IonQ Forte: Our Highest Performing, Commercially Available Quantum Computer

Today, we are excited to announce that IonQ Forte is commercially available worldwide. 

At IonQ, we gauge performance based on a computer’s ability to return useful, measurable results for practical algorithms: a system’s #AQ. This single-number metric is derived from algorithmic benchmarking protocols recently established in an independent industry-wide study conducted by the Quantum Economic Development Consortium (QED-C). By this measure, Forte is now our highest-performing, commercially available quantum computer. We got here thanks to a consistent and long-term focus on our qubit and operation fidelities. We have long known that qubit count doesn’t matter if the errors in gate operations limit the number of qubits that can be successfully used. This is why we have always focused on advancing the two in tandem. This approach has led to yet another generation of systems from IonQ, Forte, that pushes our accuracy and scale to new heights, resulting in new possibilities for our customers and partners. 

Forte offers a number of improvements over our previously commercially-available systems and integrates highly specialized acousto-optic deflectors (AODs) to direct laser beams at individual qubits in the ion chain to apply logic gates. This means that compared to our previous systems, Forte decouples the qubit arrangement in space from a fixed optical addressing system, leading to higher performance, the support of more qubits, and more software-driven flexibility.

This approach provides unprecedented precision and stability to the laser beams contributing to both higher fidelity and reliability by minimizing noise and unintended residual light on neighboring qubits.

Forte Delivers Exciting New Possibilities to Customers

As a result of these improvements, Forte’s computing power increased to #AQ 29, at which point we opened access to select existing partners so they could explore new use cases in cooperation with our Applications team. The early results have been extremely promising. Work has already been done on a number of interesting applications, resulting in a number of ‘firsts’ that would not have been possible on previously commercially available systems.

For example, we co-developed an algorithm with one partner which was used to solve optimization problems. Forte has also begun running computer vision projects that were impossible to run on either Aria or Harmony, as well as boolean satisfiability problems that lay the groundwork for potential near-term algorithms capable of demonstrating quantum advantage.

Higher Performance Opens Up New Possibilities

For many quantum computers, the accuracy of calculations–known colloquially as ‘fidelity’–is a bottleneck because it limits the size of the circuit that can be accurately executed. Forte’s higher #AQ means customers can now run circuits that use up to 29 qubits and roughly 840 gates.

A good way to conceptualize fidelity is that the observable results from a quantum computer calculation will always deviate from a quantum algorithm’s ideal end-histogram (the latter of which will produce a clear signal, usually in the form of a single amplitude (peak) in the wave function). If the errors in calculation become too numerous (i.e.: no longer faithful to the ideal) no obvious peak emerges in the observable results, and by extension, no answer. 

Because errors compound with each logic gate the quantum computer applies, the chance a calculation will result in a histogram with no clear peak increases commensurately with the length of the algorithm. Another way to think of this is that the higher the fidelity, the longer the program a quantum computer can run and generate a histogram close enough to the algorithm's ideal to produce a useful answer. This is why high fidelity is so important to running the longer algorithms required to solve complex problems.

Forte increases fidelity via new AODs that allow customers to use software to configure the laser beams that are directed at individual qubits in the ion chain to apply logic gates. This software-controlled method (as opposed to having the lasers set at a fixed distance, as was the case with the multi-channel AOMs used in our previous system) increases the precision of the laser pulses, which is a critical part of accurate calculations.

An illustrated comparison of the AOD architecture in Forte

In addition to the AODs, our error mitigation techniques further push the boundaries of accuracy, allowing customers to solve larger problem sizes than any other system. And to enhance the performance of quantum computers with high-quality qubits, we have also introduced a strategy based on symmetrization and nonlinear aggregation that improves the performance of multiple practical algorithms by 100x with no qubit or gate overhead.

Our Most Powerful Commercially Available Quantum Computer

Customers have been conditioned to write circuits that use many fewer qubits than what the quantum computer offers them, mostly due to the inability of many larger quantum computers to successfully execute circuits that use all available qubits.

However, by combining an #AQ of 29 and 32 qubits with the increases in fidelity outlined above, Forte raises the bar for what is possible. In short, Forte can accurately run the widest circuits of any commercially available quantum computer. This means Forte allows our customers to generate more possible answers from their quantum circuit–setting the standard for the accuracy and nuance of quantum calculations.

Each additional qubit doubles the power of a quantum computer. At #AQ 25, we were able to offer customers 33.5 million usable computational states–meaning the possible answers that can be sampled at the end of a quantum circuit. Forte, with #AQ 29, has increased the usable computational states we are making available to customers all the way up to 536,870,912.

Another way to say this is that the wave functions produced by Forte can express as many as 536m+ terms, all of which could be sampled as an answer. This is why we are encouraging our customers to think bigger than ever before about what is possible with a quantum computer; Forte’s large increase in the volume of possible terms presents new and exciting possibilities to perform computations for complex use cases like chemistry or machine learning.

So far, we have run the full suite of benchmark algorithms that comprise #AQ and confirmed that indeed Forte is outperforming any of IonQ’s previous quantum systems with the same number of tested qubits.

We are still at the very beginning of Forte’s story. But by making Forte’s combination of power and accuracy accessible to all commercial customers for the first time, we are raising the bar for what is possible with quantum computing.

We are hopeful that this expanded access can lead to many new applications that are not possible on any other commercially available quantum computer.

To learn more about the technical aspects of Forte, visit our resource page, or get started right now by signing up for direct access to our systems.