  We consider from a microscopic perspective large deviation properties of
several stochastic interacting particle systems, using their mapping to
integrable quantum spin systems. A brief review of recent work is given and
several new results are presented: (i) For the general disordered symmectric
exclusion process (SEP) on some finite lattice conditioned on no jumps into
some absorbing sublattice and with initial Bernoulli product measure with
density $\rho$ we prove that the probability $S_\rho(t)$ of no absorption event
up to microscopic time $t$ can be expressed in terms of the generating function
for the particle number of a SEP with particle injection and empty initial
lattice. Specifically, for the symmetric simple exclusion process on $\mathbb
Z$ conditioned on no jumps into the origin we obtain the explicit first and
second order expansion in $\rho$ of $S_\rho(t)$ and also to first order in
$\rho$ the optimal microscopic density profile under this conditioning. For the
disordered ASEP on the finite torus conditioned on a very large current we show
that the effective dynamics that optimally realizes this rare event does not
depend on the disorder, except for the time scale. For annihilating and
coalescing random walkers we obtain the generating function of the number of
annihilated particles up to time $t$, which turns out to exhibit some universal
features.
