Vacuum decay constraints on a cosmological scalar field

Area of Science:

• Cosmology
• Quantum Field Theory
• Fundamental Physics

Background:

• The nature of dark energy, which drives the accelerated expansion of the Universe, is unknown.
• Scalar fields are theoretical constructs used to explain phenomena like dark energy.
• The potential energy of a scalar field can have different shapes, including minima.

Purpose of the Study:

• To investigate the cosmological implications of a scalar field potential with a minimum.
• To determine constraints on the properties of the dark energy scalar field based on the absence of vacuum decay.
• To assess the viability of cyclic or ekpyrotic universe models in light of vacuum decay.

Main Methods:

• Analysis of quantum tunneling and bubble nucleation in a scalar field potential.
• Calculation of the minimum separation required between the current dark energy field value and a potential minimum.
• Evaluation of vacuum decay rates under different cosmological scenarios.

Main Results:

• Any potential minimum for the dark energy scalar field must be significantly separated from its current value.
• The observed universe's stability places constraints on the depth and location of potential minima.
• Vacuum decay is shown to be untenable for cyclic or ekpyrotic universe models with specific energy scales.

Conclusions:

• The properties of the dark energy scalar field potential are constrained by the non-occurrence of vacuum decay.
• Certain models of cyclic and ekpyrotic universes are incompatible with current cosmological observations.
• Further research into scalar field potentials is crucial for understanding dark energy and the Universe's evolution.