qml.estimator.templates.UniformStatePrep¶

class UniformStatePrep(num_states, wires=None)[source]

Bases: ResourceOperator

Resource class for preparing a uniform superposition.

This operation prepares a uniform superposition over a given number of basis states. The uniform superposition is defined as:

\[\frac{1}{\sqrt{l}} \sum_{i=0}^{l} |i\rangle\]

where \(l\) is the number of states.

This operation uses Hadamard gates to create the uniform superposition when the number of states is a power of two. If the number of states is not a power of two, the amplitude amplification technique defined in arXiv:1805.03662 is used.

Parameters:

num_states (int) – the number of states in the uniform superposition
wires (WiresLike | None) – the wires the operation acts on

Resources:: The resources are obtained from Figure 12 in arXiv:1805.03662. The circuit uses amplitude amplification to prepare a uniform superposition over \(l\) basis states.

Example

The resources for this operation are computed using:

>>> import pennylane.estimator as qre
>>> unif_state_prep = qre.UniformStatePrep(10)
>>> print(qre.estimate(unif_state_prep))
--- Resources: ---
Total wires: 5
    algorithmic wires: 4
    allocated wires: 1
    zero state: 1
    any state: 0
Total gates : 124
'Toffoli': 4,
'T': 88,
'CNOT': 4,
'X': 12,
'Hadamard': 16

Attributes

`resource_keys`
`resource_params`	Returns a dictionary containing the minimal information needed to compute the resources.

resource_keys = {'num_states'}¶

resource_params¶

Returns a dictionary containing the minimal information needed to compute the resources.

Returns:

A dictionary containing the resource parameters:

num_states (int): the number of states over which the uniform superposition is being prepared

Return type:

dict

Methods

`resource_decomp`(num_states)	Returns a list representing the resources of the operator.
`resource_rep`(num_states)	Returns a compressed representation containing only the parameters of the Operator that are needed to compute the resources.

classmethod resource_decomp(num_states)[source]¶

Returns a list representing the resources of the operator. Each object in the list represents a gate and the number of times it occurs in the circuit.

Parameters:: num_states (int) – the number of states over which the uniform superposition is being prepared

Resources:: The resources are obtained from Figure 12 in arXiv:1805.03662. The circuit uses amplitude amplification to prepare a uniform superposition over \(l\) basis states.

Returns:: A list of GateCount objects, where each object represents a specific quantum gate and the number of times it appears in the decomposition.
Return type:: list[GateCount]

classmethod resource_rep(num_states)[source]¶

Returns a compressed representation containing only the parameters of the Operator that are needed to compute the resources.

qml.estimator.templates.UniformStatePrep¶

Attributes

Methods

Contents