Saving the Unruh Signal: Coherent Cancellation of Spontaneous Emission with Entangled Detectors

TL;DR

This paper proposes a method using entangled detectors to coherently cancel spontaneous emission noise, enabling the potential detection of the elusive Unruh effect.

Contribution

It introduces a novel multi-detector entanglement scheme that destructively interferes with spontaneous emission, providing a new approach to observe the Unruh signal.

Findings

Derivation of conditions for complete emission cancellation

Identification of a specific entangled state with geometric constraints

Potential for improved detection of the Unruh effect

Abstract

The Unruh effect is notoriously difficult to detect, as it is exponentially overwhelmed by Wigner--Weisskopf spontaneous emission. We show that this fundamental obstacle can be overcome by harnessing multi-detector quantum interference. By preparing a system of three entangled Unruh--DeWitt detectors in a specific W-state, the spontaneous emission channels can be forced to destructively interfere and vanish, thereby "saving" the Unruh signal by coherently silencing this dominant noise. Our central result is the derivation of the condition for complete and simultaneous cancellation of all right- and left-traveling emission modes. We find this requires preparing the detectors in a unique entangled state whose real-valued coefficients are fixed by an elegant geometric constraint, given by a ratio of sines of the logarithms of the detector accelerations. This work establishes multi-detector entanglement as a precision tool for noise cancellation in relativistic quantum settings, offering a new pathway toward the definitive observation of the Unruh signal.