Fingerprints of preformed pairs in two-electron angle-resolved photoemission spectroscopy

Bonča, Janez (author), Damascelli, Andrea (author), Berciu, Mona (author)

We use variational exact diagonalization (VED) to calculate the two-electron removal spectral weight for the Hubbard-Holstein model, starting from the ground state with two electrons on a one-dimensional chain. We argue that this spectral weight provides a valuable proxy for the intensity of 2eARPES processes. Our results show that when contrasted to the presumably larger signal due to two electrons ejected from two different pairs, the presumably weaker signal due to two electrons ejected from the same pair (i) is segregated in energy, appearing at a lower binding energy, and (ii) has a very characteristic momentum dependence, with a different symmetry than that of the signal corresponding to two electrons emitted from two different pairs. We verify that these fingerprints appear for pairs with different symmetries, and prove that they arise as a direct consequence of momentum and energy conservation, therefore they are generic for any model with electron-boson coupling that can lead to formation of electron pairs. Experimental observation of these fingerprints will confirm the existence of pairs. Moreover, the momentum dependence map allows one to distinguish whether the pairs are coherent (superconducting) or not. Finally, we argue that these considerations generalize to finite but low electron concentrations, finite temperatures, and higher dimensions.

• Language: English
• Keywords: angle-resolved photoemission spectroscopy, bosons, polarons, Holstein model, Hubbard model
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FMF - Faculty of Mathematics and Physics
• Publication status: Published
• Publication version: Author Accepted Manuscript
• Year: 2026
• Number of pages: Str. 196504-1-196504-6
• Numbering: Vol. 136, iss. 19
• PID: 20.500.12556/RUL-182577
• UDC: 538.9
• ISSN on article: 0031-9007
• DOI: 10.1103/4c3d-1bm7
• COBISS.SI-ID: 278414083
• Publication date in RUL: 18.05.2026

Record is a part of a journal

• Title: Physical review letters
• Shortened title: Phys. rev. lett.
• Publisher: American Physical Society
• ISSN: 0031-9007
• COBISS.SI-ID: 1282575

Secondary language

• Language: Slovenian
• Keywords: kontno razločna fotoemisijska spektroskopija, bozoni, polaroni, Holsteinov model, Hubbardov model

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P1-0044
• Name: Teorija trdnih snovi in statistična fizika

• Funder: Other - Other funder or multiple funders
• Funding programme: Univerza v Ljubljani
• Project number: SN-ZRD/22-27/510
• Name: Kvantne tehnologije za transport in komunikacije v 21. stoletju
• Acronym: KTTK21