There is no single "quantum computer." Seven different physical systems each hold a qubit in a different way, and each one trades gate speed, coherence time, operating temperature, and engineering difficulty against the others. This guide lays out the seven, which companies run each, and where each one stands in 2026.
The seven modalities at a glance
| Modality | Qubit is | Gate speed | Coherence | Runs at | Leading builders |
|---|---|---|---|---|---|
| Superconducting | a microwave circuit | 10 to 100 ns | around 100 µs | 10 mK | IBM, Google, Rigetti |
| Trapped ion | a single charged atom | 1 to 100 µs | seconds to minutes | room temperature | IonQ, Quantinuum |
| Neutral atom | a single atom in tweezers | around 1 µs | seconds | room temperature | QuEra, Pasqal, Atom Computing |
| Photonic | a single photon | nanoseconds | loss-limited | room temperature | PsiQuantum, Xanadu |
| Spin qubit | an electron spin in silicon | nanoseconds | up to seconds | around 1 K | Intel, Diraq, HRL |
| Topological | a braided quasiparticle | unproven | theoretical | mK | Microsoft |
| Annealing | an analog flux qubit | analog sweep | nanoseconds | 10 mK | D-Wave |
Superconducting: the incumbent
A superconducting qubit is a printed circuit that oscillates at microwave frequency, around 5 GHz. At 10 millikelvin the circuit behaves as a single quantum object with two energy levels. Gates are microwave pulses and run in tens of nanoseconds, the fastest of any commercial qubit. The tradeoff is short memory: T1 and T2 times sit near 100 microseconds. IBM, Google, and Rigetti all run this modality, and it holds the largest share of commercial QPUs today. Read the deep dive in Superconducting Qubits Explained.
Trapped ion: slow but precise
A trapped ion qubit is a single charged atom held in an electromagnetic trap and controlled with lasers. Gates run a thousand times slower than superconducting, in microseconds, but the qubit keeps its state for seconds to minutes, and any ion in the trap connects to any other. IonQ and Quantinuum lead here. Quantinuum's Helios reached 48 logical qubits, the highest reported fault-tolerant count to date.
Neutral atom: the scaling story
A neutral atom qubit is a single uncharged atom pinned by laser tweezers. Arrays scale to thousands of atoms, the largest physical-qubit counts in the field. Atoms hold their state for seconds and need no dilution refrigerator. QuEra, Pasqal, and Atom Computing lead. See Neutral Atom and Photonic Qubits Explained.
Photonic: no fridge required
A photonic qubit encodes information in a single photon traveling a waveguide. Photons keep their quantum state at room temperature and move naturally between chips, which makes this modality attractive for networking. The hard part is photon loss and building deterministic gates. PsiQuantum and Xanadu lead.
Silicon spin: the semiconductor play
A spin qubit stores information in the spin of a single electron trapped in silicon, the same material as a classical transistor. Gates run in nanoseconds and coherence reaches seconds in isotopically purified silicon. The bet: borrow CMOS fabrication to scale. Intel, Diraq, and HRL lead, though qubit counts remain small.
Topological: the long shot
A topological qubit would store information in the braiding of quasiparticles called Majorana zero modes, a state distributed across the material rather than sitting in one place. The promised reward is protection against noise built into the hardware itself. The problem: nobody has conclusively demonstrated the necessary physics. Microsoft is the main commercial bet. See Topological Qubits Explained.
Annealing: a different machine
A quantum annealer does not run circuits. It holds thousands of flux qubits and slowly cools a system to find low-energy states, a process aimed at optimization problems. D-Wave builds the only commercial annealers, with over 5,000 qubits. It is not a universal gate machine, which limits which problems it reaches. See Quantum Annealing vs Gate-Based Quantum Computing.
No modality has won
As of 2026 no single modality dominates. Superconducting leads in commercial deployment, neutral atoms lead in qubit count, trapped ions lead in fidelity, and topological remains unproven. The market runs several architectures in parallel, which means the useful comparison is per problem, not per vendor. For a ranked list of the companies, see Top Quantum Computing Companies in 2026.
Next steps
- What's inside a quantum computer: the fridge, the chip, and the wiring
- How much does a quantum computer cost: rent versus buy
- Getting started with free quantum computing: run a circuit today without paying