Radiative loss of coherence in free electrons:a long-range quantum phenomenon  

作　　者：Cruz I.Velasco Valerio Di Giulio F.Javier García de Abajo 

机构地区：[1]ICFO-Institut de Ciencies Fotoniques,The Barcelona Institute of Science and Technology,08860,Castelldefels(Barcelona),Spain [2]ICREA-InstitucióCatalana de Recerca i Estudis Avançats,Passeig Lluís Companys 23,08010,Barcelona,Spain

出　　处：《Light(Science & Applications)》2024年第2期294-301,共8页光（科学与应用)（英文版）

基　　金：We thank Archie Howie and Morgan Mitchell for helpful and enjoyable discussions.This work has been supported in part by the European Research Council(Advanced Grant 789104-eNANO);the European Commission(Horizon 2020 Grants No.101017720 FET-Proactive EBEAM and No.964591-SMART-electron);the Spanish MICINN(PID2020-112625GB-I00 and Severo Ochoa CEX2019-000910-S);the Catalan CERCA Program,and Fundaciós Cellex and Mir-Puig.

摘　　要：Quantum physics rules the dynamics of small objects as they interact over microscopic length scales.Nevertheless,quantum correlations involving macroscopic distances can be observed between entangled photons as well as in atomic gases and matter waves at low temperatures.The long-range nature of the electromagnetic coupling between charged particles and extended objects could also trigger quantum phenomena over large distances.Here,we reveal a manifestation of quantum mechanics that involves macroscopic distances and results in a nearly complete depletion of coherence associated with which-way free-electron interference produced by electron-radiation coupling in the presence of distant extended objects.This is a ubiquitous effect that we illustrate through a rigorous theoretical analysis of a two-path electron beam interacting with a semi-infinite metallic plate and find the inter-path coherence to vanish proportionally to the path separation at zero temperature and exponentially at finite temperature.The investigated regime of large distances originates in the coupling of the electron to radiative modes assisted by diffraction at material structures but without any involvement of material excitations.Besides the fundamental interest of this macroscopic quantum phenomenon,our results suggest an approach to measuring the vacuum temperature and nondestructively sensing the presence of distant objects.

关 键 词：temperature QUANTUM MACROSCOPIC 

分 类 号：O41[理学—理论物理]