Ana Maria Rey, Deborah Jin and Jun Ye
JILA, NIST and University of Colorado
DARPA OLE Review,
Polar Molecules
Miami, Nov 27, 2012
Optical atomic clocks
Coherent spectroscopy
Nicholson et al., arXiv:1210.0064
3P (e)
0
3P
0-
1S
1S (g)
0
0:
Effective spin 1/2 system
during clock interrogation
With atom-light coherence times reaching
several seconds, even very weak
interactions can dominate the dynamics.
Collective-spin
S
reactive
Vab: p-wave int
Uab: s-wave int
S x ,y ,z   Snx , y , z
n
n: Harmonic oscillator mode
Ramsey fringe decay vs. the spin tipping angle
Mean field.

N- dependent effective B
field

H  2  Sz  CN S z
Quantum fluctuactions Further decay
Poissonian distribution  Ramsey
fringe dephasing
Full master Eq.
Normalized Contrast
Normalized Contrast
1D

 (nˆ  S )
2
2
 4
  Laser
2
N
2
one-axis twisting
900 atoms
20 ms
4000 atoms
KitagawaLaser+Many-body
& Ueda, PRA, 1993.
20 ms
(spin squeezing) Polzik,
Vuletic, Thompson …
Laser
40 ms
40 ms
()
()
Reactive collisions: M. Foss-Feig et al, arXiv:1207.4741, PRL (in press)
Conventional wisdom: losses are a problem to be avoided.
Are there any circumstances under which they can be exploited?
Under certain reasonable conditions, yes!
- Two component fermions
- Non degenerate (allowing for incoherent spin mixtures)
- Still ultracold, so that s-wave scattering dominates
Losses induce
entanglement, no
engineering!!
SU(N) Heisenberg Models
N=2I+1 I: nuclear spin
N=10 in Sr
Quantum Magnetism and beyond: Chiral Spin Liquids, Valence Bond
solids,..
Hermele, Gurarie, AMR PRL 103, 135301 (2009)
Adiabatic Loading
Optical lattices
KRA Hazzard, V Gurarie, M Hermele, AM Rey, PRA 85, 041604(R) (2012)
Experiments on 173Yb (N=6)
Taie, R Yamazaki, S Sugawa, Y Takahashi, arxiv:1208:4883 (Nature Physics, to appear)
our theory
L Bonnes et al, PRL 109, 205305 (2012)
Stochastic series expansion QMC (1D: no sign problem)
Spin structure factor
related: L Messio and F Mila arxiv:1207.1320
log10(density [cm-3])
Carr, DeMille, Krems, Ye, New. J. Phys. 2009.
Novel phases
& quantum many-body
Dipolar quantum gas
12 Quantum information
Ultracold Chemistry
Molecule optics & circuitry
Cold controlled chemistry
9
Phase
space
density
Novel collisions
Fundamental tests
Precision measurement
6
log10(temperature [K])
3
-9
-6
-3
0




40K
Temperature ~ 160 nK
T/TF = 1.4
Density ~1012/cm3
r ~ 0.1
Fermions
K. Ni et al.,
Science 322, 231 (2008).
87Rb
Bosons
KRb molecules
(Dipole
~0.5 Debye)
3D gas
Fast decay rates: millisecond lifetime
Ospelkaus et al., Science (2010). K.-K. Ni et al., Nature (2010).
Solution
2D quantum gas
M. de Miranda, et al.,Nat. Phys. 7, 502 (2011).
Lifetime~ 1 second
E
Further Suppression 3D lattice
0D gas
Low density: filling ~0.1-0.2
1D gas
A. Chotia et al PRL 108, 080405 (2012).
Use rotational degrees of freedom as effective spin
degrees of freedom.
N:rotation
N=1 |
N=0
H 
i, j
Select two
dressed levels :
Effective spin ½
system
|
1  3 cos 2 ij
| ri  rj |
3
J S S
z
z i
Ising
z
j
(
dipole moment
 J S S  S S
x
i
x
j
Flip-flop
A. Gorshkov et al: PRL.107.115301(2011)
PRA 84,033619 (2011)
y
i
y
j
)
Even at current filling dipolar interactions should be visible in
K. Hazzard et al , arxiv:1209.4076
Ramsey spectroscopy
1D system, DMRG solution
Tipping angle
dependence
p/10
Use split electric field
plates to independently
control E & gradient.
Vertical E field polarizes
KRb; Radial E-field
gradient tilts the trap.
-V
-(V+dV)
V
V + dV
In 2D, TF  N , Log(N)/Log(T) < 2 means increasing PSD.
KRb Number (x 103)
30
30
10
10
3
E=0, anti-evaporate time 3
Log(N)/Log(T) = 2.3
1
0.2
0.22
0.24
1
30
E = 3.4 kV/cm
10
10
3
3
0.2
0.3
0.4
0.5
0.6
0.7
0.3
0.4 0.5 0.6
E = 4.3 kV/cm
Log(N)/Log(T) = 1.2
Log(N)/Log(T) = 1.5
1
E gradient
~ 40 V/cm2
Log(N)/Log(T) = -5
0.18
30
E = 2.8 kV/cm
1
0.15
Temperature (mK)
0.2
0.25 0.3 0.35
Decrease T/TF
by 20%
Electric field
OH
HCO
H2CO
H2O
Stuhl et al., arXiv:1209.6343 ,Nature, in press (2012).
Cooling by at least an
order of magnitude in
temperature and three
orders in phase space
density!!
MW
Hummon, Yeo, Stuhl, Collopy, Xia, Ye, arXiv:1209.4069
Reach final T ~2 m K
Theory:
M. Foss-Feig K. Hazzard S. Manmana A. Gorshkov
S. Wessel and L.
Bonnes
M. Hermele
V. Gurarie
J. Bohn, G. Quemener, P. Julienne, J. v. Stecher
The Sr team:
The KRb team:
D. Jin
Jun Ye
M. Swallows, M. Martin, M. Bishof,S
Blatt, X. Zhang, C. Benko
OH – YO team:
B. Yan, B. Neyenhuis, S. Moses,
B. Gadway, J. Covey
B. Stuhl, M.Hummon, M. Yeo