Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Infrared Sensitivity of Unstable Vacua

Dmitry Krotov, Alexander M. Polyakov

TL;DR

The authors show that unstable vacua in curved spacetime exhibit infrared sensitivity and long-time memory, even for massive fields, through non-equilibrium dynamics and UV/IR mixing, especially in global de Sitter space. Using Schwinger–Keldysh formalism, they compare electric-field, expanding, contracting, and dS backgrounds to reveal how IR effects alter correlators, backreaction, and potentially the cosmological constant. They find that while expanding patches suppress memory, contracting and global de Sitter geometries generate infrared logs and Planck-scale UV/IR mixing, suggesting infrared physics could influence cosmology more than previously thought. The work highlights the need for real-time analyses of quantum fields in curved spacetime and points toward IR-driven mechanisms for addressing the cosmological constant problem.

Abstract

We discover that some unstable vacua have long memory. By that we mean that even in the theories containing only massive particles, there are correllators and expectation values which grow with time. We examine the cases of instabilities caused by the constant electric fields, expanding and contracting universes and, most importantly, the global de Sitter space. In the last case the interaction leads to a remarkable UV/IR mixing and to a large back reaction. This gives reasons to believe that the cosmological constant problem could be resolved by the infrared physics.

Infrared Sensitivity of Unstable Vacua

TL;DR

The authors show that unstable vacua in curved spacetime exhibit infrared sensitivity and long-time memory, even for massive fields, through non-equilibrium dynamics and UV/IR mixing, especially in global de Sitter space. Using Schwinger–Keldysh formalism, they compare electric-field, expanding, contracting, and dS backgrounds to reveal how IR effects alter correlators, backreaction, and potentially the cosmological constant. They find that while expanding patches suppress memory, contracting and global de Sitter geometries generate infrared logs and Planck-scale UV/IR mixing, suggesting infrared physics could influence cosmology more than previously thought. The work highlights the need for real-time analyses of quantum fields in curved spacetime and points toward IR-driven mechanisms for addressing the cosmological constant problem.

Abstract

We discover that some unstable vacua have long memory. By that we mean that even in the theories containing only massive particles, there are correllators and expectation values which grow with time. We examine the cases of instabilities caused by the constant electric fields, expanding and contracting universes and, most importantly, the global de Sitter space. In the last case the interaction leads to a remarkable UV/IR mixing and to a large back reaction. This gives reasons to believe that the cosmological constant problem could be resolved by the infrared physics.

Paper Structure

This paper contains 11 sections, 96 equations, 7 figures.

Table of Contents

  1. Introduction
  2. Lorentzian vs Euclidean calculations
  3. Electric fields and new anomaly
  4. Expanding Universe (free fields)
  5. Contracting Universe (free fields)
  6. Secular interactions and the leading logarithms, Poincare patch
  7. Secular interactions and leading logarithms, complete $dS$ space
  8. Conclusions
  9. Acknowledgements
  10. First geometry, Poincare patch
  11. Geometry of the Complete de Sitter space

Figures (7)

  • Figure 1: The contours of integration on a sphere and after analytic continuation to $dS$ space.
  • Figure 2: Standard contour of integration in Lorentzian approach.
  • Figure 3: One-loop diagram responsible for infrared logarithms in Poincare patch.
  • Figure 4: Conformal diagram. Poincare patch is shown by the gray area. Solid black line represents the past light cone of the observer. The intersection of this cone with Poincare patch touches past infinity only at one point.
  • Figure 5: Relevant diagram, leading to IR divergence, in complete $dS$ space.
  • ...and 2 more figures