Restriction lift date: 2025-09-30
Evaluation and properties of site-controlled pyramidal quantum dots for quantum information processing
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Date
2023
Authors
Ranjbar Jahromi, Iman
Journal Title
Journal ISSN
Volume Title
Publisher
University College Cork
Published Version
Abstract
Semiconductor quantum dots (QDs) are a promising platform for optical quantum information processing (QIP) due to their unique optoelectronic properties, such as their discrete energy levels and strong light-matter interactions. These properties allow for the manipulation and control of the optical and spin states of individual QDs, making them suitable for applications such as quantum cryptography,quantum computing, and quantum simulation.One of the key advantages of QDs for QIP is, aside of being embedded in asemiconductor matrix, their small size, which allows for the confinement of carriers within a few nanometers. This results in a discrete energy spectrum and a strong confinement of the carrier wavefunctions, which leads to a strong light-matter interaction. This strong interaction allows for the manipulation of the optical and spin states of individual QDs, enabling the implementation of quantum gates and other quantum operations.In particular, site-controlled pyramidal QDs have emerged as a promising candidate for optical quantum information processing, due to their unique structuraland optical properties. Pyramidal QDs are formed by patterning a semiconductor material into a pyramid shape recesses, which results in a confinement of the electronic and optical states in the inverted pyramid apex. This confinement allows for a high level of control over the electronic and optical properties of the dot, such as the energy level spacing and the optical transition dipole moment. Furthermore,pyramidal QDs (intrinsically) could exhibit a high degree of symmetry, which makes them well suited for implementing various quantum operations.One of the key advantages of pyramidal QDs is their ability to achieve high optical quality, which is crucial for implementing high-fidelity quantum operations. In addition, pyramidal QDs can be integrated with other semiconductor technologies, such as waveguides and electro-optic modulators, which allows for the implementation of more complex quantum operations. This integration can be done using various techniques such as epitaxial growth, nano-fabrication and transfer printing or other heterogeneous integration techniques.Overall, site-controlled pyramidal quantum dots have emerged as a promising candidate for optical quantum information processing, due to their unique structuraland optical properties, which allow for high-fidelity quantum operations and the integration with other semiconductor technologies. This research field is still in the early stage and a lot of work is currently ongoing to improve the performance and scalability of pyramidal QD devices.In this work, we evaluate and optimize some features of this specific type of QDs for optical quantum information processing. One of the main prominent factor/feature, called fine structure splitting (FSS), which is detrimental to the quality of entanglement (essential to quantum information processing), is widely studied and different strategies are discussed to minimize its pernicious effect in the GaAs QD family. Resonant excitation of anti-binding InGaAs QDs, bindingGaAs QDs and charge distribution of GaAs QDs sandwiched between super-lattice structure are other topics covered in this work.
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Partial Restriction
Keywords
Site controlled pyramidal quantum dots , Optical quantum information
Citation
Ranjbar Jahromi, I. 2023. Evaluation and properties of site-controlled pyramidal quantum dots for quantum information processing. PhD Thesis, University College Cork.