Observability of the superkick effect within a quantum-field-theoretical approach

Abstract

An atom placed in an optical vortex close to the axis may, upon absorbing a photon, acquire a transverse momentum much larger than the transverse momentum of any plane-wave component of the vortex lightfield. This surprising phenomenon dubbed superkick has been clarified previously in terms of the atom wave packet evolution in the field of an optical vortex treated classically. Here, we study this effect within the quantum field theoretical (QFT) framework. We consider collision of a Bessel twisted wave with a compact Gaussian beam focused to a small focal spot $\sigma$ located at distance $b$ from the twisted beam axis. Through a qualitative discussion supported by exact analytical and numerical calculations, we recover the superkick phenomenon for $\sigma \ll b$ and explore its limits when $\sigma$ becomes comparable to $b$. On the way to the final result within the QFT treatment, we encountered and resolved apparent paradoxes related to subtle issues of the formalism. These results open a way to a detailed QFT exploration of other superkick-related effects recently suggested to exist in high-energy collisions.

16 pages, 7 figures. v2: clarifications added, pictures updated, comments on previous papers modified, results unchanged

References in corpus (10)

• Electromagnetic Angular Momentum
• Electromagnetic Force and Momentum
• Colliding particles carrying non-zero orbital angular momentum
• Twisted electron in a strong laser wave
• Elastic scattering of vortex electrons provides direct access to the Coulomb phase
• Scattering of wave packets with phases
• Modification of multipole transitions by twisted light
• Optical super-resolution sensing of a trapped ion's wave packet size
• Delta baryon photoproduction with twisted photons
• Wave function of a photon produced in the resonant scattering of twisted light by relativistic ions

Cited by in corpus (7)

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• Unambiguous detection of high energy vortex states via the superkick effect
• Superkicks and the photon angular and linear momentum density
• Threshold effects in high-energy vortex state collisions
• Photon emission by vortex particles accelerated in a linac
• Universal features of high-energy scattering of Laguerre-Gaussian states