State
Physical qubits
Real hardware: a physical error rate, a noise model, a connectivity constraint, and a measurement-and-feedback cycle time. Everything above is written as if this floor were not there; error correction is the layer that pays for the pretence.
A state is an object you can be holding, named once so that two routes reaching the same thing are drawn as reaching the same thing. It says nothing about how you got here or where you can go next — that is entirely in the processes below.
This is a kind of
This state is not recorded as a kind of anything else. It stands on its own in the vocabulary.
Narrower kinds of this
No state in the vocabulary is recorded as a narrower kind of this one.
Records that are this object
Nothing in the catalogue has been joined to this state. That is a gap in the join rather than a claim that no such object exists; the shelf on /repository lists what is joined and what is not, with the reason.
Work that arrives here
No recorded process returns this. Either it is where a reader starts — a problem, a matrix, a machine — or it is an object this graph names and no route yet reaches.
Work that starts here
- Build logical qubits at a target logical error rate
Encode physical qubits whose error rate sits below a code- and decoder-specific threshold into logical qubits meeting a target logical error rate per round, by spending qubits and time on redundancy and decoding syndromes in real time. Which code sits underneath reaches the layers above only as a physical-qubit count and a demand on connectivity.
- Measure what the machine can actually do
Run a protocol whose answer is already known, on the hardware, and read the machine's own performance off how far the result falls short. Nothing here computes anything a user wanted — the point is that the answer is known in advance, because that is what makes the shortfall a measurement.