On the quantum-to-classical transition of a particle in a box

The exact formulation of the correspondence principle and in particular understanding the quantum-to-classical transition remains an open problem in quantum mechanics. In this paper we present our investigation into the quantumto-classical transition of the most trivial of quantum systems — a particle in a box. Whilst it is perhaps surprising, even this example can produce new physical insight into these fundamental problems. With modern fabrication techniques of nano-mechanical systems we will be able to experimentally investigate these results and directly observe the quantum-to-classical transition. This will enable us to build technologies that probe the fundamental questions of quantum mechanics, such as the maximum size of a quantum object.