Quantum tomography is a method of reconstructing a quantum state based on information about the probability distributions associated with the quadrature operators, linear combinations of position...Show moreQuantum tomography is a method of reconstructing a quantum state based on information about the probability distributions associated with the quadrature operators, linear combinations of position and momentum. The theory says that if one knows these distributions precisely, the quantum state can be faithfully reconstructed. This thesis delves into the mathematical formalism behind quantum tomography, how it can be applied to quantum systems one might encounter in practice. We rigorously define the quantum tomogram of a state and give an example of an experimental set-up which allows one to measure the quadratures of single mode light.Show less
Galileon models form a class of models where an additional scalar field is added to the Lagrangian describing the general theory of relativity. The addition of the scalar field causes a wide array...Show moreGalileon models form a class of models where an additional scalar field is added to the Lagrangian describing the general theory of relativity. The addition of the scalar field causes a wide array of phenomena within our universe to change. Among those phenomena are both the expansion of the universe and the formation of large scale structures. We will study how they are both changed within a subclass of the Galileon models, called the Galileon ghost condensate models. First, we explore the parameter space of the model to find the values that give rise to non-singular evolu- tions of the expansion of the universe. Then, we examine how the large scale structures would form within those universes. To do that we use the spherical collapse model, in which the evolution of a spherical overden- sity is tracked. The spherical overdensity models how a relatively small perturbation leads to the formation of dark matter halos. We will show that the Galileon ghost condensate models still allow for a large degree of freedom within the spherical collapse, which would allow further research to constrain its parameter space.Show less
This research aims to improve the existing capabilities of Scanning Tunneling Microscopy (STM) in a dry-dilution refrigerator, at the Oosterkamp group. The group currently has an STM setup that can...Show moreThis research aims to improve the existing capabilities of Scanning Tunneling Microscopy (STM) in a dry-dilution refrigerator, at the Oosterkamp group. The group currently has an STM setup that can resolve step edges in highly oriented pyrolytic graphite (HOPG) and is poised to achieve atomic resolution [1]. Currently the STM is mounted in the dry-dilution refrigerator, which allows for the study of samples at milli-Kelvin temperatures. The use of a dry-dilution refrigerator gives rise to some complications. Specifically we analyse the contributions of the compressor from the pulse tube cooling system. It was found that this compressor is the dominant source of mechanical noise in setup. We determined that the vibrations enter through both the compressor lines and via the ground through the outer frame. The compressors vibrations gave rise to 0.88 ̊ARMS noise. By placing the compressor on compressed gas springs and running the compressor lines through a trough filled with sandbags, we were able to reduce this noise to 0.13 ̊ARMS. This should no longer stand in the way of reaching atomic resolution STM.Show less
On the hunt for spin triplet superconductivity in ferromagnet-superconductor multilayers, additions were made to an RF insert with an open co-planar waveguide. The low loss setup, with a -1dB per...Show moreOn the hunt for spin triplet superconductivity in ferromagnet-superconductor multilayers, additions were made to an RF insert with an open co-planar waveguide. The low loss setup, with a -1dB per GHz characteristic, was used to obtain FMR spectra with a vector network analyzer. A superconducting coil was designed to generate magnetic fields in situ at cryogenic temperatures. Many cobalt-niobium thin film multilayers were created by means of e-beam evaporation. The FMR spectra were recorded at room temperature and cryogenic temperatures as low as 4.5K. The spectra were analyzed to determine the linewidth of the FMR resonance above and below the critical temperature of different thicknesses of the superconducting layer. The initial results are promising, but not sufficient to conclude decreased gilbert damping in the ferromagnet below the Tc of the superconductor.Show less
Van der Waals materials like graphite consist of stacked atomically thin layers. These two-dimensional layers have different electronic properties from their three-dimensional counterparts. Low...Show moreVan der Waals materials like graphite consist of stacked atomically thin layers. These two-dimensional layers have different electronic properties from their three-dimensional counterparts. Low energy electron microscopy (LEEM) is well suited to the study of these materials, but can only measure above the work function of the material. Deposition of caesium and oxygen is known to lower the work function through the formation of strong surface dipoles. In this research, the LEEM reflectivity spectrum of epitaxial few-layer graphene on silicon carbide (0001) during the deposition of caesium and oxygen is analysed to better understand this process. Caesiation is found to bring down the work function by approximately 1.8 eV, but subsequent oxygenation increases the work function by approximately 0.8 eV. For smaller amounts of caesium, reducing the work function by only 0.5 eV, oxygenation is not found to have any significant effect.Show less
Cosmic rays produce muons that cast Cherenkov light cones in the water. With the Cherenkov light cones, KM3NeT can reconstruct the track of the muon across the sky, this result is named an event....Show moreCosmic rays produce muons that cast Cherenkov light cones in the water. With the Cherenkov light cones, KM3NeT can reconstruct the track of the muon across the sky, this result is named an event. Between September 22 2022 GMT and June 09 2023 GMT, the ARCA site was measuring, and detecting Cherenkov light from any bypassing muon. From this measurement simulations were created, containing 6 times more events as the measurement. In this thesis, we analyse the events from the simulation. We bin the events on one- \& two-dimensional maps of the sky, where we bin all reconstructed events relative to the location of the Moon. Two models are fitted to the maps. One model assumes the absence of the Moon; another model respects a valley in events at the Moon's location. These fits are tested with the use of $\chi^2$-tests. The one-dimensional analysis indicates a relative amplitude of $0.65 \pm 0.10$ and angular resolution of $0.81\degree \pm 0.12\degree$. The rotational calibration of the telescope is tested. Although the $\chi^2$ values differ most for no rotational calibration an angle of -0.2 and -0.4 are larger than expected. Quality cuts of the data set are based on the variables' likelihood and track reconstruction uncertainty. It is the superposition of a likelihood of 100 or higher and a track reconstruction uncertainty of 0.1 or smaller that causes an increase in the difference in $\chi^2$ values.Show less
In this work the measurement setup of the TECH flow test setup is expanded with a laser to illuminate two-dimensional slices of the flow in the cavity. Results obtained from Shear Stress Transport...Show moreIn this work the measurement setup of the TECH flow test setup is expanded with a laser to illuminate two-dimensional slices of the flow in the cavity. Results obtained from Shear Stress Transport and Detached Eddy Simulation numerical simulation methods are then compared with laser measurements to determine whether the simulations are accurate, both quantitatively by comparing vortex positions and qualitatively by comparing phenomena that are observed. Finally, the Shear Stress Transport model is used to simulate flow for a number of nozzle designs that were designed to prevent arcing in the coaxial inlet.Show less
With the discovery of graphene in 2004, a new field of study opened up. This field of study is based on ”atomically thin materials”. These materials are only one to a few atoms thick. When...Show moreWith the discovery of graphene in 2004, a new field of study opened up. This field of study is based on ”atomically thin materials”. These materials are only one to a few atoms thick. When materials are this thin, they are considered 2D materials. The materials are interesting because of possible future applications. Some of these materials are extremely sensitive to air. This sensitivity makes it very difficult, to impossible to research the intrinsic properties of these materials as well as to use the materials in large-scale applications. The Bhattacharyya group is working on these atomically thin materials to explore phenomena such as the quantum spin Hall effect and the quantum anomalous Hall effect. Observing these phenomena requires creating a hybrid of novel 2D materials and contacting these stacks with metal in the deposition process in an ultrahigh vacuum chamber. The environmental degradation of the samples while they are being transported is one of the present bottlenecks in this research. The samples are exposed to ambient air while being transported from the glove box’s inert environment to the Raman spectroscope and finally to the UHVatmosphere of the vacuum deposition chamber. This research will focus on designing and creating novel instrumentation solutions to facilitate the protection of these 2D materials (Fe3GeTe3, CrGeTe3 and NbSe2) under transport and measurement. The effectiveness of the instrument will be tested in multiple different methods. These methods include the optical micro-graph, Raman spectroscopy and atomic force microscopy. After the container was designed and built, a leak tester was used to establish a leak rate of 10-7 mbarl/s. Then, graphene was used successfully to test the effects of the optical glass on reproducing the Raman spectrum of graphene. Then, Raman spectroscopy was performed on thin flakes of CrGeTe3 to test the degradation due to air exposure outside the container compared to the inert environment inside the container. Finally, an atomic force microscopy was performed to determine the thickness of these thin flakes of CrGeTe3.Show less
KM3NeT is a collaboration that is currently constructing a research infras- tructure in the Mediterranean Sea, consisting of deep-sea neutrino tele- scopes. Its main scientific goals are to probe...Show moreKM3NeT is a collaboration that is currently constructing a research infras- tructure in the Mediterranean Sea, consisting of deep-sea neutrino tele- scopes. Its main scientific goals are to probe into the cosmos for high- energy neutrino sources, and to determine fundamental properties of these particles. These goals are pursued by dividing the detector volume over two sites, ORCA and ARCA, each housing a detector that is opti- mised for a distinct energy range. To achieve the final science, KM3NeT re- quires a time and position calibration accuracy of roughly 1 ns and 20 cm, respectively. This study presents an examination of two independent cali- bration methods, which utilise the detection of muons produced by cosmic ray showers. The time calibration provides consistent results for different cuts of data. When the movement of detection units due to varying sea currents is low, the systematic error is entirely explained via an asymme- try in the detector geometry. Ultimately, an accuracy of 2.5 ns is achievable. The position calibration is a novel technique that is developed during this project. We demonstrate its feasibility by applying it to the detector data, and estimate the currently obtainable accuracy to be within 2 m. Although both methods currently cannot meet the standards set by KM3NeT, their techniques are far from perfected. Overall, a fast cross check of the exist- ing calibration techniques can be provided, while requiring no additional setups or measurements.Show less
This thesis investigates the dynamics of tunable active chiral particles, aiming towards the creation of a chiral fluid. The unique aspect of this research is that our individual spinning particles...Show moreThis thesis investigates the dynamics of tunable active chiral particles, aiming towards the creation of a chiral fluid. The unique aspect of this research is that our individual spinning particles do not have an imposed rotation-orientation distribution, and they are dynamically tunable through combined electrokinetic effects. We analyze both the single-particle behaviour and the collective dynamics over a range of packing densities and concentrations, to identify basic parameters that influence motion and interactions. Our findings demonstrate the effects of packing density and activity in this active particle system, and reveal both fundamental dynamics and intricate phenomena such as cluster formation and spin-spin correlations.Show less
This thesis explores the application of polarization resolved hyperspectral imaging as a technique to study the optical properties of beetles, in particular the P. s. jousselini. A setup and method...Show moreThis thesis explores the application of polarization resolved hyperspectral imaging as a technique to study the optical properties of beetles, in particular the P. s. jousselini. A setup and method is provided to measure the four Stokes parameters in hyperspectral resolution, from which the state of polarization is retrieved. The reflection spectra of the P. jousselini are analyzed and fitted to a double Lorentzian. The resulting parameters conclude a different photonic strength for each of the two visible peaks as well as a varying Bragg wavelength. Furthermore, the spectra between different individuals posses distinct shapes and properties, suggesting a role of environmental factors in the exocuticle’s development. In chapter 6, other subfamilies of Scarabaeidae are imaged as well and a relation between reflection and polarization spectrum is discussed. The accuracy of the setup is, in the end, criticized for reasons that include: optical placements, uneven illumination and angle of incidence. Improvements to the setup deem necessary when the goal is to more accurately explore the optical properties of various subjects.Show less
Depletion force induces the flocculation of colloidal particles, providing a means to influence the stable states of colloidal structures. By determining the depletion force across various sizes...Show moreDepletion force induces the flocculation of colloidal particles, providing a means to influence the stable states of colloidal structures. By determining the depletion force across various sizes and concentrations of depletants, we identified the optimal size and concentration range for effective depletion forces. Our results highlight the existence of an optimal depletant size. Steric interactions obstruct the proximity of colloids, hindering small depletants from creating depletion force. On the other side of the spectrum, larger polymers either adhere to colloidal surfaces \cite{Kuhl1996} or generate a lower depletion force due to their lower number density. Nevertheless, the force magnitude remains significant. The advantage of larger depletants, is that they offer a larger interaction range, enabling the formation of colloidal hysterons. All polymers measured create sporadically strong attractive interactions between colloids, creating unpredictability in the control of colloidal structures.Show less
Surface acoustic waves (SAW) are used in many technological applications like small RF filters in everyday electronics. Additionally, a lot of research has been done to use SAWs in quantum...Show moreSurface acoustic waves (SAW) are used in many technological applications like small RF filters in everyday electronics. Additionally, a lot of research has been done to use SAWs in quantum technologies like quantum transduction. In this thesis, Young’s double-slit experiment has been carried out using SAWs on anisotropic gallium arsenide with the goal of comparing the results to the existing scalar optical diffraction theory. Simulations have been made based on the mentioned theory and the measurements have been done using a Michelson interferometer with lock-in detection. Despite non-ideal samples, the diffraction and interference of SAWs have been observed. The experimental data agrees somewhat with the simulations taking into account the anisotropic wave speed. We have also measured the angular phase velocity relation of gallium arsenide and found it to be consistent with the literature.Show less
The KM3NeT neutrino telescope, located presently at two different sites in the Mediterranean Sea, consists of two neutrino detecors As the telescope is still being built, the calibration is fully...Show moreThe KM3NeT neutrino telescope, located presently at two different sites in the Mediterranean Sea, consists of two neutrino detecors As the telescope is still being built, the calibration is fully underway. This research focuses on four potential biases present in the astrophysical focused part of the detector, ARCA. Muon light, both detected and reconstructed from simulations and $^{40}$K decay being used to determine the size of those biases. It is found that the PMTs shadowed by the titanium collar on the DOM show a different bias dependent on what hemisphere they are located. Furthermore it is found that the different gel transperacy in the DOMs causes different efficiencies, and that the new PMTs show lower efficiencies than the old PMTs.Show less
The unification of general relativity and quantum mechanics has been a persistent challenge in the field of physics. This study introduces a design for a milligram-scale gravity source, termed the...Show moreThe unification of general relativity and quantum mechanics has been a persistent challenge in the field of physics. This study introduces a design for a milligram-scale gravity source, termed the Gravity Propeller. When coupled with the Magnetic Zeppelin, a gravity detector of comparable scale, it could potentially enable the measurement of gravitational interactions between two milligram objects. This measurement could provide insights into the unification of general relativity and quantum mechanics. The propeller, composed of two sets of Meissner levitated magnets connected by a stick, is designed to levitate within a type I superconducting trap and rotate to create a variable gravity potential. This research confirms the levitation of the propeller and demonstrates several optimizations, for instance, the minimization of damping. However, the rotation of the propeller is yet to be accomplished.Show less
In this project, the simulation software MRI2D was developed. It is a program that allows students to simulate the motion of spins during the magnetic resonance imaging experiment. Already...Show moreIn this project, the simulation software MRI2D was developed. It is a program that allows students to simulate the motion of spins during the magnetic resonance imaging experiment. Already available tools did not model multiple spins rotating to image tissues. Besides filling this niche, other design requirements were taken from existing educational tools. All requirements have been met. MRI2D is open-source software and can be downloaded for free. It comes with a manual for downloading and installing and three example exercises directly for classroom use. MRI2D is ready to now be implemented in education. Further development suggestions are given.Show less
