- anti_crossing_loops(num_variables: int) dimod.binary.binary_quadratic_model.BinaryQuadraticModel ¶
Generate an anti-crossing problem with two loops.
The low-energy space of this model consists of a unique ground state of all \(+1\)s and a degenerate first excited state, centered at all \(-1\)s, with these two lowest states well separated in Hamming distance and by an energy barrier. These features are sufficient to yield a small anti-crossing when employed in a transverse-field annealing process. A closely related approach is employed in [DJA].
Note that for small values of
num_variables, the loops can be as small as a single edge.
num_variables – Number of variables used to generate the problem. Must be an even number greater than or equal to 8.
A binary quadratic model.