---
title: FermionAction (latest version)
description: API reference for qiskit_fermions.operators.fermion_action.FermionAction in the latest version of qiskit-fermions
source: https://quantum.cloud.ibm.com/docs/en/api/qiskit-fermions/operators-fermion-action-fermion-action
---

# FermionAction

A fermionic creation or annihilation action.

A 2-tuple `(action, mode)` where `action` is `True` for a creation and `False` for an annihilation action, and `mode` is the spin-less fermionic mode index on which to act.

alias of [`tuple`](https://docs.python.org/3/library/stdtypes.html#tuple)\[[`bool`](https://docs.python.org/3/library/functions.html#bool), [`int`](https://docs.python.org/3/library/functions.html#int)]