Quantum Computing Stack Exchange
Quantum Computing Stack Exchange

Questions tagged [chemistry]

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

83 questions
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Number of Qubits Required for Simulation of Caffeine and Penicillin Molecules

I recently read this report from BCG, which stated: For scientists trying to design a compound that will attach itself to, and modify, a target disease pathway, the critical first step is to determine the electronic structure of the molecule.…
Greenstick
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Quantum Chemistry and Quantum Computing

Predicting the energy of molecules to high accuracy during the course of a chemical reaction, which in turn allows us to predict reaction rates, equilibrium geometries, transition states among others is a Quantum Chemical problem. Quantum Computing…
user3483902
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Roughly speaking, How many qubits will be needed to study (or simulate) a molecule such as: C29H31N7O?

It is often said that one of the early applications for Quantum Computers will be drug discovery. Q: Roughly speaking, How many qubits will be needed to study (or simulate) a molecule such as: $C_{29}H_{31}N_{7}O$ (Imatinib, sold under the brand…
david
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Quantum chemistry: references

I have heard about Quantum chemistry as one of the main applications of quantum computers. However, I have not found concrete related articles with circuit-implementations for these applications. Does anyone have articles on simulating molecules…
nippon
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Impact of ordering Hamiltonian terms for Trotterization

In Trotterization, the typical Hamiltonian considered is: $$ H = \sum_{p, q} h_{pq} a^{\dagger}_p a_q + \sum_{p, q, r, s} a^{\dagger}_p a^{\dagger}_q a_r a_s $$ Which is then converted into a sequence of gates by the Jordan Wigner…
C. Kang
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If a Hamiltonian is quadratic in the ladder operator, why is its time evolution linear in the ladder operator?

How can one show that $\hat{U}^\dagger\hat{a}\hat{U}$ (with $\hat{U} =e^{-i\hat{H}t}$) involves only linear orders of the ladder operator, when $H$ is the general quadratic Hamiltonian $(\hat{H} = \alpha (\hat{a}^\dagger)^2+ \beta…
heromano
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What problems in chemistry or materials science could be solved with 100 fault-tolerant qubits?

Background IBM, Infleqtion, QuEra, and other quantum hardware companies have announced roadmaps where they expect to have 100 or more fault-tolerant qubits by the end of the decade. It seems increasingly likely that at least one of them will…
taciteloquence
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What are some current applications of Quantum Computing in drug discovery? Are there any test examples of this?

I am interested in applying the power of Quantum Computing to drug discovery. Although I realize that quantum computing is limited in regards to modeling drug-like compounds and their interactions right now, I was curious as to any useful resources…
Rob James
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Developing quantum circuits for specific quantum chemistry configurations

I am interested in learning more about the following: would it be possible for me to simulate a molecule consisting of copper ions through a quantum circuit? And if so, can that circuit allow me to measure the decoherence time of that molecule? I…
Enrique Segura
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Do we know anything about the computational complexity of the exchange-correlation functional?

Density functional theory is based on the Hohenberg-Kohn (HK) theorems and aims to compute the ground-state many-body wavefunction of a physical material and/or molecules. To put it simply, the HK theorems show that there is a unique one-to-one…
Dr. T. Q. Bit
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Defining qubit operator from scratch

I'm a beginner with Qiskit and the Python language at all. Here is my question: One of the VQE function arguments is qubit operator (qubitOp). I saw some examples where the qubitOp object was produced by some already existing Qiskit module. For…
Alex Tarantul
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Why aren’t electrons in our atoms suffering from decoherence?

I know about how the current era of quantum computing is trying to find ways in order to improve the coherence times of the quantum states and so on and that decoherence and noise are the greatest obstacles, some needing extremely isolated…
yousef elbrolosy
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Use one_body_integrals to know which orbitals to freeze in ElectronicStructureProblem

In exercise 5 of the this year's IBM Quantum Challenge, you need to use the FreezeCoreTransformer (along two_qubit_reduction and z2symmetry_reduction) to reduce the number of qubits to 4 and achieve a cost of 3. I managed to figure out that the…
epelaez
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If you had a 1000 qubit NISQ machine with arbitrary connectivity, what would you do?

Many current devices are constrained to nearest neighbor connectivity or small system sizes, but suppose that a NISQ machine with 99-99.5% level two-qubit gate fidelities and arbitrary connectivity were available, with 1000 qubits. Are there really…
shixian105
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Molecular orbitals in Qiskit

During the same minute as asking this question, I also asked this at Matter Modeling SE. In Qiskit, each qubit corrrespond to one spin orbital. For example, the $\text{N}_2$ molecule have 10 molecular orbitals, which correspond to 20 spin orbitals…
ironmanaudi
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