Schr\"odinger cat states of a nuclear spin qudit in silicon

TL;DR

This paper demonstrates the creation and manipulation of Schr"odinger cat states in a high-spin nuclear spin qudit within silicon, advancing quantum information processing and error correction capabilities.

Contribution

It introduces a method to generate and control Schr"odinger cat states in a nuclear spin qudit in silicon, enabling scalable quantum information applications.

Findings

Successfully created Schr"odinger cat states in a nuclear spin qudit.

Implemented logical Pauli operations preserving qudit symmetry.

Showed potential for quantum error correction in silicon-based platforms.

Abstract

High-dimensional quantum systems are a valuable resource for quantum information processing. They can be used to encode error-correctable logical qubits, which has been demonstrated using continuous-variable states in microwave cavities or the motional modes of trapped ions. For example, high-dimensional systems can be used to realise `Schr\"{o}dinger cat' states, superpositions of widely displaced coherent states that can also be used to illustrate quantum effects at large scales. Recent proposals have suggested encoding qubits in high-spin atomic nuclei, finite-dimensional systems that can host hardware-efficient versions of continuous-variable codes. Here we demonstrate the creation and manipulation of Schrodinger cat states using the spin-7/2 nucleus of an antimony atom embedded in a silicon nanoelectronic device. We use a multi-frequency control scheme to produce spin rotations that preserve the symmetry of the qudit, and constitute logical Pauli operations for qubits encoded in the Schrodinger cat states. Our work demonstrates the ability to prepare and control nonclassical resource states, a prerequisite for applications in quantum information processing and quantum error correction using our scalable, manufacturable semiconductor platform.