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- ItemBeyond the standard model with scalars: long-lived particles and dimuon Higgs decay(2025) Norero Cárdenas, Sebastián; Díaz, Marco A.; Pontificia Universidad Católica de Chile. Facultad de FísicaThis thesis explores two extensions of the Standard Model. The first modifies the Scotogenic Model to explain deviations in Dimuon Higgs decays, while satisfying LFV constraints. The second extends the Georgi-Machacek model by incorporating a type-II seesaw, leading to a long-lived doubly charged scalar. Both models offer collider signatures, with one probing loop-induced Higgs decays and the other emphasizing LLP searches. Future experiments will be crucial in testing these predictions.
- ItemOutflows from tungsten conical wire arrays. Characterization and applications(2024) Muñoz-Cordovez, Gonzalo; Veloso Espinosa, Felipe Eduardo; Pontificia Universidad Católica de Chile. Facultad de FísicaA tungsten conical wire array is used as load in the Llampudken pulsed power generator(∼400 kA in ∼350 ns) to study the outflows produced by it. At pressures of 10 −4 Torrthe dynamics of the wire array is probe by UV/XUV imaging and laser schlieren andinterferometry. These diagnostics show the expulsion of a dense plasma jet (n e = 3 × 10 24m −3 ) of a couple of centimeters in the axial direction above the anode. This plasma jet havevelocities between 10 4 − 10 5 m/s and its dimensionless parameters are computed in orderto compare the experimentally produced plasma jet with the astronomically producedones. At pressures that varies from 10 −5 Torr to 10 −2 Torr the upwards axial emission ofcharged particles is study using negatively biased Faraday cups. At 10 −5 Torr only ionsare detected by the cups but from 10 −4 Torr to 10 −2 Torr the detection of both electronsand ions moving together in the same direction is observed due to the ionization of thebackground gas. Velocity computed for the electrons and ions is in the order of 10 6 m/simplying MeV ions. Finally, the interaction of these outflows with stationary targets isstudy by placing silicon targets at different heights above the conical wire array. Resultsshow that visible damage over the target was observed from 10 cm to 21 cm above thearray where two main damages are appreciated. For targets located closer to the arraymainly micro-pores are observed but for targets located farther from the array stripes-likeformations are appreciated. These damages indicate that the silicon target boiled and wasfastly heated by the conical wire array outflows. Detail measurements of these outflowsand the damages produced on the silicon targets are shown an discussed in this thesis.
- ItemSingle Molecules for Quantum Information and Metrology(2024) Escalante, Richard; Maze Ríos, Jerónimo; Pontificia Universidad Católica de Chile. Facultad de FísicaSingle luminescent molecules provide a unique approach in the development of quantum technologies utilizing single photon sources. This includes quantum metrology by using a molecule’s sensitivity of its emission and magnetic properties to the local environment. In this thesis, we present our investigation of the optical properties of several different classes of luminescent molecules. We begin by providing some theoretical background of single quantum emitters as well as a brief description of the experimental methodologies and equipment. Next, we present an optical investigation of an ensemble of iron phthalocyanines molecules. This molecule possesses a ground state triplet, which is a desirable property for optically active spin qubits, but has a very weak optical emission. Diffraction limited spots displayed photo-instability in the form of blinking and irreversible bleaching. In ensemble form however, their optical stability allowed us to identify a possible Raman peak where we calculated the associated phonon frequency. Next, we present our single molecule study of vanadium phthalocyanine. This molecule has been documented as displaying very long spin coherence times even at room temperatures. We confirmed the presence of a single molecule by measuring the second order correlation function. Additionally, we looked at the intensity and spectral response as a function of the excitation laser polarization. The spectrum was fitted to a two Gaussian function, which may correspond to the two dipole transitions as suggested by theoretical calculations. Lastly, we looked at the optical properties of rare earth europium complexes known for having very sharp optical transitions in the emission spectrum, with each having varying levels of sensitivity to the local environment. Motivated by techniques to investigate non-radiative decay channels, we looked at the optical response of four different europium complexes under two 1 µs pulses of 515 nm laser separated by 1 µs. Each displayed a very different results and allowed us to identify the best candidates for single molecule studies. Finally, we looked at the emission spectrum as well as the optical response under a 6 µs long pulse using time-correlation single photon spectroscopy.
- ItemDelving into the phenomenology of very special relativity: from subatomic particles to binary stars(2024) Santoni, Alessandro; Muñoz Tavera, Enrique; Koch, Benjamin; Pontificia Universidad Católica de Chile. Facultad de FísicaEn esta tesis, se investigan las implicaciones de las teorías de violación de Lorentz (LV), enfocándose en Very Special Relativity (VSR) y sus consecuencias fenomenológicas. Presentada inicialmente como un mecanismo alternativo para las masas de los neutrinos, VSR se ha convertido en una parte significativa del marco general de la LV, distinguida por su estructura de grupo y la presencia de operadores no locales.Después de una introducción exhaustiva a los principios de la LV y VSR, presentamos sus modificaciones a la ecuación de Dirac. Una parte significativa de la tesis está dedicada al desarrollo de un formalismo Hamiltoniano dentro del contexto de VSR, abordando sus no-localidades. Este enfoque se extiende al límite no relativista, conectándolo al esquema de Schrödinger.Luego establecemos límites superiores en los parámetros de VSR, examinando sus correcciones a una amplia gama de sistemas y escenarios físicos, como los niveles de Landau de partículas cargadas, el factor g de los electrones, el espectro de energía de neutrones ultrafríos en el campo gravitatorio terrestre, y la emisión gravitacional de estrellas binarias. Este último análisis nos llevó a la construcción de una teoría de campo en VSR para partículas de espín-2, que resultó acomodar una masa del gravitón gauge-invariante.Mediante este estudio, conectamos varias predicciones teóricas con datos experimentales, allanando el camino para futuras exploraciones en teorías de LV y evidenciando su potencial para abordar preguntas no resueltas en la física moderna.
- ItemQuantum measurement transition and entanglement of trapped ions and optomechanical systems(2024) Araya Sossa, Kevin Jordan; Orszag Posa, Miguel; Pontificia Universidad Católica de Chile. Instituto de FísicaAlthough quantum mechanics has been able to explain a wide range of physical, chemical, and even biological events with unprecedented accuracy, fundamental problems remain. For instance, the problem of quantum measurement and quantum entanglement, which are the most perplexing problems that have persisted since the foundation of quantum mechanics. Both are crucial quantum resources with broad applications in quantum information science, quantum computing and quantum optics. For this reason, this thesis is devoted to research the quantum measurement from the weakest regime to the strongest one as well as the dynamics of entanglement of different quantum systems. In this work, we study the measurement transition for a coherent-squeezed pointer state through a transition factor Γ that involves a system-pointer coupling by using an arbitrary measured observable A. In addition, we show that the shift in the pointer’s position and momentum establishes a relationship with a new value defined as the transition value, which generalizes the weak value as well as the conditional expectation value. Furthermore, a new strategy is introduced to achieve different measurement regimes by just adjusting the r and ϕξ parameters of the coherent-squeezed pointer state, opening an interesting way to test quantum mechanics foundations. Our scheme has been theoretically applied in a trapped ion illuminated by a bichromatic laser beam, with a high potential to be implemented in future experimental setups. Besides, we propose a method to regulate the quantum entanglement in the system mentioned before as well as a dispersive-hybrid system where a qubit is directly coupled to a cavity and a mechanical resonator. Entanglement can be controlled by only tuning the squeezing parameters associated with the vibrational mode. As the squeezing amplitude becomes larger, the maximal entanglement abruptly falls to zero at specific squeezing phases. For the hybrid system, it is also possible to generate entanglement for bipartitions from the qubit-cavity-resonator system after applying this strategy. Entangled qubit-cavity states are created through squeezing, even though there is no direct interaction between them. We also analyze the effect of atomic, optical, and vibrational losses on the quantum entanglement. We finally discuss our schemes to be implemented in future experimental setups and promote further studies to generalize the concept of “monogamy of entanglement” in tripartite systems outside qubit-composite states, in particular, (2 ⊗ 2 ⊗ n)-dimensional systems.