Superconducting qubit circuit emulation of a vector spin-1/2

TL;DR

This paper introduces a superconducting qubit circuit capable of emulating a quantum vector spin-1/2 with three controllable components, enabling advanced quantum simulations and processing techniques.

Contribution

It presents a novel superconducting circuit design that fully emulates a vector spin-1/2, including independent control of all three spin components.

Findings

Enables hardware emulation of arbitrary quantum spin-1/2 systems.

Allows for the simulation of the Heisenberg model.

Facilitates exploration of quantum error suppression and Hamiltonian quantum computing.

Abstract

We propose a superconducting qubit circuit that can fully emulate a quantum vector spin-1/2, with an effective dipole moment having three independent components whose operators obey the commutation relations of a vector angular momentum in the computational subspace. Each component couples to an independently-controllable external bias, emulating the Zeeman effect due to a fictitious, vector magnetic field, and all three of these vector components remain relatively constant over a broad range of emulated total fields around zero. This capability, combined with established techniques for qubit coupling, should enable for the first time the direct hardware emulation of nearly arbitrary quantum spin-1/2 systems, including the canonical Heisenberg model. Furthermore, it would constitute a crucial step both towards realizing the full potential of quantum annealing, as well as exploring important quantum information processing capabilities that have so far been inaccessible to available hardware, such as quantum error suppression, Hamiltonian and holonomic quantum computing, and adiabatic quantum chemistry.