-Newman-Winicour and Garfinkle-Horowitz-Strominger black hole solutions; and certain singular distributions of D-branes. In all these cases, the Sharpened Dynamical Cobordism
Conjecture leads to results consistent with our expectations.
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High Energy Physics (Theory) · Cross-listed from quant-ph
Physics inspired quantum algorithm for QCD splitting functions
Gabriel Rouxinol, Yacine Haddad, Cenk Tüysüz et al. (+2 more)
We introduce a modular
quantum circuit primitive to model
entanglement dynamics in QCD parton splitting and use it as a composable building block for data-driven, physics-consistent modelling of parton-shower kinematics. For the pure-
gluon channel, we derive an analytic expression for the helicity
entanglement generated at the splitting vertex, quantified via the concurrence, and construct a two-
qubit circuit whose $\sigma_3$ expectation values encode the momentum shared between outgoing
gluons. The
circuit reproduces the QCD-predicted concurrence by construction, which fixes a two-
qubit correlator that the momentum fractions alone do not determine. Iterating the primitive, the concurrence obeys a product rule across successive splittings. Calibrating the
circuit parameters to LHC jet substructure data relates the reconstructed momentum-sharing fractions directly to
circuit rotation angles. Composing multiple splitting primitives yields multi-prong momentum-fraction distributions; we compare the three- and four-prong cases against experimental data, reproducing the core of the distributions. For the three-prong configuration, we execute the
circuit on superconducting
quantum hardware, recover the momentum-fraction distributions after a device-bias correction calibrated on a held-out subset, and study how noise alters the
entanglement-dependent observable. This work provides a concrete framework for
quantum-native parton-shower modules that encode
quantum correlations at the level of splitting dynamics, and offers physics-informed ansätze for future
quantum algorithms for QCD.
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All authors Gabriel Rouxinol, Yacine Haddad, Cenk Tüysüz, Sofia Vallecorsa, Michele Grossi
High Energy Physics (Theory) · Cross-listed from hep-ph
The structure of multi-axion solutions to the strong CP problem
Mario Fernández Navarro, Marta F. Zamoro, Marko Pesut et al. (+1 more)
A broad experimental program is targeting the QCD
axion band predicted by single-
axion solutions to the strong CP problem. Multi-
axion theories provide a well-motivated departure from this canonical picture, since additional states generically modify the mass-
photon-coupling relation. We investigate the general structure of multi-
axion solutions to the strong CP problem and study the different qualitative mass-coupling patterns that arise, including
axions to the right of the QCD band,
axions in the experimentally accessible region to its left, and scenarios in which the QCD
axion band itself is displaced. This general treatment reveals a broad set of phenomenological possibilities that are not captured by more restrictive assumptions. In particular, we identify the structure of Peccei-Quinn
symmetry breaking and the relative
alignment between the QCD and electromagnetic anomalies as key ingredients determining the location of the
axions in parameter space. Combining these ingredients, we derive a general sum rule for $N$-
axion systems that incorporates both general PQ breaking and non-universal anomaly coefficients. We apply the framework to the two-
axion system and to general multi-
axion setups, identifying UV-complete theories in which the different phenomenological regimes arise naturally. Our results motivate an extended
axion search program and have implications for our understanding of fundamental physics and the ultraviolet completion of the Standard Model.
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All authors Mario Fernández Navarro, Marta F. Zamoro, Marko Pesut, Xavier Ponce Díaz
High Energy Physics (Theory)
Kinetic Theory of Carroll Hydrodynamics
Victor Chabirand, Adrien Fiorucci, P. Marios Petropoulos et al. (+1 more)
We develop the foundations of Carrollian statistical mechanics by considering a system of interacting instantonic space-filling branes on a flat background, thereby providing the closest Carrollian analogue to the Galilean gas of interacting particles that underpins Boltzmann's collision theory. By adapting Boltzmann's statistical approach within this framework, we provide a first-principles microscopic derivation of the so-called Carrollian fluid equations, which were previously obtained as the vanishing-speed-of-light limit of relativistic conservation laws. We then use this analysis as a basis for formulating the first elements of Carrollian thermodynamics.
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All authors Victor Chabirand, Adrien Fiorucci, P. Marios Petropoulos, Matthieu Vilatte
High Energy Physics (Theory)
A Semiclassical Diagnostic for Spacetime Emergence
Netta Engelhardt and Elliott Gesteau
Recent developments have shown that some semiclassical spacetimes cannot emerge from a traditional application of the rules of holography, prompting proposals for restoring their emergence with "observer rules". In this paper, we propose a general semiclassical diagnostic of such failures of emergence, and of the extent to which observer rules can fix them. Our diagnostic is the presence of certain "evanescent"
quantum extremal surfaces, which are distinguished by an upper bound on their area rather than their generalized
entropy. In particular, the generalized
entropy of an evanescent QES may be large: even though its area term must be small, its bulk
entanglement term is unconstrained. This feature is explained by an operational distinction between classical and
quantum connectivity in semiclassical
gravity, or equivalently between the two summands of the generalized
entropy.
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High Energy Physics (Theory)
Universal Planar Abelian Duals for 3d $\mathcal{N}=2$ Symplectic CS-SQCD
Sergio Benvenuti, Vittorio Cagioni, Simone Rota et al. (+1 more)
We propose a new class of infrared dualities relating three-dimensional $\mathcal{N}=2$ $USp(2N)$ Chern–Simons SQCD to planar Abelian quiver gauge theories. These dual descriptions are constructed via real mass deformations of established $\mathcal N=4$ mirror dualities between $\mathcal{N}=4$ $USp(2N)$ SQCD and
unitary $D$-type quiver gauge theories. The resulting $\mathcal N=2$ dual pairs exhibit the characteristic exchange of topological and
flavor symmetries. We provide nontrivial evidence for these dualities by matching $\mathbf{S}^3_b$ partition functions, superconformal indices, and gauge-invariant operator spectra. Furthermore, we systematically incorporate additional real mass deformations on both sides of the duality, allowing us to extend the construction to $\mathcal{N}=2$
symplectic SQCD with generic ranks,
flavors, and Chern–Simons levels.
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All authors Sergio Benvenuti, Vittorio Cagioni, Simone Rota, Anant Shri
High Energy Physics (Theory)
Finite-time memory detectors and fully constraining Faddeev-Kulish dressings in QED and gravity
Brett Oertel
We show that for both QED and perturbative
quantum gravity, finite-time Faddeev-Kulish dressings can be fully constrained by
symmetry, and that this gives the unique choice which reproduces the classical
memory effect. For
gravity, we show that using this dressing to construct finite-time Fock spaces, as well as a carefully defined finite-time
memory detector allows us to recover both the first order gravitational
memory, as well as higher order Christodoulou contributions from the gravitational field. We explain how these higher order perturbative corrections arise in inclusive in-in calculations.
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High Energy Physics (Theory) · Cross-listed from cond-mat.stat-mech
Direct Experimental Test of Conformal Invariance via Grazing Scattering: A Proposal for X-ray and Neutron Experiments
Alessandro Podo and Slava Rychkov
We propose a test of conformal invariance in critical phenomena based on the study of a two-point correlation function in the presence of a boundary. This two-point function can be studied using X-ray or
neutron scattering in the conditions of total reflection (so-called grazing scattering). The conformal Ward identity in momentum space is here expressed as a differential constraint on the scattering cross-section, as a function of the momentum transfer and the scattering angle. Experimental verification using X-rays and binary
alloys appears well within the existing techniques, while feasibility for
neutron scattering requires further study. This would be the first direct experimental test of conformal invariance in critical phenomena, a
symmetry widely assumed but never directly verified.
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High Energy Physics (Theory) · Cross-listed from cs.AI
When Does Critique Improve AI-Assisted Theoretical Physics? SCALAR: Structured Critic–Actor Loop for Agentic Reasoning
Vasilis Niarchos, Constantinos Papageorgakis, Alexander G. Stapleton et al. (+1 more)
As large
language models (LLMs) show increasing promise on research-level physics
reasoning tasks and agentic AI becomes more common, a practical question emerges: How does the interaction between researchers and
agents affect the results? We study this using SCALAR (Structured Critic–Actor Loop for Agentic
Reasoning), an Actor–Critic–Judge pipeline applied to
quantum field theory and string theory problems. The Actor proposes solutions, the Critic provides iterative feedback, and an independent Judge evaluates the transcript against reference solutions. We vary the Actor persona, the Critic feedback strategy, and the Actor model family and scale. Multi-turn dialogue improves over single-shot attempts throughout, but both the mechanism of improvement and the value of different prompting choices depend strongly on the Actor–Critic pairing. Increasing the scale within one model family (e.g. from the 8B-parameter DeepSeek-R1 variant to DeepSeek-R1 70B) improves some easier-problem behavior, but does not remove the hardest bottleneck we observe. Critic feedback strategy matters most clearly in the asymmetric Actor–Critic setting (e.g, a lightweight Haiku Actor guided by a stronger Sonnet Critic), where constructive feedback improves mean-score outcomes. In same-family Actor–Critic settings, strategy effects are weaker: lenient feedback is sometimes favored, while strict and
adversarial feedback are not beneficial. Taken together, SCALAR provides a controlled testbed for evaluating which interaction structures help or hinder AI-assisted
reasoning on known-answer scientific problems.
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All authors Vasilis Niarchos, Constantinos Papageorgakis, Alexander G. Stapleton, Sokratis Trifinopoulos
High Energy Physics (Theory) · Cross-listed from cond-mat.str-el
Pro-Tensor Network
Gen Yue, Ansi Bai, Linqian Wu et al. (+1 more)
We introduce the pro-tensor network, a categorification of the tensor network, as a fully rigorous yet graphically transparent framework for studying the collection of many many-body theories, which we dub many-many-body theory. We provide a comprehensive toolbox for the graphical calculations using pro-tensor networks. As applications, we recover the Levin-Wen model as a "uniform" pro-tensor network and generalize a result of Kitaev and Kong by characterizing particles as modules over promonads. One can also interpret the string-net pro-tensor network as the space of symmetric tensor networks, thus our framework also applies to the study of generalized
symmetry and topological holography. Notably, our generalization dispenses with the assumptions of semisimplicity, finiteness, and
rigidity, potentially facilitating the exploration of many-body physics beyond these constraints.
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All authors Gen Yue, Ansi Bai, Linqian Wu, Tian Lan
High Energy Physics (Theory)
From Baby Universes to Narain Moduli: Topological Boundary Averaging in SymTFTs
Xingyang Yu
Building on the viewpoint that ensemble averages in TQFT
gravity can be organized by topological boundary data, we develop a SymTFT interpretation of ensemble averaging in low-dimensional holography. The central operation is to keep fixed both the SymTFT and the physical boundary condition, while averaging over topological boundary conditions at the other end of the SymTFT slab. Each such boundary condition gives an absolute completion of the same relative theory, so the ensemble is interpreted as an average over topological completions rather than over arbitrary local dynamics. We formulate this construction in terms of cap functionals and their natural groupoid or Haar-type measures, and illustrate it in two examples. In the closed-string sector of the Marolf–Maxfield model, topological boundary conditions are labelled by finite sets, and the groupoid sum reproduces the Poisson/Bell-
polynomial moments. In the Narain case, compact topological boundary conditions of an \(\mathbb{R}\)-valued BF SymTFT are identified with maximal isotropic subgroups, so that topological-boundary averaging reproduces the usual Narain
moduli average with Zamolodchikov measure. We also discuss possible extensions to JT
gravity, random
matrix theory, Virasoro T(Q)FT, and 3D
gravity.
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High Energy Physics (Theory) · Cross-listed from quant-ph
Machine Learning Approaches to Building Quantum Circuits for Sets of Matrices
Matvei Fedin and Andrei Morozov
Machine learning nowadays becomes a useful instrument in many subjects. In this paper we use interpretable machine learning to build
quantum algorithm. By studying the parameters of the machine learning
algorithm we were able to construct universal shortest analytic
quantum algorithm for arbitrary diagonal
matrix of any size.
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