Questions tagged [openfermion]

For questions related to OpenFermion python library for studying quantum algorithms related to fermionic systems such as those arising in quantum chemistry.

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What does PhISwap gate mean in Cirq?

I am currently using the Cirq pakage and when drawing the circuit structure, I constantly encountered the PhISwap gate, like in here. What does this gate mean?
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What operators preserve antisymmetry?

I would like to understand better what kind of operators maintain antisymmetry as explained in Quantum simulation of chemistry with sublinear scaling in basis size: Evolution under the Hamiltonian ...
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How to perform a controlled Pauli string rotation gate?

I would like to know some circuit decomposition for an arbitrary controlled Pauli string rotation: \begin{equation} |0\rangle\langle 0| \otimes e^{i \theta (P_1\otimes...\otimes P_n)}+ |1\rangle\...
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Freeze electrons in openfermion

I am trying to generate a hamiltonian for the H2O molecule using openfermion-pyscf. As far as I understand by default openfermion is generating two 1s orbitals for H atoms and 1s, 2s, 2px, 2py, 2pz ...
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Hartree Fock state in Openfermion

I wonder what is the Hartree Fock state in openfermion. Is it 110000 or 000011, assume 6 qubits and 2 particles?
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Evaluating $\texttt{FermionOperator}$ equality in Openfermion

Apologies if this is the wrong place to ask this kind of question. I have a simple question about Openfermion. I have two normal ordered FermionOperators ...
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1 answer
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Openfermion state transformation from Bravyi-Kitaev basis to occupation number

I'm working in the Bravyi-Kitaev basis implemented by the openfermion.bravyi_kitaev() function to find the ground state of a fermionic operator in the BK ...
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Questions about OpenFermion

I have some questions about OpenFermion. I'm exploring the code, does anybody knows how to implement triatomic molecules like Li-H2? How should I set the number of orbitals? Last but not least, once ...
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Compute expectation value of an operator in openfermion

I am trying to compute the 2-electron reduced-density matrix (2-RDM) for a given quantum state with openfermion. The code is as follow ...
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Openfermion : `get_sparse_operator` issue

I am trying to use operfermion to calculated the eigen values for different molecules. Tried for Hydrogen, LithiumHydride, Water. It works fine. When Itried to calculated the same thing for Ozone, ...
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5 votes
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Finding the norm of a Hamiltonian

I am experimenting with https://journals.aps.org/prx/pdf/10.1103/PhysRevX.8.041015 and in equation 36 I find that they use the norm of the Hamiltonian. Is there a clean way to compute it, or an upper ...
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How to get eigenvectors of Hamiltonian in OpenFermion

In OpenFermion you can create a Hamiltonian in terms of creation and annihilation pretty easily: ...
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Molecular Docking using Quantum Computing

I would like to ask if somebody could suggest me a pair of ligand-Protein which had been validated and the corresponding resulting drug is already being used commercially. I am interested in ...
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1 answer
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noisy circuit by openfermion

I am working on designing quantum error mitigation algorithms for simulating chemical systems. Therefore, a necessary component is to add noisy to the ideal circuit when using a quantum simulator. But ...
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1 answer
300 views

implement variational quantum eigensolver with openfermion

Can someone provide me with an example about how to implement VQE with OpenFermion, for example, use the UCCSD ansatz to get the ground state energy of LiH. I have checked some code, but none of them ...
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2 votes
1 answer
223 views

How to get a molecular Hamiltonians in OpenFermion

I want to get a jordan_wigner_hamiltonians of a molecule-ion by using ...
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"$W_n$ state" in Bravyi-Kitaev encoding

For a particular simulation, I need the initial (physical) state of the QC to represent the equal superposition of all single-occupancy fermionic second-quantized states. In Jordan-Wigner encoding, I ...
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Openfermion to qiskit

Is there a direct way to go from an object generated in openfermion to objects usable in Qiskit. I can't find anything about any plugin. It's not too hard to translate into pyQuil and then to Qiskit ...
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Error during Forest openfermion installation

I tried installing Forest openfermion by pip install forestopenfermion and I got the following long error message (cut): ...
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