{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://git.transaction.science/Transaction-Science/open-standards/raw/branch/main/wai/wai-quantum/schemas/target.v1.json",
  "title": "wai.quantum.target/1",
  "description": "A device target: its qubits, the pairs it couples, its native gates with their errors and durations, and the calibration snapshot they come from. A value not known is left out, never written as zero. Every field but format, name, source, qubits, gates and coupling is optional, and a field the format does not name is refused, so a misspelt one never reads as absent. Its canonical text is its RFC 8785 form, and the BLAKE3 of that text, the target's hash, names the snapshot in a receipt.",
  "type": "object",
  "required": [
    "format",
    "name",
    "source",
    "qubits",
    "gates",
    "coupling"
  ],
  "additionalProperties": false,
  "properties": {
    "format": {
      "const": "wai.quantum.target/1"
    },
    "name": {
      "type": "string",
      "minLength": 1,
      "maxLength": 200
    },
    "source": {
      "type": "object",
      "required": [
        "format"
      ],
      "additionalProperties": false,
      "properties": {
        "format": {
          "type": "string",
          "description": "The format the target was read from (wai-quantum targets import --help lists them)."
        },
        "note": {
          "type": "string",
          "maxLength": 400
        }
      }
    },
    "calibration": {
      "type": "object",
      "additionalProperties": false,
      "properties": {
        "id": {
          "type": "string",
          "maxLength": 400,
          "description": "The calibration snapshot's id, as the source names it, or a content id of the snapshot read."
        },
        "timestamp": {
          "type": "string",
          "maxLength": 400,
          "description": "When the snapshot was taken, as the source writes it."
        }
      }
    },
    "qubits": {
      "type": "array",
      "minItems": 1,
      "maxItems": 2048,
      "description": "Every qubit, in order.",
      "items": {
        "type": "object",
        "required": [
          "qubit"
        ],
        "additionalProperties": false,
        "properties": {
          "qubit": {
            "type": "integer",
            "minimum": 0,
            "description": "Its index: its place in the list."
          },
          "label": {
            "type": "string",
            "description": "The source's own name for it, when that is not its index."
          },
          "resonator": {
            "const": true,
            "description": "A computational resonator, not a qubit: a qubit's state is moved into it (move, listed on the qubit and the resonator) so that a cz on it acts on that state, and moved back out. It takes no one-qubit gate, is never measured and is never paired with another resonator. Written only when true."
          },
          "t1_us": {
            "type": "number",
            "minimum": 0,
            "description": "T1, microseconds."
          },
          "t2_us": {
            "type": "number",
            "minimum": 0,
            "description": "T2 (the echo or Ramsey time the source reports), microseconds."
          },
          "frequency_ghz": {
            "type": "number",
            "minimum": 0,
            "description": "Its frequency, gigahertz."
          },
          "readout": {
            "type": "object",
            "required": [
              "p01",
              "p10"
            ],
            "additionalProperties": false,
            "properties": {
              "p01": {
                "type": "number",
                "minimum": 0,
                "maximum": 1,
                "description": "P(reads 1 | holds 0)."
              },
              "p10": {
                "type": "number",
                "minimum": 0,
                "maximum": 1,
                "description": "P(reads 0 | holds 1)."
              }
            }
          },
          "measure_ns": {
            "type": "number",
            "minimum": 0,
            "description": "The measurement's duration, nanoseconds."
          }
        }
      }
    },
    "gates": {
      "type": "array",
      "maxItems": 262144,
      "description": "Each native gate where the device runs it, sorted by gate then qubits.",
      "items": {
        "type": "object",
        "required": [
          "gate",
          "qubits"
        ],
        "additionalProperties": false,
        "properties": {
          "gate": {
            "type": "string",
            "pattern": "^[a-z0-9_]{1,40}$"
          },
          "qubits": {
            "type": "array",
            "minItems": 1,
            "maxItems": 2,
            "items": {
              "type": "integer",
              "minimum": 0
            }
          },
          "error": {
            "type": "number",
            "minimum": 0,
            "maximum": 1,
            "description": "The average gate infidelity."
          },
          "duration_ns": {
            "type": "number",
            "minimum": 0,
            "description": "Nanoseconds."
          },
          "error_sd": {
            "type": "number",
            "minimum": 0,
            "maximum": 1,
            "description": "One standard deviation of the error, as the source states it."
          },
          "leakage": {
            "type": "number",
            "minimum": 0,
            "maximum": 1,
            "description": "Of the error, the chance the gate leaves a qubit outside its two levels."
          },
          "coherent": {
            "type": "object",
            "required": [
              "theta_rad",
              "phi_rad"
            ],
            "additionalProperties": false,
            "description": "A two-qubit gate's coherent error: the angles by which the gate it runs differs from the one it is meant to be, read as an exchange-and-phase gate.",
            "properties": {
              "theta_rad": {
                "type": "number",
                "minimum": -3.141592653589793,
                "maximum": 3.141592653589793,
                "description": "The difference in its exchange (swap) angle, radians."
              },
              "phi_rad": {
                "type": "number",
                "minimum": -3.141592653589793,
                "maximum": 3.141592653589793,
                "description": "The difference in its conditional phase, radians."
              }
            }
          }
        }
      }
    },
    "crosstalk": {
      "type": "array",
      "description": "The static ZZ interaction between pairs of qubits, sorted by pair, each once. Written only when the source states one.",
      "items": {
        "type": "object",
        "required": [
          "qubits",
          "zz_khz"
        ],
        "additionalProperties": false,
        "properties": {
          "qubits": {
            "type": "array",
            "minItems": 2,
            "maxItems": 2,
            "description": "The pair, the lower qubit first.",
            "items": {
              "type": "integer",
              "minimum": 0
            }
          },
          "zz_khz": {
            "type": "number",
            "description": "The shift of one qubit's frequency when the other holds 1 rather than 0, both idle, kilohertz; it may be negative."
          }
        }
      }
    },
    "layer_fidelity": {
      "type": "array",
      "description": "Layered benchmarks the source measured, sorted by the chain's length, then its qubits. Written only when the source states one.",
      "items": {
        "type": "object",
        "required": [
          "qubits",
          "fidelity"
        ],
        "additionalProperties": false,
        "properties": {
          "qubits": {
            "type": "array",
            "minItems": 2,
            "description": "The chain, in its order: each qubit coupled to the next.",
            "items": {
              "type": "integer",
              "minimum": 0
            }
          },
          "fidelity": {
            "type": "number",
            "minimum": 0,
            "maximum": 1,
            "description": "The fidelity of every two-qubit gate along the chain, run in two layers between random one-qubit gates on every qubit: the product of the layers' process fidelities."
          }
        }
      }
    },
    "coupling": {
      "type": "array",
      "description": "The pairs a two-qubit gate may act on, each once, the lower qubit first, sorted.",
      "items": {
        "type": "array",
        "minItems": 2,
        "maxItems": 2,
        "items": {
          "type": "integer",
          "minimum": 0
        }
      }
    }
  }
}