The Ultimate Fate of Matter in ΛCDM Cosmology

From Quark Confinement to Cosmic Evaporation in de Sitter Space

Fundamental Principles

In the ΛCDM model with a de Sitter future, gluons continue to bind quarks into hadrons regardless of the Carnot limit or de Sitter horizon. The strong nuclear force operates at energy scales of ~200 MeV (10¹² Kelvin), while the de Sitter thermal background is ~10⁻³³ eV (10⁻³⁰ Kelvin), making the cosmological thermal noise completely irrelevant to local quantum chromodynamics.

The binding of quarks by gluons is a local quantum phenomenon governed by Quantum Chromodynamics and its property of confinement. This occurs on femtometer scales and remains unaffected by the large-scale cosmological evolution toward de Sitter space.

The Cosmic Evaporation Timeline

Stage 1: Evaporation of Bound Structures Now to 10¹⁴-10²⁰ Years

Galaxy clusters and individual galaxies become unbound as dark energy pushes their components beyond causal contact. Stars exhaust their nuclear fuel, leaving behind stellar remnants: white dwarfs, neutron stars, and black holes. Planetary systems are disrupted through gravitational interactions, and frozen degenerate matter objects drift through an ever-expanding intergalactic void.

Stage 2: Decay of Elementary Matter 10³⁴ to 10⁴⁰ Years

If Grand Unified Theories are correct, protons are not truly stable. Protons decay into positrons and pions, which subsequently decay into photons. Neutrons in neutron stars decay through similar processes. This marks the end of all atomic matter, transforming white dwarfs and neutron stars into diffuse clouds of leptons and radiation.

Stage 3: The Black Hole Era 10⁴⁰ to 10¹⁰⁰ Years

Black holes become the only remaining macroscopic structures. Through Hawking radiation, they slowly evaporate—stellar-mass black holes vanishing first, followed by supermassive black holes. Each black hole ends its existence in a final burst of particles, contributing to the cosmic background.

Stage 4: The Final De Sitter Epoch Beyond 10¹⁰⁰ Years

The universe enters its simplest and final state. The particle content consists primarily of an ultra-dilute gas of photons with minute quantities of stable particles: electrons, positrons, and neutrinos. The expansion becomes so rapid that it can prevent even electromagnetic binding—electron-positron pairs may be stretched apart by cosmological expansion before they can annihilate.

The Final Particle Census

In the eternal de Sitter state, the universe contains an ultra-dilute, cold distribution of fundamental particles. Photons dominate the energy budget, their wavelengths stretched to cosmological scales by exponential expansion. A sparse population of leptons (electrons, positrons, neutrinos) persists, separated by distances that grow without bound. Dark matter particles may remain if stable, though their ultimate fate remains uncertain.

The powerful forces that once structured the cosmos—the strong nuclear force binding quarks and the electromagnetic force binding atoms—become cosmologically irrelevant. Their limited range is infinitesimal compared to the exponentially growing distances between the last remaining particles. The universe concludes not with destruction but with infinite dilution into a state of maximum entropy—the heat death in de Sitter space.