EVA: a quantum Exponential Value Approximation algorithm

Understand

VQE is currently one of the most widely used algorithms for optimizing problems using quantum computers.

• A necessary step in this algorithm is calculating the expectation value given a state, which is calculated by decomposing the Hamiltonian into Pauli operators and obtaining this value for each of them.
• In this work, we have designed an algorithm capable of figuring this value using a single circuit.
• A time cost study has been carried out, and it has been found that in certain more complex Hamiltonians, it is possible to obtain a good performance over the current methods.