Room-Temperature Inter-Dot Coherent Dynamics in Multilayer Quantum Dot Materials

Collini, Elisabetta; Gattuso, Hugo; Kolodny, Yehoshua; Bolzonello, Luca; Volpato, Andrea; Fridman, Hanna T.; Yochelis, Shira; Mor, Morin; Dehnel, Johanna; Lifshitz, Efrat; Paltiel, Yossi; Levine, R. D.; Remacle, Françoise

doi:10.1021/acs.jpcc.0c05572

Cited by 35 publications

(91 citation statements)

References 58 publications

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“…Our computing device is an array of CdSe quantum dot QD dimers. Addressing the device is by a sequence of laser pulses and read-out is performed simultaneously on many dots [19][20][21][22][23][24] as in 2D electronic spectroscopy [25,26]. Measuring over a classical ensemble of dots importantly means that we directly read the mean values and that there is no interference between measuring different observables that individually do not commute.…”

Section: The Computing Devicementioning

confidence: 99%

“…Smaller QD have larger energy difference between their two lower excited electronic states and therefore one needs a larger energy bandwidth of the pulse or a higher carrier frequency to simultaneously address them. On the other hand, for larger dots, the energy difference between the two lowest excited states may become smaller or comparable to strength of the spin-orbit coupling, which leads to a loss of resolution between the different bands [23,24]. Commercially available fast lasers in the visible can easily address coherently all the states of the four lowest bands.…”

Section: The Computing Devicementioning

confidence: 99%

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Parallel Quantum Computation of Vibrational Dynamics

et al. 2020

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The vibrational dynamics in a linear triatomic molecule is emulated by a quantum information processing device operating in parallel. The quantum device is an ensemble of semiconducting quantum dot dimers addressed and probed by ultrafast laser pulses in the visible frequency range at room temperature. A realistic assessment of the inherent noise due to the inevitable size dispersion of colloidal quantum dots is taken into account and limits the time available for computation. At the short times considered only the electronic states of the quantum dots respond to the excitation. A model for the electronic states quantum dot (QD) dimers is used which retains the eight lowest bands of excitonic dimer states build on the lowest and first excited states of a single QD. We show how up to 8 2 64 quantum logic variables can be realistically measured and used to process information for this QD dimer electronic level structure. This is achieved by addressing the lowest and second excited electronic states of the QD's. With a narrower laser bandwidth ( longer pulse) only the lower band of excited states can be coherently addressed enabling 4 2 16 logic variables. Already this is sufficient to emulate both energy transfer between the two oscillators and coherent motions in the vibrating molecule.

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Section: The Computing Devicementioning

confidence: 99%

Section: The Computing Devicementioning

confidence: 99%

Parallel Quantum Computation of Vibrational Dynamics

et al. 2020

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“…However, a dipolar nonradiative resonance energy transfer interaction can still be efficient with time scale down to tens of picoseconds. 30 , 31 , 33 These reports emphasized the distinct nature of the exciton kinetics compared to isolated quantum system in ambient conditions, driving further the motivation to generate and study isolated colloidal quantum dot molecules.…”

Section: Strategies To Fabricate Artificial Quantum Moleculesmentioning

confidence: 99%

Coupled Colloidal Quantum Dot Molecules

et al. 2021

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Conspectus Electronic coupling and hence hybridization of atoms serves as the basis for the rich properties for the endless library of naturally occurring molecules. Colloidal quantum dots (CQDs) manifesting quantum strong confinement possess atomic-like characteristics with s and p electronic levels, which popularized the notion of CQDs as artificial atoms. Continuing this analogy, when two atoms are close enough to form a molecule so that their orbitals start overlapping, the orbitals energies start to split into bonding and antibonding states made out of hybridized orbitals. The same concept is also applicable for two fused core–shell nanocrystals in close proximity. Their band edge states, which dictate the emitted photon energy, start to hybridize, changing their electronic and optical properties. Thus, an exciting direction of “artificial molecules” emerges, leading to a multitude of possibilities for creating a library of new hybrid nanostructures with novel optoelectronic properties with relevance toward diverse applications including quantum technologies. The controlled separation and the barrier height between two adjacent quantum dots are key variables for dictating the magnitude of the coupling energy of the confined wave functions. In the past, coupled double quantum dot architectures prepared by molecular beam epitaxy revealed a coupling energy of few millielectron volts, which limits the applications to mostly cryogenic operation. The realization of artificial quantum molecules with sufficient coupling energy detectable at room temperature calls for the use of colloidal semiconductor nanocrystal building blocks. Moreover, the tunable surface chemistry widely opens the predesigned attachment strategies as well as the solution processing ability of the prepared artificial molecules, making the colloidal nanocrystals as an ideal candidate for this purpose. Despite several approaches that demonstrated enabling of the coupled structures, a general and reproducible method applicable to a broad range of colloidal quantum materials is needed for systematic tailoring of the coupling strength based on a dictated barrier This Account addresses the development of nanocrystal chemistry to create coupled colloidal quantum dot molecules and to study the controlled electronic coupling and their emergent properties. The simplest nanocrystal molecule, a homodimer formed from two core/shell nanocrystal monomers, in analogy to homonuclear diatomic molecules, serves as a model system. The shell material of the two CQDs is structurally fused, resulting in a continuous crystal. This lowers the potential energy barrier, enabling the hybridization of the electronic wave functions. The direct manifestation of the hybridization reflects on the band edge transition shifting toward lower energy and is clearly resolved at room temperature. The hybridization energy within the single homodimer molecule is strongly correl...

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Section: The Computing Devicementioning

confidence: 99%

Parallel Quantum Computation of Vibrational Dynamics

Komarova¹,

Gattuso²,

Levine³

et al. 2020

Preprint

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The vibrational dynamics in a linear triatomic molecule is emulated by a quantum information processing device operating in parallel. The quantum device is an ensemble of semiconducting quantum dot dimers addressed and probed by ultrafast laser pulses in the visible frequency range at room temperature. A realistic assessment of the inherent noise due to the inevitable size dispersion of colloidal quantum dots is taken into account and limits the time available for computation. At the short times considered only the electronic states of the quantum dots respond to the excitation. We show how up to 82 = 64 quantum logic variables can be realistically measured and used to process information. This is achieved by addressing the lowest and second excited electronic states of the quantum dots. With a narrower laser bandwidth (= longer pulse) only the lower band of excited states can be coherently addressed enabling 42 = 16 logic variables. Already this is sufficient to emulate both energy transfer between the two oscillators and coherent motions in the vibrating molecule.

show abstract

Room-Temperature Inter-Dot Coherent Dynamics in Multilayer Quantum Dot Materials

Cited by 35 publications

References 58 publications

Parallel Quantum Computation of Vibrational Dynamics

Parallel Quantum Computation of Vibrational Dynamics

Coupled Colloidal Quantum Dot Molecules

Parallel Quantum Computation of Vibrational Dynamics

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