Calibration-aware timing and idle noise

Purpose and scope

Proposes explicitly binding a frozen calibration snapshot to a timed execution plan. Displaying T1/T2 values and using those values in simulation are separate actions.

Core design rules

• Snapshot identity, SHA-256 digest and target profile are validated before compilation; runtime does not fetch live provider data.
• Target lowering and scheduling happen first, followed by idle windows and their channels.
• Age checks use an explicit observation time; missing values have no defaults and T2 <= 2*T1 is checked.

Example from the original

This example illustrates the design recorded in the original. It is not by itself a claim of executable or stable support; check required options and the current version.

@target("local-density-reference");
@calibration_binding(
  "calibration.lab.reference@2026.08.11",
  digest: "sha256:...",
  max_age_hours: 168
);
@timing_noise("idle-t1-t2-v1");

qreg q[2];
sample 1024 {
  H(q[0]);
  CNOT(q[0], q[1]);
  measure(q[0]);
  measure(q[1]);
}

Limits and interpretation

• This local replay model is not live-device accuracy or a provider guarantee.
• The initial slice is restricted to the approved density backend; it is not silently adapted to statevector or stabilizer paths.

Status and implementation boundary

The proposal defines an execution binding separate from calibration comparison. Retain source digest, capture/observation times and units with the evidence.