With billions of qubits integrated in one chip, our quantum computer fits in a single refrigerator. Without our technology, quantum processors need to be fragmented in thousands of separate cryostats.
Besides the obvious costs, filling a warehouse with refrigerators consumes megawatts of energy. Moreover, the traffic of quantum information between chips requires technology that hasn't been invented yet.
Individual electrons are trapped in devices made using the most advanced semiconductor fabrication technology. Radio-frequency pulses control the movement of the electron and its spin state. An electron spin pointing up or down represents a qubit in the 0 or 1 state.
Smallest qubits (50 nm), so can fit a full useful quantum processor on a single chip; Qubits can be moved around; Can tolerate heating effects; Errors are easier to correct (biased errors).
Small size requires state-of-the-art manufacturing partners; Tolerance to materials defects is low; requirement for advanced fabrication reflects in late onset for qubit count.
Certain metals when cooled down can conduct electric currents without resistance. These currents can be manipulated with microwave pulses and local magnetic fields using relatively large devices. The states 0 and 1 can be stored in different properties of these superconducting currents.
Large qubit size (millimetres), so easy to fabricate systems with moderate qubit counts; Current leading technology for numbers of qubits.
Large size limits the number of qubits in a chip, requiring wiring thousands of chips together; Temperature requirements are strict; Errors are frequent and hard to correct (unbiased).
Atoms, which naturally present quantum behaviour, are stripped of an electron (ionised) and dynamically trapped by oscillatory electric fields. Focused lasers and microwaves create long-lived superpositions of internal atomic states that represent 0 and 1.
Naturally lower error rates, with bias (easier to correct); First qubit technology (head start in R&D); all-to-all connectivity demonstrated in groups of tens of qubits.
Hard to individually access each qubit (only done in linear arrays); Hard to trap many ions; Operations are relatively slow.
Quanta of light are created in photon factories and run through tracks made using photonic waveguides, with calculations performed by measuring photons in a particular order.
All-to-all connectivity; Photonic waveguides are relatively large and easy to fabricate.
Tolerance to detector imperfections is low; Number of qubits in a single chip is very limited; Uses non-standard computation method (one-way quantum computing).