Add optional default noise models to devices (#676)

* Default noise model on devices

* Add `prefer_device_noise_model` option to EmulatorConfig

* Docstrings

* Unit tests

* Fix formatting

* Add NoiseModel JSON schema

* Convert NoiseModel lists into tuples

* Make NoiseModel fully immutable and comparable

* Support NoiseModel (de)serialization

* Move noise_model out of pulser.backends

* Finish UTs

* Fix UT in Python 3.8

* Update device JSON schema

* Add NoiseModel and EmulatorConfig to API reference

docs/source/apidoc/backend.rst

@@ -12,6 +12,11 @@ QPU
 Emulators
 ----------
 
+Configuration
+^^^^^^^^^^^^^^
+.. autoclass:: pulser.EmulatorConfig
+   :members:
+
 Local
 ^^^^^^^
 .. autoclass:: pulser_simulation.QutipBackend

docs/source/apidoc/core.rst

@@ -110,7 +110,10 @@ which when associated with a :class:`pulser.Sequence` condition its development.
 
 .. autodata:: pulser.devices.DigitalAnalogDevice
 
-
+Noise Model
+--------------
+.. automodule:: pulser.noise_model
+  :members:
 
 Channels
 ---------------------

docs/source/apidoc/simulation.rst

@@ -21,7 +21,7 @@ in favour of :class:`QutipEmulator`.
 SimConfig
 ----------------------
 
-.. automodule:: pulser_simulation.simconfig
+.. autoclass:: pulser_simulation.SimConfig
    :members:
 
 Simulation Results

pulser-core/MANIFEST.in

@@ -5,3 +5,4 @@ include pulser/json/abstract_repr/schemas/device-schema.json
 include pulser/json/abstract_repr/schemas/sequence-schema.json
 include pulser/json/abstract_repr/schemas/register-schema.json
 include pulser/json/abstract_repr/schemas/layout-schema.json
+include pulser/json/abstract_repr/schemas/noise-schema.json

pulser-core/pulser/__init__.py

@@ -26,11 +26,11 @@
 )
 from pulser.pulse import Pulse
 from pulser.register import Register, Register3D
+from pulser.noise_model import NoiseModel
 from pulser.devices import AnalogDevice, DigitalAnalogDevice, MockDevice
 from pulser.sequence import Sequence
 from pulser.backend import (
     EmulatorConfig,
-    NoiseModel,
     QPUBackend,
 )
 
@@ -59,6 +59,8 @@
     # pulser.register
     "Register",
     "Register3D",
+    # pulser.noise_model
+    "NoiseModel",
     # pulser.devices
     "AnalogDevice",
     "DigitalAnalogDevice",
@@ -67,6 +69,5 @@
     "Sequence",
     # pulser.backends
     "EmulatorConfig",
-    "NoiseModel",
     "QPUBackend",
 ]

pulser-core/pulser/backend/__init__.py

@@ -13,8 +13,9 @@
 # limitations under the License.
 """Classes for backend execution."""
 
+import pulser.noise_model as noise_model  # For backwards compat
 from pulser.backend.config import EmulatorConfig
-from pulser.backend.noise_model import NoiseModel
+from pulser.noise_model import NoiseModel  # For backwards compat
 from pulser.backend.qpu import QPUBackend
 
 __all__ = ["EmulatorConfig", "NoiseModel", "QPUBackend"]

pulser-core/pulser/backend/config.py

@@ -19,7 +19,7 @@
 
 import numpy as np
 
-from pulser.backend.noise_model import NoiseModel
+from pulser.noise_model import NoiseModel
 
 EVAL_TIMES_LITERAL = Literal["Full", "Minimal", "Final"]
 
@@ -63,15 +63,22 @@ class EmulatorConfig(BackendConfig):
 
             - "all-ground" for all atoms in the ground state
             - An array of floats with a shape compatible with the system
+
         with_modulation: Whether to emulate the sequence with the programmed
             input or the expected output.
+        prefer_device_noise_model: If the sequence's device has a default noise
+            model, this option signals the backend to prefer it over the noise
+            model given with this configuration.
         noise_model: An optional noise model to emulate the sequence with.
+            Ignored if the sequence's device has default noise model and
+            `prefer_device_noise_model=True`.
     """
 
     sampling_rate: float = 1.0
     evaluation_times: float | Sequence[float] | EVAL_TIMES_LITERAL = "Full"
     initial_state: Literal["all-ground"] | Sequence[complex] = "all-ground"
     with_modulation: bool = False
+    prefer_device_noise_model: bool = False
     noise_model: NoiseModel = field(default_factory=NoiseModel)
 
     def __post_init__(self) -> None:

pulser-core/pulser/channels/base_channel.py

@@ -75,7 +75,7 @@ class Channel(ABC):
     clock_period: int = 1  # ns
     min_duration: int = 1  # ns
     max_duration: Optional[int] = int(1e8)  # ns
-    min_avg_amp: int = 0
+    min_avg_amp: float = 0
     mod_bandwidth: Optional[float] = None  # MHz
     eom_config: Optional[BaseEOM] = field(init=False, default=None)
 

pulser-core/pulser/devices/_device_datacls.py

@@ -29,14 +29,20 @@
 from pulser.json.abstract_repr.serializer import AbstractReprEncoder
 from pulser.json.abstract_repr.validation import validate_abstract_repr
 from pulser.json.utils import get_dataclass_defaults, obj_to_dict
+from pulser.noise_model import NoiseModel
 from pulser.register.base_register import BaseRegister, QubitId
 from pulser.register.mappable_reg import MappableRegister
 from pulser.register.register_layout import RegisterLayout
 from pulser.register.traps import COORD_PRECISION
 
 DIMENSIONS = Literal[2, 3]
 
-ALWAYS_OPTIONAL_PARAMS = ("max_sequence_duration", "max_runs", "dmm_objects")
+ALWAYS_OPTIONAL_PARAMS = (
+    "max_sequence_duration",
+    "max_runs",
+    "dmm_objects",
+    "default_noise_model",
+)
 PARAMS_WITH_ABSTR_REPR = ("channel_objects", "channel_ids", "dmm_objects")
 
 
@@ -74,6 +80,9 @@ class BaseDevice(ABC):
             (in ns).
         max_runs: The maximum number of runs allowed on the device. Only used
             for backend execution.
+        default_noise_model: An optional noise model characterizing the default
+            noise of the device. Can be used by emulator backends that support
+            noise.
     """
 
     name: str
@@ -91,6 +100,7 @@ class BaseDevice(ABC):
     channel_ids: tuple[str, ...] | None = None
     channel_objects: tuple[Channel, ...] = field(default_factory=tuple)
     dmm_objects: tuple[DMM, ...] = field(default_factory=tuple)
+    default_noise_model: NoiseModel | None = None
 
     def __post_init__(self) -> None:
         def type_check(
@@ -218,6 +228,9 @@ def type_check(
                 f" not '{type(self.interaction_coeff_xy)}'."
             )
 
+        if self.default_noise_model is not None:
+            type_check("default_noise_model", NoiseModel)
+
         def to_tuple(obj: tuple | list) -> tuple:
             if isinstance(obj, (tuple, list)):
                 obj = tuple(to_tuple(el) for el in obj)
@@ -506,6 +519,9 @@ class Device(BaseDevice):
             (in ns).
         max_runs: The maximum number of runs allowed on the device. Only used
             for backend execution.
+        default_noise_model: An optional noise model characterizing the default
+            noise of the device. Can be used by emulator backends that support
+            noise.
         pre_calibrated_layouts: RegisterLayout instances that are already
             available on the Device.
     """
@@ -704,6 +720,9 @@ class VirtualDevice(BaseDevice):
             (in ns).
         max_runs: The maximum number of runs allowed on the device. Only used
             for backend execution.
+        default_noise_model: An optional noise model characterizing the default
+            noise of the device. Can be used by emulator backends that support
+            noise.
         reusable_channels: Whether each channel can be declared multiple times
             on the same pulse sequence.
     """

pulser-core/pulser/json/abstract_repr/__init__.py

@@ -17,7 +17,7 @@
 
 SCHEMAS_PATH = Path(__file__).parent / "schemas"
 SCHEMAS = {}
-for obj_type in ("device", "sequence", "register", "layout"):
+for obj_type in ("device", "sequence", "register", "layout", "noise"):
     with open(
         SCHEMAS_PATH / f"{obj_type}-schema.json", "r", encoding="utf-8"
     ) as f:

pulser-core/pulser/json/abstract_repr/deserializer.py

@@ -56,6 +56,7 @@
 )
 
 if TYPE_CHECKING:
+    from pulser.noise_model import NoiseModel
     from pulser.register.base_register import BaseRegister
     from pulser.sequence import Sequence
 
@@ -381,6 +382,28 @@ def _deserialize_register(
     return reg
 
 
+def _deserialize_noise_model(noise_model_obj: dict[str, Any]) -> NoiseModel:
+
+    def convert_complex(obj: list | tuple) -> list:
+        if isinstance(obj, (list, tuple)):
+            return [convert_complex(e) for e in obj]
+        elif isinstance(obj, dict):
+            return obj["real"] + 1j * obj["imag"]
+        else:
+            return obj
+
+    eff_noise_rates = []
+    eff_noise_opers = []
+    for rate, oper in noise_model_obj.pop("eff_noise"):
+        eff_noise_rates.append(rate)
+        eff_noise_opers.append(convert_complex(oper))
+    return pulser.NoiseModel(
+        **noise_model_obj,
+        eff_noise_rates=tuple(eff_noise_rates),
+        eff_noise_opers=tuple(eff_noise_opers),
+    )
+
+
 def _deserialize_device_object(obj: dict[str, Any]) -> Device | VirtualDevice:
     device_cls: Type[Device] | Type[VirtualDevice] = (
         VirtualDevice if obj["is_virtual"] else Device
@@ -412,6 +435,8 @@ def _deserialize_device_object(obj: dict[str, Any]) -> Device | VirtualDevice:
             params[key] = tuple(
                 _deserialize_layout(layout) for layout in obj[key]
             )
+        elif param.name == "default_noise_model":
+            params[param.name] = _deserialize_noise_model(obj[param.name])
         else:
             params[param.name] = obj[param.name]
     try:
@@ -565,3 +590,17 @@ def deserialize_abstract_register(obj_str: str) -> BaseRegister:
     obj = json.loads(obj_str)
     layout = _deserialize_layout(obj["layout"]) if "layout" in obj else None
     return _deserialize_register(qubits=obj["register"], layout=layout)
+
+
+def deserialize_abstract_noise_model(obj_str: str) -> NoiseModel:
+    """Deserialize a noise model from an abstract JSON object.
+
+    Args:
+        obj_str: the JSON string representing the noise model encoded
+            in the abstract JSON format.
+
+    Returns:
+        The NoiseModel instance.
+    """
+    validate_abstract_repr(obj_str, "noise")
+    return _deserialize_noise_model(json.loads(obj_str))

pulser-core/pulser/json/abstract_repr/schemas/device-schema.json

@@ -116,13 +116,21 @@
             "$schema": {
               "type": "string"
             },
+            "accepts_new_layouts": {
+              "description": "Whether registers built from register layouts that are not already calibrated are accepted.  Only enforced in QPU execution.",
+              "type": "boolean"
+            },
             "channels": {
               "description": "The available channels on the device.",
               "items": {
                 "$ref": "#/definitions/PhysicalChannel"
               },
               "type": "array"
             },
+            "default_noise_model": {
+              "$ref": "noise-schema.json",
+              "description": "An optional noise model characterizing the default noise of the device."
+            },
             "dimensions": {
               "description": "The maximum dimension of the supported trap arrays.",
               "enum": [
@@ -185,6 +193,10 @@
               },
               "type": "array"
             },
+            "requires_layout": {
+              "description": "Whether the register used in the sequence must be created from a register layout.  Only enforced in QPU execution.",
+              "type": "boolean"
+            },
             "reusable_channels": {
               "const": false,
               "description": "Whether each channel can be declared multiple times on the same pulse sequence.",
@@ -234,6 +246,10 @@
               },
               "type": "array"
             },
+            "default_noise_model": {
+              "$ref": "noise-schema.json",
+              "description": "An optional noise model characterizing the default noise of the device."
+            },
             "dimensions": {
               "description": "The maximum dimension of the supported trap arrays.",
               "enum": [
@@ -295,6 +311,10 @@
               "description": "A unique name for the device.",
               "type": "string"
             },
+            "requires_layout": {
+              "description": "Whether the register used in the sequence must be created from a register layout.  Only enforced in QPU execution.",
+              "type": "boolean"
+            },
             "reusable_channels": {
               "description": "Whether each channel can be declared multiple times on the same pulse sequence.",
               "type": "boolean"