Speaker
Mr
Davide Romano
(University of Lausanne)
Description
I want to present a general scheme for the classical limit within the framework of Bohmian mechanics (BM). The choice of BM follows from the following consideration: classical mechanics (CM) has a realistic and objective ontology, that is, particles that follow Newtonian trajectories in 3D space. In order to recover CM, it seems therefore preferable to start with a quantum theory that is presented in terms of trajectories of individual particles, i.e., with BM.
In a Bohmian framework, the problem of the classical limit reduces to the following main questions:
1. Why do we not perceive the existence of the wave function in the classical world?
2. Why do the Bohmian trajectories become Newtonian in the macroscopic regime?
My paper aims to present an answer to the first question. The answer is essentially due to the mechanism of effective factorization of the wave function, which generally emerge in the decoherence regime. Indeed, interaction with the environment produces effective wave functions (EWFs) for the Bohmian subsystems, and it is possible to show that systems described by EWFs loose the typical quantum non-locality and describe a “local” dynamical regime.
In the final part, I will sketch a possible new approach for deriving the Newtonian trajectories from the Bohmian ones in the classical limit. The approach is based on the use of the quantum potential and decoherence.
References:
- Bohm & Hiley (1987): An ontological basis for the quantum theory, Physical Report.
- Romano (2015): Bohmian classical limit in bounded regions, SILFS proceedings.
- Zurek, Habib, Paz (1993): Coherent states via decoherence, Physical Review Letters.
