Quantum error correction and fault-tolerant quantum computation are two fundamental concepts which make quantum computing feasible. While providing a theoretical means with which to ensure the arbitrary accuracy of any quantum circuit, fault-tolerant error correction is predicated upon the robust preparation of logical states. An optimal direct circuit and a more complex fault-tolerant circuit ...

We present a model of Quantum Finite State Machines (QFSM) based on the quantum circuit representation. In this model, properties of quantum bits are exploited in order to implement Quantum Finite State Machines without an explicit external memory. We show that because of the the natural ability of quantum systems to retain the quantum state, quantum circuits can be directly used to implement s...

The design of efficient quantum circuits is an important issue in quantum computing. It is in general a formidable task to find a highly optimized quantum circuit for a given unitary matrix. We propose a quantum circuit design method that has the following unique feature: It allows to construct efficient quantum circuits in a systematic way by reusing and combining a set of highly optimized qua...

We experimentally study a circuit quantum acoustodynamics system, which consists of superconducting artificial atom, coupled to both two-dimensional surface acoustic wave resonator and one-dimensional microwave transmission line. The strong coupling between the atom is confirmed by observation vacuum Rabi splitting at base temperature dilution refrigerator. show that propagation photons in line...

Abstract Variational quantum algorithms (VQAs) are expected to be a path advantages on noisy intermediate-scale devices. However, both empirical and theoretical results exhibit that the deployed ansatz heavily affects performance of VQAs such an with larger number gates enables stronger expressivity, while accumulated noise may render poor trainability. To maximally improve robustness trainabil...