  While capable of imaging the atoms constituting thin slabs of material, the
achievable resolution of conventional electron imaging techniques in a
transmission electron microscope (TEM) is very sensitive to the partial spatial
coherence of the electron source, lens aberrations and mechanical instabilities
of the microscope. The desire to break free from the limitations of the
apparatus spurred the popularity of ptychography, a computational phase
retrieval technique that, to some extent, can compensate for the imperfections
of the equipment. Recently it was shown that ptychography is capable of
resolving specimen features as fine as the blurring due to the vibrations of
atoms, a limit defined not by the microscope, but by the investigated sample
itself. Here we report on the successful application of a mixed-object
formalism in the ptychographic reconstruction that enables the resolution of
fluctuations in atomic positions within real space. We show a reconstruction of
a symmetric {\Sigma}9 grain boundary in silicon from realistically (molecular
dynamics) simulated data. By reconstructing the object as an ensemble of 10
different states we were able to observe movements of atoms in the range of
0.1-0.2 \AA in agreement with the expectation. This is a significant step
forward in the field of electron ptychography, as it enables the study of
dynamic systems with unprecedented precision and overcomes the resolution limit
so far considered to be imposed by the thermal motion of the atoms.
