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

# ImaginaryVariationalPrinciple

*class* `qiskit.algorithms.time_evolvers.variational.ImaginaryVariationalPrinciple(qgt, gradient)`

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

Bases: [`VariationalPrinciple`](/docs/api/qiskit/0.46/qiskit.algorithms.time_evolvers.variational.VariationalPrinciple "qiskit.algorithms.time_evolvers.variational.variational_principles.variational_principle.VariationalPrinciple"), [`ABC`](https://docs.python.org/3/library/abc.html#abc.ABC)

Abstract class for an Imaginary Variational Principle. The imaginary variant means that we consider imaginary time dynamics.

**Parameters**

- **qgt** ([*BaseQGT*](/docs/api/qiskit/0.46/qiskit.algorithms.gradients.BaseQGT "qiskit.algorithms.gradients.BaseQGT")) – Instance of a class used to compute the GQT.
- **gradient** ([*BaseEstimatorGradient*](/docs/api/qiskit/0.46/qiskit.algorithms.gradients.BaseEstimatorGradient "qiskit.algorithms.gradients.BaseEstimatorGradient")) – Instance of a class used to compute the state gradient.