Fellner Michael, Messinger Anette, Ender Kilian, Lechner Wolfgang
Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria.
Parity Quantum Computing GmbH, A-6020 Innsbruck, Austria.
Phys Rev Lett. 2022 Oct 28;129(18):180503. doi: 10.1103/PhysRevLett.129.180503.
We propose a universal gate set for quantum computing with all-to-all connectivity and intrinsic robustness to bit-flip errors based on parity encoding. We show that logical controlled phase gate and R_{z} rotations can be implemented in parity encoding with single-qubit operations. Together with logical R_{x} rotations, implemented via nearest-neighbor controlled-NOT gates and an R_{x} rotation, these form a universal gate set. As the controlled phase gate requires only single-qubit rotations, the proposed scheme has advantages for several cornerstone quantum algorithms, e.g., the quantum Fourier transform. We present a method to switch between different encoding variants via partial on-the-fly encoding and decoding.