Sprecher
Beschreibung
I discuss the implementation of a two-dimensional $Z_2$ lattice gauge theory on a shallow quantum circuit, suitable for near-term quantum computers.
The ground state preparation of this model is numerically analyzed on a small lattice with a variational quantum algorithm, the quantum approximate optimization algorithm, which requires a small number of parameters to reach high fidelities and can be efficiently scaled up on larger systems.
Despite the reduced size of the considered lattices (up to 5x5), a transition between confined and deconfined regimes can be detected by measuring the expectation values of Wilson loop operators or the topological entropy.
Moreover, if periodic boundary conditions are implemented, the same optimal solution is transferable among all four different topological sectors, without any need for further optimization on the variational parameters.
These results show that variational quantum algorithms provide a useful technique to be added in the growing toolbox for digital simulations of lattice gauge theories.
