Questions tagged [chemistry]

For questions regarding (or related to) applications of quantum information theory in chemistry or applications of chemistry in quantum computing.

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Difference between Qiskit and Openfermion two body integrals

I am struggling with understanding the differences between OpenFermion and Qiskit libraries when it comes to Molecular Data, two body integrals. For example, I am working with the following ...
Eugen's user avatar
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Updating qiskit.chemistry.core.Hamiltonian to qiskit-nature Framework

I recently saw a piece of code that computes molecular bond energy with respect to bond length. I am trying to update the code to the newer qiskit framework (I'm running qiskit 0.45.1 and ...
ScientiaNatura's user avatar
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Advantage of quantum computers over classical computers in fully modeling interactions between atoms?

I'm trying to better understand the advantage quantum computers offer in terms of their ability to more accurately model chemical reactions. As a way to come to a deeper understanding, my question is: ...
Poe's user avatar
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1 answer
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What is the convention of indices for the one and two-body integrals in qiskit

I was able to calculate the one and two-body integrals for the H2 with the following code ...
fagd's user avatar
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3 votes
1 answer
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VQE jobs do not appear in queue

I am trying to calculate the ground state energy of some simple molecules using 'MolecularGroundStateEnergy' tools in qiskit. When I run the calculations for very small molecules (e.g. H2, HeH+) the ...
Joshua's user avatar
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How to apply unitary coupled cluster to a spin problem?

I understand how to apply UCC to a problem formulated in a second-quantized (fermion) form: you start with some state and then create a unitary operator out of single-body (or double-, triple- and so ...
Alexey Uvarov's user avatar
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Can one make NV centred type qubits from analogus materials in the periodic table?

Can one replace Nitrogen with Phosphorus and Carbon with Silicon and so on? What would be the conditions that would preclude such a realisation? Are there any implemenations so far?
Tejas Shetty's user avatar
3 votes
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Spin precession using a laser

According to Christopher Monroe: "Modular Ion Trap Quantum Networks: Going Big", the hyperfine states of the valence electron in the Yb+ is used as a qubit. I know that we can change the spin ...
Tech Solver's user avatar
2 votes
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Understanding the Role of Qiskit's VQE Code in Light of Pre-calculated Zero-Point Vibrational Energy in Gaussian Files

In the context of quantum computational chemistry, the Qiskit VQE (Variational Quantum Eigensolver) code is often used to calculate the vibrational energies of molecules, including the zero-point ...
Akash Yadav's user avatar
2 votes
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83 views

Reproducing Hydrogen Molecule Hamiltonian in OpenFermion

I am learning quantum chemistry at the moment and I'm trying to understand the Hamiltonian generated by the OpenFermion package. I'm now stuck at understanding how openfermion calculates the ...
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2 votes
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Save output, wavefunction file and orbital information in Qiskit

I am going through LiH ground state energy calculation. I would like to know how to save the output file in Qiskit as one would do in classical computing using software like Gaussian or Psi4. Can ...
Rag's user avatar
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Calculating energy function with 1&2-RDM (reduced density matrix) in Qiskit

I am now working on designing quantum error mitigation with variational quantum eigensolvers (VQE). I need to get the 1&2-RDM from Qiskit, which has already been realized by Openchemist pakages ...
ironmanaudi's user avatar
1 vote
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Pennylane Spectral gap for Molecules

Pennylane's dataset has a lot of systems, including Quantum Chemistry molecules. Can I extract the spectral gap of the molecule from the dataset (assuming it contains the number). In the case that ...
Zee's user avatar
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1 vote
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Subespace Search Variational Quantum Eigensolver (SSVQE) with contraints

I am trying to reproduce this paper: https://arxiv.org/pdf/2211.02302.pdf. However, I am having problems in getting the singlet first excited state (S1). The authors in the paper, they use the SSVQE ...
bjail66's user avatar
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Quantum simulation for finding eigenfunctions of complicated Hamiltonians exactly

Currently I am an undergrad in chemistry taking a quantum computing class and I'm looking for a topic for a small project involving literary review of QC articles. I was wondering if quantum computing ...
quantaq's user avatar
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Why measurement error mitigation does not seem to improve the result of VQE?

I try to follow this to perform measurement error mitigation for calculating H2 energy with VQE. With some modification, I did the calculation on "qasm_simulator" with the noise model built ...
fagd's user avatar
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1 vote
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157 views

Is there a connection between the definitions of one- and two-particle reduced density matrices?

In quantum chemistry, there are concepts about one-particle reduced density matrix (1-RDM) and similarly, the two-particle reduced density matrix (2-RDM). Generally, for an $n$ particle wavefunction $|...
刘环宇's user avatar
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Solving the one-electron integral manually in second quantized form

When I am looking into the Hartree-Fock solution to the many bodies electronic system, I came across the one electron integral, which is defined as: $$h_{pq}=\int{\psi_p^\ast\left(r\right)\left(-\frac{...
ScientiaNatura's user avatar
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229 views

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 ...
QuantumNeeraj's user avatar