QFT OF PARTICLE MIXING IN CURVED SPACETIME, DARK MATTER AND QUANTUM INFORMATION

THIS THESIS PRESENTS THE MAIN RESULTS OBTAINED DURING THREE YEARS OF DOCTORAL RESEARCH, ALL MOTIVATED BY THE SEARCH FOR PHYSICS BEYOND THE STANDARD MODEL. THE WORK FOLLOWS THREE MAIN RESEARCH DIRECTIONS. FIRST OF ALL, THE QUANTUM FIELD THEORY OF PARTICLE MIXING IN CURVED SPACETIME WHERE WE INVESTIGATE HOW QUANTUM FIELD THEORETICAL EFFECTS IN CURVED BACKGROUNDS INFLUENCE NEUTRINO OSCILLATIONS AND HOW SUCH CORRECTIONS COULD CONTRIBUTE TO EXPLAINING THE DARK MATTER PROBLEM IN GALAXIES. MOREOVER, WE DERIVE NEW OSCILLATION FORMULAE ACCOUNTING FOR SPACETIME TORSION EFFECTS. THE SECOND RESEARCH DIRECTION IS BASED ON NEW METHODS TO REVEAL DARK MATTER AND THE $X_{17}$ BOSON WHERE WE PROPOSE A NOVEL SINGLE-ARM INTERFEROMETRIC TECHNIQUE TO PROBE THE EXISTENCE OF PREDICTED BUT STILL UNOBSERVED PARTICLES. FURTHERMORE, WE SHOW HOW THE INTRODUCTION OF A NEW VECTOR BOSON, $X_{17}$, COULD EXPLAIN SEVERAL EXPERIMENTAL ANOMALIES INCLUDING THE MUON ANOMALOUS MAGNETIC MOMENT AND THE LAMB SHIFT OBSERVED IN MUONIC ATOMS. FINALLY, THE DECOHERENCE AND THE EXTENSION OF THE LINDBLAD APPROACH WHERE WE EXPLORE THE POTENTIAL OF QUANTUM COMPUTING TECHNIQUES IN HIGH-ENERGY PHYSICS AND PROPOSE AN ALTERNATIVE MODEL TO DESCRIBE DECOHERENCE IN MANY-BODY SYSTEMS, PARTICULARLY IN SCENARIOS WHERE THE LINDBLAD FORMALISM EXHIBITS INTRINSIC LIMITATIONS.