# Quantum computing modalities compared

Compare superconducting, trapped-ion, neutral-atom, photonic, spin-qubit and topological quantum computers by qubit count, fidelity, connectivity and cloud availability.

Updated 2026-11-01. Also on the [web page](https://quantumcompanies.fyi/guides/quantum-computing-modalities-compared).

Quantum computers use different physical systems to realize qubits. Each modality has distinct trade-offs in qubit count, gate fidelity, connectivity, coherence time, operating temperature and cloud availability.

## Modality comparison

| Modality | Leading vendors | Typical qubit count (2024) | 1-qubit fidelity | 2-qubit fidelity | Connectivity | Operating temp | Cloud access |
|---|---|---|---|---|---|---|---|
| Superconducting | IBM, Google, Rigetti, IQM, OQC | 100–1000+ | 99.9%+ | 99%–99.9% | Fixed, nearest-neighbor | ~15 mK | IBM Quantum, AWS Braket, Azure Quantum, Google Cloud |
| Trapped ion | IonQ, Quantinuum, AQT | 25–56 | 99.99%+ | 99.7%–99.9% | All-to-all | Room temp or ~4 K | IonQ Cloud, AWS Braket, Azure Quantum |
| Neutral atom | QuEra, Pasqal, Atom Computing | 100–1000+ (arrays) | 99.9%+ | 99%–99.5% | Reconfigurable | Room temp or ~4 K | AWS Braket, Azure Quantum, QuEra Cloud |
| Photonic | Xanadu, PsiQuantum, QuiX | 12–216 (modes) | 99%+ | N/A (measurement-based) | All-to-all (via interferometer) | Room temp | Xanadu Cloud |
| Spin qubit | Intel, Diraq, Quantum Motion | 2–12 | 99.9%+ | 99%+ | Nearest-neighbor | ~10–100 mK | Limited (research) |
| Topological | Microsoft (research) | < 10 (demonstrated) | N/A | N/A | N/A | ~15 mK | Not commercially available |
| Quantum annealing | D-Wave | 5000+ (qubits) | N/A | N/A | Sparse, fixed | ~15 mK | D-Wave Leap, AWS Braket |

## Key considerations

**Superconducting** (transmon qubits): Most mature modality. IBM's Condor (1,121 qubits) and Google's Willow (105 qubits) lead on qubit count. Fixed connectivity requires SWAP gates for non-adjacent qubits. Dilution refrigerators required.

**Trapped ion**: Highest gate fidelities and all-to-all connectivity. IonQ Forte (36 qubits) and Quantinuum H2 (56 qubits) available commercially. Slower gate speeds (~microseconds vs nanoseconds). Laser control systems complex.

**Neutral atom**: Large arrays (100s–1000s of atoms) with reconfigurable connectivity via optical tweezers. QuEra Aquila (256 qubits) and Pasqal Fresnel (100 qubits) on clouds. Mid-circuit measurement and atom loss are challenges.

**Photonic**: Room-temperature operation. Measurement-based quantum computing with continuous variables. Xanadu Borealis (216 squeezed modes) demonstrates quantum advantage. Loss and error correction are primary challenges.

**Spin qubit**: Silicon-based, CMOS-compatible fabrication. Intel Tunnel Falls (12 qubits) and academic devices show promise. Very small footprint enables dense scaling. Requires dilution refrigeration and sophisticated control electronics.

**Quantum annealing**: D-Wave Advantage2 (5000+ qubits) for optimization and sampling. Not gate-model universal. Available on D-Wave Leap and AWS Braket.

## Sources

- [IBM Quantum hardware roadmap](https://www.ibm.com/quantum/roadmap) — fetched 2026-11-01.
- [IonQ Forte specifications](https://ionq.com/forte) — fetched 2026-11-01.
- [Quantinuum H2 specifications](https://www.quantinuum.com/hardware) — fetched 2026-11-01.
- [QuEra Aquila specifications](https://www.quera.com/aquila) — fetched 2026-11-01.
- [Pasqal Fresnel specifications](https://www.pasqal.com/technology) — fetched 2026-11-01.
- [Xanadu Borealis demonstration](https://www.nature.com/articles/s41586-022-04725-x) — Nature, 2022.
- [D-Wave Advantage2 specifications](https://www.dwavesys.com/advantage2) — fetched 2026-11-01.
- [AWS Braket quantum computers](https://aws.amazon.com/braket/quantum-computers/) — fetched 2026-11-01.
- [Azure Quantum providers](https://learn.microsoft.com/en-us/azure/quantum/provider-overview) — fetched 2026-11-01.

## Questions

### Which modality is best?

No single modality leads on all metrics. Superconducting has the highest qubit counts. Trapped-ion has the highest gate fidelities. Neutral-atom scales to large arrays. Photonic operates at room temperature. Choose based on your workload requirements.

### Are qubit counts comparable across modalities?

No. A 100-qubit superconducting processor and a 36-qubit trapped-ion processor may solve different problem sizes. Compare gate fidelity, connectivity, coherence time and error rates, not just qubit count.

### Which modalities are available on public clouds?

IBM, Google and Rigetti offer superconducting on their clouds. IonQ and Quantinuum offer trapped-ion on AWS Braket, Azure Quantum and their own clouds. QuEra and Pasqal offer neutral-atom on AWS Braket and Azure Quantum. Xanadu offers photonic on its cloud.