11 research outputs found
Mass scaling and non-adiabatic effects in photoassociation spectroscopy of ultracold strontium atoms
We report photoassociation spectroscopy of ultracold Sr atoms near the
intercombination line and provide theoretical models to describe the obtained
bound state energies. We show that using only the molecular states correlating
with the asymptote is insufficient to provide a mass scaled
theoretical model that would reproduce the bound state energies for all
isotopes investigated to date: Sr, Sr and Sr. We attribute
that to the recently discovered avoided crossing between the
() and () potential
curves at short range and we build a mass scaled interaction model that
quantitatively reproduces the available and bound state energies
for the three stable bosonic isotopes. We also provide isotope-specific
two-channel models that incorporate the rotational (Coriolis) mixing between
the and curves which, while not mass scaled, are capable of
quantitatively describing the vibrational splittings observed in experiment. We
find that the use of state-of-the-art ab initio potential curves significantly
improves the quantitative description of the Coriolis mixing between the two -8
GHz bound states in Sr over the previously used model potentials. We
show that one of the recently reported energy levels in Sr does not
follow the long range bound state series and theorize on the possible causes.
Finally, we give the Coriolis mixing angles and linear Zeeman coefficients for
all of the photoassociation lines. The long range van der Waals coefficients
~a.u. and ~a.u. are reported.Comment: 14 pages, 7 tables, 5 figures. Submitted to Phys. Rev.
Absolute measurement of the ^{1}S_{0} − ^{3}P_{0} clock transition in neutral ^{88}Sr over the 330 km-long stabilized fibre optic link
We report a stability below of two independent optical
lattice clocks operating with bosonic Sr isotope. The value
(429228066418008.3(1.9)(0.9)~Hz) of the absolute
frequency of the - transition was measured with an
optical frequency comb referenced to the local representation of the UTC by the
330 km-long stabilized fibre optical link. The result was verified by series of
measurements on two independent optical lattice clocks and agrees with
recommendation of Bureau International des Poids et Mesures
Accuracy budget of the optical atomic clocks at KL FAMO
This paper presents a detailed accuracy budget of two independent strontium optical lattice clocks at the National Laboratory FAMO (KL FAMO) probed with a single shared ultra-narrow laser. The combined instability of the two frequency standards was after of averaging