Autonomous quantum error correction of a grid state qubit
Abstract: Quantum error correction is expected to play an important role in the realization of large-scale quantum computers. At the lowest level, it takes advantage of embedding qubits in a larger Hilbert space, giving redundancy which allows measurements which preserve logical information while revealing the presence of errors. While many codes rely on multiple physical systems, Bosonic codes make use of the higher dimensional Hilbert space of a single harmonic oscillator mode.
Capacity and Quantum Geometry of Parametrized Quantum Circuits
Abstract: To harness the potential of noisy intermediate-scale quantum devices, it is paramount to find the best type of circuits to run hybrid quantum-classical algorithms. Key candidates are parametrized quantum circuits that can be effectively implemented on current devices. Here, we evaluate the capacity and trainability of these circuits using the geometric structure of the parameter space via the effective quantum dimension [1]. We find that the capacity exhibits scaling laws and striking differences depending on the type of entangling gates used.