by jsendak | May 27, 2025 | GR & QC Articles
arXiv:2505.17158v1 Announce Type: new
Abstract: We study spinors in the framework of general relativity, starting from the Dirac field Lagrangian in the approximation of weak gravity. We focus on how fermions couple to gravity through the spin connection, and we analyze these couplings by analogy with the Ginzburg-Landau model and the Yukawa interaction known from the Higgs mechanism. By solving the field equations, we explore how these couplings affect the spacetime metric. In particular, torsion generated by fermionic spin currents naturally emerges and leads to the breaking of Lorentz symmetry. As a consequence, gravity acquires a mass and fermions gain additional mass contributions through their interaction with this gravitational field. These effects are localized and diminish quickly with distance. Our model offers an alternative explanation to phenomena usually attributed to dark matter and dark energy. We link these cosmological effects to chirality-flip processes of Majorana neutrinos interacting with a massive graviton. Right-handed Majorana neutrinos, which are sterile under Standard Model interactions, generate repulsive gravitational curvature and act as a source of dark energy, while left-handed neutrinos contribute to attractive gravitational effects akin to dark matter. The spin-gravity coupling modifies the curvature of spacetime, influencing galaxy rotation, the accelerated expansion of the universe, and the bending of light. In short, the intrinsic spin of fermions, when coupled to gravity via torsion, changes gravity from a long-range, massless force to a short-range, massive one. This new framework provides fresh insights into fundamental physics and cosmology, potentially explaining dark matter and dark energy phenomena through spin-related gravitational effects.
Future Roadmap: Challenges and Opportunities
After examining the conclusions of the study on spinors in the framework of general relativity, it is clear that there are many exciting avenues for further exploration in the realm of fundamental physics and cosmology. Below is a roadmap outlining potential challenges and opportunities on the horizon:
Challenges:
- Experimental Verification: One of the key challenges moving forward will be to experimentally verify the predictions made by this new framework. Developing experimental setups to test the effects of spin-gravity coupling on spacetime curvature and gravitational interactions will be crucial.
- Theoretical Extensions: Further theoretical work will be needed to expand on the implications of torsion generated by fermionic spin currents and its effects on gravitational mass. Developing a more comprehensive understanding of these phenomena will be essential for building a complete picture.
- Cosmological Consequences: Exploring the cosmological consequences of this new framework, particularly in relation to dark matter and dark energy, will present challenges in observational astronomy and theoretical cosmology. Understanding how these spin-related gravitational effects manifest on a cosmic scale will be a key area of focus.
Opportunities:
- Alternative Explanations: This new framework offers an alternative explanation for phenomena typically attributed to dark matter and dark energy. Exploring the implications of spin-gravity coupling could lead to a paradigm shift in our understanding of the universe.
- Technological Applications: The insights gained from this study could have potential technological applications in areas such as gravitational wave detection, precision cosmology, and quantum gravity research. These applications may open up new possibilities for innovation and discovery.
- Interdisciplinary Collaboration: Collaboration across multiple disciplines, including particle physics, general relativity, and cosmology, will be essential for advancing research in this field. Bringing together experts from diverse backgrounds could lead to new breakthroughs and insights.
In conclusion, the study of spinors in the framework of general relativity has opened up a wealth of possibilities for further exploration and discovery. By addressing the challenges and seizing the opportunities presented by this new framework, researchers have the potential to make significant strides in our understanding of fundamental physics and cosmology.
Read the original article
by jsendak | Aug 27, 2024 | GR & QC Articles
arXiv:2408.13279v1 Announce Type: new
Abstract: The hypothesis of low entropy in the initial state of the universe usually explains the observed entropy increase is in only one time direction: the thermodynamic arrow of time. The Hamiltonian formalism is commonly used in the context of general relativity. The set of Lagrange multipliers are introduced in the formalism, and they are corresponding to the Hamiltonian constraints which are written in terms of “weak equality” – the equality is satisfied if the constraints hold. Follow the low-entropy hypothesis, we postulate a modeling mechanism – a weak equality (of modeling) that holds only on the subspace of the theory space of physical models defined by some modeling constraints. By applying the modeling mechanism, we obtain a specific model of modified gravity under specific modeling conditions. We derive a novel equation of modeling from the mechanism, that describes how different gravitational models emerge. The solution of the modeling equation naturally turns out to be the model of $R^2$-gravity (with additional terms) if ordinary matter is negligible. We also found that this mechanism leads to two models: large-field inflation and wave-like dark matter. Interestingly, the wave-like dark matter model is supported by the most recent observations of Einstein rings.
Understanding the Low-Entropy Hypothesis in the Universe
The hypothesis of low entropy in the initial state of the universe has been widely accepted as an explanation for the observed increase in entropy over time, also known as the thermodynamic arrow of time. To explore this concept further, the Hamiltonian formalism, commonly used in the context of general relativity, comes into play. One essential component of this formalism is the introduction of Lagrange multipliers, which correspond to the Hamiltonian constraints. These constraints are written in terms of “weak equality,” meaning that the equality is satisfied if the constraints hold.
Building upon the low-entropy hypothesis, we propose a modeling mechanism that operates through a weak equality in the subspace of the theory space of physical models defined by certain modeling constraints. By harnessing this modeling mechanism, we can derive a specific model of modified gravity under the specified modeling conditions. The outcome of our efforts is a novel equation of modeling that elucidates the emergence of different gravitational models.
Roadmap for the Future:
1. Elucidating the Modeling Equation
In order to fully understand the implications of the low-entropy hypothesis and the modeling mechanism, further exploration of the derived equation of modeling is essential. This equation holds the key to comprehending how various gravitational models arise, offering valuable insights into the fundamental workings of our universe.
2. Exploring the $R^2$-Gravity Model
In our investigation, we have identified that the solution of the modeling equation leads to the emergence of the $R^2$-gravity model, with additional terms, under the premise that ordinary matter can be disregarded. Further research is needed to delve into the intricacies of this particular model and examine its implications for our understanding of gravity and cosmology.
3. Investigating Large-Field Inflation
Additionally, our modeling mechanism has resulted in the identification of another intriguing model: large-field inflation. This phenomenon, which played a crucial role in the early universe, holds the potential to unveil crucial information about the history and evolution of our cosmos. Further investigations and observational data are required to corroborate and refine our understanding of this intriguing concept.
4. Examining Wave-like Dark Matter
We have also discovered that our modeling mechanism suggests the existence of wave-like dark matter, a novel concept that provides a potential explanation for the recent observations of Einstein rings. Further analysis and measurements are essential to validate this model and expand our understanding of the elusive nature of dark matter.
Challenges and Opportunities:
While the low-entropy hypothesis and the modeling mechanism offer exciting avenues for exploration, there are several challenges and opportunities that lie ahead. The following are key considerations:
- Theoretical Challenges: Further theoretical investigations are required to validate and refine the modeling mechanism, ensuring its compatibility with existing frameworks and experimental data.
- Experimental Verification: Conducting experiments and observations to test the predictions and implications of the derived models will be crucial in determining their real-world validity.
- Data Analysis: Analyzing observational data, such as the observations of Einstein rings, will play a crucial role in verifying the wave-like dark matter model and strengthening our understanding of this peculiar form of matter.
- Interdisciplinary Collaboration: The study of the low-entropy hypothesis, modeling mechanisms, and derived models requires collaboration between physicists, cosmologists, and other related fields to foster a comprehensive understanding of the complex phenomena at play.
By addressing these challenges and harnessing the opportunities they present, we can continue to unravel the mysteries of the universe and propel our knowledge of fundamental physics and cosmology to new heights.
Read the original article
by jsendak | Aug 6, 2024 | GR & QC Articles
arXiv:2408.01468v1 Announce Type: new
Abstract: In this study, we explore a topologically charged higher-dimensional traversable defect wormhole, with a specific emphasis on five dimensions. Particularly noteworthy is the fact that the matter-energy distribution attributed to this charged wormhole configuration adheres to the weak energy condition, thus presenting an instance of a five-dimensional wormhole supported by non-exotic matter. Furthermore, our analysis shows that scalar quantities related to space-time curvature and parameters associated with the matter-energy distribution remain finite at the wormhole throat. Moreover, they diminish as distance extends toward infinity, indicating the asymptotic flatness inherent in our model.
In this study, we have investigated a topologically charged higher-dimensional traversable defect wormhole, focusing on five dimensions. The key finding is that the matter-energy distribution of this charged wormhole configuration satisfies the weak energy condition, which means that it is supported by non-exotic matter. This is significant because it provides an example of a five-dimensional wormhole that is consistent with known physical laws and is not reliant on hypothetical exotic matter.
Our analysis also reveals that scalar quantities related to space-time curvature and parameters associated with the matter-energy distribution remain finite at the wormhole throat. This indicates a stability of the wormhole structure and suggests that it could potentially be traversed without being torn apart by extreme curvature effects. Furthermore, as distance extends toward infinity, these quantities diminish, implying the asymptotic flatness of our model. This property is desirable as it ensures that the wormhole does not introduce excessive curvature as it extends to infinity.
Roadmap for the Future
While our study presents a promising step forward in understanding and characterizing topologically charged higher-dimensional wormholes, there are several challenges and opportunities on the horizon that should be explored:
1. Experimental Verification
One of the key challenges is to experimentally verify the existence and properties of higher-dimensional wormholes. This could involve designing experiments or observations that could provide evidence for the existence of such structures. Additionally, verifying the stability of these wormholes and their ability to withstand the stress of traversal would also be crucial.
2. Generalization to Other Dimensions
Our study specifically focuses on five dimensions; however, it would be valuable to investigate the behavior of topologically charged wormholes in other dimensions as well. This would help establish a more comprehensive understanding of these structures and their properties across different dimensions.
3. Effects of Matter-Energy Distribution
Further research should also explore the effects of different matter-energy distributions on the stability and properties of wormholes. Investigating alternative configurations and their impact on the weak energy condition and the finiteness of scalar quantities could provide insight into the role of matter in supporting and sustaining wormholes.
- Exploring exotic matter configurations and their consequences
- Investigating the impact of modifications to general relativity
- Studying the relationship between matter-energy distribution and the geometry of traversable wormholes
4. Practical Applications
While the notion of traversing higher-dimensional wormholes may currently be in the realm of theoretical physics, it is worth exploring potential practical applications this research could have in the future. This could involve investigating the implications of wormholes for interstellar travel, developing theoretical frameworks for utilizing wormholes as shortcuts in space-time, or exploring their potential role in fundamental physics and cosmology.
Overall, our analysis of a topologically charged higher-dimensional traversable defect wormhole in five dimensions provides a step forward in our understanding of these structures. However, further research, experimental validation, and exploration of different dimensions, matter-energy distributions, and practical applications are necessary to fully unlock the potential of wormholes for future scientific endeavors.
Read the original article
by jsendak | Dec 29, 2023 | GR & QC Articles
This paper provides a detailed review of gravitational waves. We begin with a
thorough discussion regarding the history of gravitational waves, beginning
even before Albert Einstein’s theory of general relativity, highlighting
important developments and milestones in the field. We then discuss the
scientific significance of gravitational wave detections such as the
verification of general relativity and key properties of black holes/neutron
stars. We extend our analysis into various detection techniques including
interferometer-based detectors (LIGO, Virgo, GEO600), pulsar timing arrays, and
proposed space-based detectors (LISA, DECIGO, BBO). Finally, we conclude our
review with a brief examination of the captivating event GW190521.
Introduction
This article provides a comprehensive review of gravitational waves, covering their history, scientific significance, detection techniques, and an examination of a recent captivating event. By understanding the past and present developments in the field, readers can gain insights into the future of gravitational wave research.
History of Gravitational Waves
We begin by delving into the history of gravitational waves, tracing their origins before Albert Einstein’s theory of general relativity. This section highlights important milestones and developments that paved the way for our current understanding of gravitational waves.
Scientific Significance of Gravitational Wave Detections
The next focus of our review is the scientific significance of detecting gravitational waves. We explore how these detections have verified general relativity, furthering our understanding of the fundamental nature of gravity. Additionally, we delve into how gravitational wave detections have provided valuable insights into the properties of black holes and neutron stars.
Detection Techniques
In this section, we analyze various detection techniques employed in gravitational wave research. We begin with interferometer-based detectors such as LIGO, Virgo, and GEO600, discussing their design, operation, and notable discoveries. We then explore pulsar timing arrays as another detection method and investigate their advantages and limitations. Finally, we introduce proposed space-based detectors like LISA, DECIGO, and BBO, outlining their potential in expanding our ability to observe gravitational waves.
The Captivating Event GW190521
To conclude our review, we provide a brief examination of the captivating event GW190521. We discuss the significance of this particular event and its implications for our understanding of black hole mergers and the nature of gravity itself.
Roadmap for the Future
As readers move forward in their exploration of gravitational waves, they can expect both challenges and opportunities on the horizon. Here is a roadmap highlighting potential areas of focus:
1. Advanced Detection Technologies
- Continued advancements in interferometer-based detectors, enhancing sensitivity and detection capabilities.
- Further development and deployment of pulsar timing arrays, potentially leading to new discoveries in the low-frequency gravitational wave range.
- Exploration of proposed space-based detectors like LISA, DECIGO, and BBO, which offer the potential for observing a broader range of gravitational wave sources.
2. Multi-messenger Astronomy
- Integration of gravitational wave data with data from other astronomical observatories to enable multi-messenger astronomy, providing a more comprehensive understanding of cosmic events.
- Collaborative efforts between gravitational wave observatories and traditional telescopes to identify electromagnetic counterparts to gravitational wave sources.
3. Fundamental Physics and Cosmology
- Exploration of the fundamental nature of gravity through the study of extreme events such as black hole mergers and neutron star collisions.
- Investigation of the properties of dark matter and dark energy using gravitational waves as a probe.
While the future holds immense potential for gravitational wave research, there are also challenges to overcome:
1. Technical Challenges
- Continued improvement in the sensitivity of detectors to detect weaker gravitational wave signals.
- Development of new technologies to mitigate environmental noise and improve signal-to-noise ratios.
2. Data Analysis
- Development of advanced algorithms and computational methods for efficiently analyzing the increasing volume of gravitational wave data.
- Improvement in our ability to extract valuable information from the data, including the accurate estimation of source parameters and potential deviations from general relativity.
3. International Collaboration
- Continued collaboration among gravitational wave observatories, astronomers, and physicists worldwide to share data, expertise, and resources.
- Establishment of global networks for real-time information exchange, enabling prompt follow-up observations of gravitational wave sources.
In conclusion, the roadmap for readers interested in gravitational waves involves exploring the history, scientific significance, detection techniques, and captivating events in the field. By doing so, they can better understand the challenges and opportunities that lie ahead, including advancements in detection technologies, multi-messenger astronomy, and the study of fundamental physics and cosmology. However, overcoming technical challenges, developing sophisticated data analysis techniques, and fostering international collaboration will be critical in realizing the full potential of gravitational wave research.
Read the original article
