# Tag Info

### How does the recent Chinese quantum supremacy claim compare with Google's?

"how honest is the Chinese claim of quantum supremacy?" It's equally (or at least as) honest in comparison to Google's claim. In a comment to this answer at Quantum Computing Stack Exchange,...
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### How can quantum computing accelerate materials modeling?

Quantum computers provide the possibility of simulating systems that are so mathematically complex that classical computers cannot practically be used. The difficulty comes from the fact that the ...
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### How are quantum computers being used in drug design?

How are quantum computers being used in drug design? They are not. Because useful quantum computers do not exist yet. Ask again in a couple decades :)
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### How can quantum computing accelerate materials modeling?

Quantum computing has been extensively discussed as long as the first quantum computers have become a reality. As already pointed out, we are still at very early stages of such development. What we ...
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### How can quantum computing accelerate materials modeling?

Quantum computers potentially could provide a far more efficient way to solve the electronic structure problem: finding the ground state energy (or other properties) of electrons in a compound. The ...
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Accepted

### What class of materials are closest to realizing the tunable coupling Hamiltonian?

Realizing this Hamiltonian in a natural material I cannot imagine a material in which all nearest-neighbor spin-spin interactions can be adjusted arbitrarily at the same time. Spin-spin couplings ...
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Accepted

### Molecular orbitals and active space

As you said above, nitrogen has 2 s orbitals and one p orbital. However, one would typically freeze the chemically inactive 1s orbital, leaving you 5 electrons in 4 orbitals per atom, or 10 electrons ...
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Accepted

### The correlation energy from frozen natural orbtials (FNOs) using CCSD and MPBT(2)?

The idea in the FNO method is to do a MP2 calculation for the one-particle density matrix and diagonalize it to get the natural orbitals (NOs) and natural orbital occupation numbers (NOONs). So, ...
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### Are there interesting applications of estimating the energy for generalizations of the Heisenberg model?

When you have more than two Pauli operators in a single term, you can model multipolar terms, as described in this paper: ... multipolar correlators of order $p=1$ (spin, dipolar), $p=2$ (quadrupolar)...
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Accepted

### How to solve time-dependent Schrodinger equation and plot trajectory on Bloch sphere?

The angles $\phi$ and $\theta$ never contain a non-zero imaginary part (they are always purely real numbers). The general solution to Eq. 1 is:  \tag{1} |\Phi(t)\rangle = e^{-\textrm{i}H t} | \Phi(0)...
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Accepted

### Are there interesting applications of estimating the energy for generalizations of the Heisenberg model?

It is probably worth mentioning that, in the context of strongly correlated electron system / antiferromagnetism / superexchange, the spin-spin interactions arise from perturbation theory. In the ...
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