JoshuaMandlazi said:
1. Looking at matter in normal everyday life it is hard to believe that the building blocks or subatomic particles move in a different way following different sets of rules.
2. Does the act of tracking the photon actually alter its path? Thus as you put it constrains it to one path? Or does the act of tracking allow you to find which of the multiple possible paths it took? Does the act of measuring alter the state of a subatomic particle?
It's tough to "make sense of", but consider this:
1. The building blocks - quantum particles/systems - follow a single set of rules (called Quantum Mechanics). Their classical behavior (what you see everyday) follows from that, not the other way around. You don't see the quantum behavior directly! If you could, it would seem normal to you. What you see is essentially an averaging of the quantum behavior.
2. You probably are aware there is something called the Heisenberg Uncertainty Principle (HUP). You need to have a basic understanding of this - which is a consequence of Quantum Mechanics. The HUP makes it difficult to answer your questions as you have asked them. So here are a few comments:
a. A particle in an unknown (indeterminate) state WILL be altered by a measurement or observation. For example, an x-spin measurement will place the particle in either a + state or a - state.
b. Once the state is known from a. above, generally a subsequent measurement (x-spin in our example) will reveal the same value (there is NO change).
c. Quantum particles ALWAYS have indeterminacy in some or all of their quantum properties. Measurements can yield information about some quantum properties, but that information is limited in accordance with the HUP. Indeterminacy means: the property does not possesses a well-defined value.
d. The relative number of available paths for a particle determines the likelihood of a particle result. The paths do interfere as if each is actually occurring. Yet the final observation always reveals a single outcome from available outcomes. Measuring position repeatedly and often therefore reduces the available paths and eliminates most of the interference. That yields a path that looks (to us) as if it agrees with a classical particle path. But that is a very special case, something seen in a laboratory and is rare elsewhere. The particles in your body do not behave classically and do not have a specific position, momentum, etc. because those attributes are not being observed.
