Cosmological Correlators Using Tensor Networks

• URL: http://arxiv.org/abs/2603.26090v1
• Date: Fri, 27 Mar 2026 05:42:13 GMT
• Title: Cosmological Correlators Using Tensor Networks
• Abstract summary: We develop a nonperturbative tensor-network framework for computing cosmological correlators in de Sitter space.<n>We test the proposal that suitably defined in-in correlators can be obtained from an in-out formalism by gluing the expanding and contracting Poincaré patches.
• Score: 2.102846336724103
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: We develop a nonperturbative tensor-network framework for computing cosmological correlators in de Sitter space and use it to test the proposal that suitably defined in-in correlators can be obtained from an in-out formalism by gluing the expanding and contracting Poincaré patches. Focusing on interacting $1+1$-dimensional $φ^4$ theory, we formulate finite-time lattice observables using Matrix Product State (MPS) techniques and analyze the regulator subtleties associated with the singular behavior near the patching surface. Within this regulated framework, we find controlled nonperturbative evidence for the proposed relation between in-in and in-out correlators in several examples. We also find suggestive evidence that the perturbative obstructions present for sufficiently light fields can be softened nonperturbatively, albeit in a regime of substantially larger entanglement. A central outcome of our analysis is an entanglement-based picture of the computation: for in-in evolution the entanglement remains modest and can decrease toward late times, whereas in the patched in-out set-up it grows significantly after the gluing slice. Thus, although the in-out formalism is perturbatively economical, the in-in formulation is numerically more favorable. We briefly discuss how the same strategy extends to low-angular-momentum sectors in $3+1$ dimensions, and why regimes of rapid entanglement growth may eventually motivate quantum-computing implementations.

Related papers

• Entropy-Gradient Inversion: Moving Toward Internal Mechanism of Large Reasoning Models [47.195670444638715]
  We identify and formally define textbfEntropy-Gradient Inversion, a robust correlation between token entropy and logit gradients.<n>We propose textbfCorrelation-Regularized Group Policy Optimization (CorR-PO), which embeds this inversion signature into reinforcement learning.<n>Experiments on various reasoning benchmarks across multiple model scales show CorR-PO consistently outperforms state-of-the-art baselines.
  arXiv  Detail & Related papers  (2026-05-18T02:41:53Z)
• Kinetic theory for Transformers and the lost-in-the-middle phenomenon [1.0705399532413615]
  We study causal self-attention dynamics -- a toy model for decoder Transformers.<n>For iid uniformly distributed tokens, the limiting correlation equation can be solved in closed form.
  arXiv  Detail & Related papers  (2026-05-09T23:16:19Z)
• Some progress on the use of the variational method in quantum field theory [0.0]
  Variational methods, despite their success for quantum many-body physics on the lattice, have long lacked a natural ansatz adapted to the relativistic setting.<n>This explains the intuition behind relativistic continuous matrix product states (RCMPS)<n>We obtain competitive non-perturbative approximations to ground state energies and local observables in the $4$, Sine-Gordon, and Sinh-Gordon models.<n>Beyond energy density and local observables, we show how the framework can be used to evaluate non-local observables (defects) and to extract spectral data such as particle masses.
  arXiv  Detail & Related papers  (2026-04-11T16:55:39Z)
• Symmetry-protected topology and deconfined solitons in a multi-link $\mathbb{Z}_2$ gauge theory [45.88028371034407]
  We study a $mathbbZ$ lattice gauge theory defined on a multi-graph with links that can be visualized as great circles of a spherical shell.<n>We show that this leads to state-dependent tunneling amplitudes underlying a phenomenon analogous to the Peierls instability.<n>By performining a detailed analysis based on matrix product states, we prove that charge deconfinement emerges as a consequence of charge-fractionalization.
  arXiv  Detail & Related papers  (2026-03-02T22:59:25Z)
• Emergent Manifold Separability during Reasoning in Large Language Models [46.78826734548872]
  Chain-of-Thought prompting significantly improves reasoning in Large Language Models.<n>We quantify the linear separability of latent representations without the confounding factors of probe training.
  arXiv  Detail & Related papers  (2026-02-23T20:36:17Z)
• Entanglement measures for causally connected subregions and holography [2.7408136146752056]
  We investigate entanglement for causally connected subregions $A$ and $B$ in quantum field theory and holography.<n>By employing the Schwinger-Keldysh formalism and the real-time replica method, we show how to construct $T_AB$ and compute associated entanglement measures.
  arXiv  Detail & Related papers  (2025-08-07T08:44:26Z)
• A Signed Graph Approach to Understanding and Mitigating Oversmoothing in GNNs [54.62268052283014]
  We present a unified theoretical perspective based on the framework of signed graphs.<n>We show that many existing strategies implicitly introduce negative edges that alter message-passing to resist oversmoothing.<n>We propose Structural Balanced Propagation (SBP), a plug-and-play method that assigns signed edges based on either labels or feature similarity.
  arXiv  Detail & Related papers  (2025-02-17T03:25:36Z)
• Loschmidt echo, emerging dual unitarity and scaling of generalized temporal entropies after quenches to the critical point [0.0]
  We show how the Loschmidt echo of a product state after a quench can be predicted by using conformal field theories.<n>We are also able to predict and confirm an emerging dual-unitarity of the evolution at late times.
  arXiv  Detail & Related papers  (2024-05-23T15:40:37Z)
• Slow semiclassical dynamics of a two-dimensional Hubbard model in disorder-free potentials [77.34726150561087]
  We show that introduction of harmonic and spin-dependent linear potentials sufficiently validates fTWA for longer times. In particular, we focus on a finite two-dimensional system and show that at intermediate linear potential strength, the addition of a harmonic potential and spin dependence of the tilt, results in subdiffusive dynamics.
  arXiv  Detail & Related papers  (2022-10-03T16:51:25Z)
• Convex Analysis of the Mean Field Langevin Dynamics [49.66486092259375]
  convergence rate analysis of the mean field Langevin dynamics is presented. $p_q$ associated with the dynamics allows us to develop a convergence theory parallel to classical results in convex optimization.
  arXiv  Detail & Related papers  (2022-01-25T17:13:56Z)
• Lindbladian dissipation of strongly-correlated quantum matter [0.9290757451344674]
  The Sachdev-Ye-Kitaev Lindbladian is a paradigmatic solvable model of dissipative many-body quantum chaos. Analytical progress is possible by developing a mean-field theory for the Liouvillian time evolution on the Keldysh contour.
  arXiv  Detail & Related papers  (2021-12-22T18:17:52Z)
• Out-of-time-order correlations and the fine structure of eigenstate thermalisation [58.720142291102135]
  Out-of-time-orderors (OTOCs) have become established as a tool to characterise quantum information dynamics and thermalisation. We show explicitly that the OTOC is indeed a precise tool to explore the fine details of the Eigenstate Thermalisation Hypothesis (ETH) We provide an estimation of the finite-size scaling of $omega_textrmGOE$ for the general class of observables composed of sums of local operators in the infinite-temperature regime.
  arXiv  Detail & Related papers  (2021-03-01T17:51:46Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.