Cluster-state preparation and multipartite entanglement analyzer with fermions

Quantum cluster states and entangled state analyzers are essential to measurement-based quantum computing. We propose to generate a quantum cluster-state and to make multipartite entanglement analyzer by using noninteracting free electrons or conduction electrons in quantum dots, based on polarizing beam splitters, charge detectors and single-spin rotations. Our schemes are deterministic without the need of qubit-qubit interaction.