Actually in the process that is misleadingly called "teleportation" is just for carrying(?!) the quantum state so you don't "store light between to particle" (also process's speed is classicaly bounded).
You need something else to store light, for instance a medium which decreases the speed...
In general teleportation protocol, an entagled pair is used as a source for teleporting an unknown quantum state and the fidelity, which depends on the source characteristics, is defined as the resemblance of final state to the teleportated state .
Suppose we have given a density matrix for an...
"A positive operator A is defined to be an operator such that for any vector |v>=!0, <v|A|v> is real, non-negative number."
Can somebody tell me how can I check if a matrice (for example 4x4) is positive or not?
Thanks in advance