Ehhhhhh that’s purely a problem of the “setting up” a quantum computer (ok ok and how many qubits are involved). They SHOULD be extremely capable of it. Literally able to get a ‘correct’ answer in one cycle.
It’s just very unfortunate that quantum computers benefit greatly from slower cycles, and the setup of the computations are a real nightmare. As you say, I’m unaware of any that can solve protein folding in a single cycle, and the more cycles there are involved, the more subject it is to the algorithm implemented and setup steps taken.
Maybe one day, we’ll have billion-qubit quantum computers solving all sorts of problems reliably, but that day is definitely not today!
SmoothOperator@lemmy.world 3 weeks ago
The quantum phase estimation (QPE) algorithm which calculates ground states of molecules is theoretically predicted to have exponential speedup over classical methods on unstructured problems. Protein folding is a ground state problem.
Not saying it will be best in practice, but that’s at least a theoretical framework.
ranzispa@mander.xyz 3 weeks ago
Hello, thank you for the lead. I tried replying the other day but I had just woken up drunk in the campment of a homeless guy and I was not in the best conditions to go through the math.
I took a look at this worked example: dojo.qulacs.org/…/7.1_quantum_phase_estimation_de…
As far as I understand they use the iterative approach because it requires less qbits and are able to decompose the eigenvalues of a Hamiltonian in more or less a single step.
If it is as I understand it this would be quite huge, since you’d be able to directly apply this to the Hartree-Fock equation or Density Functional Theory without having to come up with new ways to represent molecules.
One thing which appears quite critical is:
What does sufficient overlap mean? Could we take an AlphaFold model and that’s sufficient to then determine the ground state?
I guess this is easy with helium when you have 2 atoms, but when you have hundred of thousands it becomes a difficult task even to get to that point.
Moreover, I’m not exactly sure what they’re calculating: they plot an error; but it appears to be an error over the computed energy and not atom positions.
We already have reliable ways, and moderately fast, to compute the energy of a system. What we’re missing is a quick way to explore different spatial conformations of atoms to identify the one which leads to the lowest energy.
Another problem which I could not determine is whether the amount of required qbits scales with the dimensions of the molecular system. I suppose it does. In that case, could we estimate how many qbits would be required for a protein or at least a peptide?