CPConstantinos Papageorgakis

Constantinos Papageorgakis

*This is an algorithmically generated author record based on publicly available information.

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Constantinos Papageorgakis has a total of 47 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Neural networks, dispersion relations and the thermal bootstrap

    by Vasilis Niarchos, Constantinos Papageorgakis

    We review a framework for the conformal bootstrap that does not rely on positivity and treats the infinite tower of high-dimension OPE contributions to conformal correlators through dispersion relations and neural networks. We apply it to scalar thermal two-point functions on [Formula: see text]. We discuss the stability properties of the relevant nonconvex optimization scheme and potential relations to recent discussions of smoothness properties in CFT correlators. We illustrate the numerical application of the method to Generalized Free Fields and 4d holographic CFTs. This is a proceedings contribution to the “Athens Workshop in Theoretical Physics: 10th Anniversary”, held at the National and Kapodistrian University of Athens on December 17–19 2025.

  • Open Access

    Efficient conformal block evaluation with a novel software implementation

    by J. Chryssanthacopoulos, V. Niarchos, C. Papageorgakis, A. G. Stapleton

    Conformal blocks in odd spacetime dimensions are not known in closed analytic form. To facilitate efficient computations in the conformal bootstrap, we introduce : a novel conformal-block generator implemented in the Go programming language, designed for rapid, on-the-fly, parallel evaluation in general spacetime dimensions using recursive relations. The package supports both multipoint and derivative-based bootstrap approaches and allows flexible control over accuracy and performance. We benchmark against the _ package, finding significant speed improvements in applications where computational speed and moderate accuracy are critical, but ultrahigh precision is not essential. As an illustration, we apply to the mixed-correlator bootstrap of the three-dimensional Ising model, formulated as a nonconvex optimization problem in a suitable truncation scheme. We simultaneously optimize over external scaling dimensions and OPE CFT data. In addition, we discuss how the approach scales as we increase the number of mixed correlators in more general O ( N ) vector models.

  • Open Access

    FeynTune: large language models for high-energy theory

    by Paul Richmond, Constantinos Papageorgakis, Vasilis Niarchos, Borun Chowdhury, Prarit Agarwal

    We present specialized large language models (LLMs) for theoretical high-energy physics, obtained as 20 fine-tuned variants of the 8 billion parameter Llama-3.1 model. Each variant was trained on arXiv abstracts (through August 2024) from different combinations of hep-th, hep-ph and gr-qc. For a comparative study, we also trained models on datasets that contained abstracts from disparate fields such as the q-bio and cs categories. All models were fine-tuned using two distinct low-rank adaptation fine-tuning approaches and varying dataset sizes, and outperformed the base model on hep-th abstract completion tasks. We compare performance against leading commercial LLMs (ChatGPT, Claude, Gemini, DeepSeek) and derive insights for further developing specialized language models for high-energy theoretical physics.


  • Open Access

    Deep finite temperature bootstrap

    by V. Niarchos, C. Papageorgakis, A. Stratoudakis, M. Woolley

    We introduce a novel method to bootstrap crossing equations in conformal field theory (CFT) and apply it to finite temperature theories on S 1 × R d − 1 . The proposed approach does not rely on positivity constraints and does not employ uncontrolled truncation schemes. Instead, we capture the contribution of an infinite number of operators in conformal block expansions using suitable functions, which are bootstrapped (numerically) together with a finite number of exposed CFT data. Our approach at finite temperature employs three key ingredients: (1) the Kubo-Martin-Schwinger (KMS) condition, (2) thermal dispersion relations, and (3) neural networks that model spin-dependent tail functions within the conformal block expansions. We test the efficiency of the new method in the case of generalized free fields and use it to perform a preliminary bootstrap analysis of double-twist thermal data in holographic CFTs.


  • Open Access

    Learning S -matrix phases with neural operators

    by Vasilis Niarchos, Constantinos Papageorgakis

    We use Fourier neural operators (FNOs) to study the relation between the modulus and phase of amplitudes in 2→2 elastic scattering at fixed energies. Unlike previous approaches, we do not employ the integral relation imposed by unitarity, but instead train FNOs to discover it from many samples of amplitudes with finite partial wave expansions. When trained only on true samples, the FNO correctly predicts (unique or ambiguous) phases of amplitudes with infinite partial wave expansions. When also trained on false samples, it can rate the quality of its prediction by producing a true/false classifying index. We observe that the value of this index is strongly correlated with the violation of the unitarity constraint for the predicted phase and present examples where it delineates the boundary between allowed and disallowed profiles of the modulus. Our application of FNOs is unconventional: it involves a simultaneous regression-classification task and emphasizes the role of statistics in ensembles of neural operators. We comment on the merits and limitations of the approach and its potential as a new methodology in theoretical physics.


  • Open Access

    Bootstrability in Line-Defect CFT with Improved Truncation Methods

    by V. Niarchos, C. Papageorgakis, P. Richmond, A. G. Stapleton, M. Woolley

    We study the conformal bootstrap of 1D CFTs on the straight Maldacena-Wilson line in 4D ${\cal N}=4$ super-Yang-Mills theory. We introduce an improved truncation scheme with an 'OPE tail' approximation and use it to reproduce the 'bootstrability' results of Cavaglià et al. for the OPE-coefficients squared of the first three unprotected operators. For example, for the first OPE-coefficient squared at 't Hooft coupling $(4π)^2$, linear-functional methods with two sum rules from integrated correlators give the rigorous result $0.294014873 \pm 4.88 \cdot 10^{-8}$, whereas our methods give with machine-precision computations $0.294014228 \pm 6.77 \cdot 10^{-7}$. For our numerical searches, we benchmark the Reinforcement Learning Soft Actor-Critic algorithm against an Interior Point Method algorithm (IPOPT) and comment on the merits of each algorithm.


  • Open Access

    Bootstrability in line-defect CFTs with improved truncation methods

    by V. Niarchos, C. Papageorgakis, P. Richmond, A. G. Stapleton, M. Woolley

    We study the conformal bootstrap of 1D CFTs on the straight Maldacena–Wilson line in 4D N=4 super-Yang–Mills theory. We introduce an improved truncation scheme with an “OPE tail” approximation and use it to reproduce the “bootstrability” results of Cavaglià et al. for the OPE-coefficients squared of the first three unprotected operators. For example, for the first OPE-coefficient squared at ’t Hooft coupling (4π)2, linear-functional methods with two sum rules from integrated correlators give the rigorous result 0.294014873±4.88×10−8, whereas our methods give with machine-precision computations 0.294014228±6.77×10−7. For our numerical searches, we benchmark the reinforcement learning soft actor-critic algorithm against an interior point method algorithm (IPOPT) and comment on the merits of each algorithm.


  • Open Access

    Covariantly constant anomalies on conformal manifolds

    by Enrico Andriolo, Vasilis Niarchos, Constantinos Papageorgakis, Elli Pomoni

    Operators with integer scaling dimensions in even-dimensional conformal field theories exhibit well-known type-B Weyl anomalies. In general, these anomalies depend nontrivially on exactly marginal couplings. We study the corresponding fully covariantized anomaly functional on conformal manifolds in several examples. We show that a natural consequence of the Wess-Zumino consistency condition is that the anomalies are covariantly constant with respect to the exactly marginal couplings. The argument is general and applies even when the conformal symmetry is spontaneously broken on moduli spaces of vacua.


  • Open Access

    6D (2,0) bootstrap with the soft-actor-critic algorithm

    by Gergely Kántor, Vasilis Niarchos, Constantinos Papageorgakis, Paul Richmond

    We study numerically the 6D (2,0) superconformal bootstrap using the soft-actor-critic (SAC) algorithm as a stochastic optimizer. We focus on the four-point functions of scalar superconformal primaries in the energy-momentum multiplet. Starting from the supergravity limit, we perform searches for adiabatically varied central charges and derive two curves for a collection of 80 conformal field theory (CFT) data (70 of these data correspond to unprotected long multiplets and 10 to protected short multiplets). We conjecture that the two curves capture the A- and D-series (2,0) theories. Our results are competitive when compared to the existing bounds coming from standard numerical bootstrap methods, and data obtained using the OPE inversion formula. With this paper we are also releasing our python implementation of the SAC algorithm, bootstop. The paper discusses the main functionality features of this package.


  • Open Access

    Covariantly Constant Anomalies on Conformal Manifolds

    by Enrico Andriolo, Vasilis Niarchos, Constantinos Papageorgakis, Elli Pomoni

    Operators with integer scaling dimensions in even-dimensional conformal field theories exhibit well-known type-B Weyl anomalies. In general, these anomalies depend non-trivially on exactly marginal couplings. We study the corresponding fully covariantised anomaly functional on conformal manifolds in several examples. We show that a natural consequence of the Wess-Zumino consistency condition is that the anomalies are covariantly constant with respect to the exactly marginal couplings. The argument is general and applies even when the conformal symmetry is spontaneously broken on moduli spaces of vacua.