The field of quantum information applies the concepts of quantum physics to problems in computer science, and shows great potential for allowing efficient computation. In this thesis I concentrate on a particular quantum information theoretic tool known as the quantum walk. There are two widely studied versions of the quantum walk, the continuous time walk, and the discrete time walk. The discr...

Perfect state transfer is possible in modulated spin chains [Phys. Rev. Lett. 92, 187902 (2004)], imperfections however are likely to corrupt the state transfer. We study the robustness of this quantum communication protocol in the presence of disorder both in the exchange couplings between the spins and in the local magnetic field. The degradation of the fidelity can be suitably expressed, as ...

We investigate the most general mechanisms that lead to perfect synchronization of quantum states all subsystems an open system starting from arbitrary initial state. provide a necessary and sufficient condition for such ``quantum-state synchronization,'' prove tight lower bounds on dimension ancilla's Hilbert space in two main classes quantum-state synchronizers, give analytical solution their...

I show a scheme which allows a perfect transfer of an unknown single-qubit atomic state from one atom to another by letting two atoms interact simultaneously with a cavity QED. During the interaction between atom and cavity, the cavity is only virtually excited and accordingly the scheme is insensitive to the cavity field states and cavity decay. Based on this scheme, a network for transfer of ...

Quantum walks are an analog of classical random in quantum systems. have smaller hitting times compared to on certain types graphs, leading a advantage quantum-walks-based algorithms. An important feature is that they accompanied by the excitation transfer from one site another, and moment destination characterized maximum probability amplitude observing this site. It therefore prospective cons...

We study perfect state transfer in Grover walks, which are typical discrete-time quantum walk models. In particular, we focus on states associated to vertices of a graph. call such vertex type states. Perfect between can be studied via Chebyshev polynomials. derive necessary condition eigenvalues graph for occur. addition, perfectly determine the complete multipartite graphs whose partite sets ...