Oxford Ionics sets new world record, slashes quantum errors by 1,300%

Researchers from Oxford Ionics, a quantum computing company backed by the University of Oxford’s physics department, have developed and tested a new protocol for finding and rejecting faulty qubits.

They claim their protocol has set a new world record for quantum state preparation and measurement (SPAM). It shows a 13-fold decrease in SPAM errors compared to the current best method, making it the best-performing and most reliable quantum platform in the industry.

The researchers believe their new SPAM protocol would play a major role in improving existing quantum systems and in the development of next-generation quantum computers.

The significance of high SPAM fidelity

SPAM is the process in quantum computing that prepares qubits in specific quantum states and measures those states after quantum operations.

It is critical in ensuring the accuracy and reliability of quantum computation because the quality of results delivered by a quantum system directly depends on how well the qubits are prepared.

If qubits are incorrectly prepared, it leads to errors and makes it difficult to read or measure qubit states at the end of a computation.

So, basically, to build a functional quantum computer, it is essential to achieve high SPAM fidelity, i.e., high accuracy in qubit preparation and measurement.

“Low errors in SPAM, along with two-qubit and single-qubit gates, are therefore among the three most important metrics when evaluating the precision and accuracy of a quantum computer,” the study authors note .

Testing the new protocol

Oxford Ionics focuses on trapped-ion technology. This approach involved trapping ions using electric or magnetic fields.

In the next step, the state of these ions is changed using lasers to process quantum information. Finally, the state of the ions is measured to obtain the results of the quantum computation .

The new SPAM protocol is a combination of standard SPAM methods and a series of mid-circuit non-demolition (QND) measurements. The latter allows scientists to monitor qubits and detect issues without interrupting ongoing calculations.

To test the new SPAM protocol, they employed it for three different qubit encodings in a single trapped ₁₃₇ Ba+ ion.

“For all three, we achieve the lowest reported SPAM infidelities of 7(4)×10 ⁻⁶ (optical qubit), 5(4)×10 ⁻⁶ (metastable-level qubit), and 8(4)×10 ⁻⁶ (ground-level qubit),” the study authors said .

The protocol achieved the highest SPAM fidelity of 99.9993% (a world record). These results prove that it’s great at identifying and eliminating erroneous qubits and can be used for any quantum system.

“The world records set by Oxford Ionics, in tandem with this unique approach, bring it one step closer to delivering quantum computers capable of delivering widespread commercial impact,” the study authors added.

The study is published in arXiv .