Fermi two-atom problem: non-perturbative approach via relativistic quantum information and algebraic quantum field theory

TL;DR

This paper presents a non-perturbative, algebraic quantum field theory approach to the Fermi two-atom problem, extending analysis to curved spacetimes and providing a clearer, operational interpretation within relativistic quantum information.

Contribution

It introduces a non-perturbative, algebraic quantum field theory framework for the Fermi two-atom problem, applicable to arbitrary curved spacetimes, and reinterprets the original solution in terms of qubits and quantum fields.

Findings

Provides a non-perturbative analysis of the Fermi two-atom problem.

Extends the problem's analysis to curved spacetimes.

Offers a clearer operational interpretation of the original solution.

Abstract

In this work we revisit the famous Fermi two-atom problem, which concerns how relativistic causality impacts atomic transition probabilities, using the tools from relativistic quantum information (RQI) and algebraic quantum field theory (AQFT). The problem has sparked different analyses from many directions and angles since the proposed solution by Buchholz and Yngvason (1994). Some of these analyses employ various approximations, heuristics, perturbative methods, which tends to render some of the otherwise useful insights somewhat obscured. It is also noted that they are all studied in flat spacetime. We show that current tools in relativistic quantum information, combined with algebraic approach to quantum field theory, are now powerful enough to provide fuller and cleaner analysis of the Fermi two-atom problem for arbitrary curved spacetimes in a completely non-perturbative manner. Our result gives the original solution of Buchholz and Yngvason a very operational reinterpretation in terms of qubits interacting with a quantum field, and allows for various natural generalizations and inclusion of detector-based local measurement for the quantum field (Phys. Rev. D 105, 065003).