Quantum State Sharing of an Arbitrary Three-Atom State by Using Five-Atom Cluster State in Cavity QED

We present a scheme for implementing the deterministic quantum state sharing of an arbitrary three-atom state by using a five-atom cluster state and a Bell-state in cavity QED. In the scheme, it does not involve Bell-state measurement and only needs to perform the single-atom measurements. Our scheme is not sensitive to both the cavity decay and the atom radiation, which is of importance in view of decoherence.     

Curved traversable wormholes in (3+1)-dimensional spacetime

We present the general method of constructing curved traversable wormholes in (3+1)-d spacetime and proceed to thoroughly discuss the physics of a zero tidal force metric without cross-terms. The (3+1)-d solution is compared with the recently studied lower-dimensional counterpart, where we identify that the much richer physics—involving pressures and shear forces of the mass-energy fluid supporting the former—is attributed to the mixing of all three spatial coordinates. Our (3+1)-d universe is the lowest dimension where such nontrivial terms appear. An explicit example, the static zero tidal force (3+1)-d catenary wormhole is analysed and we show the existence of a geodesic through it supported locally by non-exotic matter, similar to the (2+1)-d version. A key difference is that positive mass-energy is used to support the entire (3+1)-d catenary wormhole, though violation of the null energy condition in certain regions is inevitable. This general approach of first constructing the geometry of the spacetime and then using the field equations to determine the physics to support it has the potential to discover new solutions in general relativity or to generalise existing ones. For instance, the metric of a time-evolving inflationary wormhole with a conformal factor can actually be geometrically constructed using our method.     

Wavefront reconstruction of Fresnel diffraction field by optical methods and digital algorithm

The experimental methods for measuring the phase distribution of Fresnel diffraction field by using interference and polarization information are given in this paper. An effective algorithm for phase retrieval under Fresnel-zone transform is also presented.     

Membrane tube pearling induced by a coupling of osmotic pressure and nanoparticle adhesion

ABSTRACT

In this work, a coarse-grained molecular dynamics simulation method that belongs to the class of dissipative particle dynamics scheme with implicit solvent was used to indicate that adsorption of nanoparticles (NPs) inside a lipid membrane tube and pressure difference across the membrane, e.g. osmotic pressure, cooperatively induce membrane tube pearling. We demonstrate that NP adsorption and aggregation initiate the shape transformation of the lipid tube, and pressure difference provides a driving force for pearling transition. Depending on the dynamic coupling of tube shape transition and NP aggregation in the interior of the tube, different shape transitions via four kinds of pearling pathways are recognised, including pearls on a string (i.e. vesicles are interconnected via either a chain or double-chain of NPs) and tube-to-vesicle transition that is dominated kinetically either by NP-membrane attraction or by pressure difference. Considering the fact that biological membranes are semipermeable and many proteins interact with the membranes, these findings not only provide a mechanism of membrane tube pearling but also demonstrate the importance of osmotic pressure and protein–membrane interaction for many cell activities related to shape transitions of biomembrane.     

Beam-based calibrations of the BPM offset at C-ADS Injector Ⅱ

Beam-based BPM offset calibration was carried out for Injector II at the C-ADS demonstration facility at the Institute of Modern Physics(IMP), Chinese Academy of Science(CAS). By using the steering coils integrated in the quadrupoles, the beam orbit can be effectively adjusted and BPM positions recorded at the Medium Energy Beam Transport of the Injector II Linac. The studies were done with a 2 m A, 2.1 Me V proton beam in pulsed mode.During the studies, the "null comparison method" was applied for the calibration. This method is less sensitive to errors compared with the traditional transmission matrix method. In addition, the quadrupole magnet's center can also be calibrated with this method.     

Interaction mechanism between serine functional groups and single‐walled carbon nanotubes

The adsorption of serine (Ser) on the (8, 8) and (10, 0) single‐walled carbon nanotubes (CNTs) was studied by density‐functional tight‐binding calculations. For Ser, the two most stable configurations were chosen to research the interactions with the CNT. It found that the most stable Ser/(8, 8) and Ser/(10, 0) complexes have similar structures, in which the amino group, carboxyl, and side chain of serine directly interact with the CNT. The binding energies, charge transfer properties, the shortest distance (d₁) between the H atom and the corresponding benzene ring, distance (d₂) between the H atom and the center of benzene ring (HCB), and the angle (α) between the HCB line and the corresponding benzene ring plane were analyzed to explain the interactions. Because of the interaction, the ?CH of the main chain runs away from the surface of CNT, and the angles between the ?C?H bond of the main chain and the carboxyl, the amino group, and the side chain of the Ser become small. The strain energies and changes of angles and dihedral angles of the serine after adsorption were analyzed to illustrate the deformation. The interactions of Ser with the CNT were further illustrated by calculating the molecular orbitals and the partial density of states of the stable complexes. We further compared the binding energies of armchair (n, n) and zigzag (n, 0) CNTs to investigate the diameter dependence of binding energies. Copyright © 2015 John Wiley & Sons, Ltd.     

Improved crystal quality of GaN film with the in-plane lattice-matched Ino.17Alo.s3N interlayer grown on sapphire substrate using pulsed metal-organic chemical vapor deposition

We report on an improvement in the crystal quality of GaN film with an Ino.17Alo.83N interlayer grown by pulsed metal-organic chemical vapor deposition, which is in-plane lattice-matched to GaN films. The indium composition of about 17% and the reductions of both screw and edge threading dislocations （TDs） in GaN film with the InA1N interlayer are estimated by high resolution X-ray diffraction. Transmission electron microscopy （TEM） measurements are employed to understand the mechanism of reduction in TD density. Raman and photoluminescence measurements indicate that the InA1N interlayer can improve the crystal quality of GaN film, and verify that there is no additional residual stress induced into the GaN film with InA1N interlayer. Atomic force microscopy measurement shows that the InA1N interlayer brings in a smooth surface morphology of GaN film. All the results show that the insertion of the InA1N interlayer is a convenient method to achieve excellent crystal quality in GaN epitaxy.     

A facile method for the synthesis of large‐size Ag nanoparticles as efficient SERS substrates

Silver nanoparticles (Ag NPs) enjoy a reputation as an ultrasensitive substrate for surface‐enhanced Raman spectroscopy (SERS). However, large‐scale synthesis of Ag NPs in a controlled manner is a challenging task for a long period of time. Here, we reported a simple seed‐mediated method to synthesize Ag NPs with controllable sizes from 50 to 300 nm, which were characterized by scanning electron microscopy (SEM) and UV–Vis spectroscopy. SERS spectra of Rhodamine 6G (R6G) from the as‐prepared Ag NPs substrates indicate that the enhancement capability of Ag NPs varies with different excitation wavelengths. The Ag NPs with average sizes of ~150, ~175, and ~225 nm show the highest SERS activities for 532, 633, and 785‐nm excitation, respectively. Significantly, 150‐nm Ag NPs exhibit an enhancement factor exceeding 10⁸ for pyridine (Py) molecules in electrochemical SERS (EC‐SERS) measurements. Furthermore, finite‐difference time‐domain (FDTD) calculation is employed to explain the size‐dependent SERS activity. Finally, the potential of the as‐prepared SERS substrates is demonstrated with the detection of malachite green. Copyright © 2016 John Wiley & Sons, Ltd.     

“Eigen-Operator” Method of the Square of Schroedinger Operator in Interaction Picture and Its Application in Describing Parametric Amplifiers

We extend the method of searching “eigen-operator” of the square of the Schroedinger operator to the interaction picture, which not only helps to construct Hamiltonians of two kinds of parametric amplifiers but also leads to a new uncertainty relation regarding to the free Hamiltonian and the interacting Hamiltonian.     

Polarity switching and transient responses in single nanotube nanofluidic transistors

We report the integration of inorganic nanotubes into metal-oxide-solution field effect transistors (FETs) which exhibit rapid field effect modulation of ionic conductance. Surface functionalization, analogous to doping in semiconductors, can switch the nanofluidic transistors from p-type to ambipolar and n-type field effect transistors. Transient study reveals the kinetics of field effect modulation is controlled by ion-exchange step. Nanofluidic FETs have potential implications in subfemtoliter analytical technology and large-scale nanofluidic integration.