a way to transmit data by modifying the properties of one of two entangled photons
- two entangled photons are sent each to two different devices .
-The polarisation of the two photons is not decided until the closest device is reached by the photon that was sent to it.
-The polarisation is decided by photon absorbtion in one of two adjustable states among many other possible states, acording to the data that needs to be sent.
- the polarisation of the second photons is read at the second device..
Optical fibers can transmit photons to about 100km. Statistical counts of recieved photon states can help decide which information was sent.
Photons can also be sent though freepace, for instance from a satellite. The main limitation on distance is then set by the precision of the lens transmitting the photons.
The photons are entangled and therefore the polarisation of the second photons is immedaitely set according to the polarisation of the first photon whatever the distance between them.