sf.ops.Thermal¶
-
class
Thermal
(n=0)[source]¶ Bases:
strawberryfields.ops.Preparation
Prepare a mode in a thermal state.
The requested mode is traced out and replaced with the thermal state \(\rho(\bar{n})\). As a result the state will be described using a density matrix.
- Parameters
n (float) – mean thermal population of the mode
Details and Conventions
Definition
The thermal state is a mixed Gaussian state defined by
\[\rho(\nbar) := \sum_{n=0}^\infty\frac{\nbar^n}{(1+\nbar)^{n+1}}\ketbra{n}{n}\]where \(\nbar:=\tr{(\rho(\nbar)\hat{n})}\) is the mean photon number. In the Gaussian formulation one has \(\mathbf{V}=(2 \nbar +1) \frac{\hbar}{2} I\) and \(\bar{\mathbf{r}}=(0,0)\).
Attributes
Extra dependencies due to parameters that depend on measurements.
-
measurement_deps
¶ Extra dependencies due to parameters that depend on measurements.
- Returns
dependencies
- Return type
set[RegRef]
-
ns
= 1¶
Methods
apply
(reg, backend, **kwargs)Ask a local backend to execute the operation on the current register state right away.
decompose
(reg, **kwargs)Decompose the operation into elementary operations supported by the backend API.
merge
(other)Merge the operation with another (acting on the exact same set of subsystems).
-
apply
(reg, backend, **kwargs)¶ Ask a local backend to execute the operation on the current register state right away.
Takes care of parameter evaluations and any pending formal transformations (like dagger) and then calls
Operation._apply()
.- Parameters
reg (Sequence[RegRef]) – subsystem(s) the operation is acting on
backend (BaseBackend) – backend to execute the operation
- Returns
the result of self._apply
- Return type
Any
-
decompose
(reg, **kwargs)¶ Decompose the operation into elementary operations supported by the backend API.
See
strawberryfields.backends.base
.
-
merge
(other)¶ Merge the operation with another (acting on the exact same set of subsystems).
Note
For subclass overrides: merge may return a newly created object, or self, or other, but it must never modify self or other because the same Operation objects may be also used elsewhere.
- Parameters
other (Operation) – operation to merge this one with
- Returns
other * self. The return value None represents the identity gate (doing nothing).
- Return type
Operation, None
- Raises
MergeFailure – if the two operations cannot be merged