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This thesis is devoted to the study of mass effects in higher order radiative corrections within QED and QCD. The first part of the thesis deals with the process of deep-inelastic scattering. We compute the full mass dependence of the pure singlet Wilson coefficient in the polarized and unploarized case to next-to-leading order using iterated integrals over square root valued letters. Through explicit expansion in the asymptotic limit we proof the factorization of the heavy Wilson coefficie...
Blazars like Markarian 421 or Markarian 501 are active galactic nuclei (AGN), with their jets orientated towards the observer. They are among the brightest objects in the very high energy (VHE) gamma ray regime (>100 GeV). Their emitted gamma-ray fluxes are extremely variable, with changing activity levels on timescales between minutes, months, and even years. Several questions are part of the current research, such as the question of the emission regions or the engine of the AGN and the part...
Graphene-ferromagnet interfaces possess remarkable properties like induced magnetism in the graphene film, increased magnetic anisotropy in the ferromagnetic film, and chiral magnetism. Previously, the graphene-ferromagnet interface was investigated mainly on metallic substrates. Yet, silicon carbide (SiC) is a promising graphene substrate due to its semi-insulating properties and its industrial relevance. This thesis investigates for the first time the intercalation of thin cobalt films...
This thesis includes two parts presenting the results on the research on the deformation of ferrofluid-filled elastic capsules in external magnetic fields as well as on the possibility of the usage of swelling elastic disks as microswimmers by triggering hysteretic shape transformations. The first part is a primarily theoretical study of deformations and shape transitions of ferrofluid capsules induced by homogeneous and inhomogeneous magnetic fields. The thin elastic shell is modelled b...
Voltage control of ferromagnetism on the nanometer scale is highly appealing for the development of novel electronic devices with low power consumption, high operation speed, reliable reversibility and compatibility with semiconductor technology. Hybrid structures based on the assembly of ferromagnetic and semiconducting building blocks are expected to show magnetic order as a ferromagnet and to be electrically tunable as a semiconductor. Here, we demonstrate the electrical control of the exc...
We report on the fabrication and characterization of a novel magnetophotonic structure designed as iron garnet based magneto-optical nanoresonator cavity constrained by two noble metal mirrors. Since the iron garnet layer requires annealing at high temperatures, the fabrication process can be rather challenging. Special approaches for the protection of metal layers against oxidation and morphological changes along with a special plasma-assisted polishing of the iron garnet layer surface were ...
The effects of exchange coupling on magnetic switching properties of all-garnet multilayer thin film structures are investigated. All-garnet structures are fabricated by sandwiching a magneto-soft material of composition type Bi1.8Lu1.2Fe3.6Al1.4O12 or Bi3Fe5O12:Dy2O3 in between two magneto-hard garnet material layers of composition type Bi2Dy1Fe4Ga1O12 or Bi2Dy1Fe4Ga1O12:Bi2O3. The fabricated RF magnetron sputtered exchange-coupled all-garnet multilayers demonstrate a very attractive combina...
The prospect of utilizing the highly localized electron spin of singly charged semiconductor quantum dots as building blocks for quantum information processing sparked interest in the behavior of the spins in such a system. In this thesis we focus on the theoretical modeling of pump-probe experiments which provide an experimental approach to investigate the spin dynamics. We derive a semiclassical description of the spin dynamics in the periodically pulsed quantum dot including not only ...
Active Galactic Nuclei emit radiation over the whole electromagnetic spectrum up to TeV energies. Blazars are one subtype with their jets pointing towards the observer. One of their typical features is extreme variability on timescales, from minutes to years. The fractional variability is an often used parameter for investigating the degree of variability of a light curve. Different detection methods and sensitivities of the instruments result in differently binned data and light curves with ...
The presented thesis deals with the branching ratio measurement of the decay channel Bs0 → KS0 KS0 reconstructed as two charged pion pairs. The data correspond to an integrated luminosity of 5 fb^{-1} collected by the LHCb experiment in proton-proton collisions at the centre-of-mass energies of sqrt{s} = 7 TeV (1 fb^{-1}), 8 TeV (2 fb^{-1}) and 13 TeV (2 fb^{-1}). As normalisation channel the decay B0 → φKS0 is used in which the φ meson is reconstructed as two charged kaons. The branching rat...
Blazars are known to show variability on time scales from minutes to years covering a wide range of flux states. Studying the flux distribution of a source allows for various insights. The shape of the flux distribution can provide information on the nature of the underlying variability processes. The level of a possible quiescent state can be derived from the main part of the distribution that can be described by a Gaussian distribution. Dividing the flux states into quiescent and active, th...
This thesis presents the measurement of decay-time-dependent 𝐶𝑃 violation in the decays of 𝐵0 → 𝜓(2𝑆)𝐾S0 and 𝐵0 → 𝐽/𝜓𝐾S0 using data collected with the LHCb experiment in 𝑝𝑝 collisions at centre-of-mass energies of 7 TeV and 8 TeV, corresponding to a total integrated luminosity of 3 fb−1. In both considered decay modes, the 𝐾S0 meson is reconstructed from two charged pions, while the 𝜓(2𝑆) meson is reconstructed from two muons, whereas the 𝐽/𝜓 meson is reconstructed from...
The sensitive detection of different biochemical species is of great interest both for the fundamental research and for practical applications concerning the disease diagnostics and drug screening. The high demand in selective, sensitive, fast and low-cost diagnostic techniques has resulted in the rapid development of various-types biochemical sensors (biosensors). Being analytical devices for the qualitative or/and quantitative determination of biological targets, biosensors usually consist ...
In this thesis, the production of a single top quark in association with a Higgs boson (tH) is studied at √s = 13 TeV in the H → γγ decay channel at the ATLAS experiment. Similar to the production of a Higgs boson in association with a top-antitop quark pair (ttH), tH production allows for a direct measurement of the Yukawa coupling, Yt, of the top quark. Due to a destructive interference in tH production, it also provides sensitivity to negative values of the coupling strength modifier κt = ...
This thesis discusses two analyses of rareBmeson decays that are sensitive to effectsbeyond the Standard Model of particles physics. Both measurements are based on theLHCb Run 1 data sample of proton-proton collisions corresponding to an integratedluminosity of3 fb−1recorded at centre-of-mass energies of 7 and 8 TeV.The first measurement is a search for light scalar particles inB0(s)→μ+μ−μ+μ−decays. Additionally to the Standard Model contributions without intermediateresonances, a specific s...
In this work, several types of biosensors are fabricated, characterized, and utilized for the reliable and accurate detection of speci c biomolecules that playing a crucial role in biochemical processes inside the human organism. During the work, di erent types of biosensing techniques, including whispering-gallerymode (WGM) resonators and eld-e ect transistors (FETs), as well as electrolyteinsulator- semiconductor (EIS) sensors were introduced and used as highly sensitive tools to stu...
Coherent optical spectroscopy such as four-wave mixing and photon echo generation deliver rich information on the energy levels involved in optical transitions through the analysis of polarization of the coherent response. In semiconductors, it can be applied to distinguish between different exciton complexes, which is a highly non-trivial problem in optical spectroscopy. We develop a simple approach based on photon echo polarimetry, in which polar plots of the photon echo amplitude are measu...
This thesis focuses on fourth-order spin correlation functions in semi-conductor quantum dots. Widely studied are the second order spin noise power spectrum and its counterpart in the time domain. However, the information extracted from the second order correlation function is limited, and it stands to reason that higher order correlators carry additional physics. The best and most accessible option to study higher order statistics are fourth order correlators. These can be observe...
An action potential is typically described as a purely electrical change that propagates along the membrane of excitable cells. However, recent experiments have demonstrated that non-linear acoustic pulses that propagate along lipid interfaces and traverse the melting transition, share many similar properties with action potentials. Despite the striking experimental similarities, a comprehensive theoretical study of acoustic pulses in lipid systems is still lacking. Here we demonstrate that a...