# Wave-particle duality of many-body quantum states

## TL;DR

This paper develops a comprehensive theory of wave-particle duality for many-body quantum states, linking which-way information and interference to understand the quantum-to-classical transition in complex systems.

## Contribution

It introduces a general framework for quantifying wave-particle duality in many-body quantum states, extending concepts from single-particle physics to interacting many-particle systems.

## Key findings

- Quantifies how distinguishability affects interference in many-particle systems
- Analyzes the quantum-to-classical transition via wave-particle duality
- Illustrates framework with Hong-Ou-Mandel and Bose-Hubbard models

## Abstract

We formulate a general theory of wave-particle duality for many-body quantum states, which quantifies how wave- and particle-like properties balance each other. Much as in the well-understood single-particle case, which-way information -- here on the level of many-particle paths -- lends particle-character, while interference -- here due to coherent superpositions of many-particle amplitudes -- indicates wave-like properties. We analyze how many-particle which-way information, continuously tunable by the level of distinguishability of fermionic or bosonic, identical and possibly interacting particles, constrains interference contributions to many-particle observables and thus controls the quantum-to-classical transition in many-particle quantum systems. The versatility of our theoretical framework is illustrated for Hong-Ou-Mandel- and Bose-Hubbard-like exemplary settings.