Experimental Study of Quantum Entanglement in Superconducting Circuits

The proposed work is to experimentally investigate quantum coherent interaction between artificial quantum objects and light fields. We will take the platform of circuit cavity quantum electrodynamics to study this problem. We will use the transmon design and superconducting coplanar waveguide (CPW) resonators to construct required qubits and cavities, respectively, and to realize strong coupling between qubits and cavities. We are particularly interested in quantum entanglement of transmon qubits via a CPW cavity. In the project we expect to first achieve qubit-cavity interaction in strong coupling regime. We will then work on a system containing two transmon qubits coupled to a CPW cavity. We anticipate finding out qubit-qubit interaction via the virtual photons in the cavity, and discovering the evidence of two qubit entanglement. We will develop heterodyne detection to perform dispersive readout for qubit quantum state in strong dispersive regime. This technique will offer quantum nondemolition measurement for determination of qubit state. Finally we will seek to use microwave pulsing technique for preparation of quantum entangled states in qubit-cavity systems.