Why Bohmian Mechanics? One- and Two-Time Position Measurements, Bell Inequalities, Philosophy, and Physics.

Nicolas Gisin

doi:10.3390/e20020105

Abstract

In Bohmian mechanics, particles follow continuous trajectories, so two-time position correlations have been well defined. However, Bohmian mechanics predicts the violation of Bell inequalities. Motivated by this fact, we investigate position measurements in Bohmian mechanics by coupling the particles to macroscopic pointers. This explains the violation of Bell inequalities despite two-time position correlations. We relate this fact to so-called surrealistic trajectories that, in our model, correspond to slowly moving pointers. Next, we emphasize that Bohmian mechanics, which does not distinguish between microscopic and macroscopic systems, implies that the quantum weirdness of quantum physics also shows up at the macro-scale. Finally, we discuss the fact that Bohmian mechanics is attractive to philosophers but not so much to physicists and argue that the Bohmian community is responsible for the latter.

Highlights

Bohmian mechanics differs deeply from standard quantum mechanics
Morchio [1] and more recently Kiukas and Werner [2] to conclude that Bohmian mechanics
The Bohmian community maintains its claim that Bohmian mechanics makes the same predictions as standard quantum mechanics

Summary

Introduction

In Bohmian mechanics, particles, here called Bohmian particles, follow continuous trajectories; in Bohmian mechanics, there is a natural concept of time-correlation for particles’ positions. The Bohmian community maintains its claim that Bohmian mechanics makes the same predictions as standard quantum mechanics (at least as long as only position measurements are considered, arguing that, at the end of the day, all measurements result in position measurement, e.g., a pointer’s positions). We raise questions about Bohmian positions, about macroscopic systems, and about the large differences in appreciation of Bohmian mechanics between philosophers and physicists

Bohmian Positions

Two-Time Position Correlation in a Bell Test

What about Large Systems?

Assumption H Revisited

Why Bohmian Mechanics

Conclusions