Interference between non-overlapping waves

TL;DR

This paper explores how interference-like effects can occur without overlapping waves by analyzing quantum interactions with a single detector at different locations, supported by a theoretical model and superconducting circuit implementation.

Contribution

It introduces a novel regime of interference where independent fields interact with a single detector at separate locations, extending traditional wave interference concepts.

Findings

Interference-like phenomena can emerge without wave overlap.

A theoretical model of a spatially extended atom coupled to two fields.

Proposed superconducting circuit implementation for experimental realization.

Abstract

In classical mechanics and electromagnetism, interference occurs when two or more waves overlap at the same point in spacetime. However, the advent of quantum electrodynamics (QED) and its remarkable success in describing light-matter interactions at the microscopic level invites us to reconsider whether interference-like effects could arise even when the waves do not physically overlap. In this work, we extend the notion of wave interference to a novel and unconventional regime. Building upon the fundamental description of interference in terms of the interaction with the observer [Phys. Rev. Lett. 134, 133603 (2025)], we demonstrate that interference-like phenomena can emerge when two independent fields interact with a single detector at different locations in Minkowski space. We begin by developing a theoretical model in which a spatially extended atom simultaneously couples to two distant fields. We then propose an experimentally feasible implementation using superconducting circuits, where a giant artificial atom interacts with two independent resonators. Our findings open new directions for exploring interference in quantum systems and suggest new possibilities for optical quantum technologies, including the realization of atom-transparent devices controlled by spatially separated laser fields.