http://hdl.handle.net/11422/53 Mon, 20 Jul 2026 23:54:24 GMT 2026-07-20T23:54:24Z http://hdl.handle.net/11422/29715 Title: Dynamical Casimir effects with atoms and spinning nanoparticles Author(s)/Inventor(s): Matos, Guilherme Costa Advisor: Maia Neto, Paulo Américo Abstract: Motivated by recent experiments with levitated, ultra-fast rotating nanoparticles, this thesis presents new effects in the interaction of spinning particles with the quantum vacuum. The first part of the thesis studies the quantum electrodynamical analog of the Sagnac effect, in which the rotation of a neutral particle in the vicinity of an atom interferometer induces a phase on the propagating matter waves. The resulting phase is a geometric Berry phase proportional to the angular velocity of the particle. A rotation confined to a region of space leaving a trace of non-inertiality in an inertial frame suggests an analogy with the Aharonov-Bohm effect. Taking the particle’s plasmon resonances account, the analysis reveals that the phase magnitude is close to the limit of measurement for current state of the art atom interferometers. The force on an atom by a rotating particle is also calculated, and is shown to be analogous to the Coriolis force. The second part of the thesis deals with the photon emission by a rotating non-spherical neutral particle. Provided that the rotation axis is orthogonal to particle symmetry axis, the interaction of the particle with the field produces frequency sidebands of the scattered field, leading to the emission of dynamical Casimir photon pairs. The photon emission rate is obtained for metallic and dielectric spheroids and is enhanced when the rotation frequency is near a plasmonic or polaritonic resonance. In order to optimize the emission rate, the velocity of the particle’s tip is fixed and the dependence with the particle’s geometry is considered. Publisher: Universidade Federal do Rio de Janeiro Type: Tese Thu, 18 Dec 2025 00:00:00 GMT http://hdl.handle.net/11422/29715 2025-12-18T00:00:00Z http://hdl.handle.net/11422/29669 Title: Estudo do espalhamento elástico com feixes exóticos no regime de baixas energias Author(s)/Inventor(s): Souza, Bernard Lucas Brandão Suhett de Advisor: Santos, Antônio Carlos Fontes dos Abstract: In this work, elastic scattering measurements were performed for the 6He + 197Au system at the energies ELab = 18.0, 21.8, and 23.0 MeV, close to the Coulomb barrier (ELab = 19.11 MeV). The angular distributions were analyzed using Woods–Saxon optical potentials, the S˜ao Paulo Potential (SPP), and four-body CDCC calculations, also performed at the energy of 27.0 MeV. Experimental data available in the literature were also analyzed for the systems 6He+ 51V (15.4 and 23.0 MeV), 7Be+51V (26.0 MeV), and 8Li+51V (18.5 and 26.0 MeV), aiming to investigate effects associated with weakly bound nuclei. All experimental measurements were performed at the Radioactive Ion Beams in Brazil (RIBRAS) system, installed at the Pelletron Laboratory of the Institute of Physics of the University of S˜ao Paulo. The results obtained from the 4B-CDCC calculations evidenced the importance of coupling effects associated with the halo nature of the 6He nucleus. The experimental data for the 7Be + 51V system were satisfactorily reproduced by the S˜ao Paulo Potential. On the other hand, the results for the 8Li+51V system demonstrated the relevance of the transfer channel for the description of this interaction. Publisher: Universidade Federal do Rio de Janeiro Type: Tese Mon, 15 Dec 2025 00:00:00 GMT http://hdl.handle.net/11422/29669 2025-12-15T00:00:00Z http://hdl.handle.net/11422/29659 Title: Exploring quantum optics and quantum information: from the interferometer to the generation of correlated photons Author(s)/Inventor(s): Araújo, Jailson Sales Advisor: Aguilar, Gabriel Horacio Abstract: This thesis investigates, in photonics, how to design, diagnose, and exploit open quantum dynamics and light–matter interactions along three complementary fronts. First, we present a programmable interferometer in linear optics in which the path degree of freedom encodes the system and polarization serves as an ancilla qubit to implement Kraus maps; we implement decoherence and dissipation channels (dephasing, amplitude damping, and Pauli), including finite-temperature extensions (GAD/SGAD). Next, using a recently defined quantum-reality quantifier, we demonstrate that Alice’s local operations correlate with the erasure of the reality of observables in Bob’s photon in a scenario of causally disconnected measurements; a modified optical quantum eraser, with entangled pairs and quantum-state tomography, confirms this correlation experimentally. Finally, we investigate the generation and control of Stokes–anti-Stokes correlations in Raman scattering and propose an experimental route to (i) analyze orbital-angular-momentum conservation in this process and (ii) study field-induced anisotropy in polar liquids under a uniform electric field. Publisher: Universidade Federal do Rio de Janeiro Type: Tese Tue, 16 Dec 2025 00:00:00 GMT http://hdl.handle.net/11422/29659 2025-12-16T00:00:00Z http://hdl.handle.net/11422/29632 Title: Dispersion forces on Proca electrodynamics Author(s)/Inventor(s): Pinho, Gabriel Camacho de Advisor: Zarro, Carlos Augusto Domingues Abstract: The effects of a finite photon mass have been analyzed in multiple scenarios involving dispersive forces. To describe the interactions relevant to such forces, Proca electrodynamics was employed. Initially, we considered the dispersion interaction between two atoms in their ground states, for which we determined the interaction potential over all distance regimes. As in the case mediated by massless photons, we also determined the dispersive potential in two asymptotic regimes: the non-retarded regime and the retarded (here referred to as asymptotic) regime. We also concluded that the photon mass, by introducing a new length scale, modifies the conditions required for the validity of each regime. For instance, for a given interatomic separation, the larger the photon mass, the more accurate the non-retarded approximation becomes. The effects of non-additivity in dispersive forces were also considered within Proca electrodynamics. These effects were divided into two main groups: free atoms interacting with each other, and atoms interacting with grounded, neutral, conducting surfaces. For the first group, we found that the photon mass always weakens the non-additive interaction and reduces its relevance compared to the total dispersive interaction. For the interaction between atoms and surfaces, however, we found that there are scenarios in which the non-additive force becomes dominant for nonzero photon mass values. Publisher: Universidade Federal do Rio de Janeiro Type: Tese Mon, 01 Dec 2025 00:00:00 GMT http://hdl.handle.net/11422/29632 2025-12-01T00:00:00Z