MapperFnEvolutionSynthesis

class MapperFnEvolutionSynthesis(mapper_fn, product_formula=None)

Bases: object

A F2QSynthesisPlugin for transpiling Evolution under a custom mapping.

This plugin maps the fermionic Hamiltonian $H$ of the incoming Evolution gate to a qubit operator using mapper_fn and emits a PauliEvolutionGate. It thereby preserves the $e^{-i t H}$ convention of the Evolution gate, with the same evolution time $t$ .

How that PauliEvolutionGate is subsequently decomposed into basis gates is governed by the product formula passed as product_formula. Leaving it at its default (None) defers to the PauliEvolutionGate’s own default synthesis (a first-order LieTrotter decomposition with a single repetition). Supplying an explicit EvolutionSynthesis – for example a higher-order SuzukiTrotter or one with several repetitions – selects a different Trotter-Suzuki product formula, trading circuit depth for a smaller Trotter error.

Initializing this transpiler pass plugin can be done with the arguments listed below.

Parameters

mapper_fn (MapperFunction) – the fermion-to-qubit operator mapping function.
product_formula (EvolutionSynthesis | None) – the product formula with which to synthesize the emitted PauliEvolutionGate. If None (the default), the gate’s own default synthesis is used (a first-order LieTrotter decomposition with a single repetition).

Attributes

mapper_fn

Type: MapperFunction

The fermion-to-qubit operator mapping function.

The two input arguments should be the following:

the operator to be mapped.
the number of qubits that the resulting operator should be defined on.

Note

It is the user’s responsibility to ensure that this function is in-sync with the global transpilation F2QLayout setting.

product_formula

Type: EvolutionSynthesis | None

The product formula used to synthesize the emitted PauliEvolutionGate, or None to defer to that gate’s own default synthesis.

Methods

run

run(in_node, out_dag, *, f2q_layout)

Runs this transpilation plugin.

The fermionic Hamiltonian of the incoming Evolution gate is mapped to a qubit operator via mapper_fn, simplified, and appended to out_dag as a PauliEvolutionGate implementing $e^{-i t H}$ with the original evolution time $t$ and the product_formula synthesis.

Parameters

in_node (DAGOpNode) – the input fermion-based circuit instruction. When this plugin gets called, the in_node.op attribute must be of type Evolution.
out_dag (DAGCircuit) – the output qubit-based circuit.
f2q_layout (dict[QuantumRegister, QuantumRegister]) – the global transpilation F2QLayout setting.

Return type

None