From Yahoo Finance · · 2m
IonQ vs. Rigetti: The quantum computing showdown
Two pure-play quantum stocks are racing to build useful computers using completely different technological approaches.
In brief
Two pure-play quantum stocks are racing to build useful computers using completely different technological approaches. IonQ has the technology edge today with better accuracy and connectivity, but Rigetti's speed advantage could close the gap if it solves its scaling challenges. Originally reported by Yahoo Finance.
Two quantum paths diverge
IonQ uses trapped-ion technology with charged atoms held by electromagnetic fields. Rigetti uses superconducting qubits cooled to extremely low temperatures. Same goal, completely different routes.
Accuracy numbers need context
IonQ claims 99.99% fidelity on 2-qubit gates, while Rigetti reports 99.1% on its 108-qubit Cepheus system. But IonQ's figure came from testing a single operation, not a full commercial system.
The real accuracy gap is smaller
IonQ's comparable Forte systems show 99.3% to 99.5% fidelity versus Rigetti's 99.1%. That's roughly 1.8 times higher error rate for Rigetti, but much closer than the headline numbers suggest.
IonQ's connectivity advantage
IonQ's trapped-ion systems offer all-to-all connectivity, meaning any qubit can directly interact with any other. Rigetti's limited connectivity requires extra SWAP operations that introduce more errors.
Speed versus accuracy tradeoff
IonQ's Forte systems take about 950 microseconds for a 2-qubit gate. Rigetti's Cepheus performs the same operation in about 60 nanoseconds. IonQ trades speed for accuracy and connectivity.
IonQ's scaling test begins
IonQ's next-generation Superion 256 platform with 256 qubits is being manufactured but not yet delivered to customers. Commercial deliveries are expected to begin in 2027. This is the real test of trapped-ion technology at scale.
IonQ demonstrates error correction
IonQ used 18 physical qubits to encode 4 logical qubits and achieved breakeven performance, where logical qubits preserved information as long as individual physical qubits. This shows progress beyond simulations.
Rigetti's chiplet strategy
Rigetti's 108-qubit Cepheus combines 12 interconnected 9-qubit chiplets. This modular approach could help scale to 1,000 qubits while avoiding manufacturing complexity of building massive single chips.
Rigetti's accuracy drops at scale
Rigetti achieved 99.8% fidelity on 9 qubits, 99.6% on 36 qubits, but only 99.1% on 108 qubits. Maintaining accuracy while scaling remains its biggest challenge.
Rigetti's three-year roadmap
Management aims to build a 1,000-qubit system with 99.9% fidelity and sub-50-nanosecond gate operations within three years. Success would significantly narrow the gap with IonQ.
IonQ leads today, but vulnerable
IonQ has the technology edge now with superior accuracy and error correction demonstrations. But its Superion 256 is still in prototype stage. Rigetti could catch up if it improves accuracy while keeping its speed advantage.
The main idea
IonQ has the technology edge today with better accuracy and connectivity, but Rigetti's speed advantage could close the gap if it solves its scaling challenges.
