# Quantum Information Transport

1. Apr 15, 2005

### Spin_Network

In quantum systems/domain, the transporting of information from two locations, say A to B is the basis of all quantum connective logistic processes.

What process, is available for the transport of information, without altering the information, surely if your moving information, you are 'handling' it, if you are 'handling' it, according to the HUP, you have changed it by default?.. then what certainty level is there for the information to be transported, and be unaltered?

Or in another way, how can Quantum Systems interact with information, without changing the information content?

2. Apr 16, 2005

### marlon

Well, in stead of repeating myself, i suggest you read the "faster then light communication"-entry of my journal : https://www.physicsforums.com/journal.php?s=&action=view&journalid=13790&perpage=10&page=6

The fact that this way of transporting info is perfectly secure has to do with the probabilistic nature of the processes at hand. If an eavesdropper measures a qubit incorrectly , it's content will change and that can be detected without actually revealing the content itself. If the eavesdropper measures correctly (to which he has a 50% change : which is at random because there are only two options) then still, he will have a 50/50% change that his actual result is the correct one out of two possibilities. You gotta compare it with this : you need to measure a spin along some axis. There are two possible outcomes (up,down) but you also need to measure along the correct axis (x or y axis). The latter part is what i mean with 'measuring correctly'. If you measured along the correct axis, then still there is a 50/50% chance that you measured the correct spin value (up or down)

All of this is also in the entry

regards
marlon

3. Apr 16, 2005

### Spin_Network

I see, so if I interxept the information more than 'once' from A to B, then I still have a 50-50 chance of being either correct or incorrect>?..the only Random paramiter, seems to be either 1 or 0..which is the same as Yes or No..Correct or Incorrect..Up or Down..Left or Right.. Vertical or Horizontal..Black or White...Ad-Infinitum...........

A definate Maybe if ever I heard one!..I am going to have to enquire into David Deutch lectures once again, thanks anyway.

4. Apr 16, 2005

### Spin_Network

With regard to the Eavesdropping 'paradox'..if the information between Bob and Alice is of the utmost urgency, and lets face it if one is conducting information correspondence, then secrecy and speed is name of the game, then the advantage of Eve, can render the system useless, just by making the obvious WRONG choice, Eve will render the correspondence between Alice And Bob USELESS, by fact that Alice and Bob would KNOW that there is Eavesdropping occurring, and cannot continue with any confidence.

The 'Confidence Trickster' will always have the upper hand!..a good name for such a Third_Person would be...Harry?