Status Symbol: Teleportation and Telecommunication
Quantum dots, usually created from semiconducting material, are artificial atoms that can be formed with particular characteristics. They are comprised of several layers, which can be excited to emit individual photons. If one can manage to successfully hold a predefined, specific number of photons in a quantum system, one can speak of a “Fock state” − a situation that has great significance for many applications. In her LIT project, Dr. Gaby Slavcheva is attempting to achieve the generation of Fock states on chips using gallium arsenide quantum dots, a type of dot on which little research has yet been completed.
Slavcheva’s approach is to fill the “holes” between the quantum dots with gallium arsenide. This creates a well-organized system with multiple layers. These layers have different spins and can be manipulated, for example by using current or pressure. During this process, photons migrate from the manipulated layer to one of the others. “This technique has been successfully applied to atoms, but not yet to semiconductors,” says Slavcheva. She is also employing resonators, “as it has become clear that sound is very useful for photon emission.”
Over the past few years, Slavcheva has already developed a statistical model of photon emission for this method.
One of the advantages of her approach is, among others, that the position of the quantum dots can be accurately determined. This is very different from the case with atoms, which are difficult to control and can never be located with precision. This makes it possible to accurately describe non-classical light sources like photonic sources. Additionally, the positions of the quantum dots ideal for the creation of a Fock state can be precisely calculated.
Fock states are important in a variety of applications, for example in the field of telecommunication, where it is needed to achieve optimum capacities, or quantum teleportation, in which many complex states must be formed based on the Fock state.
From the age of 15, Dr. Gabriela Slavcheva attended a school in Sofia, Bulgaria, with particular focus on mathematics and physics, where students were taught by university lecturers. This automatically qualified her to study at the University of Sofia without sitting a university entrance exam. As a student, she specialized in theoretical semiconductor physics. After a fellowship at the University of Rome, Slavcheva became a visiting professor at the Forum for Theoretical Sciences at Chulalongkorn University, Bangkok, Thailand.
Afterwards she completed fellowships in France, Italy and the UK, where she worked at the University of Bath.
Slavcheva’s research interests include the theory and modelling of light-matter interactions in semiconductor quantum photonic structures, the theory of optical quantum coherence phenomena in semiconductors, nanophysics and quantum photonics, nonlinear and quantum optics, and ultrafast semiconductor dynamics.
In the context of theoretical semiconductor physics, she develops quantum-statistical methods for electronic band structure and optical property calculation and investigates transport phenomena and lattice dynamics.
Although her background is in theoretical semiconductor physics, interaction with experimental scientists is important to her: “It’s essential that a theory also holds up in experiments!”