# Quantinuum sets a new record with the highest quantum volume ever recorded

Quantinuum President and COO Tony Uttley announced three major accomplishments during his keynote address at the IEEE Quantum Week event in Colorado.

The three milestones, representing an actionable acceleration for the quantum computing ecosystem, are: (i) new arbitrary-angle gate capabilities on H-series hardware, (ii) another QV record for model hardware H1 system, and (iii) over 500,000 downloads of Quantinuum’s open source TKET, a quantum software development kit (SDK). The announcements were made during Uttley’s keynote titled “A Measured Approach to Quantum Computing”.

These advancements are the latest examples of the company’s continued demonstration of its leadership in the quantum computing community.

“Quantinuum is accelerating the impact of quantum computing on the world,” Uttley said. “We are making significant progress with our hardware and software, in addition to building a community of developers who use our TKET SDK.”

This latest quantum volume measurement of 8192 is particularly noteworthy and marks the second time this year that Quantinuum has released a new QV record on its trapped ion quantum computing platform, System Model H1, Powered by Honeywell.

A key to achieving this latest record is the new ability to directly implement arbitrary-angle two-qubit gates. For many quantum circuits, this new way of making a two-qubit gate allows for more efficient circuit construction and leads to more faithful results.

Dr. Brian Neyenhuis, Director of Business Operations at Quantinuum, said, “This new capability offers several benefits to users. In many cases, this includes shorter interactions with qubits, which reduces the error rate. This allows our customers to run long calculations with less noise.

These arbitrary-angle gates build on the overall design strength of the H1’s trapped-ion architecture, Neyenhuis said.

“With the quantum charge-coupled device (QCCD) architecture, the interactions between qubits are very simple and can be limited to a small number of qubits, which means we can precisely control the interaction and we don’t don’t have to worry about additional crosstalk,” he added. said.

This new gate design represents a third way for Quantinuum to improve H1 generation efficiency, said Dr. Jenni Strabley, Senior Director of Offer Management at Quantinuum.

“Quantinuum’s goal is to accelerate quantum computing. We know we need to improve the hardware and make the algorithms smarter, and we are doing that,” she said. “Now we can also implement the algorithms more efficiently on our H1 with this new gate design.”

Currently, researchers can make single-qubit gates — single-qubit rotations — or a fully entangled two-qubit gate. It is possible to build any quantum operation from these building blocks.

With arbitrary-angle gates, instead of just having a two-qubit gate that fully tangles, scientists can use a two-qubit gate that partially tangles.

“There are many algorithms where you want to evolve the quantum state of the system one small step at a time. Previously, if you wanted a very small tangle for a small time step, you had to tangle it completely, do it pivot a bit and then untangle it almost all the way back,” Neyenhuis said. “Now we can just add that tiny bit of tangle natively and then take the next step in the algorithm.”

There are other algorithms where this arbitrary-angle two-qubit gate is the natural cornerstone, according to Neyenhuis. An example is the quantum Fourier transform. Using arbitrary-angle two-qubit gates halves the number of two-qubit gates (and overall error), greatly improving circuit fidelity. Researchers can use this new gate design to solve more difficult problems that have resulted in catastrophic errors in previous experiments.

“By switching to an arbitrary-angle gate, in addition to halving the number of two-qubit gates, the error we get per gate is lower because it scales with the amplitude of that gate,” Neyenhuis said. .

This is a powerful new capability, especially for noisy mid-scale quantum algorithms. Another demonstration by the Quantinuum team involved using arbitrarily angled two-qubit gates to study non-equilibrium phase transitions, the technical details of which are available on the arXiv here.

“For the algorithms that we’re going to want to run in this NISQ regime that we’re in right now, that’s a more efficient way to run your algorithm,” Neyenhuis said. “There are many different circuits that you would want to run where this arbitrary angle gate gives you a pretty significant increase in the fidelity of your overall circuit. This capability also helps to speed up circuit execution by removing unnecessary gates, which ultimately reduces the time it takes to complete a job on our machines. »

Researchers working with machine learning algorithms, variational algorithms, and time-evolution algorithms would benefit most from these new gates. This advance is particularly relevant for simulating the dynamics of other quantum systems.

“It just gave us a big win in fidelity because we can run the kind of interaction you’re looking for natively, rather than building it out of other Lego blocks,” Neyenhuis said.

Quantum volume testing requires running arbitrary circuits. At each slice of the quantum volume circuit, the qubits are randomly paired and a complex two-qubit operation is performed. This SU(4) gate can be constructed more efficiently using the arbitrary-angle two-qubit gate, reducing the error at each step of the algorithm.