Simulation of quantum jump in qutrit photonic path system

• Autor(a) principal: Arthur Castro Cardoso
• Data de Publicação: 2021
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/40697
• topic: Atomic decay; Quantum jump; Quantum logic gates; Quantum operations; Quantum simulation; Three-level systems; Simulação quântica; Sistemas quânticos; Fótons

In this thesis, we use an experimental platform of laser beams in Gaussian modes attenuated to the level of a few photons. The quantum state is prepared in a superposition of transverse Gaussian paths states. By making use of the techniques proposed by Baldijão et. al. [Phys. Rev. A. 96, 032329 (2017)] and characterized by Borges et. al. [Phys. Rev. A. 97, 022301 (2018)], to perform generalized quantum operations in this degree of freedom. We are able to generate three-path (qutrits) quantum states and implement the necessary operations to simulate spontaneous decay in a tree-level atom with quantum jumps. By using periodic diffraction phase gratings in a spatial light modulator, we implement the quantum operations for the simulation of the decay dynamics in three-level systems with quantum jumps in terms of the Kraus decomposition, for each one of the configurations: cascade, and V . In this experimental simulation, the average number of photons in each path state plays the role of the population in each one of the energy levels of the atom. The coherences between the energy eigenstates are related to the visibilities of the interference patterns between the pair of beams that form the base of the photonic path states. The states are characterized by image measurements of the beams with transversal Gaussian profile and by the interference patterns between the pairs of these spatial modes. Also we propose theoretically, making use of the same methodology, the experimental realization of quantum logic gates and controlled quantum logic gates in photonic path states. With the proposed experimental setup, we show that it is possible to implement in qubits paths states, all the logic gates described by the Pauli matrices (sigma x, sigma y e sigma z), beyond the phase logic gates. The same method can be explored for qutrits, or even multi-path systems of higher dimensions. In the simulation of the decay dynamics, we obtained satisfactory results for the diagonal terms and for the modulus of the off-diagonal terms, that is, despite of a small deviation, they are in agreement with the theoretical predictions. This simulation provide us a better comprehension of how the quantum jumps can affect the coherence of a three-level state. Moreover, this implementation may be used to understand how the quantum jumps, in high dimension systems, affect the quantum protocols due to decoherence.