Suppressing the loss of ultracold molecules via the continuous quantum Zeno effect

We develop theoretical methods to explain the recently observed suppression of chemical reactions between two rotational states of fermionic KRb molecules confined in 1D tubes with a superimposed optical lattice along them [Yan {\it et al}., Nature 501, 521 (2013)]. The loss suppression is a consequence of both lattice confinement and the continuous quantum Zeno effect, which in this case takes place in the regime where the two-body loss is larger than other energy scales in the lattice. To quantitatively analyze the experiment, we derive a renormalized single-band model which accounts for 3D multi-band effects, and formulate from it a rate equation and mean-field theory validated by comparing with numerically exact t-DMRG. We demonstrate that the renormalized model captures the measured dependence of the loss rate on all lattice parameters, allowing us to determine the filling fraction.