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Quantum Oscillons are Long-Lived

Jarah Evslin, Katarzyna Slawińska, Tomasz Romańczukiewicz, Andrzej Wereszczyński

TL;DR

The paper revisits quantum oscillons and argues that treating the oscillon as a squeezed coherent state, rather than a coherent state, eliminates leading-order radiation and yields a periodic, long-lived quantum state. By constructing a Floquet-based field decomposition and a squeezed ground state, the authors show that the dominant radiative channel observed in previous studies corresponds to relaxation to a squeezed state rather than true decay, thereby extending the oscillon lifetime in proportion to an inverse power of the coupling. This reframes the relevance of oscillons in quantum settings, with potential implications for cosmology, dark matter, and low-energy QCD, and outlines a path for incorporating higher-order corrections. The work leverages a careful separation of discrete and continuum modes, a displacement-operator framework, and a detailed analysis of operator evolution to establish a periodic quantum oscillon sector at leading order.

Abstract

As the longest lived transient, oscillons play a critical role in classical field theory simulations of many phenomena. However, beyond the classical approximation, it is well-known that quantum corrections open decay channels through which oscillons radiate rapidly. Therefore it is believed that in the real world, oscillons are too short-lived to be phenomenologically relevant. We observe that previous calculations of the radiated power assume that the oscillon is in a coherent state. We show that a squeezed coherent state, on the other hand, would emit no radiation at leading order in the coupling. This leads us to the conclusion that the instantaneous radiation calculated in the literature corresponds not to the oscillon's decay, but rather to its relaxation from a coherent state to a lower-energy, squeezed coherent state, which then radiates much more slowly. As a result, the lifetime of the quantum oscillon is enhanced by an inverse power of the coupling.

Quantum Oscillons are Long-Lived

TL;DR

The paper revisits quantum oscillons and argues that treating the oscillon as a squeezed coherent state, rather than a coherent state, eliminates leading-order radiation and yields a periodic, long-lived quantum state. By constructing a Floquet-based field decomposition and a squeezed ground state, the authors show that the dominant radiative channel observed in previous studies corresponds to relaxation to a squeezed state rather than true decay, thereby extending the oscillon lifetime in proportion to an inverse power of the coupling. This reframes the relevance of oscillons in quantum settings, with potential implications for cosmology, dark matter, and low-energy QCD, and outlines a path for incorporating higher-order corrections. The work leverages a careful separation of discrete and continuum modes, a displacement-operator framework, and a detailed analysis of operator evolution to establish a periodic quantum oscillon sector at leading order.

Abstract

As the longest lived transient, oscillons play a critical role in classical field theory simulations of many phenomena. However, beyond the classical approximation, it is well-known that quantum corrections open decay channels through which oscillons radiate rapidly. Therefore it is believed that in the real world, oscillons are too short-lived to be phenomenologically relevant. We observe that previous calculations of the radiated power assume that the oscillon is in a coherent state. We show that a squeezed coherent state, on the other hand, would emit no radiation at leading order in the coupling. This leads us to the conclusion that the instantaneous radiation calculated in the literature corresponds not to the oscillon's decay, but rather to its relaxation from a coherent state to a lower-energy, squeezed coherent state, which then radiates much more slowly. As a result, the lifetime of the quantum oscillon is enhanced by an inverse power of the coupling.

Paper Structure

This paper contains 11 sections, 47 equations, 1 figure.

Table of Contents

  1. Introduction
  2. The Oscillon
  3. Linearized Perturbations
  4. Decomposing the Field
  5. The Displacement Operator
  6. Time Evolution
  7. The Oscillon State
  8. Conclusions
  9. Collective Coordinates
  10. Floquet Modes and Their Orthogonality
  11. The Evolution of the Operators

Figures (1)

  • Figure 1: The real (left) and imaginary (right) parts of the long wavelength continuum modes $\mathfrak g_k(\epsilon x,t)$ at $k=m$ (top) and $k=3m$ (bottom). Here $\epsilon=0.1$. When $k/m\gg 1$ so that the wavelength is much shorter than the oscillon, these tend to plane waves.