Comment on "Energy-speed relationship of quantum particles challenges Bohmian mechanics"

TL;DR

This paper refutes a recent claim that experimental results challenge Bohmian mechanics, clarifying that the observed phenomena are consistent with Bohmian predictions and that the reported speeds are not particle velocities.

Contribution

The authors demonstrate that the experimental findings do not contradict Bohmian mechanics and clarify the distinction between operational speeds and actual particle velocities.

Findings

Experimental results align with Bohmian mechanics.

Operational speeds are unrelated to Bohmian particle velocities.

The claim of challenging Bohmian mechanics is unfounded.

Abstract

In their recent paper [Nature 643, 67 (2025)], Sharaglazova et al. report an optical microcavity experiment yielding an "energy-speed relationship" for quantum particles in evanescent states, which they infer from the observed population transfer between two coupled waveguides. The authors argue that their findings challenge the validity of Bohmian particle dynamics because, according to the Bohmian guiding equation, the velocities in the classically forbidden region would be zero. In this note, we explain why this claim is false and the experimental findings are in perfect agreement with Bohmian mechanics. We also clarify why the operationally defined speeds reported in the paper are unrelated to particle velocities in the sense described by Bohmian mechanics. In contrast to other recent replies, our analysis relies solely on the standard Bohmian guidance equation for single particles.