3.10 Tesis magíster

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Browsing 3.10 Tesis magíster by Subject "09 Industria, innovación e infraestructura"

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    Anomalous Positron and Antiproton Cosmic Ray Flux in the Minimal Supersymmetric Standard Model Plus R-Parity Violation
    (2025) Ortega Gutiérrez, Gonzalo; Díaz Gutiérrez, Marco Aurelio; Pontificia Universidad Católica de Chile. Instituto de Física
    The Alpha Magnetic Spectrometer (AMS) located in the International Space Station, measured anomalous fluxes of positrons and antiprotons. The standard astronomical sources are not enough to describe the fluxes measured. We explain it with physics beyond the Standard Model: the Minimal Supersymmetric Standard Model plus R-Parity Violation. Gravitino, the graviton suṕerpartner, plays a fundamental role in our study because the different gravitino decay channels would contribute to the positron and antiproton fluxes measured by AMS. The main focus of our study is to find the best branching ratios associated with the decay channels, which adjust to AMS measurements, considering gravitino properties as its mass and lifetime.
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    Optical characterization of single molecules for quantum technologies
    (2025) Vera Castillo, Nicolás; Maze Ríos, Jerónimo; Pontificia Universidad Católica de Chile. Facultad de Física
    In this thesis, the optical properties of Vanadium Oxide Phthalocyanine (VOPc) molecules were studied using a home-built confocal microscope setup. Single VOPc molecules were successfully isolated and identified by their distinct diffraction-limited spots. Two sample preparation techniques were compared: spin coating and ion exchange. Spin coating produced less density of spots, while ion exchange resulted in more photostable spots.The emission spectra of the isolated spots were consistent with the known spectrum of VOPc, showing two peaks around 855 nm and 877 nm. The polarization response of the molecules indicated that they are randomly oriented in the sample. The lifetime of VOPc molecules was measured using time-correlated single photon counting (TCSPC), revealing an unexpected oscillatory behavior at high excitation powers, which disappeared at lower powers. This behavior suggests that the oscillation might be due to the laser's stability or noise. The lifetimes measured in an ensemble of VOPc were τ1 = 0.038 ns and τ2 = 0.221 ns for a power of 3.5 μW, and τ1 = 0.034 ns and τ2 = 0.084 ns. This power dependence on the excitation power is not the expected behavior as the lifetime should be a fixed characteristic of the molecule. Overall, the study provided valuable insights into the optical properties and isolation of VOPc molecules. Future work could focus on measuring the saturation curve of the fluorescence, confirming the presence of single molecules using second-order autocorrelation, and investigating the interaction of VOPc molecules with magnetic fields for potential applications in quantum technologies.