Time Contraction Within Lightweight Reference Frames

TL;DR

This paper explores how the lightness of a moving laboratory amplifies time contraction effects in special relativity, highlighting implications for relativistic quantum reference frames and photon frequency shifts.

Contribution

It introduces a model with lightweight, independent plates to analyze time contraction, emphasizing effects often overlooked in realistic finite-mass bodies.

Findings

Lightweight laboratory accentuates time contraction effects.

Photon frequency shifts occur upon reflection in moving mirrors.

Effects are fundamental for relativistic quantum reference frames.

Abstract

The special theory of relativity teaches us that, although distinct inertial frames perceive the same dynamical laws, space and time intervals differ in value. We revisit the problem of time contraction using the paradigmatic model of a fast-moving laboratory within which a photon is emitted and posteriorly absorbed. In our model, however, the laboratory is composed of two independent parallel plates, each of which allowed to be sufficiently light so as to get kickbacks upon emission and absorption of light. We show that the lightness of the laboratory accentuates the time contraction. We also discuss how the photon frequency shifts upon reflection in a light moving mirror. Although often imperceptible, these effects will inevitably exist whenever realistic finite-mass bodies are involved. More fundamentally, they should necessarily permeate any eventual approach to the problem of relativistic quantum frames of reference.