Quantum process where a metastable vacuum state decays, potentially producing gravitational waves.False vacuum decay is a quantum process in which a metastable state of a quantum field—the 'false vacuum'—transitions to a lower-energy 'true vacuum' state. This decay proceeds through the nucleation of bubbles of the true vacuum within the false vacuum, which then expand at speeds approaching the speed of light. In cosmology, this process is invoked to explain the early universe's dynamics, including the possibility of a first-order phase transition that could generate a stochastic background of gravitational waves.
The theory of false vacuum decay was developed by Sidney Coleman and Curtis Callan in the late 1970s, building on earlier work on metastable states in quantum field theory.
Quantum fields can exist in a local minimum of their potential energy that is not the global minimum—this is the false vacuum. Quantum fluctuations allow the field to tunnel through the energy barrier to the true vacuum, a process described by Coleman's theory of bubble nucleation. Once a bubble forms, it expands, converting false vacuum to true vacuum and releasing energy. If many bubbles nucleate and collide, they produce ripples in spacetime—gravitational waves.
In laboratory settings, false vacuum decay has been simulated using ultracold atomic systems, where quantum tunneling between metastable states can be observed and studied in detail.
The expansion of a true vacuum bubble is so violent that it would destroy everything in its path, making the ultimate fate of our universe potentially dependent on whether our vacuum is truly stable.
| V | variable | Potential energy — potential energy joule |
| r | variable | Radial distance from source — distance metre |
| g | variable | Coupling strength (not a universal constant) joule metre |
| λ | variable | Screening length (range of interaction) — length metre |
| ψ | variable | perturbation amplitude — wave function |
| A | variable | initial amplitude — amplitude |
| ω_I | variable | imaginary part of frequency (decay rate) — decay rate per second |
| ω_R | variable | real part of frequency (oscillation frequency) — angular frequency per second |
| φ | variable | phase offset — phase |
| \tau | variable | lifetime — lifetime second |
| \lambda | variable | decay rate constant — decay rate per second |






















