



02029nas a2200241   4500008004100000245006600041210006500107260001400172490000800186520133800194100002601532700001801558700002301576700001201599700002201611700002101633700002001654700002301674700001201697700002101709700002001730856003701750       2014                        eng d00aMany-body dynamics of dipolar molecules in an optical lattice0 aManybody dynamics of dipolar molecules in an optical lattice  c2014/11/70 v1133 a  Understanding the many-body dynamics of isolated quantum systems is one of
the central challenges in modern physics. To this end, the direct experimental
realization of strongly correlated quantum systems allows one to gain insights
into the emergence of complex phenomena. Such insights enable the development
of theoretical tools that broaden our understanding. Here, we theoretically
model and experimentally probe with Ramsey spectroscopy the quantum dynamics of
disordered, dipolar-interacting, ultracold molecules in a partially filled
optical lattice. We report the capability to control the dipolar interaction
strength, and we demonstrate that the many-body dynamics extends well beyond a
nearest-neighbor or mean-field picture, and cannot be quantitatively described
using previously available theoretical tools. We develop a novel cluster
expansion technique and demonstrate that our theoretical method accurately
captures the measured dependence of the spin dynamics on molecule number and on
the dipolar interaction strength. In the spirit of quantum simulation, this
agreement simultaneously benchmarks the new theoretical method and verifies our
microscopic understanding of the experiment. Our findings pave the way for
numerous applications in quantum information science, metrology, and condensed
matter physics.
1 aHazzard, Kaden, R. A.1 aGadway, Bryce1 aFoss-Feig, Michael1 aYan, Bo1 aMoses, Steven, A.1 aCovey, Jacob, P.1 aYao, Norman, Y.1 aLukin, Mikhail, D.1 aYe, Jun1 aJin, Deborah, S.1 aRey, Ana, Maria  uhttp://arxiv.org/abs/1402.2354v102020nas a2200265   4500008004100000245009000041210006900131260001400200490000800214520123900222100001501461700001801476700002301494700002801517700001801545700002601563700001201589700002201601700002101623700002101644700001201665700002001677700002001697856003701717       2014                        eng d00aSuppressing the loss of ultracold molecules via the continuous quantum  Zeno effect
0 aSuppressing the loss of ultracold molecules via the continuous q  c2014/2/200 v1123 a  We investigate theoretically the suppression of two-body losses when the
on-site loss rate is larger than all other energy scales in a lattice. This
work quantitatively explains the recently observed suppression of chemical
reactions between two rotational states of fermionic KRb molecules confined in
one-dimensional tubes with a weak lattice along the tubes [Yan et al., Nature
501, 521-525 (2013)]. New loss rate measurements performed for different
lattice parameters but under controlled initial conditions allow us to show
that the loss suppression is a consequence of the combined effects of lattice
confinement and the continuous quantum Zeno effect. A key finding, relevant for
generic strongly reactive systems, is that while a single-band theory can
qualitatively describe the data, a quantitative analysis must include multiband
effects. Accounting for these effects reduces the inferred molecule filling
fraction by a factor of five. A rate equation can describe much of the data,
but to properly reproduce the loss dynamics with a fixed filling fraction for
all lattice parameters we develop a mean-field model and benchmark it with
numerically exact time-dependent density matrix renormalization group
calculations.
1 aZhu, Bihui1 aGadway, Bryce1 aFoss-Feig, Michael1 aSchachenmayer, Johannes1 aWall, Michael1 aHazzard, Kaden, R. A.1 aYan, Bo1 aMoses, Steven, A.1 aCovey, Jacob, P.1 aJin, Deborah, S.1 aYe, Jun1 aHolland, Murray1 aRey, Ana, Maria  uhttp://arxiv.org/abs/1310.2221v2