Work

Lessons from the Klein paradox

Year: 2026

Type: article

Abstract: We re-examine the Klein paradox from a many-particle perspective in quantum field theory. Specifically, we compute the expectation value of the particle current induced by a sufficiently strong steplike electric potential in 1 + 1 dimensions. First, for a constant (eternal) potential, we calculate the current for different Fock space ground states corresponding to distinct mode bases. While one basis yields a zero current, another produces the standard nonzero value. We then consider a potential that is rapidly switched on, recovering the standard current in the asymptotic future. This result is generalized to potentials that interpolate between different constant values at spatial infinity. Finally, we analyze a potential acting for a finite duration and again reproduce the standard current. A physical interpretation of these results is provided.

Source: Physical review. D/Physical review. D.

DOI: 10.1103/1mb6-7hb4

Authors: E. T. Akhmedov, D. V. Diakonov, V. I. Lapushkin, D. I. Sadekov

Institutions: Moscow Institute of Physics and Technology, Kurchatov Institute, Russian Academy of Sciences, Institute for Information Transmission Problems, P.N. Lebedev Physical Institute of the Russian Academy of Sciences

Language: English

Topic: Quantum and Classical Electrodynamics

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Funders: Ministry of Science and Higher Education of the Russian Federation, Foundation for the Advancement of Theoretical Physics and Mathematics

Award: G2258008615