by jsendak | Dec 31, 2023 | GR & QC Articles
We study numerically the existence in a false vacuum, of magnetic monopoles
which are “thin-walled”, ie, which correspond to a spherical region of
radius $R$ that is essentially trivial surrounded by a wall of thickness
$Deltall R$, hence the name thin wall, and finally an exterior region that
essentially corresponds to a pure Abelian magnetic monopole. Such monopoles
were dubbed false monopoles and can occur in non-abelian gauge theories where
the symmetry-broken vacuum is actually the false vacuum. This idea was first
proposed in cite{Kumar:2010mv}, however, their proof of the existence of false
monopoles was incorrect. Here we fill this lacuna and demonstrate numerically
the existence of thin-wall false monopoles. The decay via quantum tunnelling of
the false monopoles could be of importance to cosmological scenarios which
entertain epochs in which the universe is trapped in a symmetry-breaking false
vacuum.
The Existence of Thin-Walled False Monopoles
We have conducted numerical studies to investigate the existence of magnetic monopoles in a false vacuum that have a “thin-walled” structure. These monopoles are characterized by a central region with a radius of R, which is essentially trivial, surrounded by a thin wall with a thickness of Δ that is much smaller than R. The exterior region corresponds to a pure Abelian magnetic monopole.
Initially proposed in a paper by Kumar et al. (2010), the concept of false monopoles in non-Abelian gauge theories suggests that the symmetry-broken vacuum is actually a false vacuum. However, the original proof of the existence of false monopoles was found to be incorrect.
Numerical Evidence of Thin-Wall False Monopoles
In this study, we address the previous gap in research and provide numerical evidence for the existence of thin-wall false monopoles. Our investigations support the idea that these monopoles can indeed occur in certain non-Abelian gauge theories with a false vacuum.
Potential Significance in Cosmological Scenarios
The decay of false monopoles through quantum tunneling may have important implications for cosmological scenarios. In particular, this phenomenon could be relevant during epochs where the universe is trapped in a symmetry-breaking false vacuum. Understanding the behavior of thin-wall false monopoles can contribute to our knowledge of such cosmological events.
Roadmap for Future Research
- Further Validation: Additional numerical simulations and mathematical analyses are needed to validate our findings and confirm the existence of thin-wall false monopoles in various non-Abelian gauge theories.
- Quantum Tunneling Studies: Investigating the decay process of false monopoles through quantum tunneling is crucial for comprehending their behavior and potential cosmological consequences.
- Cosmological Applications: Explore the impact of thin-wall false monopoles on cosmological scenarios, such as inflationary models or early universe dynamics, to assess their significance in shaping the evolution of the universe.
- Extended Gauge Theories: Extend our investigations to more complex gauge theories beyond non-Abelian theories, considering the potential existence of thin-wall false monopoles in these extended frameworks.
Challenges:
- Complex Numerical Simulations: Numerically studying the properties and dynamics of thin-wall false monopoles requires computationally intensive simulations.
- Verification of Results: Ensuring the accuracy and reliability of numerical results through techniques like convergence tests and comparisons with other analytical or numerical approaches can be time-consuming.
Opportunities:
- Improved Cosmological Understanding: Gaining insights into the decay mechanisms and behavior of false monopoles can enhance our understanding of cosmological phenomena and potentially bridge gaps in current theories.
- Technological Advancements: Development of more efficient computational methods and high-performance computing infrastructure can expedite numerical investigations and facilitate larger-scale simulations.
Overall, the study of thin-wall false monopoles offers promising avenues for advancing our knowledge of non-Abelian gauge theories, the behavior of monopoles in false vacua, and their implications in cosmology. Further research and rigorous validation are essential for establishing the significance of these phenomena in broader theoretical frameworks and practical cosmological scenarios.
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by jsendak | Dec 31, 2023 | GR & QC Articles
In this paper we study the shear free spherical symmetric gravitational
collapse of charged radiating star. All the physical quantities including
pressure, density are regular. Energy conditions are satisfied throughout the
interior of the matter configuration. The luminosity is time independent and
mass is radiated linearly. The causal and non causal temperature remains
greater than that of the uncharged collapsing scenario.
Conclusions:
The study focuses on the shear-free spherically symmetric gravitational collapse of a charged radiating star. The physical quantities, such as pressure and density, are found to be regular and satisfy energy conditions within the interior of the star. The luminosity remains time independent, and the mass is radiated linearly. Additionally, the temperature, both causal and non-causal, is found to be greater than that of an uncharged collapsing scenario.
Future Roadmap:
1. Further Investigation on Charged Radiating Stars:
The study opens up avenues for additional research on charged radiating stars. Since the physical quantities are regular and energy conditions are satisfied, it would be interesting to explore the behavior of other variables under different conditions or assumptions. For example, studying the effect of different charge densities on the collapse could yield valuable insights into the stability and evolution of these stars.
2. Comparative Analysis with Uncharged Collapsing Stars:
The finding that the temperature of the charged radiating star remains higher than that of an uncharged collapsing scenario invites a comparative study. Examining the differences in collapse dynamics, evolution of mass and luminosity between charged and uncharged stars could provide a better understanding of the role of charge in gravitational collapse.
3. Cosmological Applications:
Considering that this study focuses on gravitational collapse, exploring the cosmological implications of charged radiating stars might be worthwhile. Investigating how the presence of charge affects the formation and evolution of galaxies, black holes, or other cosmic structures could have significant implications for our understanding of the universe.
Potential Challenges:
- The complexity of modeling charged radiating stars may pose challenges in accurately predicting the behavior of various physical quantities.
- Obtaining observational data to validate the theoretical findings could be challenging due to the limited number of known charged radiating stars.
- Understanding the interplay between charge and other factors impacting gravitational collapse requires sophisticated mathematical models and computational resources.
Potential Opportunities:
- The unique behavior of charged radiating stars provides an opportunity for novel discoveries and advancements in our understanding of astrophysics.
- Further research on charged radiating stars can contribute to the broader knowledge of general relativity, gravity, and the properties of matter under extreme conditions.
- Advancements in modeling and computational techniques can be made as a result of the challenges faced, benefiting not only the study of charged radiating stars but also other areas of scientific research.
Conclusion:
The study of shear-free spherical symmetric gravitational collapse of charged radiating stars has presented promising results. Building on these conclusions, future research should focus on investigating other aspects of charged radiating stars, conducting comparative analyses with uncharged collapsing scenarios, and exploring cosmological implications. While challenges exist, such opportunities have the potential to significantly expand our knowledge of astrophysics, general relativity, and the universe as a whole.
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by jsendak | Dec 29, 2023 | GR & QC Articles
We develop a novel framework for describing quantum fluctuations in field
theory, with a focus on cosmological applications. Our method uniquely
circumvents the use of operator/Hilbert-space formalism, instead relying on a
systematic treatment of classical variables, quantum fluctuations, and an
effective Hamiltonian. Our framework not only aligns with standard formalisms
in flat and de Sitter spacetimes, which assumes no backreaction, demonstrated
through the $varphi^3$-model, but also adeptly handles time-dependent
backreaction in more general cases. The uncertainty principle and spatial
symmetry emerge as critical tools for selecting initial conditions and
understanding effective potentials. We discover that modes inside the Hubble
horizon emph{do not} necessarily feel an initial Minkowski vacuum, as is
commonly assumed. Our findings offer fresh insights into the early universe’s
quantum fluctuations and potential explanations to large-scale CMB anomalies.
We have developed a novel framework for describing quantum fluctuations in field theory, with a particular focus on cosmological applications. Unlike traditional approaches that rely on operator/Hilbert-space formalism, our method utilizes classical variables, quantum fluctuations, and an effective Hamiltonian. This framework aligns with standard formalisms in flat and de Sitter spacetimes, even without assuming no backreaction, as demonstrated through the $varphi^3$-model. Additionally, it handles time-dependent backreaction in more general cases.
In our research, we have found that the uncertainty principle and spatial symmetry play crucial roles in selecting initial conditions and understanding effective potentials. Contrary to common assumptions, we have discovered that modes inside the Hubble horizon do not necessarily experience an initial Minkowski vacuum. These findings offer valuable insights into quantum fluctuations in the early universe and could provide potential explanations for large-scale cosmic microwave background (CMB) anomalies.
Future Roadmap
Potential Challenges
- Testing the Framework: The first challenge will be to further test and validate the proposed framework. It is essential to compare its predictions with existing theories and empirical observations to ensure its accuracy and reliability.
- Models with Time-Dependent Backreaction: While our framework adeptly handles time-dependent backreaction, exploring and modeling specific cases with this characteristic may present additional challenges. Developing mathematical techniques and computational methods to study these cases will be crucial.
- Addressing CMB Anomalies: Our findings suggest a potential link between quantum fluctuations and large-scale CMB anomalies. To fully understand and explain these anomalies, further investigations, data analysis, and collaborations with observational cosmologists will be necessary.
Potential Opportunities
- Improved Cosmological Models: Our framework opens up new avenues for improving cosmological models by incorporating more realistic treatments of quantum fluctuations. This can lead to more accurate predictions and a better understanding of the early universe.
- Exploring Alternative Initial Conditions: The discovery that modes inside the Hubble horizon do not necessarily start with a Minkowski vacuum opens up possibilities for exploring alternative initial conditions. By considering different starting points, we can gain insights into the dynamics of the early universe and its impact on cosmic structures.
- Bridging Quantum Field Theory and Cosmology: Our method offers a unique approach to bridging the gap between quantum field theory and cosmology. By providing a framework that connects classical variables, quantum fluctuations, and an effective Hamiltonian, we can further our understanding of the fundamental nature of the universe.
Overall, our research presents a promising new framework for describing quantum fluctuations in cosmological field theory. While further testing, modeling, and investigations are needed, this approach offers exciting opportunities for advancing our knowledge of the early universe and cosmic anomalies.
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