DIPC Colloquium: Quantum parallelism at room temperature by coherent excitonic dynamics of an ensemble CdSe quantum dot dimers
DIPC Seminars
 Speaker

Francoise Remacle, Department of Chemistry, University of Liege, Belgium
 When

2023/04/27
18:00  Place
 Donostia International Physics Center
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The ultrafast fs electronic coherences can be experimentally characterized in
semiconducting colloidal quantum dot (QD) assemblies at room temperature by
twodimensional electronic spectroscopy (2DES). These electronic coherences
exhibit a wide range of beating periods and provide a versatile basis for
parallel quantum information processing on a fs time scale at room
temperature. An excitonic model Hamiltonian based on the effective mass
approximation is used to compute the quantum dynamics. It includes the
Coulomb, spinorbit and crystal field interactions that give rise to the fine
structure splittings. The interdot distance is sufficiently small to allow for
efficient interdot coupling and delocalization of the excitons over the two
QDs of the dimer. To account for the inherent few percent size dispersion of
colloidal QDs, the optical response is modeled by averaging over an ensemble
of 2000 dimers. The size dispersion is responsible for an inhomogeneous
broadening that limits the lifetimes of the excitonic coherences that can be
probed to about 150200 fs.
We use the dynamics of the electronic coherences as they are probed in 2DES to
design quantum emulators of non equilibrium vibrational dynamics of a linear
triatomic molecule. The implementation relies on the underlying Lie algebraic
structure of the hardware system: the _N_ quantum levels of the QD dimers
provide _N 21_ observables, the _N(N1)_ electronic coherences and _N1_
populations, which allows for processing _N 21_ logic variables in parallel.
Furthermore, the use of the classical ensemble allows a simultaneous reading
of the observables.
Homepage: http://www.tcp.ulg.ac.be/
Wikipedia: https://en.wikipedia.org/wiki/Fran%C3%A7oise_Remacle