‘LOST IN TRANSLATION’: COLLECTIVE MEMORY AND CONRAD AS A READER

‘LOST IN TRANSLATION’: COLLECTIVE MEMORYAND CONRAD AS A READE

Spectroscopy and accurate spatial positioning of quantum emitters hosted by two-dimensional semiconductors

Atomically-thin semiconductors offer intriguing technological advantages for quantum photonic applications. Advantages include a lack of dangling bonds, atomically-precise interfaces, the potential to design novel heterostructures with an absence of nuclear spins, and the ease of integration with photonic integrated chip platforms. These benefits offer a new opportunity to construct a scalable quantum architecture with a coherent lightmatter interface, an exciting prospect for future quantum technologies. This thesis takes the first steps in this direction. Atomically-thin flakes of transition metal dichalcogenides (WSe2 or MoSe2) are transferred to substrates with smooth and nanopatterned regions. Using cryogenic microphotoluminesce spectroscopy, a correlation between isolated quantum emitters and localised strain ‘pockets’ is observed. This observation is exploited to fabricate WSe2 arrays of highly pure single photon (g(2)(0) <0.5%) emitters at deterministic spatial positions (120±30 nm accuracy) with nearly 100% efficiency. The quantum emitters intrinsic optical properties are characterised via magnetic field and temperature dependent spectroscopy. The nanoscale strain engineering approach provides a universal scheme to create spatially and spectrally isolated quantum emitters in other two-dimensional materials. The thesis concludes with a discussion on the origin and dynamics of strain-tuned localized excitons in 2D semiconductors, presenting local disorder and exciton funnelling as important ingredients

Discrete quantum dot like emitters in monolayer MoSe2: Spatial mapping, Magneto-optics and Charge tuning

Transition metal dichalcogenide monolayers such as MoSe2,MoS2 and WSe2 are direct bandgap semiconductors with original optoelectronic and spin-valley properties. Here we report spectrally sharp, spatially localized emission in monolayer MoSe2. We find this quantum dot like emission in samples exfoliated onto gold substrates and also suspended flakes. Spatial mapping shows a correlation between the location of emitters and the existence of wrinkles (strained regions) in the flake. We tune the emission properties in magnetic and electric fields applied perpendicular to the monolayer plane. We extract an exciton g-factor of the discrete emitters close to -4, as for 2D excitons in this material. In a charge tunable sample we record discrete jumps on the meV scale as charges are added to the emitter when changing the applied voltage. The control of the emission properties of these quantum dot like emitters paves the way for further engineering of the light matter interaction in these atomically thin materials.Comment: 5 pages, 2 figure

Management Evaluation of a Selected Football Club

Bakalářská práce se zabývá zhodnocením vybraného fotbalového klubu pomocí metod SWOT analýzy a rozhovoru. V první části práce jsou objasněny pojmy, důležité k pochopení problematiky zhodnocení managementu. Praktická část obsahuje charakteristiku a historii zkoumaného klubu, hospodaření klubu ve specifickém roce a metody popsané výše. Dále byly shrnuty výsledky šetření a dány doporučení klubu k odstranění nedostatků.The bachelor thesis deals with the evaluation of a selected football club using SWOT analysis and interview methods. The first part of the thesis clarifies the concepts important for understanding the issues of management evaluation. The practical part contains the characteristics and history of the researched club, the management of the club in a specific year and the methods described above. Furthermore, the results of the survey were summarized and the club was recommended to eliminate the shortcomings.115 - Katedra managementuvelmi dobř

Determinación de riesgo cardiovascular según el Score de Framingham y edad vascular en pacientes del Centro de Salud Ciudad Blanca - Arequipa 2021-2022

Objetivo: Determinar riesgo cardiovascular según el score de Framingham y edad vascular en pacientes del centro de salud Ciudad Blanca- Arequipa 2021- 2022. Método: Se realizó un estudio de forma transversal y descriptiva. La población estudiada fueron pacientes del centro de salud Ciudad Blanca, tomándose como muestra 314 pacientes, escogidos mediante un muestreo no probabilístico por conveniencia. Resultados: El 70.38% de los pacientes tienen un riesgo bajo, un 19.75% riesgo moderado, 7.32% tienen un riesgo alto y finalmente un 2.55% tiene un riesgo muy alto de desarrollar algún evento cardiovascular en un periodo de 10 años. Dentro de los factores de riesgo encontrados, el 73.57% tenía niveles de presión arterial normal, el 12.1% tenía presión arterial normal- alta, el 11.15% hipertensión arterial de grado I y el 3.18% hipertensión arterial grado II, un 43.31% de los pacientes tienen un IMC normal, los pacientes con sobrepeso representan un 36.62%, mientras que pacientes con obesidad tipo I, II y III representan un 18.79%, 0.96% y 0.32% respectivamente. 134 pacientes (60.63%) de los pacientes de bajo riesgo, 11 pacientes (17.74%) de los pacientes de riesgo moderado, 1 paciente (4.35%) de los pacientes de alto riesgo tiene valores ideales de c-LDL, ningún paciente catalogado como “muy alto riesgo” tiene valores recomendados de c-LDL. El 14.97% eran diabéticos, 14.33% eran fumadores. La edad cardiovascular promedio era de 49.34 años y supera a la edad cronológica en un promedio de 1.59 ± 4.24años. Conclusiones: El riesgo de enfermedad cardiovascular estimada a 10 años es de moderado a muy alto en aproximadamente 30% de la muestra y el 44.9% tienen una edad cardiovascular mayor que su edad cronológica

Atomically-thin quantum dots integrated with lithium niobate photonic chips

The electro-optic, acousto-optic and nonlinear properties of lithium niobate make it a highly versatile material platform for integrated quantum photonic circuits. A prerequisite for quantum technology applications is the ability to efficiently integrate single photon sources, and to guide the generated photons through ad-hoc circuits. Here we report the integration of quantum dots in monolayer WSe2 into a Ti in-diffused lithium niobate directional coupler. We investigate the coupling of individual quantum dots to the waveguide mode, their spatial overlap, and the overall efficiency of the hybrid-integrated photonic circuit

Coulomb blockade in an atomically thin quantum dot coupled to a tunable Fermi reservoir

Gate-tunable quantum-mechanical tunnelling of particles between a quantum confined state and a nearby Fermi reservoir of delocalized states has underpinned many advances in spintronics and solid-state quantum optics. The prototypical example is a semiconductor quantum dot separated from a gated contact by a tunnel barrier. This enables Coulomb blockade, the phenomenon whereby electrons or holes can be loaded one-by-one into a quantum dot. Depending on the tunnel-coupling strength, this capability facilitates single spin quantum bits or coherent many-body interactions between the confined spin and the Fermi reservoir. Van der Waals (vdW) heterostructures, in which a wide range of unique atomic layers can easily be combined, offer novel prospects to engineer coherent quantum confined spins, tunnel barriers down to the atomic limit or a Fermi reservoir beyond the conventional flat density of states. However, gate-control of vdW nanostructures at the single particle level is needed to unlock their potential. Here we report Coulomb blockade in a vdW heterostructure consisting of a transition metal dichalcogenide quantum dot coupled to a graphene contact through an atomically thin hexagonal boron nitride (hBN) tunnel barrier. Thanks to a tunable Fermi reservoir, we can deterministically load either a single electron or a single hole into the quantum dot. We observe hybrid excitons, composed of localized quantum dot states and delocalized continuum states, arising from ultra-strong spin-conserving tunnel coupling through the atomically thin tunnel barrier. Probing the charged excitons in applied magnetic fields, we observe large gyromagnetic ratios (~8). Our results establish a foundation for engineering next-generation devices to investigate either novel regimes of Kondo physics or isolated quantum bits in a vdW heterostructure platform.Comment: Published in Nature Nanotechnology. 7 pages + 14 supplementary information pages. 14 figure