Dissertação de Mestrado #583: Leonardo Morais

The Path of Light: An Investigation About Photon Trajectories in a Double-Slit Interferometer

Autor: Leonardo Assis Morais

Banca Avaliadora

Leonardo Teixeira Neves (orientador)

Física - UFMG

Pablo Lima Saldanha

Física - UFMG

Nadja Kolb Bernardes

Física - UFMG

Orientadores

Leonardo Teixeira Neves (orientador)

Departamento de Física - UFMG

Resumo do Trabalho

– In quantum mechanics the trajectory of a single particle is an ill defined concept, since, as a consequence of the Heisenberg uncertainty relation, one is not able to simultaneously know its position and momentum. Nevertheless, recently Kocsis et al. [Science, 332, 1170 (2011)] proposed an operational way to define the average trajectory of an ensemble of quantum particles. Using the weak measurement protocol, which is a procedure developed by Aharonov, Albert and Vaidman [Physical Review Letters 60, 1351 (1988)] with the purpose of performing a measurement barely changing the system state, they were able to reconstruct average trajectories of single photons in a double-slit interferometer. Their strategy consists in making a weak measurement of the photon momentum followed by a post-selection in a given position. In this way, they are able to map the weak value of momentum as a function of position and, using this information, to reconstruct the average trajectories of a post-selected ensemble of photons. In this dissertation, we present a review of the weak measurement protocol and some of its most recent extensions and applications. Within this framework, we reproduced the results obtained by Kocsis et al. and analyse some different scenarios through numerical simulations. Our main proposal is to extend their work, trying to reconstruct the trajectories of a pair of photons in a double-slit interferometer and evaluate the effects of the entanglement in the trajectory of each photon individually, and most importantly, of the pair as a whole.