Onestep transfer of quantum information for a photonic catstate qubit We present a way to transfer quantum information of a photonic catstate qubit (cqubit) between two cavities coupled to an artificial atom. The two logic states of the photonic cqubit here are encoded by two orthogonal cat states (i.e. superpositions of coherent states) of photons. We show that quantum information of one photonic cqubit can be deterministically transferred between two cavities, with a singlestep operation only. As a specific example, we numerically analyse the experimental implementation of this proposal, by considering a setup of two microwave cavities coupled to a superconducting artificial atom. This proposal can also be applied to transfer onecqubit quantum information between two modes of a quantum field coupled by a natural or artificial atom.

Experimental realization of quantum teleportation of an arbitrary twoqubit state using a fourqubit cluster state Quantum teleportation is extensively used in quantum communication where a sender sends a information to a receiver at a large distance through a quantum entangled channel. Li and Cao (Commun Theor Phys 47(3):464, 2007) proposed a theoretical scheme for teleportation of a twoparticle entangled state via cluster state. Here, we present the above scheme of teleportation for an arbitrary state by using a fourqubit cluster state. We demonstrate the scheme on the IBM quantum computer by designing appropriate quantum circuits using singlequbit and twoqubit quantum gates. We collect the experimental results with good fidelity revealing the teleportation of an arbitrary twoqubit state using a fourqubit cluster state.