Fixes to the amplitude noise implementation (#768)

* Include the beam's propagation direction in Channel

* Apply amplitude fluctuations from run to run instead of pulse to pulse

* Correct emulation of finite-waist effects on amplitude

* Fix handling or laser_waist to/from SimConfig

* UTs for the noise

* Include propagation_dir in the JSON schema

* Fix error in conversion between SimConfig and NoiseModel

* Add the pulser version to serialized devices

* Missing UT for Channel

* Adopting review suggestions

pulser-core/pulser/channels/base_channel.py

@@ -34,7 +34,7 @@
 
 ChannelType = TypeVar("ChannelType", bound="Channel")
 
-OPTIONAL_ABSTR_CH_FIELDS = ("min_avg_amp",)
+OPTIONAL_ABSTR_CH_FIELDS = ("min_avg_amp", "propagation_dir")
 
 # States ranked in decreasing order of their associated eigenenergy
 States = Literal["u", "d", "r", "g", "h", "x"]
@@ -78,6 +78,8 @@ class Channel(ABC):
         min_avg_amp: The minimum average amplitude of a pulse (when not zero).
         mod_bandwidth: The modulation bandwidth at -3dB (50% reduction), in
             MHz.
+        propagation_dir: The propagation direction of the beam associated with
+            the channel, given as a vector in 3D space.
 
     Example:
         To create a channel targeting the 'ground-rydberg' transition globally,
@@ -96,6 +98,7 @@ class Channel(ABC):
     min_avg_amp: float = 0
     mod_bandwidth: Optional[float] = None  # MHz
     eom_config: Optional[BaseEOM] = field(init=False, default=None)
+    propagation_dir: tuple[float, float, float] | None = None
 
     @property
     def name(self) -> str:
@@ -196,7 +199,12 @@ def __post_init__(self) -> None:
                     getattr(self, p) is None
                 ), f"'{p}' must be left as None in a Global channel."
         else:
+            assert self.addressing == "Local"
             parameters += local_only
+            if self.propagation_dir is not None:
+                raise NotImplementedError(
+                    "'propagation_dir' must be left as None in Local channels."
+                )
 
         for param in parameters:
             value = getattr(self, param)
@@ -244,6 +252,18 @@ def __post_init__(self) -> None:
                 "modulation bandwidth."
             )
 
+        if self.propagation_dir is not None:
+            dir_vector = np.array(self.propagation_dir, dtype=float)
+            if dir_vector.size != 3 or np.sum(dir_vector) == 0.0:
+                raise ValueError(
+                    "'propagation_dir' must be given as a non-zero 3D vector;"
+                    f" got {self.propagation_dir} instead."
+                )
+            # Make sure it's stored as a tuple
+            object.__setattr__(
+                self, "propagation_dir", tuple(self.propagation_dir)
+            )
+
     @property
     def rise_time(self) -> int:
         """The rise time (in ns).
@@ -340,6 +360,7 @@ def Global(
         cls: Type[ChannelType],
         max_abs_detuning: Optional[float],
         max_amp: Optional[float],
+        # TODO: Impose a default propagation_dir in pulser-core 1.3
         **kwargs: Any,
     ) -> ChannelType:
         """Initializes the channel with global addressing.
@@ -361,6 +382,8 @@ def Global(
                 bandwidth at -3dB (50% reduction), in MHz.
             min_avg_amp: The minimum average amplitude of a pulse (when not
                 zero).
+            propagation_dir: The propagation direction of the beam associated
+                with the channel, given as a vector in 3D space.
         """
         # Can't initialize a channel whose addressing is determined internally
         for cls_field in fields(cls):

pulser-core/pulser/devices/_device_datacls.py

@@ -24,6 +24,7 @@
 import numpy as np
 from scipy.spatial.distance import squareform
 
+import pulser
 import pulser.json.abstract_repr as pulser_abstract_repr
 import pulser.math as pm
 from pulser.channels.base_channel import Channel, States, get_states_from_bases
@@ -565,7 +566,13 @@ def _to_abstract_repr(self) -> dict[str, Any]:
         for ch_name, ch_obj in self.channels.items():
             ch_list.append(ch_obj._to_abstract_repr(ch_name))
         # Add version and channels to params
-        params.update({"version": "1", "channels": ch_list})
+        params.update(
+            {
+                "version": "1",
+                "pulser_version": pulser.__version__,
+                "channels": ch_list,
+            }
+        )
         dmm_list = []
         for dmm_name, dmm_obj in self.dmm_channels.items():
             dmm_list.append(dmm_obj._to_abstract_repr(dmm_name))