Hello Chris,
Nice essay!
You ask, "Who knows? At high velocities, different particle behaviors may not all be affected to the exact same degree? An inertial frame which contains all types of particles and their force carriers moving through various fields at near-light velocity, may one day be able to detect its own inertial motion by observing various fundamental behaviors operating at different relative rates as compared to rates in low velocity."
Well, so far, in all our cyclotrons and atom-smashers--in all our observations of cosmic rays and muons and other high-velocity particles, relativity has never been violated. OF course it might some day, but unless we have a good reason to think it should be violated, there doesn't seem to be much gained by supposing relativity might be violated. Someday I might replace Axl Rose as the lead singer in Guns and Roses, but I have no real reason to think so.
I love your title!
"Is there a physical mechanism responsible for what we perceive as time?"
Yes! That physical mechanism is provided by a fundamental universal invariant--the fourth expanding dimension. The fourth dimension is expanindg reltaive to the three spatial dimensions, distributing locality and fathering time.
You would enjoy my essay which shows how time naturally emerges from a deeper physical invariant:
http://fqxi.org/community/forum/topic/238 "Time as an Emergent Phenomenon: Traveling Back to the Heroic Age of Physics by Elliot McGucken"
Einstein's Relativity may be derived from dx4/dt= ic, which represents a more fundamental invariance of this universe--the fourth dimension is expanding relative to the three spatial dimensions. Einstein introduced relativity as a principle--as a law of nature not deduced from anything else, and well, I guess I was dumb enough to ask, 'why relativity?' And I found the answer in a more fundamental invariance--the fourth dimension is expanding relative to the three spatial dimensions, or dx4/dt = ic.
And not only can all of relativity be derived from this, but suddenly we are liberated from the block universe and time and progress in theoretical physics are unfrozen. And change is seen in a most fundamental equation that weaves change into the very fabric of space-time, where it needs to be, as change pervades every realm of physics and all acts of *physical* measurement. And suddenly we have a *physical* model for entropy, time and its arrows and assymetries in all realms, free will, and quantum mechanics' nonlocality, entanglement, and wave-particle duality. The fourth expanding dimension distributes locality, fathering time. MDT accounts for the constant speed of light c--both its independence of the source and its independence of the velocity of the observer, while establishing c as the fastest, slowest, and only velocity for all entities and objects moving through space-time, as well as the maximum velocity that anything is measured to move. And suddenly we see a physical basis for the dualities--for space/time, wave/matter, and energy/mass or E=mc^2. Energy and mass are the same thing--it's just that energy is mass caught upon the fourth expanding dimension, and thus it surfs along at "c."
MDT provides your *physical* mechanism for time and all change, and a while host of other physical phenomena.
Indeed, MDT finally provides, in Feyman's words, "the thing that makes the whole phenomena of the world seem to go one way."
Feynman stated, "Now if the world of nature is made of atoms, and we too are made of atoms and obey physical laws, the most obvious interpretation of this evident distinction between past and future, and this irreversibility of all phenomena, would be that some laws, some of the motion laws of the atoms, are going one way - that the atom laws are not such that they can go either way. There should be somewhere in the works some kind of principle that uxles only make wuxles, and never vice versa, and so the world is turning away from uxley character to wuxley character all the time - and this one-way business of the interactions of things should be the thing that makes the whole phenomena of the world seem to go one way. But we have not found this yet. That is, in all the laws of physics that we have found so far there does not seem to be any distinction between the past and the future. The moving picture should work the same going both ways, and the physicist who looks at it should not laugh."--(The Distinction of Past and Future, from The Character of Physical Law, Richard Feynman, 1965)
Best & keep asking those questions!
Dr. E (The Real McCoy)