Probing the spatial structure of the Dirac vacuum via phase-controlled colliding laser pulses

¹ State Key Laboratory for GeoMechanics and Deep Underground Engineering, China University of Mining and Technology - Beijing 100083, China
² Key Laboratory for Laser Plasmas and School of Physics and Astronomy, Shanghai Jiao Tong University Shanghai 200240, China
³ Intense Laser Physics Theory Unit and Department of Physics, Illinois State University Normal, IL 61790-4560, USA

^(a) E-mail: qcsu@ilstu.edu (corresponding author)

Received: 30 November 2022
Accepted: 10 February 2023

Abstract

A highly charged nucleus can induce spatial structures into the otherwise spatially homogeneous Dirac quantum vacuum state. We propose that the electron-positron pair creation process triggered by two counter-propagating laser pulses can be used to probe these structures. The particle yield can be controlled by the phase relationship between the beams. Once the pulses overlap, they form standing waves whose nodal patterns are determined by this laser phase. Due to the spatial deformation of the vacuum state, the maximal pair creation yield is observed for those phases that lead to nodes (and not anti-nodes!) where the nucleus is located. This means rather counterintuitively that the particle yield is maximum, despite the fact that the electrical field intensity almost vanishes in the interaction zone.