- The paper demonstrates that quantum corrections to the Higgs potential can trigger vacuum decay via quantum tunneling under cosmic conditions.
- It employs renormalization group and heat kernel techniques to assess vacuum stability within a curved spacetime framework.
- The study derives cosmological constraints, showing how inflation and reheating dynamics modulate electroweak vacuum stability.
The paper "Cosmological Aspects of Higgs Vacuum Metastability" presents a comprehensive examination of the implications of Higgs vacuum metastability on cosmology. The authors begin by discussing how the current parameters of the Standard Model (SM) suggest a metastable electroweak vacuum, which implies that it can decay into a lower energy state leading to catastrophic consequences for the universe. This paper explores this implication by analyzing the theoretical framework and the cosmological context, paying particular attention to the effects during the early universe.
The stability of the Higgs vacuum depends critically on two parameters: the mass of the Higgs boson and the top quark. The potential instability arises primarily from quantum corrections to the Higgs potential, which could induce the vacuum to decay from a higher-energy metastable state to a lower-energy true vacuum state through a process akin to quantum tunneling. The authors explore the specifics of these quantum corrections using renormalization group (RG) methods, which optimize the effective potential for scenarios with varying energy scales, including the incredibly high energies characterizing the early universe.
Theoretical Implications and Methodology
The authors review the Higgs potential by employing quantum field theory on curved spacetime principles, requiring consideration of additional terms such as a non-minimal coupling to curvature and the effects of spacetime dynamics. By utilizing the heat kernel method, they compute one-loop quantum corrections in a curved background, extending the analysis to incorporate renormalization group improvement with curvature-dependent scale choices. This formalism reveals how the curvature of spacetime, especially during the rapid expansion of the universe, affects the behavior of the Higgs field.
An innovative aspect of their analysis is the treatment of multiverse quantum tunneling events, both under zero-temperature Minkowski conditions and finite-temperature conditions reflective of the early universe's thermal environment. The authors also explore Hawking-Moss and Coleman-de Luccia instantons, which facilitate vacuum transitions under de Sitter (inflationary) conditions, offering a nuanced look at potential decay rates of the electroweak vacuum in various cosmic epochs.
Cosmological Context and Applications
Using the established theoretical frameworks, the authors examine how different cosmological eras — including inflation, reheating, and the radiation-dominated epoch— influence vacuum stability. The presence of large spacetime curvature during inflation and subsequent reheating can either suppress or accelerate vacuum decay. For instance, a significant non-minimal Higgs-curvature coupling can stabilize the vacuum against decay during inflation but destabilize it post-inflation during periods of coherent inflaton oscillations.
Moreover, the paper derives constraints on cosmological parameters like the Hubble rate during inflation, as well as the Higgs-curvature coupling, by considering potential vacuum decay events. These constraints are more robust than those obtained from collider experiments, emphasizing the importance of cosmological perspectives on high-energy physics.
Discussion and Future Implications
The findings advance our understanding of the consequences of a metastable Higgs field within the broader cosmic landscape. Notably, the possibility of vacuum decay implies stringent conditions for the stability of the electroweak vacuum over the universe's history, which could inform future research into physics beyond the Standard Model or guide observations probing the early universe's dynamics.
This paper opens avenues for exploring richer inflationary models and multifaceted reheating phases, which may further elucidate the complex interplay between high-energy physics and cosmology. Additionally, it demonstrates the power of integrating quantum field theory with cosmological insights to explore the universe's fundamental structure and evolution. As knowledge in this area grows, it may lead to a deeper understanding of our universe's early moments and the fundamental forces that govern its evolution.