RESUMEN
Phonon nonlinearities play an important role in hybrid quantum networks and on-chip quantum devices. We investigate the phonon statistics of a mechanical oscillator in hybrid systems composed of an atom and one or two standard optomechanical cavities. An efficiently enhanced atom-phonon interaction can be derived via a tripartite atom-photon-phonon interaction, where the atom-photon coupling depends on the mechanical displacement without practically changing a cavity frequency. This novel mechanism of optomechanical interactions, as predicted recently by Cotrufo et al. [Phys. Rev. Lett.118, 133603 (2017)10.1103/PhysRevLett.118.133603], is fundamentally different from standard ones. In the enhanced atom-phonon coupling, the strong phonon nonlinearity at a single-excitation level is obtained in the originally weak-coupling regime, which leads to the appearance of phonon blockade. Moreover, the optimal parameter regimes are presented both for the cases of one and two cavities. We compared phonon-number correlation functions of different orders for mechanical steady states generated in the one-cavity hybrid system, revealing the occurrence of phonon-induced tunneling and different types of phonon blockade. Our approach offers an alternative method to generate and control a single phonon in the quantum regime and could have potential applications in single-phonon quantum technologies.
RESUMEN
During storage of a spring onion (Allium fistulosa var. dacong), the plant is unable to assimilate external resource, nutrient requirement of the new bud is entirely drawn from the withering leaf where both food reserves and protoplasmic constituents (i.e. organic complexes containing the essential mineral elements) are to be mobilized. Evidences were given to show that the withdrawal process of cell contents from the old part for establishing the new growth should be considered as an alternative mode or a supplementary measure of normal phloem transport of leaf photosynthates. Removal of cell contents from the declining old part to the developing new growth is of frequent occurrence in higher plants. In the present case, it followed the process of programmed cell death (PCD). That was examined and shown by electron microscopy and biochemical analysis. There appeared shrinkage of cell volume, dissolution of cell constitution and degradation of DNA. The present investigation has also shown that the withdrawal of cell contents from the declining leaf sheath of spring onion can be wholly exhaustive. It may be carried out by active movement of the partially degraded protoplasmic constituents in forms of fragments and vesicles across the tissue, until hardly anything in the cellulose framework of the dry papery sheath, except a few crystals of Ca2+. Presence of high ATPase and APase activities along the transport path also supports this view.
