There are two distinct sets of laws acting on our universe: the quantum laws, which describe the interactions of elementary particles and the classic laws, which describe macroscopic matter and heavy objects. The physics community is mostly divided into two groups, each supporting one of the theories. One group says that the quantum laws arise from the classic theory and the other one states that classic theory came from the quantum. A third group thinks that the quantum physics theory must be modified, so it can explain macroscopic mechanics, which is now mostly restricted by additional laws.

Johannes Fofler from the University of Vienna and the Institute for Quantum Optics And Quantum Information of the Austrian Academy of Science, belonging to the former group, published a theory to approach the understanding of classic physics through the quantum theory.

This new theory approaches decoherence. The interactions with the environment at microscopic levels bring decoherence, destroying the quantum coherence and making the observation of quantum phenomena virtually impossible. The team who has published the paper containing the theory thinks that they have found a complementary process to decoherence, which can be used to explain the transition from quantum to classical theory.

Kofler created a theoretical frame to stress the use of measurement apparatuses, without referring to the environment of a system, or even to change quantum laws. Kofler thinks that the limitations of the observation of quantum phenomena are mainly because of the restricted accuracy of the instruments.

They took the rotating spin as a model system to exemplify. Kofler says, that there is a condition which all classical theories must obey, named the Leggett-Garg inequality, which does not apply to quantum mechanics, since it violates this equation. They then demonstrated that the time evolution of a quantum system, no matter how macroscopic the system, can be explained by the classical theory. Just because a body is massive, it doesn't mean it can be explained by using classical physics.

"Arbitrarily large spins can still have a quantum time evolution and violate the Leggett-Garg inequality," said Kofler.

Along with Caslav Brukner, Kofler realized that coarse-grained measurements are being used in realistic conditions in every day life and the instruments used to measure the results have a limited resolution and cannot give accurate data. If tools with restricted resolutions are used to gain data about coarse-grained measurements of the spin, then the result can be described by using Newton's laws of motion.

By measuring a large system's spin and applying the Schrödinger equations, then the result will be a quantum time evolution, restricting the measurement and you end up with the classical Newtonian physics.

So far the theory is not complete yet but he and Brukner are optimistic, thinking they will be able to formulate a complete description of how the classical world emerges from the quantum physics.