Worldline-Induced Transparency

TL;DR

This paper introduces worldline-induced transparency, a relativistic analogue of electromagnetically induced transparency, demonstrating how the Unruh response can be suppressed or restored in a superposed accelerated detector through phase and gap tuning.

Contribution

It presents a novel mechanism for controlling the Unruh effect via superposition of accelerated worldlines, extending electromagnetically induced transparency concepts to relativistic quantum fields.

Findings

Conditional excitation amplitude can be canceled or restored by phase tuning.

Finite switching times introduce residual signals, defining a tolerance window.

The mechanism is interpreted as a relativistic analogue of electromagnetically induced transparency.

Abstract

We show that the Unruh response can be interferometrically suppressed or restored in a single Unruh--DeWitt detector whose center-of-mass is prepared in a coherent superposition of two uniformly accelerated worldlines. The two paths remain physically disjoint; the detector is read out in a path-erasing basis so that no which-path information is revealed. If the detector's energy gap is path dependent during the interaction, the branch amplitudes for first-order excitation become operationally indistinguishable and therefore add coherently. With appropriate tuning -- matching the gap-to-acceleration ratios of the two branches and choosing a single relative phase -- the conditional first-order excitation amplitude cancels, while reversing the phase restores the response. We derive these conditions in two complementary formalisms and interpret the mechanism as a relativistic analogue of electromagnetically induced transparency, which we term worldline-induced transparency. We also treat finite switching times explicitly and quantify how imperfect matching produces a residual signal, yielding a tolerance window rather than an idealized infinitely sharp condition.