Semi-FTL quantum communications

I'm trying to come up with idea's that have some plausibility of sending information FTL.

So we can entangle particles together. When you measure them you influence them. If you measure one up the other becomes down. If you measure one left the other becomes right.

Lets assume that for whatever reason, someone has found a way to keep an entanglement going for 1 hour (I'll up this for my fluff story but that just complicates matters for the question). We have two computers, one on earth and one on a sattelite at half an hour lightspeed away. Each computer has a quantum segment in a hamsterball configurarion that is aligned compared to the sun (or galactic center or whatever, as long as they can change themselves to always be in more or less the same orientation its fine). We entangle some bits in the quantum segment with light and send this to the sattelite that can capture these and store them in the quantum segment (or any copies made or whatever). The quantum segment can for convenience send 100 megabite worth of entangled particles per second without running out of bits to entangle. Bits that disentangle can be re-used allowing a constant stream of entangled bits to be send.

the problem with this method is always that you can use these bits just once, and they need to travel at lightspeed to the destination so you cant send messages faster than light. But maybe you still can by cheating a bit?

Imagine this: up/down is a 0. Left/right is a 1. Diagonal means the bit hasnt been used. Now you send out a packet of bits containing non-entangled information and entangled "blanko" information that hasnt been influenced yet. The non-entangled information contains a timestamp when the packet was made and when the entangled information will be measured to give it a meaning. The non-engltangled bits could also carry other non-timesensitive information. The time it will be given meaning is set, for example at 50 minutes after it was made so no disentanglement will happen before it can be read.

The sattelite receives these packets half an hour after they were send and sees how much time has elapsed and other info in the non-entangled information. Then after the remaining 20 minutes +50 milliseconds have elapsed it reads the quantum information (taking all types of relativity into account when measuring time like we do with our current sattelites).

Now comes the cheating bit. Instead of sending packets with data to the sattelite ("how are you doing", "change course by this much" etc) you write those into the quantum bits that are at the 50 minute mark by influencing their orientation. This creates a string of zero's and one's and the unused bits are set to the front/back configuration to indicate they arent used. Then a few milliseconds later this information is read by the sattelite who cant influence the directions of the bits anymore. Immediately after reading them the send entangled particles are discarded to make space for the next string of entangled bits.

While the particles take time to get there, you've effectively send information faster than light compared to when the instruction within the entangled bits were set (this idea is somewhat similar to how alcubierre drives can use sequenced highways to overcome the "cant send negative matter FTL" problem).

Because I'm an optimist my question is: what is wrong with this setup?

posted about 4 years ago

Demigan‭

11 reputation 25 1 1 0