Trapped-ion qubits
Individual atoms held by electric fields and steered with lasers. Highest fidelity.
Trapped-ion computers use single charged atoms suspended in vacuum by electromagnetic fields as qubits, manipulated with lasers. Because every qubit is an identical atom, they achieve the highest gate fidelities and longest coherence times, with all-to-all connectivity — at the cost of slower gates.
In plain terms
Picture a row of marbles floating perfectly still in mid-air, each spinning. A laser is a finger that can nudge any marble — or make two spin in lockstep. The marbles are flawless copies of each other, so they behave identically every time.
How it works
Ions (often ytterbium or calcium) are held in a vacuum by a trap made of tiny electrodes. Their internal energy levels store the qubit; lasers (or microwaves) drive gates.
Two-qubit gates work by nudging the ions' shared motion, so any ion can interact with any other — full connectivity, which many other modalities lack.
Gates are slower (microseconds) and scaling one long chain gets harder, so leaders are moving to modular architectures that shuttle ions between zones or link multiple traps.
The problem it solves
When you need the cleanest possible qubits — for early fault tolerance or algorithms sensitive to error — trapped ions lead on quality. They target high-value chemistry and error-correction milestones.
- +Best-in-class gate fidelity and long coherence.
- +All-to-all connectivity — any qubit can talk to any other.
- +Identical atoms mean no manufacturing variation.
- –Slower gates than superconducting.
- –Scaling a single trap is hard; needs modular/shuttling approaches.
- –Complex laser and vacuum systems.
Companies building this
Holds record quantum-volume and fidelity marks; pairs leading hardware with the TKET software stack.
Trapped-ion systems on every major cloud, lowering the barrier for enterprises to experiment.
Uses electronic (not just laser) control on a chip to make ion traps more manufacturable.