1. The Formulation of Matrix Mechanics and Its Modifications 1925 1926 . ") 2. In 1925, Born and Heisenberg formulated the matrix mechanics representation of quantum mechanics. 3. The act of measurement in matrix mechanics 'collapses'the state of the system. 4. In 1925, Born and Werner Heisenberg formulated the matrix mechanics representation of quantum mechanics. 5. Matrix mechanics was the first conceptually autonomous and logically consistent formulation of quantum mechanics.6. In the matrix mechanics formulation, the unitary, and the operators can be represented as matrices. 7. In matrix mechanics , the commuting self-adjoint operators representing observables are subject to similar uncertainty limits. 8. They led to the development of matrix mechanics , the first form of modern quantum mechanics. 9. In matrix mechanics , the correspondence principle was built in and was used to construct the theory. 10. These were called the selection rules, which were a puzzle until the advent of matrix mechanics .