Quantum Hardware Database
IBM Heron (r1)
Released alongside Condor, IBM Heron represents IBM's highest-performance processor at the time — prioritizing gate fidelity over raw qubit count. Heron introduced tunable couplers between qubits, significantly reducing crosstalk (unwanted interactions between neighboring qubits) compared to previous IBM designs.
Qubit Count
133
Qubit Type
Superconducting (fixed-frequency transmon qubits)
Architecture
Heavy-hex lattice with tunable couplers
Released
2023
Gate Error (2Q)
~0.04–0.1% per two-qubit gate — IBM's best gate fidelity at release
Coherence Time
T₁ ~300 µs, T₂ ~150 µs
Operating Temp
~15 millikelvin
Cloud Access
Yes — IBM Quantum (cloud.ibm.com)
Company
IBM
Connectivity
Heavy-hex with tunable couplers between adjacent qubits
Key Features
- Tunable couplers — allows qubits to be selectively coupled or decoupled, dramatically reducing crosstalk
- Best two-qubit gate error rates in IBM's lineup at release (~3–5× better than previous generation)
- Designed as the building block for IBM's modular, multi-chip architecture
- Supports quantum error correction experiments at small scale
Limitations
- Only 133 qubits — much smaller than Condor
- Tunable couplers add control complexity
Technical Notes
Heron's tunable couplers are one of its most important innovations. Previous IBM processors used fixed couplings between qubits, meaning unwanted interactions were always present. Tunable couplers allow the interaction strength to be turned on and off, reducing errors significantly during idle periods.