The context of the thesis is Atomtronics: circuits of laser light in which the flow of cold atoms can be manipulated through quantum optical means. Specifically, we studied systems composed of Bose-Einstein condensates trapped in a ring-shaped optical potential interrupted by a weak link. In this way, we provide a physical realization of the Atomtronics Quantum Interference Device(AQUID), the atomic analog of the celebrated SQUID realized with Josephson junctions. The promise is to harness the power of a macroscopic quantum phenomena with the typically low decoherence rates of cold atom devices. In this thesis, AQUID is envisaged as a platform for possible quantum simulation as well as acting as a core unit for the quantum technologies and quantum computation. Our AQUID presents an additional lattice confinement along the ring potential. The lattice is demonstrated to bring important added features. For our system: (i) We demonstrate that the effective dynamics of our AQUID is, indeed, governed by a two-level system, demonstrating that the AQUID indeed defines a qubit. (ii) We identify the set of parameters, like atom-atom interaction, strength of the weak link, size of a system, for which the AQUID can perform as a qubit. (iii) We studied our system as a quantum simulator (iv)We demonstrate how integrated Atomtronics circuits, in which different AQUIDs can interact with each other, can be constructed - we show, in particular, how one- and two-qubit gates can be realized.