There are several theories about how Star Trek transporters work. Some of this is established in-universe (aka canon). Some of it is contradictory. None of it is rigorously established, so there's no problem if this article is inconsistent with established in-universe rules.
This is just a "what-if" of a "what-if." It also addresses the more existential, metaphysical problems of transporter technology, specifically, the so-called "Copy-Paste-Delete" problems.
Basically, this article is how transporters don't kill you.
How Transporters Don't Work
First, let's establish the widely received notion on how transporters work, specifically, the notion that a person dies on the transporter pad and is replicated in a new location.
- The subject (to be transported) is placed on the pad.
- Scan the subject on the pad and store the information.
- Destroy (kill) the subject.
- Replicate the subject at the remote location.
It's simple, right? And yes, the shows occasionally imply this. There have been situations where step 3 has been skipped. But there have been subtle references that deny this as well.
TUCKER: It's hard to imagine. Beaming someone that far.
EMORY: All breakthroughs are hard to imagine before they happen. When I developed the transporter, most people simply couldn't grasp it. Some still can't.
ARCHER: I have to confess, given a choice, I'd much rather use a good old-fashioned shuttlepod.
EMORY: I'll never forget the protests when the transporter was first approved for bio-matter.
DANICA: Oh, God. Here we go.
EMORY: People said it was unsafe, that it caused brain cancer, psychosis, and even sleep disorders. And then there was all that metaphysical chatter about whether or not the person who arrived after the transport was the same person who left, and not some weird copy.
TUCKER: Which would make all of us copies.
EMORY: I had to fight all of that nonsense, and I'm not going to tell you there weren't costs. I'm living proof of that, but I won. Mankind is better off. Makes everything I've fought for worthwhile.
Star Trek: Enterprise - Daedalus
We see here that the writers made the effort to "hang a lantern" on the specific metaphysical question.
How Transporters Work
With the above out of the way, here is how (no kill) transporters really work.
- The subject (to be transported) is placed on the pad.
- This is obvious, you just put the thing on the thing.
- The subject's wavefunction is amplified.
- This is less obvious. But understand that all objects have a wavefunction. For ordinary objects, the wavefunction is extremely small.
- For quantum particles, the wavefunction is large enough cause weird things to happen. We would like weird things to happen to ordinary objects, so we must amplify the wavefunction.
- So I guess I'll need to write another article on how to amplify a macroscopic object's wavefunction.
- At the remote location, (more) information matching the subject's current properties are hidden.
- The information being hidden, in essence, will "attract" the object to the remote location.
- We are hiding the momentum and position of the subject's new location so that the subject has a place to go.
- There is now a higher probability of the subject being in two places at once.
- Store an increasingly exact fix of the subject.
- We simultaneously care and don't care where the subject is. But we have to collect it in order to cause a violation of Heisenberg's uncertainty principle.
- From a thermal-dynamics perspective, the information is completely gathered so that it qualifies as "observed" outside an otherwise hidden quantum state.
- Keep repeating steps 3-5 until ...
- The subject's wavefunction is collapsed.
- The process of getting an exact fix on the momentum and position of the subject will cause the subject's wavefunction to collapse back to normal.
- There is now a probability of the subject being in one place or the other place (which is more likely the other, if all goes well).
There's one other thing you have to do in order for this to work. You have to inject energy into the system. There needs to be enough energy so that the subject jumps to the new location. It's similar to the energy required for a quantum particle to tunnel through a barrier. If the energy state is higher than the wavefunction, then it will probably tunnel. So it's the same for our transporter. If the energy state is higher than the subject's wavefunction, then it will probably end up in a new location (as long as we push it thereby violating uncertainty, etc.).
One of the mechanisms loosely established in-universe is a device called the Heisenberg Compensator. This device is mentioned in a few episodes.
In the show, the Heisenberg Compensator is actually more of an in-joke. If you asked the writers how the Heisenberg Compensator works, they would have told you, "It works just fine."
Instead of asking how it works, I'm more interested in what it's for. In the show, it is hinted that the Heisenberg Compensator is for finding out the momentum and position of each particle of the subject being transported without violating physical laws.
That's fine, but that's not really what it's for, I say. Yes, that's what it's for, but not what it's for.
Here's what I mean. To know the momentum and position of a particle is a violation of Heisenberg's uncertainty principle. We have examples of this in nature.
If a neutron star collapses past a certain point, that's enough to violate uncertainty, which causes an event horizon to form. So if the natural consequence of collapse results in a violation of information, the natural result is for that "illegal information" to become pinched off from reality as a black hole.
We would like to leverage this natural result. But since we're not dealing with high gravitation, we don't need an event horizon to hide the information.
All we need is an "escape path." If the act of finding the position of the subject creates a natural violation in physics, let's give physics an "out" by making a new place for the object to go.
The information is stored, more-or-less, and transmitted to the remote location. But it is not stored for the purpose of making a copy. It is stored in order to promote a violation of the uncertainty principle as well as hide the information in the new location.
Hiding the information in the new location gives the subject a possible location to go. Since it would violate physics for it to exist in the first location, it must exist in the other location.
There would still be a distance limitation is due to the ability of the system to hide information in a remote location. Theoretically, there's otherwise no limit on distance except for the capability of hiding the properties of the new location.
So what would happen to the subject if we didn't create the correct conditions in a new place for it to go? Nothing would happen. The "illegal information" would not be available and no transport would take place.
For more insight on some of these topics (specifically the quantized wavefunction of position), take a look at:
Here are some real-world examples on how you can allow one element of complementary pairs to "game" Heisenberg Uncertainty. For example, in my fictitious example, try to measure both momentum and position in order to change position (a completely sci-fi concept). In contract to the following video example, give up amplitude to gain phase detection (a very real-world concept):
