The previous roadmap called for each generation to increase this number, with the 2027 version expected to reach 10,000 gate operations while maintaining the number of 120 hardware qubits. But rather than increasing the number of qubits in the processor, it would increase the number of qubits by chaining multiple chips together. This is something it will eventually need to do to also offer a useful number of error-corrected qubits. In fact, the company’s most recent roadmap called for linking three Nighthawk processors together in 2026 to create a 360-qubit machine.
It doesn’t look like that’s going to happen this year. Instead, this year’s Nighthawk r2, released in September, is offered as a single chip. But IBM says it offers a huge performance improvement over the R1.
The main reason for this increase is that IBM has devoted a lot of hardware to resetting qubits to the ground state. This includes physical qubits that are not used for computing: the company says there are 458 physical qubits, but only 120 are programmable.
“This is an additional physical qubit that we include on the chip for each programmable qubit, which allows us to quickly remove energy from one of our programmable qubits, returning it to the ground state,” said Oliver Dial, vice president of Quantum Systems. “This capability allows our users to run circuits on this chip faster than ever before.”
This isn’t necessary for every operation, but it apparently speeds things up considerably: IBM reports up to 19 times speedup for some operations.
(The devices in question here are physically identical to programmable qubits but cannot be used as qubits, so the terminology is a bit strange; in some cases IBM calls them “dissipative reset gadgets.”)
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The plan for Nighthawk r3 in 2027 is apparently to keep this performance-enhancing technology and combine it with other hardware improvements to further increase the number of operations that can be performed without errors becoming too likely. This will also significantly increase the number of qubits, with a goal of 520 programmable qubits. Assuming the ratio of programmable qubits to reset devices remains the same as in r2, this suggests the company will make a chip with around 2,000 individual qubit-like devices. This is about double the size of the largest quantum processor the company has offered to date.
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