IonQ Forte (and Forte Enterprise)

Overview

IonQ Forte is the trapped-ion computer that put IonQ in the spotlight as a commercial vendor. Each qubit is a single ytterbium ion held in an electromagnetic trap, and lasers drive the operations. Because every ion is identical and any ion can interact with any other, Forte can run circuits without the swap operations that other architectures need.

The company sells Forte in two forms: access over the cloud, and Forte Enterprise, a rack-mountable system designed for installation in data centers. Both have 36 qubits and the same published fidelities.

History and background

IonQ was founded in 2015 by Christopher Monroe and Jungsang Kim, who had built trapped-ion systems in university labs. The company's earlier machines, Harmony (11 qubits) and Aria (25 qubits), were the first of its systems to reach commercial cloud platforms. Forte was introduced next, with algorithmic qubit scores that rose from the high 20s to 35 and then #AQ 36, which IonQ announced in December 2024.

Forte uses acousto-optic deflectors to steer laser beams to individual ions, a change from the multichannel acousto-optic modulator design of earlier systems. Forte Enterprise, announced for production use, packages the technology in a rack-mountable form. The next generation, Tempo, targets 100 qubits and began reaching benchmarks in 2025.

How it works

A trapped-ion qubit is a single atom stripped of an electron so that it carries charge. Electric fields hold a line of such ions in a vacuum chamber, where they are cooled with lasers to near rest. Two of the ion's long-lived internal energy levels, called hyperfine states, serve as the 0 and 1 of the qubit. Because these states are insensitive to many kinds of noise, the qubit can stay coherent for seconds.

Single-qubit operations are done with precisely tuned laser or microwave pulses. Two-qubit gates use the fact that the ions repel one another and share collective vibrational motion in the trap. A laser pulse can couple an ion's internal state to this shared motion, entangling it with another ion. Since the motion is shared along the whole chain, any pair of ions can be entangled directly, which is why Forte has all-to-all connectivity.

Readout is done by shining a laser on the ions and collecting fluorescence: an ion in one state scatters light and appears bright, while one in the other state stays dark. IonQ's published fidelities, about 99.98% for single-qubit gates and about 99.6% for two-qubit gates, reflect how well all of these steps work together across the chain.

Connectivity

All-to-all: any qubit can interact directly with any other qubit in the chain

Specifications in detail

Key features

• 36 qubits with all-to-all connectivity
• Single-qubit fidelity about 99.98% and two-qubit fidelity about 99.6% (IonQ figures)
• #AQ 36, reached in December 2024
• Forte Enterprise, a rack-mountable version for on-premises and data-center use
• Available through the three major cloud platforms

Limitations

• Gate operations take microseconds, far slower than the nanosecond gates of superconducting chips
• 36 qubits is small next to other platforms
• Two-qubit fidelity of 99.6% is lower than the best results reported by Quantinuum or by IonQ's own newer prototypes
• Scaling a single ion chain much beyond about 100 ions is difficult

Timeline

What it is used for

• Benchmarking quantum algorithms where all-to-all connectivity helps, such as optimization and chemistry kernels
• Research collaborations with enterprises and governments
• Quantum machine learning and finance experiments through cloud platforms
• Teaching and software development on trapped-ion hardware

How it compares

• Compared with IBM Heron, Forte has far fewer qubits and much slower gates, but better connectivity and longer coherence.
• Compared with Quantinuum H2 (56 qubits, 99.9% two-qubit fidelity), Forte has fewer qubits and lower reported two-qubit fidelity, though both are trapped-ion machines with full connectivity.
• Compared with IonQ Tempo, Forte is the earlier generation; Tempo targets about three times as many qubits.

Technical notes

IonQ's #AQ (algorithmic qubits) metric runs a suite of application-style circuits and reports the largest number of qubits for which the machine gives reliable answers. It was designed to capture both qubit count and quality in a single number. Forte's #AQ 36 means its performance on those benchmarks matches an ideal 36-qubit device within the test's tolerance. The metric is IonQ's own, so comparisons with other vendors should be made carefully.

Why it matters

Forte is a good example of the quality-first philosophy: a modest number of high-fidelity, fully connected qubits can run algorithms that a larger but noisier chip cannot. It also made trapped-ion computing commercially available on all three major cloud platforms.

It is useful for comparison, too. Reading its specification next to Heron's or Willow's shows the tradeoff between speed (superconducting) and fidelity and connectivity (ions) very clearly.

Frequently asked questions

Keep exploring

• Company profile: IonQ
• Related processor: IonQ Tempo
• Related processor: Quantinuum H2
• Related processor: IBM Heron (r1, r2, and r3)

This profile is written for educational purposes and summarizes company announcements, published papers, and vendor specification sheets. Last reviewed: September 30, 2026. Figures marked as company-reported have not all been independently verified, and benchmarks differ between vendors, so compare them with care.

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