Mid-Autumn Night, my son Cheney asked me: “Dad, does teleportation really exist?”
Teleportation is the theoretical transfer of matter, energy, or data from one point to another without traversing the physical space between them. Scientists believe we could then teleport to the moon or even Mars by the end of the century.
The key to teleportation is to use the entangled pair as a communication channel to transmit the information you want to teleport from one place to another. The exact teleportation protocol is a little tricky, so bear with me for a moment. Let’s imagine you wanted to teleport a particle A from the Earth to the Moon. First of all, you would need to generate a pair of entangled particles B and C. One of those (B), you would keep here on Earth, while the other one (C) would be sent to the Moon at the Mid-Autumn Night.
The objective of quantum teleportation is to change the identity of the particle C on the Moon and to turn it into an exact replica of A. In order to do this, we somehow need to extract all the information about A, and teleport that information to the Moon, so that C can use it as a kind of blueprint to turn itself into A. The problem however is that we cannot simply scan A to extract its information.
Earth:A−B−−−−−−−−−−−−−−−−−−−−C:Moon
So instead, we entangle A with the other particle B here on Earth. That way, some of A’s information gets shared with B, and since B is entangled with C on the Moon, the information is passed on further to C, enabling C to transform itself into a copy of A.
There is a price to pay however: the original particle A will be destroyed in the process as it loses all its information and thus also its identity. The same also happens to B. In summary, you would see the original particle A disappears here on Earth, and it appears again an instant later on the Moon. Here, you have successfully teleported your first particle.
With teleportation, you can transmit quantum information to the Moon instantaneously. This reminds me of an ancient Chinese poem which includes such a sentence: I leave my message with the moon.
Gazing at the Moon, Longing from Afar
by Jiuling Zhang (678–740)
The moment that moon grows full, the sea gives birth to a shining moon.
Brightening by heaven’s light, the other end of the world shares this moment.
Separated by the lengthy night, the whole evening gives rise to longing.
Extinguishing a candle, I feel fullness of moonlight.
Awaking in heavy dew, I put on cloths.
Unable to deliver in writing, I leave my message with the moon.
Returning to bed, I fall into a beautiful dream of reunion.
drjohnxwang 