[en] Quantum transport properties are instrumental to understanding quantum coherent transport processes. Potential applications of quantum transport are widespread, in areas ranging from quantum information science to quantum engineering, and not restricted to quantum state transfer, control and manipulation. Here, we study light transport in a ring array of coupled resonators enclosed synthetic magnetic flux. The ring configuration, with an arbitrary number of resonators embedded, forms a two-arm Aharonov–Bohm interferometer. The influence of magnetic flux on light transport is investigated. Tuning the magnetic flux can lead to resonant transmission, while half-integer magnetic flux quantum leads to completely destructive interference and transmission zeros in an interferometer with two equal arms. -- Highlights: •The light transport is investigated through ring array of coupled resonators enclosed synthetic magnetic field. •Aharonov–Bohm ring interferometer of arbitrary configuration is investigated. •The half-integer magnetic flux quantum leads to destructive interference and transmission zeros for two-arm at equal length. •Complete transmission is available via tuning synthetic magnetic flux.

[en] We study scaling behavior and phase diagram of a PT-symmetric non-Hermitian Bose–Hubbard model. In the free interaction case, using both analytical and numerical approaches, the metric operator for many-particle is constructed. The derived properties of the metric operator, similarity matrix and equivalent Hamiltonian reflect the fact that all the matrix elements change dramatically with diverging derivatives near the exceptional point. In the nonzero interaction case, it is found that even small on-site interaction can break the PT symmetry drastically. It is demonstrated that the scaling law can be established for the exceptional point in both small and large interaction limit. Based on perturbation and numerical methods, we also find that the phase diagram shows rich structure: there exist multiple regions of unbroken PT symmetry. - Highlights: ► Generalization is done to many-particle sector of PT-symmetric non-Hermitian system. ► The metric operator, similarity matrix and equivalent Hamiltonian possess diverging derivatives near the exceptional point. ► The scaling law is established for the exceptional point of a PT-symmetric non-Hermitian Bose–Hubbard model. ► The phase diagram shows that multiple regions of unbroken PT symmetry exist. ► It is shown that even small on-site interaction can break the PT symmetry drastically.

[en] We explore an alternative way of finding the link between a PT non-Hermitian Hamiltonian and a Hermitian one. Based on the analysis of the scattering problem for an imaginary potential and its time-reversal process, it is shown that any real-energy eigenstate of a PT tight-binding lattice with on-site imaginary potentials shares the same wave function with a resonant transmission state of the corresponding Hermitian lattice embedded in a chain. It indicates that the PT eigenstate of a PT non-Hermitian Hamiltonian has a connection to the resonance transmission state of the extended Hermitian Hamiltonian.

[en] We analyzed the distribution of chromogranins A and B in normal and neoplastic endocrine tissues with secretory granules using ³⁵S-labeled and biotin-labeled oligonucleotide probes by in situ hybridization (ISH). Both radioactive and nonradioactive probes detected messenger RNAs (mRNAs) in frozen and paraffin tissue sections. Endocrine tissues with variable immunoreactivities for chromogranin A protein, such as small-cell lung carcinomas, neuroblastomas, insulinomas, and parathyroid adenomas, expressed the mRNA for chromogranins A and B in most cells. Some technical problems with the biotinylated probes included nonspecific nuclear staining and endogenous alkaline phosphatase, which was not completely abolished by levamisole pretreatment. A differential distribution of chromogranins A and B was seen in pituitary prolactinomas, which expressed abundant chromogranin B but not chromogranin A mRNAs, and in parathyroid adenomas, which expressed abundant chromogranin A but only small amounts of chromogranin B mRNAs. These results indicate that ISH can be used to detect chromogranins A and B in endocrine tissues with radioactive and biotinylated oligonucleotide probes and that the mRNAs for chromogranin A and B are demonstrable in some tumors even when the chromogranin proteins cannot be detected by immunohistochemistry

[en] Beam-beam effects in HERA were studied with a self-consistent beam-beam simulation by using the particle-in-cell method. A remarkable agreement between the experimental measurement and the simulation result was observed on the emittance growth, luminosity reduction, and coherent beam-beam tune shifts. The simulation study also showed that the chaotic coherent beam-beam instability could occur in HERA and this collective beam-beam instability could be avoided with a slightly different tune

[en] We develop the partitioning technique for quantum discrete systems. The graph consists of several subgraphs: a central graph and several branch graphs, with each branch graph being rooted by an individual node on the central one. We show that the effective Hamiltonian on the central graph can be constructed by adding additional potentials on the branch-root nodes, which generates the same result as does the the original Hamiltonian on the entire graph. Exactly solvable models are presented to demonstrate the main points of this paper.

[en] Using a sample of 3 million J/ψ decays collected at BEPC e⁺e^- collider, the BES collaboration has studied the J/ψ decays into γK⁺K^- and ωππ. There is a structure near 2.2 GeV in γK⁺K^- decay and helicity amplitude ratios of f₂(1270) in ωπ⁺π^- decay have been given. (author)

[en] We investigate a pseudo-Hermitian lattice system, which consists of a set of isomorphic pseudo-Hermitian clusters coupled together in a Hermitian manner. We show that such non-Hermitian systems can act as Hermitian systems. This is made possible by considering the dynamics of a state involving an identical eigenmode of each isomorphic cluster. It still holds when multiple eigenmodes are involved and additional restrictions on the state are imposed. This Hermitian dynamics is demonstrated for the case of an exactly solvable PT-symmetric ladder system.

[en] We investigate the particle trapping and scattering properties in a tight-binding network, which consists of several subgraphs. The particle trapping condition is proved under which particles can be trapped in a subgraph without leaking. Based on exact solutions for the configuration of a π-shaped lattice, it is argued that the bound states in a specified subgraph are of two types, resonant and evanescent. We also link the result to the scattering problem. The scattering features of the π-shaped lattice is investigated in the framework of the Bethe ansatz.

[en] In cases of multi-bunches operation in storage-ring colliders, serious long-range beam-beam effects could be due to many parasitic collisions that are localized inside interaction regions or/and distributed around the ring. To reduce the long-range beam-beam effects, the compensation of long-range beam-beam interaction with magnetic multipole correctors based on minimizations of nonlinearities in one-turn or sectional maps of a collider has been proposed. With LHC as a test model, the effectiveness of the multipole compensation of long-range beam-beam interactions was studied in terms of improvement of dynamic aperture and reduction of emittance growth. The study showed that both the local and global compensation of long-range beam-beam interactions with magnetic multipole correctors is very effective in increasing the dynamic aperture and improving the linearity of the phase-space region relevant to the beams