Quantum scientists shrink hardware demands with breakthrough error correcting gate
by Simon Mansfield
Sydney, Australia (SPX) Aug 20, 2025

Quantum scientists at the University of Sydney Nano Institute have created a new type of quantum logic gate that drastically reduces the number of physical qubits required for computation, marking a milestone in the push toward scalable quantum computing.

The team employed Gottesman-Kitaev-Preskill (GKP) codes, often called the "Rosetta stone" of quantum computing, to encode logical qubits using the natural oscillations of a trapped ytterbium ion. These codes transform continuous quantum oscillations into digital-like states, making errors easier to detect and correct while allowing compact encoding of logical qubits.

Although long considered a theoretical solution, GKP codes have proven difficult to implement due to their complexity. In a study published in Nature Physics, the Sydney team successfully entangled GKP qubits within a single trapped ion, demonstrating for the first time universal logical gate operations between them.

Dr Tingrei Tan, Sydney Horizon Fellow and lead researcher, explained: "Our experiments have shown the first realisation of a universal logical gate set for GKP qubits. We did this by precisely controlling the natural vibrations of a trapped ion so we can manipulate individual GKP qubits or entangle them as a pair."

By entangling two quantum states within the same atom, PhD student and first author Vassili Matsos demonstrated a quantum logic gate using only a single ion. The experiments employed quantum control software from Sydney spin-off Q-CTRL, designed to minimise distortion and maintain the fragile structure of GKP codes during computation.

"This represents a key milestone," Dr Tan said. "GKP error correction codes have long promised to reduce the heavy hardware demands that limit scaling. Our experiments show high-quality quantum controls can efficiently manipulate more than one logical qubit, forming the basis for large-scale quantum information processing."

The work involved three experiments with a single ytterbium ion held in a Paul trap at room temperature. Lasers precisely controlled the ion's vibrations, enabling the encoding of GKP qubits and their entanglement into a functional logic gate.

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