arXiv subjects

Yulia A. Ageeva

Publications and source records attributed to Yulia A. Ageeva.

4 recordsLinked to original sources

arXiv2026

Disparity in sound speeds: implications for elastic unitarity and the effective potential in quantum field theory theory

We study interacting scalar field theories in which different fields propagate with inequivalent spatial kinetic tensors, corresponding to different sound speeds in different directions. We derive the exact elastic two-body unitarity relation and show that the phase space defines a positive kernel on the sphere, so that the scattering amplitude acts as an operator in angular-momentum space. The corresponding unitarity bounds constrain the eigenvalues of the phase-space-rescaled amplitude. In the weak-anisotropy regime, we obtain the leading correction explicitly and show that it induces $s-d$ mixing. For a two-scalar quartic model, we verify the anisotropic optical theorem at one loop and derive coupled channel elastic unitarity bounds. We also compute the local one-loop effective potential and analyze the corresponding one-loop renormalization-group structure. In the classically scale-invariant limit, the Gildener-Weinberg flat direction is unchanged, whereas anisotropy modifies the radiatively generated scalon mass. In the isotropic but unequal-velocity limit, several results become analytic and the RG flow exhibits an additional invariant ray.

hep-th↗

arXiv2026

Neural Network Quantum Field Theory from Transformer Architectures

We propose a neural-network construction of Euclidean scalar quantum field theories from transformer attention heads, defining $n$-point correlators by averaging over random network parameters in the NN-QFT framework. For a single attention head, shared random softmax weights couple different width coordinates and induce non-Gaussian field statistics that persist in the infinite-width limit $d_k\to\infty$. We compute the two-point function in an attention-weight representation and show how Euclidean-invariant kernels can be engineered via random-feature token embeddings. We then analyze the connected four-point function and identify an "independence-breaking" contribution, expressible as a covariance over query-key weights, which remains finite at infinite width. Finally, we show that summing many independent heads with standard $1/N_h$ normalization suppresses connected non-Gaussian correlators as $1/N_h$, yielding a Gaussian NN-QFT in the large-head limit.

cs.LG↗

arXiv2026

Excited String States and D-branes from Infinite Width Neural Networks

We explore recent proposal to represent worldsheet string path integrals by integrating over parameters of a wide random-feature neural network whose output is identified with the embedding field $X^μ$. In this paper we extend it focusing on scattering with excited states insertions and for worldsheets with boundaries introducing fixed-feature Gaussian normal-ordering prescription for derivative composites (removing the neural contact term at finite width), and propose realization of mixed Neumann/Dirichlet boundary conditions interpreted as a neural D$p$-brane. As concrete outputs, we derive the sphere four-point integrand with a single $(1,1)$ insertion and the disk four-tachyon amplitude on a D$p$-brane, recovering the expected derivative prefactors, boundary exponents, and momentum-conservation limits after renormalization.

hep-th↗

arXiv2026

One-Loop Renormalization of Anisotropic Two-Scalar Quantum Field Theories

We develop a basis--covariant one--loop renormalization framework for two interacting real scalars in $D=4-ε$ with the most general two--derivative Lorentz--violating quadratic form, allowing anisotropic spatial gradients and direction--dependent kinetic mixing, together with general cubic and quartic interactions forming RG complete set of operators at one-loop. In dimensional regularization with minimal subtraction we compute the full set of one--loop UV divergences and obtain closed beta functions for quartic and cubic couplings, masses. The pole coefficients admit a universal spectral representation as angular averages over the direction--dependent eigenvalues and projectors of the UV kinetic matrix; all anisotropy dependence enters through a single universal kernel admitting two--particle phase--space interpretation. We classify fixed points and fixed manifolds and show, in particular, that anisotropy restricts the existence of the coupled Wilson--Fisher--type fixed point. When the cross--gradients are turned on the coefficients in beta functions are governed by six phase--space weights admitting interpretation in terms of encoding ``populations'' and ``coherences'' of the UV normal modes.

hep-th↗