A programmable superconducting quantum processor with three all-to-all coupled qubits*

Quantum information processing (QIP) exploits the laws of quantum mechanics to enhance computational capabilities beyond the limits of classical algorithms. Among various platforms for realizing QIP, superconducting qubits are at the forefront as they offer an unparalleled combination of good coherence, fast gates, and design flexibility. A majority of recent experimental demonstrations in the superconducting architecture have utilized transmon-like qubits and transverse inter-qubit coupling for implementing small quantum algorithms. Nevertheless, efficient universal quantum computing has remained a challenge due to the limited connectivity and access to only two-qubit entangling gates. This results in reduced performance due to inefficient implementation of quantum algorithms. In this talk, I will introduce “trimon” [1], a three-qubit device based on a multi-mode superconducting circuit providing strong inter-qubit coupling and access to three-qubit native gates. I will discuss the basic working principles of the device, implementation of generalized controlled-controlled-NOT gates and universal programmability of the processor [2]. Next, I will demonstrate the high-fidelity preparation of various two- and three-qubit entangled states and implementation of a few quantum algorithms [3] like Deutsch-Jozsa, Grover's search and the quantum Fourier transform. Finally, I will talk about the possibility of scaling to larger systems using the trimon as a building block to achieve improved qubit-qubit connectivity in medium-scale quantum processors.

References:
[1]: Tanay Roy et al., Phys. Rev. Applied 7, 054025 (2017)
[2]: Tanay Roy et al., Phys. Rev. A 98, 052318 (2018)
[3]: Tanay Roy et al., arXiv:1809.00668 (2018)