Alignment of s-state Rydberg molecules in magnetic fields

TL;DR

This paper explores how weak magnetic fields can influence s-state Rydberg molecules through spin-orbit coupling, enabling their alignment despite their spherical symmetry, and suggests new experimental avenues for relativistic scattering studies.

Contribution

It reveals a mechanism by which s-state Rydberg molecules can be aligned using magnetic fields via spin-orbit effects, a novel insight into their magnetic response.

Findings

Magnetic fields can induce alignment of s-state Rydberg molecules.

Spin-orbit coupling affects electron-atom interactions under magnetic fields.

Predictions enable experimental access to relativistic scattering physics.

Abstract

We unravel some peculiar properties of ultralong-range Rydberg molecules formed by an $s$-state $^{87}$Rb Rydberg atom and a corresponding ground-state atom whose electronic orbitals are spherically symmetric and therefore should not be influenced by the presence of weak magnetic fields. However, the electron-atom interaction, which establishes the molecular bond, is under certain conditions subject to a sizeable spin-orbit coupling and, hence, sensitive to the magnetic field. This mechanism can be harnessed to counterintuitively align the $s$-state molecules with respect to the field axis. We demonstrate this by analyzing the angular-dependent Born-Oppenheimer potential energy surfaces and the supported vibrational molecular states. Our predictions open novel possibilities to access the physics of relativistic electron-atom scattering experimentally.