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We have investigated the effects of strong confinement in wurtzite InAs0.85P0.15 quantum dots embedded in wurtzite InP nanowires using microphotoluminescence spectroscopy. Strain-dependent k . p calculations were used to model the quantum dots, and it was found that the electron effective mass was increased by a factor of 2 and the band gap was increased by 190 meV compared to equivalent quantum d
Thermoelectric elements have long been anticipated to challenge conventional solutions for converting heat to electricity. However, the revolution has been stalled due to the inability to reach efficiencies comparable to their conventional counterparts, while retaining a high output power. In this work we will model a thermoelectric element based on nanowires embedded with a quantum dot superlattice
We consider a family of associative algebras, defined as the quotient of a free algebra with the ideal generated by a set of multi-parameter deformed commutation relations between four generators consisting of five quantum plane relations between pairs of generators and one sub-quadratic relation inter-linking all four generators. For generic parameter vectors, the center and the commutants of the
A theoretical study is presented, in which the nonlinear response of a bi-ased Quantum Cascade Laser (QCL) is calculated. The calculations are based on the nonequilibrium Green’s function formalism. Assuming a periodic electromagnetic field in the calculations, this formalism provides not only the stationary behavior Green’s functions, but also the part of the response that varies in time according
Quantum entanglement between electrons in nanostructures is a key concept of quantum information still waiting to be experimentally demonstrated. In this master's thesis we present and analyze the full counting statistics of the charge transfer of a sextuple quantum dot system which works as both entangler and detector of spatially separated electrons. Under certain resonance conditions the sy
Converting incoming photons to electrical current is the key operation principle of optical photodetectors and it enables a host of emerging quantum information technologies. The leading approach for continuous and efficient detection in the optical domain builds on semiconductor photodiodes. However, there is a paucity of efficient and continuous photon detectors in the microwave regime, because
X-ray and neutron crystallography, as well as cryogenic electron microscopy (cryo-EM), are the most common methods to obtain atomic structures of biological macromolecules. A feature they all have in common is that, at typical resolutions, the experimental data need to be supplemented by empirical restraints, ensuring that the final structure is chemically reasonable. The restraints are accurate f
This thesis investigates the pattern formation of supersolid states in dipolar Bose-Einstein condensates (BECs) of highly magnetic Dysprosium-162 confined in a flattened trap geometry. This is done by solving the extended Gross-Pitaevskii equation (eGPE), a framework that was developed to examine BECs. The eGPE incorporates contact interaction, the dipole-dipole interaction (DDI), and quantum fluc
We report results from a theoretical study on the solvation of the divalent cations of Mg, Ca and Sr in water at infinite dilution. The ions are treated at the Hartree-Fock level with an explicit solvent model. Electrostatics, polarization and exchange repulsion contribute to the Hamiltonian. The dominating coordination number for the ions increases from 6 for Mg through 7 for Ca to 8 for Sr. A br
Quantum cascade lasers (QCLs) are generally designed to avoid negative differential conductivity (NDC) in the vicinity of the operation point in order to prevent instabilities. We demonstrate that the threshold condition is possible under an inhomogeneous distribution of the electric field (domains) and leads to lasing at an operation point with a voltage bias normally attributed to the NDC region
The use of molecular mechanics calculations to supplement experimental data in standard X-ray crystallography and NMR refinements is discussed and it is shown that structures can be locally improved by the use of quantum chemical calculations. Such calculations can also be used to interpret the structures, e. g. to decide the protonation state of metal-bound ligands. They have shown that metal sit
The optical properties of quantum dots embedded in a catalytically grown semiconductor nanowire are studied theoretically. In comparison to dots in a bulk environment, the excitonic absorption is strongly modified by the one-dimensional character of the nanowire phonon spectrum. In addition to pronounced satellite peaks due to phonon-assisted absorption, we find a finite width of the zero-phonon l
In this thesis the tensile strength, deformation, damage resistance and tear propagation for flexible composites are analysed. There are two essential requirements common to all flexible composites; namely, high tearing strength and good matrix-to-fabric adhesion. The interaction of fabric and matrix is complex. The most critical variables are those of yarn and fabric structure, the mechanical pro
The mechanism of ethylene polymerization on phenoxy-imine (FI) titanium catalysts was studied theoretically to identify the major factors affecting the catalytic activity. Geometry optimizations of FI ligands, octahedral titanium dichloride complexes, active cationic species, and their π‐complexes with ethylene as well as calculations of the energy profile of chain propagation were performed at th
Cross junctions of carbon nanotubes (CNTs) separated by thin oxide layers have been fabricated, in which the top CNT is used as a local gate to control the electron transport through the lower CNT. Coulomb oscillation was observed in the lower CNTs at low temperatures. The gating field from the upper CNTs is seen to modulate the band structure in the lower CNTs, producing double quantum dot system
An implementation of a small quantum absorption refrigerator in a circuit QED architecture is proposed. The setup consists of three harmonic oscillators coupled to a Josephson junction. The refrigerator is autonomous in the sense that it does not require any external control for cooling, but only thermal contact between the oscillators and heat baths at different temperatures. In addition, the set
One first generation assay (manufactured by Ortho, test I) and 3 second generation anti-HCV ELISAs (manufactured by Ortho, Abbott, and UBI, tests II-IV) were compared. Sera from 4 different sources were used: (1) intravenous drug-users (IVDUs, n = 50), (2) blood donors (n = 1055), (3) all clinical samples from one day of routine anti-HCV testing (n = 89), (4) hemodialysis patients previously found
