EGAS41 - Swansea University

41 st EGAS CP 128 Gdańsk 2009
Line shapes of optical Feshbach resonances near the
intercombination transition of bosonic Ytterbium
M. Borkowski 1,∗ , R. Ciury̷lo 1 , P.S. Julienne 2 , S. Tojo 3 , K. Enomoto 4 , Y. Takahashi 5
1 Instytut Fizyki, Uniwersytet Miko̷laja Kopernika, ul. Grudzi¸adzka 5/7, 87–100 Toruń, Poland.
2 Joint Quantum Institute, National Institute of Standards and Technology and The University
of Maryland, 100 Bureau Drive, Stop 8423, Gaithersburg, Maryland 20899-8423, USA.
3 Department of Physics, Faculty of Science, Gakushuin University, Tokyo 171-8588, Japan.
4 Department of Physics, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan.
5 Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502,
Japan.
∗ Corresponding author: mateusz.borkowski@fizyka.umk.pl,
The properties of bosonic Ytterbium photoassociation spectra near the intercombination
transition 1 S 0 – 3 P 1 are studied theoretically at ultra low temperatures. We demonstrate
how the shapes and intensities of rotational components of optical Feshbach resonances
are affected by mass tuning of the scattering properties of the two colliding ground state
atoms. Particular attention is given to the relationship between the magnitude of the
scattering length and the occurrence of shape resonances in higher partial waves of the
van der Waals system. We develop a mass scaled model of the excited state potential
that represents the experimental data for different isotopes. The shape of the rotational
photoassociation spectrum for various bosonic Yb isotopes can be qualitatively different.
Γ eg
/h [MHz]
K [cm 3 /s]
10 2
10 0
172
Yb, E(Je =1)= -2237 MHz
10 -2
10 -4
10 µK
2×10 -14
0
2×10 -15
100 µK
1×10 -15
J e =1 J e =3 J e =5
0
10 -6
10 -9 10 -8 10 -7 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 10 0
ε r
/k B
[K]
4×10 -14 s-wave
d-wave
g-wave
i-wave
2×10 -16
1 mK
0
-2300 -2200 -2100 -2000
∆/h [MHz]
Γ eg
/h [MHz]
K [cm 3 /s]
10 2
10 0
10 -2
10 -4
10 -6
10 -9 10 -8 10 -7 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 10 0
ε r
/k B
[K]
2×10 -15 10 µK
s-wave
1×10 -15
d-wave
g-wave
i-wave
0
6×10 -15
3×10 -15
0
174
Yb, E(Je = 1) = -1974 MHz
100 µK
1×10 -15 1 mK 4×10 -17
5×10 -16
2×10 -17
0
0
-2000 -1900 -1800 -1700
∆/h [MHz]
Figure 1: For the two isotopes: 172 Yb and 174 Yb the light induced width Γ eg is shown as
a function of the collision energy ε r for a few lowest partial waves. The two-body loss rate
coefficient K is also presented on the plot as a function of the laser detuning ∆, at different
temperatures of the ultra cold gas. Results obtained at 100 µK clearly demonstrate the impact
of shape resonances (g-wave in the case of 172 Yb and d-wave in the case of 174 Yb) on the
simulated spectra.
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