  A novel form of quantum control is proposed by applying twisted-light also
known as optical vortex beams to drive ultra-narrow atomic transitions in
neutral Ca, Mg, Yb, Sr, Hg and Cd bosonic isotopes. This innovative all-optical
spectroscopic method introduces spatially tailored electric and magnetic fields
to fully rewrite atomic selection rules reducing simultaneously probe-induced
frequency-shifts and additional action of external ac and dc field distortions.
A twisted-light focused probe beam produces strong longitudinal electric and
magnetic fields along the laser propagation axis which opens the 1S0-3P0 doubly
forbidden clock transition with a high E1M1 two-photon excitation rate. This
long-lived clock transition is thus immune to nonscalar electromagnetic
perturbations. Zeeman components of the M2 magnetic quadrupole 1S0-3P2
transition considered for quantum computation and simulation are now
selectively driven by transverse or longitudinal field gradients with vanishing
electric fields. These field gradients are manipulated by the mutual action of
orbital and spin angular momentum of the light beam and are used in presence of
tunable vector and tensor polarizabilities. A combination of these two
different twisted-light induced clock transitions within a single quantum
system, at the same magic wavelength and in presence of a common thermal
environment significantly reduces systematic uncertainties. Furthermore, it
generates an optical synthetic frequency which efficiently limits the blackbody
radiation shift and its variations at room temperature. Engineering
light-matter interaction by optical vortices will benefit to experimental
atomic and molecular platforms targeting an optimal coherent control of quantum
states, reliant quantum simulation, novel approach to atomic interferometry and
precision tests of fundamental theories in physics and high-accuracy optical
metrology.
