At the quantum level, the nature of space and time becomes subject to the principles of quantum mechanics and the theories of quantum gravity, such as string theory or loop quantum gravity. However, our current understanding of these theories is still incomplete, and there is ongoing research to better understand the nature of space and time at the quantum level.
In general relativity, which describes the macroscopic behavior of gravity and spacetime, space and time are indeed intertwined in the concept of spacetime. However, the concept of omnidirectionality or simultaneous movement in all directions in spacetime is not accurate in the conventional sense. In our everyday experience, time appears to flow in one direction, commonly referred to as the "arrow of time," from past to future. This directional flow is related to phenomena such as entropy and the irreversible nature of certain processes.
In the realm of quantum mechanics, the situation becomes more complex. Quantum mechanics introduces inherent uncertainties and probabilistic behavior, and it challenges our classical intuitions about space and time. Quantum field theory, which combines quantum mechanics and special relativity, provides a framework for describing elementary particles and their interactions. Within this framework, spacetime is typically treated as a fixed background, and the dynamics of particles and fields take place within this fixed spacetime framework.
However, when it comes to a complete theory of quantum gravity, reconciling quantum mechanics and general relativity, there are various speculative approaches. These approaches suggest that at the most fundamental level, spacetime may have a discrete or granular structure or that it might emerge from more fundamental entities or interactions. In these scenarios, the notion of spacetime as a continuous and smooth entity breaks down at extremely small scales.
It's important to note that our understanding of quantum gravity is still an active area of research, and there is no consensus yet on the exact nature of spacetime at the quantum level. So, while the idea of omnidirectional time may be intriguing, it is not a widely accepted concept in current physics theories.