It is well known that Quantum Mechanics (QM) describes a world that follows completely counter intuitive rules, that has famous paradoxes as postulates (e.g. superposition of states, wave/particle dualism, the measurement problem...), but that at the same time it is the foundation for the description of the physical world that we experience. While in the Copenhagen Interpretation these paradoxes are fully accepted as a reality, there are other interpretations that try to find a compromise, between the classic macroscopic world and the QM results. A quite interesting one is the Cellular Automata Interpretation of QM, by Gerard 't Hooft [1], according to whom particles evolve following the rules of Cellular Automata (CA), a mathematical model consisting of discrete units that evolve following deterministic laws in discrete space and time. The states of a Cellular Automaton are, by definition, classical and thus deterministic and do not form superpositions: they are identified, in this interpretation, as Ontological States. These states are the ones in which microscopic particles find themselves in reality, whether they are observed or not. Unfortunately, it is not always possible to determine exactly the Ontological States. To overcome this obstacle, the formalism of QM works as a "template" with which a scientist can work and get reliable results even without fully knowing what is happening at the microscopic level. The problem of measuring these states is solved by considering the observer and his/her instruments as a separate physical system which is equally deterministic, so the act of measurement is interpreted as the interaction between the two systems.Finally, we will illustrate how this classical system of three Ising spins that evolves exclusively through Ontological States behaves like a quantum system, evolving through superposition states, in particular. This is an example of the potential implications of the CA Interpretation of Quantum Mechanics.
Consequences of perturbations on a classical chain of Ising spins3.