Finding the Ground State of H2O and Solving Other Hamiltonian Simulation Problems with Classiq

This note demonstrates how to use the Classiq platform to solve the Hamiltonian Simulation problem that was part of our recent coding competition. We then demonstrate a more complex example — simulating an H 2 O molecule.

Introduction

Chemical simulation is one of the most exciting applications for quantum computers. When precise simulations of electron-electron interactions are necessary, it is sometimes possible to use a classical computer, but classical computers struggle to simulate more complex molecular interactions. It is best to simulate these particle interactions at the quantum level, and an excellent way to do this is with a quantum computer.

The ability to accurately simulate molecular interactions will have extensive applications. When used for drug discovery, it will allow for the rapid development of vaccines and new cures for diseases. In materials research, we can hope to discover materials with higher strength-to-weight ratios and environmentally-friendly building materials.

The Lithium Hydride Hamiltonian Simulation Problem

In our recent coding competition, we asked contestants to generate a circuit, using no more than ten qubits, that approximates the unitary e −iH where H is the qubit hamiltonian of a LiH (lithium hydride) molecule. The LiH Hamiltonian is composed of 276 Pauli strings and can be found here. The approximation error should be less than 0.1, and the circuit should be composed only of the CX and single-qubit gates.

See the full post including code samples and an interactive quantum circuit here

Originally published at https://www.classiq.io.