We construct a generalized controlled phased gate entangler for a multi-qubit state based on the geometrical structure of quantum systems. We also investigate the relation between the generalized controlled phase construction of a quantum gate entangler and graph state for two-qubit and three-qubit states.
The emerging and innovative field of quantum computation and quantum information could bring new insight to our understanding of nature with many applications such as quantum cryptography, quantum secret sharing, quantum teleportation, and quantum computer. In conventional scheme, a quantum computer could be design by quantum gates and circuits. In this paper, we construct geometrical controlled phase quantum gate entanglers for multi-qubit states based on the complex projective Grassmann variety which is defined by the Plucker embedding of Grassmann space. We explicitly give an expression for a geometrical three-qubit quantum gate entangler. We also discuss in detail the construction of the gate entangler for four-qubit states. Moreover, We give illustrative examples of physical implementations of our quantum gate entangler for two- and multi-qubit systems.
Abstract Multi-qubit graph states generated by the action of controlled phase shift operators on a separable quantum state of a system, in which all the qubits are in arbitrary identical states, are examined. The geometric measure of entanglement of a qubit with other qubits is found for the graph states represented by arbitrary graphs. The entanglement depends on the degree of the vertex representing the qubit, the absolute values of the parameter of the phase shift gate and the parameter of state the gate is acting on. Also the geometric measure of entanglement of the graph states is quantified on the quantum computer . The results obtained on the quantum device are in good agreement with analytical ones.
Hypergraphs generalize ordinary graphs by allowing hyperedges to join any number of vertices rather than just two. Superhypergraphs extend this idea further by iterating the powerset construction, creating hierarchical, nested hyperedge structures. In parallel, quantum graphs model networks of quantum systems, with wavefunctions propagating along edges under specified boundary conditions. Quantum hypergraph states translate hypergraph connectivity into multi-qubit entanglement via generalized controlled phase gates acting on all vertices of each hyperedge. In this paper, we introduce quantum n-superhypergraph states, which marry the recursive structure of superhypergraphs with the formalism of quantum hypergraph states. We give their precise definition, explore key structural properties, and outline potential directions for their application.