Three-basis logical Bell state
A [[4,2,2]] encoded pair read out in ZZ, XX and YY on separate circuits, with its confidence interval and acceptance rate published beside it.
See the ledger entryTechnology
Nandi Q1.
Encoding, decoding and post-selection — measured on real hardware.
See the ledgerThe research stack informing Nandi Q1 produced the figures below on IBM Heron-class superconducting processors.
99.94%
logical Bell fidelity — [[4,2,2]] encoded, three bases
31/31
independent encoded pairs certified in one job
5.5×
suppression, distance 3 → 5, one basis
100,000
shots per distance point, decoded offline
[[4,2,2]] encoded pairs on IBM Heron-class hardware. Fidelity 95% CI [0.999112, 0.999608], post-selected at ~96% per-basis acceptance; the 31-pair fleet job is post-selected at 9.4% (Z) / 6.0% (X) joint acceptance; suppression measured in one basis. Conditions and job IDs on the ledger.
Built for the code it runs.
Nandi Q1 is our first-generation superconducting quantum processor, currently under development. Design targets:
- Degree-4 lattice — the code lands with zero added SWAPs
- Mid-circuit readout
- Qubit reuse
- Real-time conditional logic
- Syndrome round and coherence budgeted together
The implementation — topology map, control architecture, placement method and decode internals — is proprietary.
Every figure behind this design — the ledger →Validation on third-party hardware.
Thirty-one encoded pairs in one job
Thirty-one independent encoded pairs — 62 logical qubits — each above the witness threshold with its own confidence interval.
See the ledger entryA repetition-memory ladder
100,000 shots per distance, decoded offline with minimum-weight matching: a 5.5× suppression from distance 3 to 5, and the floor where it stops.
See the ledger entryThe connectivity tax
Routed onto degree-3 heavy-hex, a surface code costs roughly 270 two-qubit gates at distance 3 and 2,100 at distance 5. We measured what that does to the logical state.
Read the design briefEvery figure re-derives offline
Raw per-shot arrays are archived at submission and every number on this page is rebuilt from them on a laptop. Decode conventions are frozen before a job is sent, so the analysis cannot be tuned to the result.
See the ledgerPlacement that earns its couplers
Topology-aware placement — the compiler adds no detours. The same discipline that certified one encoded pair placed the whole fleet in a single submission.
Read the note
Research in preparation.
Research papers on connectivity costs, Bell-state measurements and decoder validation are in preparation.
Explore the research programme →