GraphState
class GraphState(adjacency_matrix)
Bases: qiskit.circuit.quantumcircuit.QuantumCircuit
Circuit to prepare a graph state.
Given a graph G = (V, E), with the set of vertices V and the set of edges E, the corresponding graph state is defined as
Such a state can be prepared by first preparing all qubits in the state, then applying a gate for each corresponding graph edge.
Graph state preparation circuits are Clifford circuits, and thus easy to simulate classically. However, by adding a layer of measurements in a product basis at the end, there is evidence that the circuit becomes hard to simulate [2].
Reference Circuit:
References:
[1] M. Hein, J. Eisert, H.J. Briegel, Multi-party Entanglement in Graph States,
[2] D. Koh, Further Extensions of Clifford Circuits & their Classical Simulation Complexities.
Create graph state preparation circuit.
Parameters
adjacency_matrix (Union[List, array]) – input graph as n-by-n list of 0-1 lists
Raises
CircuitError – If adjacency_matrix is not symmetric.
The circuit prepares a graph state with the given adjacency matrix.
Attributes
ancillas
Returns a list of ancilla bits in the order that the registers were added.
Return type
List[AncillaQubit]
calibrations
Return calibration dictionary.
The custom pulse definition of a given gate is of the form
{‘gate_name’: {(qubits, params): schedule}}
Return type
dict
clbits
Returns a list of classical bits in the order that the registers were added.
Return type
List[Clbit]
data
Return the circuit data (instructions and context).
Returns
a list-like object containing the tuples for the circuit’s data.
Each tuple is in the format (instruction, qargs, cargs), where instruction is an Instruction (or subclass) object, qargs is a list of Qubit objects, and cargs is a list of Clbit objects.
Return type
QuantumCircuitData
extension_lib
Default value: 'include "qelib1.inc";'
global_phase
Return the global phase of the circuit in radians.
Return type
Union[ParameterExpression, float]
header
Default value: 'OPENQASM 2.0;'
instances
Default value: 9
metadata
The user provided metadata associated with the circuit
The metadata for the circuit is a user provided dict of metadata for the circuit. It will not be used to influence the execution or operation of the circuit, but it is expected to be passed between all transforms of the circuit (ie transpilation) and that providers will associate any circuit metadata with the results it returns from execution of that circuit.
Return type
dict
num_ancillas
Return the number of ancilla qubits.
Return type
int
num_clbits
Return number of classical bits.
Return type
int
num_parameters
Convenience function to get the number of parameter objects in the circuit.
Return type
int
num_qubits
Return number of qubits.
Return type
int
parameters
Convenience function to get the parameters defined in the parameter table.
Return type
ParameterView
prefix
Default value: 'circuit'
qubits
Returns a list of quantum bits in the order that the registers were added.
Return type
List[Qubit]