Master thesis defense: Aleksandar Stanojcic

New Classes of Photon Bound States in Coupled Waveguides

A configuration of two-level emitters ingrained equidistantly into two parallel unidirectional waveguides, allowing for tunneling of photons between them, has been studied recently. In this thesis we further explore this configuration: three classes of bound states that appear in this system are identified and parametrised by the photon energy, using two different approaches. Firstly, the system Hamiltonian was diagonalised by mapping it to the impurity model and applying Green’s function formalism to it. The dispersion relation for bound states was numerically obtained. Secondly, the two special cases K = 0 and K = π of the bound states were identified as eigenstates of the S-matrix at zero energy, and the correspondence was made between the two pictures. Moreover, stability of the states K = 0 and K = π was investigated and a theoretical model was proposed.