TY - JOUR

T1 - Spectral Hong-Ou-Mandel Effect between a Heralded Single-Photon State and a Thermal Field

T2 - Multiphoton Contamination and the Nonclassicality Threshold

AU - Khodadad Kashi, Anahita

AU - Caspani, Lucia

AU - Kues, Michael

N1 - Funding Information: This research was funded by the German Research Foundation (EXC 2122, Project ID 390833453); European Research Council (Grant Agreement No. 947603 (QFreC project)); Federal Ministry of Education and Research (PQuMal project, Quantum Futur Program); EPSRC (EP/V062492/1).

PY - 2023/12/4

Y1 - 2023/12/4

N2 - The Hong-Ou-Mandel (HOM) effect is crucial for quantum information processing, and its visibility determines the system's quantum-classical characteristics. In an experimental and theoretical study of the spectral HOM effect between a thermal field and a heralded single-photon state, we demonstrate that the HOM visibility varies dependent on the relative photon statistics of the interacting fields. Our findings reveal that multiphoton components in a heralded state get engaged in quantum interference with a thermal field, resulting in improved visibilities at certain mean photon numbers. We derive a theoretical relationship for the HOM visibility as a function of the mean photon number of the thermal field and the thermal part of the heralded state. We show that the nonclassicality degree of a heralded state is reflected in its HOM visibility with a thermal field; our results establish a lower bound of 41.42% for the peak visibility, indicating the minimum assignable degree of nonclassicality to the heralded state. This research enhances our understanding of the HOM effect and its application to high-speed remote secret key sharing, addressing security concerns due to multiphoton contamination in heralded states.

AB - The Hong-Ou-Mandel (HOM) effect is crucial for quantum information processing, and its visibility determines the system's quantum-classical characteristics. In an experimental and theoretical study of the spectral HOM effect between a thermal field and a heralded single-photon state, we demonstrate that the HOM visibility varies dependent on the relative photon statistics of the interacting fields. Our findings reveal that multiphoton components in a heralded state get engaged in quantum interference with a thermal field, resulting in improved visibilities at certain mean photon numbers. We derive a theoretical relationship for the HOM visibility as a function of the mean photon number of the thermal field and the thermal part of the heralded state. We show that the nonclassicality degree of a heralded state is reflected in its HOM visibility with a thermal field; our results establish a lower bound of 41.42% for the peak visibility, indicating the minimum assignable degree of nonclassicality to the heralded state. This research enhances our understanding of the HOM effect and its application to high-speed remote secret key sharing, addressing security concerns due to multiphoton contamination in heralded states.

UR - http://www.scopus.com/inward/record.url?scp=85180126470&partnerID=8YFLogxK

U2 - 10.1103/PhysRevLett.131.233601

DO - 10.1103/PhysRevLett.131.233601

M3 - Article

AN - SCOPUS:85180126470

VL - 131

JO - Physical review letters

JF - Physical review letters

SN - 0031-9007

IS - 23

M1 - 233601

ER -