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Benchmarking the cosmological master equations

7 Pith papers cite this work. Polarity classification is still indexing.

7 Pith papers citing it
abstract

Master equations are commonly employed in cosmology to model the effect of additional degrees of freedom, treated as an "environment", onto a given "system". However, they rely on assumptions that are not necessarily satisfied in cosmology, where the environment may be out of equilibrium and the background is dynamical. In this work, we apply the master-equation program to a model that is exactly solvable, and which consists of two linearly coupled scalar fields evolving on a cosmological background. The light field plays the role of the system and the heavy field is the environment. By comparing the exact solution to the output of the master equation, we can critically assess its performance. We find that the master equation exhibits a set of "spurious" terms that explicitly depend on the initial conditions, and which arise as a consequence of working on a dynamical background. Although they cancel out in the perturbative limit of the theory (i.e. at leading orders in the interaction strength), they spoil resummation. However, when those terms are removed, the master equation performs impressively well to reproduce the power spectra and the amount of the decoherence of the light field, even in the strongly decohered regime. We conclude that master equations are able to perform late-time resummation, even though the system is far from the Markovian limit, provided spurious contributions are suppressed.

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2026 5 2025 2

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representative citing papers

Quantum Stochastic Inflation

hep-th · 2026-06-10 · unverdicted · novelty 8.0

Stochastic inflation emerges as GKLS open-system dynamics from tracing entangled modes entering a coarse-grained de Sitter patch, reproducing the classical phase-space Fokker-Planck equation.

Hidden quantum-informatic symmetries of quasi-de Sitter backgrounds

hep-th · 2026-07-01 · unverdicted · novelty 7.0

Wands-dual quasi-de Sitter backgrounds produce identical symplectic eigenvalues in the Gaussian covariance matrix of localized scalar modes, revealing a quantum-informatic symmetry preserved by the duality's canonical transformation properties.

Stochastic inflation from a non-equilibrium renormalization group

hep-th · 2026-05-11 · conditional · novelty 7.0

Stochastic inflation is the leading infrared limit of a coarse-grained Schwinger–Keldysh effective theory, and the same Fokker–Planck dynamics follows from a Polchinski-type renormalization-group flow for the reduced density matrix.

Schwinger-Keldysh Path Integral for Gauge theories

hep-th · 2026-04-29 · unverdicted · novelty 7.0 · 2 refs

Constructs a manifestly diagonal-BRST-invariant Schwinger-Keldysh path integral for open non-Abelian gauge theories with arbitrary physical initial states, yielding Ward-Takahashi-Slavnov-Taylor identities and a Keldysh BRST symmetry for the Open EFT.

When the Environment Speaks: Quantum Signatures in Non-Attractor Inflation

astro-ph.CO · 2026-07-08 · conditional · novelty 6.0

An open quantum system treatment of curvature perturbations during Ultra-Slow-Roll inflation shows that environmental decoherence erases the interference dip, modifies the growth slope, and induces oscillatory features in the scalar power spectrum and scalar-induced gravitational waves.

Gauging Open EFTs from the top down

hep-th · 2025-12-18 · unverdicted · novelty 6.0

Derives gauge-invariant influence functionals for photons and Stueckelberg fields in open U(1) gauge EFTs via BRST on the in-in contour after integrating out matter.

citing papers explorer

Showing 7 of 7 citing papers.

  • Quantum Stochastic Inflation hep-th · 2026-06-10 · unverdicted · none · ref 35

    Stochastic inflation emerges as GKLS open-system dynamics from tracing entangled modes entering a coarse-grained de Sitter patch, reproducing the classical phase-space Fokker-Planck equation.

  • Hidden quantum-informatic symmetries of quasi-de Sitter backgrounds hep-th · 2026-07-01 · unverdicted · none · ref 18

    Wands-dual quasi-de Sitter backgrounds produce identical symplectic eigenvalues in the Gaussian covariance matrix of localized scalar modes, revealing a quantum-informatic symmetry preserved by the duality's canonical transformation properties.

  • Stochastic inflation from a non-equilibrium renormalization group hep-th · 2026-05-11 · conditional · none · ref 71

    Stochastic inflation is the leading infrared limit of a coarse-grained Schwinger–Keldysh effective theory, and the same Fokker–Planck dynamics follows from a Polchinski-type renormalization-group flow for the reduced density matrix.

  • Schwinger-Keldysh Path Integral for Gauge theories hep-th · 2026-04-29 · unverdicted · none · ref 139 · 2 links

    Constructs a manifestly diagonal-BRST-invariant Schwinger-Keldysh path integral for open non-Abelian gauge theories with arbitrary physical initial states, yielding Ward-Takahashi-Slavnov-Taylor identities and a Keldysh BRST symmetry for the Open EFT.

  • When the Environment Speaks: Quantum Signatures in Non-Attractor Inflation astro-ph.CO · 2026-07-08 · conditional · none · ref 49 · internal anchor

    An open quantum system treatment of curvature perturbations during Ultra-Slow-Roll inflation shows that environmental decoherence erases the interference dip, modifies the growth slope, and induces oscillatory features in the scalar power spectrum and scalar-induced gravitational waves.

  • Gauging Open EFTs from the top down hep-th · 2025-12-18 · unverdicted · none · ref 68

    Derives gauge-invariant influence functionals for photons and Stueckelberg fields in open U(1) gauge EFTs via BRST on the in-in contour after integrating out matter.

  • Directly computing Wigner functions for open quantum systems quant-ph · 2025-12-01 · unverdicted · none · ref 57

    An expression is derived to compute time-dependent Wigner functions directly from initial values in open quantum systems of a non-relativistic particle with a general environment.