IBM's Nighthawk r2 trades idle time for circuit throughput
· TexaHub · Quantum, Semiconductors
IBM's revised 120-qubit Nighthawk processor adds a dissipative qubit reset that it says lifts throughput 25-fold over Heron and meets a 2026 gate-count target early.
What IBM released
On 31 August IBM made Nighthawk r2, a revision of its 120-qubit square-lattice processor, available on IBM Quantum Platform [1]. The chip carries 218 couplers and 120 reset elements, 458 physical quantum components in total [1]. Quantum Computing Report noted that it is deployed as ibm_phoenix and that IBM describes it as its fastest QPU to date [2].
IBM's headline figure is throughput: more than 100,000 circuits per second, against roughly 4,000 for its Heron fleet, a 25-fold increase [1]. The company says the processor delivers accurate results on circuits with 7,500 or more gates [1]. When IBM introduced the first Nighthawk in November 2025, it set out a path of up to 7,500 gates by the end of 2026, 10,000 in 2027 and 15,000 in 2028 [3], so on IBM's own account the 2026 step has arrived ahead of its year-end target.
How the reset works
The change is in how qubits are returned to their ground state between runs. IBM writes that activating a dedicated coupler pulls a qubit's effective T1 "from a median of about 200 microseconds down to roughly 25 nanoseconds", and that the reset leaves neighbouring qubits undisturbed while cutting idle time between circuit runs "to as little as a single microsecond" [1]. IBM contrasts this with conditional reset, which it says "is limited by the fidelity of measurement and cannot reset qubits that have leaked outside the computational state" [1].
IBM also reports about a 25-fold reduction in initialisation error, with gate fidelity comparable to Heron-class processors [1]. Early workloads include a neutron-scattering simulation with a 12-fold speed-up that produced spectra for laboratory comparison in about 60 seconds, and a rerun of doped Clifford sampling advantage experiments first developed with the University of Chicago [1] [2].
Reading the claim
Throughput is not the same as computational power. Faster resets shorten the wall-clock time of sampling-heavy work such as error mitigation and benchmarking, but they do not add qubits or by themselves lower two-qubit gate error. All of the performance figures so far come from IBM; independent users will be able to test them now that the system is on the cloud, and Quantum Computing Report says IBM has scheduled a performance webinar for 10 September [2].
The release sits within a larger IBM programme that includes a modular cryogenic architecture unveiled in August and a fault-tolerant Starling system targeted for 2029 [4]. IBM has said it expects the first cases of verified quantum advantage to be confirmed by the wider community by the end of 2026 [3]; whether Nighthawk r2's speed helps produce such confirmations is the next thing to watch.
Sources
[1] IBM Quantum Nighthawk r2—more circuits, faster — IBM Quantum Blog, 31 Aug 2026
[2] IBM Releases Nighthawk r2 QPU Featuring Active Dissipative Qubit Reset and 25x Circuit Throughput — Quantum Computing Report, 2 Sep 2026
[3] IBM Delivers New Quantum Processors, Software, and Algorithm Breakthroughs on Path to Advantage and Fault Tolerance — IBM Newsroom, 12 Nov 2025
[4] IBM's new modular architecture for cryogenic systems — IBM Quantum Blog, 19 Aug 2026