Hello everyone. So I just tried the Pennylane’s demo on the introduction of VQE ( A brief overview of VQE | PennyLane Demos ). I was wondering, how do I do this for more complex molecules, especially when defining the trial functions. Like, how to know about how many qubits do I need and what operatio…

Hi @verstrikt , The number of qubits is given by the molecular Hamiltonian. The following line shows you how you can get them. H, qubits = qml.qchem.molecular_hamiltonian(symbols, coordinates) In that demo take a look at the green note at the end of the Building the electronic Hamiltonian section.…

Hi @mchau , I think the questions are different. @verstrikt actually our demo on resource estimation might be exactly what you were looking for. Here we show how many qubits would be needed for simulating certain materials, including very complicated ones such as dilithium iron silicate Li_2FeSiO_4.…

Thank you for the answers. i apologize for my late response.

I’m glad it helped you @verstrikt . Enjoy using PennyLane! :smiley:

VQE for more complex molecules or systems

PennyLane Help

mchau May 2, 2024, 7:05am 3

Think @verstrikt’s question relates to my question here too https://discuss.pennylane.ai/t/setting-the-active-orbitals-or-electrons-in-a-reaction

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VQE for more complex molecules or systems

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