A promising qubit for quantum computation: excitons bound to small molecules embedded in semiconductors.

Single impurity atoms in semiconductor crystals can be spatially resolved and studied individually. Carefully selecting the nature of the impurity and the host material, an impurity center composed of one, two or three atoms can bind electrons and holes, thereby forming an exciton bound to a quantum structure. Although the electronic properties of these atomic-size quantum dots are similar to those of conventional quantum dots composed of tens of thousand atoms, their size is comparable to the volume of a few atoms. This offers excellent opportunities for the realization of a spin-based qubit of atomic dimensions for the field of quantum computation.

Using ultrafast laser pulses and optical spectroscopy techniques, we have recently demonstrated that it was possible to initialize an exciton qubit and manipulate its state over the whole Block sphere. Doing so revealed a very high optical dipole moment and a very low power induced dephasing, making this system a very attractive building block for high-fidelity quantum operations.

Faculty Supervisor:

Sebastien Francoeur


Kaustubh Wagh



Physics / Astronomy





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