Deterministic Inter-Chip Quantum State Transfer using Superconducting Resonator

As the complexity of quantum computers increases, it is likely that enough qubits will be needed that interconnects between qubits in different mounts will be required. This requires the ability to transfer quantum states between flying qubits and fixed logic qubits.;In this thesis, we demonstrate the ability to deterministically transfer quantum states between superconducting qubits on separate chips via a traveling photonic mode. Achieving a deterministic transfer without heralding or feedback requires a shaped release to the photonic mode along with shaping the capture of this mode to minimize reflections. To demonstrate the capability of doing this, we use 6GHz superconducting coplanar resonators with tunable coupling to a coaxial transmission line. We first demonstrate the efficient absorption of a shaped classical drive pulse by measuring the reflected and captured signals. With an exponentially increasing pulse, we demonstrate a deterministic single photon storage efficiency of 97.5%, and with theory for experimental absorption efficiencies with various pulse parameters and shapes. For a separate device designed to compensate for frequency shifts due to varying the coupling, we demonstrate the ability to release a single-frequency shaped pulse into the transmission line.;We then deterministically transfer quantum states between superconducting qubits on separate chips separated by 20 cm of coax. We first demonstrate transfer of single qubit states. We then transfer the single-qubit half of a Bell state, resulting in an inter-chip Bell state with a 73% fidelity. We finally demonstrate using the same hardware to repeat the transfer, a necessary ingredient for use in a fault-tolerant architecture. This inter-chip entanglement will allow for quantum computation using more qubits than what fits in a single mount.