The feature of quantum dot symmetry present on quantum dots is responsible for its exciting optical properties, according to a new physical theory developed and demonstrated by École Polytechnique Fédérale de Lausanne (EPFL)’s Laboratory of Physics of Nanostructures.
EPFL researchers have formed a pyramidal dot that has around 200 atoms on each side and a height of just below 100 nm. By passing voltage into this tiny structure, they have developed a device with a capability to emit light. This device could be utilized as components in quantum computers.
Marc-André Dupertuis
However, identifying the optical properties of the quantum dots is a complex and time-consuming calculation process. In addition to decreasing the time required to execute these calculations, EPFL’s new theory enables to obtain more knowledge about the characteristics of these unusual objects.
The application of electrical charges causes the quantum dots to vibrate, which is called the wave function. It is highly complicated to replicate these vibrations. However, according to Marc-André Dupertuis, who developed the theory with his team, the wave phenomenon and the light produced by the quantum dot can be determined adequately by symmetry. This makes the calculation simpler by utilizing a well-known mathematical tool called group theory.
This new approach allows the researchers to determine the optical properties of quantum dots according to their assumed symmetries. The researchers can then confirm the existence of the symmetries through experiments. Dupertuis stated that using well-known observational methods, the researchers can accurately determine the exact symmetry of the quantum dot, the properties of its electrical charges as well as the types of photons to be emitted. This data will be helpful in developing components that find applications in quantum computers.
Source: http://www.epfl.ch