RealMcLachlanPrinciple

class RealMcLachlanPrinciple(qgt=None, gradient=None)

Bases: qiskit.algorithms.time_evolvers.variational.variational_principles.real_variational_principle.RealVariationalPrinciple

Class for a Real McLachlan’s Variational Principle. It aims to minimize the distance between both sides of the Schrödinger equation with a quantum state given as a parametrized trial state. The principle leads to a system of linear equations handled by a linear solver. The real variant means that we consider real time dynamics.

Parameters

• qgt (BaseQGT | None) – Instance of a the GQT class used to compute the QFI. If None provided, LinCombQGT is used.

• gradient (BaseEstimatorGradient | None) – Instance of a class used to compute the state gradient. If None provided, LinCombEstimatorGradient is used.

Raises

AlgorithmError – If the gradient instance does not contain an estimator.

Methods Defined Here

evolution_gradient

Calculates an evolution gradient according to the rules of this variational principle.