Entangled Schrodinger cats in circuit QED: Experimental Architecture

The development of quantum information technology relies on creating and controling entanglement over an increasingly large Hilbert space. Superconducting cavities offer high-dimensional spaces for quantum states in a low-loss and hardware-efficient fashion, making it an ideal memory of quantum information and an important element towards fault-tolerant quantum computation. In this talk we present a cQED architecture that allows quantum control over the coherent state basis of two superconducting cavities with millisecond coherence. In particular, we show deterministic entanglement of coherent-state microwave fields in two superconducting cavities of the form: $\frac{1}{\sqrt 2 }\left( {\left| \right.\left. {\beta_{a} } \right\rangle \left| \right.\left. {\beta_{a} } \right\rangle \pm \left| - \right.\left. {\beta_{a} } \right\rangle \left| - \right.\left. {\beta_{a} } \right\rangle } \right)$. We engineer the capability to measure the joint photon number parity to achieve complete state tomography of the two-cavity state. Following widespread efforts of realizing ``Schrodinger's cat''-like mesoscopic superposition in various physical systems, this experiment demonstrates mesoscopic entanglement between two ``Schrodinger's cats''.