---
title: ImaginaryTimeEvolver (v0.46)
description: API reference for qiskit.algorithms.ImaginaryTimeEvolver in qiskit v0.46
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/0.46/qiskit.algorithms.ImaginaryTimeEvolver
---

# ImaginaryTimeEvolver

*class* `qiskit.algorithms.ImaginaryTimeEvolver`

[GitHub](https://github.com/qiskit/qiskit/tree/stable/0.46/qiskit/algorithms/time_evolvers/imaginary_time_evolver.py)

Bases: [`ABC`](https://docs.python.org/3/library/abc.html#abc.ABC)

Interface for Quantum Imaginary Time Evolution.

## Methods

### evolve

*abstract* `evolve(evolution_problem)`

Perform imaginary time evolution $\exp(-\tau H)|\Psi\rangle$.

Evolves an initial state $|\Psi\rangle$ for an imaginary time $\tau$ under a Hamiltonian $H$, as provided in the `evolution_problem`.

**Parameters**

**evolution\_problem** ([*TimeEvolutionProblem*](/docs/api/qiskit/0.46/qiskit.algorithms.TimeEvolutionProblem "qiskit.algorithms.time_evolvers.time_evolution_problem.TimeEvolutionProblem")) – The definition of the evolution problem.

**Returns**

Evolution result which includes an evolved quantum state.

**Return type**

[*TimeEvolutionResult*](/docs/api/qiskit/0.46/qiskit.algorithms.TimeEvolutionResult "qiskit.algorithms.time_evolvers.time_evolution_result.TimeEvolutionResult")