We numerically simulate the dynamics of aggregation of interacting atomic clusters deposited on a surface. We show that the shape of the structures resulting from their aggregation-limited random walk is affected by the presence of a binary interpart
icle Laplacian potential due to, for instance, the surface stress field. We characterize the morphologies we obtain by their Hausdorff fractal dimension as well as the so-called external fractal dimension, which appears more sensitive to the potential. We demonstrate the relevance of our model by comparing it to previously published experimental results for antymony and silver clusters deposited onto graphite surface.
We propose a technique that allows to simultaneously perform universal control of the evolution operator and compensate for the first order contribution of an arbitrary Hermitian constant noise. We show that, at least, a three-valued Hamiltonian is n
eeded in order to protect the system against any such noise. This technique is illystrated by an explicit algorithm for a control sequence that is applied to numerically design a safe two-qubit gate.
H.E.S.S. observations of the old-age (>10^4yr; ~0.5deg diameter) composite supernova remnant (SNR) W 28 reveal very high energy (VHE) gamma-ray emission situated at its northeastern and southern boundaries. The northeastern VHE source (HESS J1801-233
) is in an area where W 28 is interacting with a dense molecular cloud, containing OH masers, local radio and X-ray peaks. The southern VHE sources (HESS J1800-240 with components labelled A, B and C) are found in a region occupied by several HII regions, including the ultracompact HII region W 28A2. Our analysis of NANTEN CO data reveals a dense molecular cloud enveloping this southern region, and our reanalysis of EGRET data reveals MeV/GeV emission centred on HESS J1801-233 and the northeastern interaction region.
