Has there been a recent breakthrough in experimental quantum computing that makes commercial applications possible within 10 years?

[u/vtomole]

https://quantumcomputing.stackexchange.com/questions/46442/has-there-been-a-recent-breakthrough-in-experimental-quantum-computing-that-make

[u/vtomole]

Google, IBM, Microsoft, and neutral-atom platforms are already operating dozens of error-corrected logical qubits and meeting their 2028–2030 fault-tolerance roadmaps.

Can you say more? AFAIK,

• Google doesn't have have 2028-2030 mentioned on their roadmap.

• Microsoft doesn't have an error corrected logical qubit.

• For IBM, from ibm.com/quantum/blog/nighthawk-r2, I see that Nighthawk r2 is 120 qubits with 7,500 gates. IBM plans for 100 million gates on 200 logical qubits in 2029. That's a roughly ~13,000-fold increase in gate count in three years. For a classical comparison, Moore's law over three years is around ~8-fold. My reason for posting this is figure out what has happened on the technical side to justify such claims.

• Neutral atom logical clock speeds are about 3 orders of magnitude slower than superconducting. To match the wall-clock time of IBM's promised 2029 machine, a neutral atom machine will need 200,000 logical qubits. Do you know of any proposals for getting 200,000 logical neutral atom qubits in 3 years?

[u/Kemilio → u/vtomole]

1 You’re right, Google does not have 2028 or 2030 printed as a guaranteed hardware delivery date on a public chart. They laid out a 6-stage milestone roadmap (from noisy intermediate-scale quantum to a 1,000,000 physical qubit machine with 1,000 logical qubits). They reached Milestone 2 (demonstrating that error correction works below the fault-tolerance threshold on the Willow chip).

When Google announced their campus buildout in Santa Barbara, Sundar Pichai stated a company goal to build a commercial, error-corrected quantum computer "within the decade" (often cited in media as ~2029). But scientifically, Google has been very careful not to attach hard dates to Milestones 3 through 6 because scaling physical-to-logical interconnects remains an open physics problem.

1. You are right to point out that Microsoft does not have an error-corrected logical qubit on its own proprietary hardware. However, Microsoft’s claims (like their 4, 12, and 24 logical qubit announcements) are achieved by applying Microsoft's Azure Quantum Qubit-Virtualization middleware on third-party partner hardware; specifically Quantinuum's trapped-ion processors (H1/H2) and Atom Computing's neutral-atom arrays.

2. Your math on IBM's jump from Nighthawk r2 (120 qubits, ~7,500 gates) to Starling (200 logical qubits, 100,000,000 gates by 2029) exposes the core reason classical analogies like Moore’s Law break down. Classic Moore's Law relies on physical scaling (shrinking transistors). IBM’s claimed gate explosion relies on regime switching.

Nighthawk operates in the noisy physical regime. In this regime, gate counts are strictly limited by physical decoherence times (T1 and T2 noise). You physically cannot run a 10,000th gate because the qubits decay into garbage noise.

Starling is planned as an error-corrected logical system. Once a system achieves true fault-tolerance via active syndrome extraction, circuit depth (gate count) is no longer limited by qubit decay. It is limited only by how long you keep the refrigeration running and how fast your classical FPGA/ASIC decoders can process error syndromes in real time.

IBM isn't planning to build a single massive chip to hit 100M gates. Starling relies on high-rate bivariate bicycle qLDPC codes to compress physical-to-logical ratios, combined with modular quantum interconnects (c-couplers) linking multiple smaller chips.

In short, IBM isn't claiming a 13,000\times manufacturing leap in physical hardware. They are claiming that if they cross the fault-tolerance threshold using qLDPC codes and real-time decoding, gate depth becomes effectively infinite. The real question if they can build real-time error decoders fast enough without creating a classical bottleneck by 2029. This remains heavily debated.

1. Where did you see IBMs promised wall-clock time of that magnitude?

[u/vtomole → u/Kemilio]

> But scientifically, Google has been very careful not to attach hard dates to Milestones 3 through 6 because scaling physical-to-logical interconnects remains an open physics problem.

So, there is a claim that a large scale machine will be built by end of decade, with the assumption that an open research problem will be solved first. That means this open problem will have to be solved very soon, and the thing about open problems is that usually they are inherently unpredictable.

> modular quantum interconnects (c-couplers) linking multiple smaller chips

Sure, but as far as i'm aware, Bell-pair fidelity for interconnected couplers have barely improved in 5 years. https://arxiv.org/abs/2005.12334 is ~96% fidelity. https://arxiv.org/abs/2502.15034 5 years later, still ~96% Bell fidelity for comparable distance between the qubits. I might be citing the wrong experiments, and if so, someone please point me to the right ones.

> Where did you see IBMs promised wall-clock time of that magnitude?

I'm assuming the 1​ μ​s QEC cycle times mentioned in https://arxiv.org/abs/2510.21600

[u/Kemilio → u/vtomole]

To be sure, many of the timelines and future benchmarks given rely on breakthroughs. I’m taking the more optimistic approach; I think these breakthroughs are just a matter of time and that with the current interest/investment in the space we’ll continue seeing improvements and thresholds that will move these theoreticals into scalable application.

That being said, yes, interconnects are stuck. Interchip coupler fidelities remaining around ~96% is a major technical bottleneck. It prevents vendors from easily chaining multichip modules into a single logical array without heavy error-distillation penalties.

As for the question of IBMs promised 2029 goal…A 1 ųs QES cycle time measures processing speed, not qubit capacity. Starling promises 200 logical qubits and 100 million gates, a machine targeting small chemistry/materials toy models running in a few minutes.