qulacs VS qiskit-aer

qulacs (C++; obviously the most popular one with autograd support).

strange. i never faced this error while using the Aer library. could u perhaps provide the complete error? is it something like the one mentioned here?

Hello everyone, I am currently learning the work with Qiskit and I came across a curious problem. Although the documentation does not explicitly mention it, when .eval() method is applied on an operator (which was prepared using ExpectationFactory and CircuitSampler with simulator backend from a SumOp type Hamiltonian and a state Psi converted from a circuit), the expectation values is apparently evaluated by "algebraic" calculation rather than a circuit simulation, not to mention the absence of noise (the result is always the same). This fact seems to be mentioned in documentation https://qiskit.org/documentation/stubs/qiskit.opflow.expectations.ExpectationFactory.build.html . There also seems to a relevant be an issue on Qiskit Github https://github.com/Qiskit/qiskit-aer/issues/810 , but there have not been any updates from end of 2020.

is this a joke? prime/integer factorization is famously something that had a probabilistic algorithm for a long time and it was unknown whether there was a P algorithm and now there is based on AKS. and quantum systems are primarily simulated since almost no one has a functioning qpu.

Aer 0.8 with a unified AerSimulator backend for running circuit simulations using any of the supported simulation methods and a new simulator instruction library for saving various kinds of simulator data. Now is possible to run large simulations on a distributed computing environment (read more here).