Cambridge University have developed a new technique to produce a single photon by moving the light emitting diode (LED) specially designed single electron. The technique, published in " Nature Communications " magazine on , can help develop the emerging field of quantum communication and quantum computing.
The importance of the photon source
Single photon (light elementary particles) may carry hundreds of kilometers of quantum information. Thus, it is possible to produce a single photon source is an important part of many quantization techniques. So far, research laboratories have used the self-assembled semiconductor quantum dots (Q uantum Dots and structural defects formed diamond single photon source). Since the formation of these defects and the points is a random process, it is difficult to predict the position of these single-photon source and a photon energy (or wavelength). This might be the randomness of photon sources into a challenge when the large-scale quantum network.
Principles of information transfer
The researchers indicated that they can generate a single photon in a different controlled manner, without defects or quantum dots, only by a single recombination of electrons and a movement of a "hole" (loss of electrons filled "with" electronic) to realise.
Imagine trying to emit blue or red ball flow on the wall in the following ways to send a digital message. A conveyor belt with a series of spherical dimples white balls onto the ramp, and the ball falls from the top of the hill. Dr. Tzu-Kan Hsiao PhD at Cambridge University, explains: Each ball will speed up in the fall, and then when it bounced back to the wall or over the wall when it is sprayed into a blue or red (depending on the message).
Since each of the recesses on the belt is only a ball bearing, so that only one ball is coating color, it is impossible there are cases, i.e. when some of the ball is intercepted by an eavesdropper who did not notice the receiving end ball the loss , if sometimes transmit two or more balls, the eavesdropper can capture one or more of the ball and the ball receiver unaware. In this way, some messages may be inadvertently leaked.
In the experiment, the researchers use common industry manufacturing processes near the surface of a gallium arsenide (GaAs) for manufacturing a device. The team leader Christopher Ford Professor say, this device consists of a region near the region of the hole and electron a narrow passage in between components.
In order to transmit only a primary electron, we emits acoustic waves along the surface. Gallium arsenide, this surface acoustic wave `` '' will generate an electric potential wave attendant, wherein each of the minimum potential to carry only one electron. Like the conveyor belt, as the potential of a single electron wave will be brought to the ground a hole area. Before each electron a rapidly when the electrons reach the next hole recombination, it will generate a series of single photons.
Each single photon can be given a two polarizers to carry information, so eavesdroppers can not intercept the information without being detected.
Application of Quantum Computation
The study, in addition to being a novel single-photon source, it is more important is that this new technology can also be used electron spin state to convert the polarization state of photons . By using a single photon as a "flying" qubits to bridge semiconductor-based quantum computer , we can achieve the establishment of the grand goal of large-scale distributed quantum computing network.
Author | DingD editor | Sakura
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(Source: MIT News)
