Article on a “Variational Quantum Eigensolver Ansatz for the J1-J2-model”
The paper “Variational Quantum Eigensolver Ansatz for the J1-J2-model”, a work of our PhD candidate Verena Feulner, was published in Physical Review B.
The J1-J2 quantum spin model goes one step beyond a nearest-neighbor interacting system by introducing next-nearest neighbor interactions along the diagonals of a rectangular lattice. This makes the ground state properties of this model very challenging to analyze with classical methods, making it a good candidate for future quantum advantage.
A Variational Quantum Eigensolver (VQE) could for instance help preparing a quantum state close to the ground state of a given J1-J2 Hamiltonian. We propose an ansatz for the Variational Quantum Eigensolver that can work without the need for long-ranging gates due to the diagonal next-nearest-neighbor interactions. This simplification is of great importance for solid-state-based hardware as it eliminates the need for SWAP gates, bringing it one step closer to physical realisation.