With the existing theories in conflict with observations, two new quantum mechanics concepts arose. First, Heisenberg's 1925 Umdeutung paper on matrix mechanics was inspired by the correspondence principle, he did not cite Bohr. Further developed in collaboration with Pascual Jordan and Max Born resulted in a mathematical model without connection to the principle. Second, Schrodinger's wave mechanics in the following year similarly did not use the principle. Both pictures were later shown to be equivalent and accurate enough to replace old quantum theory. These approaches have no atomic orbits: the correspondence is more of an analogy than a principle.