The statement that "space" itself has no properties is a viewpoint that arises in certain philosophical and conceptual discussions about the nature of space. It suggests that space is a geometric framework or a backdrop in which objects and events occur, rather than having inherent properties of its own.
However, in the context of physics, space is often treated as a physical entity with properties that can be measured and described. One example of such properties in the electromagnetic field theory is the permeability and permittivity of free space.
Permeability (μ) and permittivity (ε) are fundamental constants that describe the behavior of electromagnetic waves in a given medium. In free space, which is often considered a vacuum, the permeability and permittivity are defined as the values that govern the propagation of electromagnetic waves in the absence of any material medium.
The values of permeability and permittivity in free space are experimentally determined quantities and have been measured to high precision. The permeability of free space (μ₀) is approximately 4π x 10^(-7) N/A², and the permittivity of free space (ε₀) is approximately 8.854 x 10^(-12) F/m. These values define the relationship between electric and magnetic fields and how they propagate through free space.
Regarding the second part of your question about the interaction rates among quantum fields and the speed of causality, it touches upon the fundamental aspects of quantum field theory and the nature of causality.
In quantum field theory, interactions between fields are described by the exchange of particles known as gauge bosons. These interactions occur within the framework of relativistic quantum mechanics, which includes the principle of causality, stating that causes must precede their effects.
The speed of causality, often referred to as the speed of light in vacuum (c), is a fundamental constant in physics. It represents the maximum speed at which information or causal influences can propagate in spacetime. In the theory of special relativity, it is postulated that the speed of light in vacuum is the same for all observers, independent of their relative motion.
The relationship between the interaction rates of quantum fields and the speed of causality is a complex topic that is still an active area of research. The structure and behavior of quantum fields, as well as the underlying principles of causality and relativity, contribute to our understanding of the fundamental limits and constraints on the propagation of information and causal influences in the universe.
It's important to note that the explanations provided here are simplified descriptions of complex topics. The fields of physics and philosophy continue to explore these questions, and different perspectives and interpretations exist on these fundamental concepts.