Generation of vortex particles via generalized measurements

TL;DR

This paper proposes a novel method to generate vortex states of various particles, including hadrons and ions, through postselection protocols in different high-energy processes, expanding possibilities beyond traditional diffraction techniques.

Contribution

It introduces a general approach to produce vortex particles at relativistic energies using entanglement and measurement uncertainty, applicable to multiple particle types and experimental setups.

Findings

Vortex states can be generated via postselection in high-energy processes.

The method applies to particles like hadrons, ions, and nuclei.

Potential for creating twisted photon sources at advanced facilities.

Abstract

The hard X-ray twisted photons and relativistic massive particles with orbital angular momentum -- vortex electrons, muons, protons, etc. -- have many potential applications in high-energy and nuclear physics. However, such states can be obtained so far mainly via diffraction techniques, not applicable for relativistic energies. Here we show that the vortex states of different particles, including hadrons, ions, and nuclei, can be generated in a large class of processes with two final particles simply by altering a postselection protocol. Thanks to entanglement and to the uncertainty relations, an evolved state of a final particle becomes twisted if the momentum azimuthal angle of the other particle is measured with a large uncertainty. We give several examples, including Cherenkov and undulator radiation, particle collisions with intense laser beams, $e\mu \to e\mu, ep \to ep$. This technique can be adapted for ultrarelativistic lepton and hadron beams of linear colliders, and it can also facilitate the development of sources of X-ray and $\gamma$-range twisted photons at storage rings and free-electron lasers.