A What are the implications of time constraints in the standard model?

[sunrah]

What are the constraints (if there are any) placed on time by the different theories in the standard model and what are their potential implications?

 

[Dale]

Time is unconstrained in the standard model. It can run from minus infinity to plus infinity

 

[sunrah]

Hi, yes I realize that. I should have phrased the question more accurately. I meant qualitatively, how do the different areas of standard physics like relativity, thermodynamics, QFT (I haven't studied this last one) etc. treat time and how may we interpret this sensibly. Time is after all common to all of areas in physics, I think.

 

[anorlunda]

Hi, yes I realize that. I should have phrased the question more accurately. I meant qualitatively, how do the different areas of standard physics like relativity, thermodynamics, QFT (I haven't studied this last one) etc. treat time and how may we interpret this sensibly. Time is after all common to all of areas in physics, I think.

That is still very unclear. I don't understand what you are asking.

 

[sunrah]

That is still very unclear. I don't understand what you are asking.

Sorry I don't mean to be cryptic. For example, Einstein introduces (amongst many things) the idea that time is no longer absolute, this has definite consequences for the simultaneity of events but what does this imply, if anything, about possible properties of time? It seems question the notion of a well defined past, present and future.

Einstein relativity also binds time to space immutably, again this should imply something in my opinion, although it could just as well show the limits of my understanding. The only quantum physics I'v done is undergraduate Quantum Mechanics and all I know is that, although time-energy uncertainty exists, time is not an observable

I realize now, this could be a very big ask. So if there are an reviews on this, I'd be happy for links.

 

[Dale]

It seems question the notion of a well defined past, present and future

It may be that you are interested in the causal structure of relativity. You may want to start with the section labeled Causal Structure here:
https://en.m.wikipedia.org/wiki/Minkowski_space#Causal_structure

 

[ImStein]

Events are locations in spacetime, which are separated by invariant spacetime intervals. Those spacetime intervals have spatial and temporal components which vary with reference frame. The components are relative (a matter of frame perspective), the intervals are not. Some compare this to laying a ruler of definite length on a piece of graph paper. Depending on the angle between the grid and the ruler, there will be a varying number of squares in describing the horizontal and vertical components of the ruler's length. Those components are relative, while the ruler's length, in that scenario, is invariant.

As compared to space, time is unidirectional offering freedom only toward the future. That future corresponds to a universe which is expanding and total entropy which is increasing.