Fundamental movement of time is... forwards, backwards, both, neither, in more than two dimensions?
https://cosmosmagazine.com/science/physics/quantum-systems-arrow-time/
The laws of nature don’t inherently favour a single direction. Whether time moves forward or backward, the equations remain the same.
What would be the perception of time were it to be experienced in reverse? We have to consider that we, the observer, was also moving in reverse, which means, our knowledge of the past would also reverse.
The explanation of our everyday experience of time is the
second law of thermodynamics derived by Austrian physicist Ludwig Boltzmann.
This law states that entropy – the inherent disorder in a system – cannot decrease with the passage of time.
“One way to explain this is when you look at a process like spilt milk spreading across a table, it’s clear that time is moving forward,” says Andrea Rocco, an associate professor in physics and mathematical biology
“But if you were to play that in reverse, like a movie, you’d immediately know something was wrong – it would be hard to believe milk could just gather back into a glass.”
This is assuming the observer were not reversing with the milk reorganizing itself. We would have to retain our knowledge (memory?) of the future. If the milk can reorganize back into the glass, our brain would reorganize back before the spill and we would be none the wiser.
In fact, we only have our moment now. The epistemological question would render our perception of a reversal in time as no difference. Each moment, each infinitesimal instant would only contain the memory of those moments from the past, never the moments of the future undoing itself. We could never witness the milk inexplicably unspilling itself.
“However, there are processes, such as the motion of a pendulum, that look just as believable in reverse,” Rocco continues. “The puzzle is that, at the most fundamental level, the laws of physics resemble the pendulum; they do not account for irreversible processes.”
Only a perfect pendulum would appear that way. What an outside observer (one who's time travel was not the same as the pendulum) would see, is a pendulum gaining momentum without any apparent force driving it. Then, when it got to the top of its maximum amplitude of swing, a hand, perhaps even the observer's own hand, would catch the pendulum and stop it before easing it down to center.
“Our findings suggest that while our common experience tells us that time only moves one way, we are just unaware that the opposite direction would have been equally possible.”
Again, we can't really say time is moving forward, only that we see it moving forward because that's the only way we can both perceive and remember the march of time.
“The surprising part of this project was that even after making the standard simplifying assumption to our equations describing open quantum systems, the equations still behaved the same way whether the system was moving forwards or backwards in time,” says first author Thomas Guff.
Is there an actual experiment here, or just a mathematical (computer) modeling of the current theories?
-Will