Definition and evolution of quantum cellular automata with two qubits per cell

Studies of quantum computer implementations suggest cellular quantum computer architectures. These architectures can simulate the evolution of quantum cellular automata, which can possibly simulate both quantum and classical physical systems and processes. It is however known that except for the trivial case, unitary evolution of one-dimensional homogeneous quantum cellular automata with one qubit per cell is not possible. Quantum cellular automata that comprise two qubits per cell are defined and their evolution is studied using a quantum computer simulator. The evolution is unitary and its linearity manifests itself as a periodic structure in the probability distribution patterns.Comment: 13 pages, 4 figure

MULTIPLE QUANTUM WALKERS ON THE LINE USING HYBRID COINS: A POSSIBLE TOOL FOR QUANTUM SEARCH

In this paper discrete quantum walks with different coins used for odd and even time steps are studied. These coins are called hybrid. The calculation results are compared with the most frequently used coin, the Hadamard transform. Furthermore, quantum walks on the line which involve two or more quantum walkers with hybrid coins are studied. Quantum walks with entangled walkers and hybrid coins are also studied. The results of these calculations show that the proposed types of quantum walks can be used for quantum search, because the walker can be directed towards preferred directions and can also be confined in certain segments of the line