[en] This study proposes a modification of existing entanglement purification protocols for pairs of qubits. The proposed protocol restores a desired pure state by standard purification local operations and classical communications, without preliminarily estimating the entangled state to be purified. The proposed protocol is demonstrated to outperform the previously proposed IBM and Oxford protocols

[en] Full text: A scheme of three-particle entanglement purification is presented in this work. The physical system undertaken for investigation is dot-like single quantum well excitons independently coupled through a single microcavity mode. The theoretical framework for the proposed scheme is based on the quantum jump approach for analyzing the progress of the trible-exciton entanglement as a series of conditional measurement has been taken on the cavity field state. We first investigate how cavity photon affects the purity of the double-exciton state and the purification efficiency in two-particle protocol. Then we extend the two-particle case and conclude that the three-exciton state can be purified into W state, which involves the one-photontrapping phenomenon, with a high yield. Finally, an achievable setup for purification using only modest and presently feasible technologies is also proposed. (author)

[en] A method is proposed to create entanglement between two coupled identical polar molecules separated at a distance of tens of nanometres. Entangled states of two coupled polar molecules controlled by half-cycle pulses are studied theoretically. The von Neumann entropy is calculated to characterize the degree of entanglement. By varying the pulse shape of the applied laser, transition from regular to irregular behaviour occurs. Moreover, the entanglement is also found to be enhanced by applying multiple laser pulses. The behaviour from quantum to classical limit is also discussed

[en] Fast radio bursts (FRBs) are millisecond-duration radio transients and can be used as a cosmological probe. However, the dispersion measure (DM) contributed by the intergalactic medium (IGM) is hard to distinguish from other components. In this paper, we use the IllustrisTNG simulation to realistically estimate DM_IGM up to z ∼ 9. We find ${\mathrm{D}\mathrm{M}}_{\mathrm{I}\mathrm{G}\mathrm{M}}={892}_{-<!--\; ???\; -->270}^{+721}$ pc cm⁻³ at z = 1. The probability distribution of DM_IGM can be well fitted by a quasi-Gaussian function with a long tail. The tail is caused by structures along the line of sight in the IGM. Subtracting DM contributions from the Milky Way and host galaxy for localized FRBs, the DM_IGM value is close to that given by the derived DM_IGM–z relation. We also show the ability to constrain the cosmic reionization history with DM_IGM of high-redshift FRBs in the IllustrisTNG universe. The derived DM_IGM–z relation at high redshifts can be well fitted by a tanh reionization model with the reionization redshift z = 5.95, which is compatible with the reionization model used by the IllustrisTNG simulation. DM_IGM of high-redshift FRBs also provides an independent way to measure the optical depth of the cosmic microwave background. Our result can be used to derive the pseudo-redshifts of nonlocalized FRBs for DM_IGM < 4000 pc cm⁻³.

[en] This study proposes quantum secret sharing protocols using product states. The first two protocols adopt the quantum key distribution protocol using product states [Guo et al.Phys. Rev. A 64, 042301 (2001)]. In these two protocols, the sender does not reveal any information about the qutrits until confirming that each receiver has received a qutrit. This study also considers the security and some possible eavesdropping strategies. In the third proposed protocol, three-level Bell states are exploited for qutrit preparation via nonlocality swapping

[en] A microchemical analysis study is reported comparing the grain and grain boundary chemistries of Cu(In,Ga)Se₂ (CIGS) films deposited by three different laboratories by different processes. An analysis of a GaAs wafer is described to provide a calibration of the accuracy and precision of the energy dispersive spectroscopy nanoprobe analysis as applied in the current instruments. When averaged over many measurements the precision of the instrument is ±0.1 at. % and the accuracy is ±1.0 at. % for individual points. The analysis of the CIGS shows less than 0.5 at. % composition difference for each constituent element between grain and grain boundary compositions when averaged over hundreds of data points for most samples. One sample deposited at 400 degree sign C as a bilayer shows different grain and grain boundary compositions with grain boundaries being In deficient and Se rich. Both grain and grain boundary data in this sample scatter along a line between the Cu(In,Ga)Se₂ and CuSe₂ phases, which is a nonequilibrium behavior. The scatter in individual analyses is significantly greater than the noise in the analysis technique indicating real composition differences at different points within both grains and grain boundaries. No evidence was found for other substitutional impurities such as O or Na in the grain boundaries. The results suggest that the grain boundaries are self-passivating without a chemistry change

[en] Through the critical speed of centrifugal pumps, internal flow field and the force of the impeller, we analyze centrifugal pump vibration. Using finite element analysis software ANSYS to calculate the natural frequency of the rotor system and the critical speed; with the help of the Fluent software to simulate pump internal flow field, we conclude that speed increase will not cause intense vibration of the fluid in the pump. Using unsteady numerical simulation we discovered that in an impeller suffering transient radial force cyclical change periodically, as well as the frequency size determined by the product of the impeller speed and number of blades, resonance phenomena should make impeller to transient radial force frequency. If wanting to avoid pump resonance when it is running away, the transient radial force frequency should avoid the frequency range which can cause resonance

[en] A general quantum search algorithm with arbitrary unitary transformations and an arbitrary initial state is considered in this work. To search a marked state with certainty, we have derived, using an SU(2) representation: (1) the matching condition relating the phase rotations in the algorithm, (2) a concise formula for evaluating the required number of iterations for the search, and (3) the final state after the search, with a complex phase in its amplitude. Moreover, the optimal choices and modifications of the phase angles in the Grover kernel are also studied

[en] Functionalization of carbon nanotubes is very challenging for their applications. The paper here describes a new method to functionalize multi-walled carbon nanotubes (MWCNTs) as specific affinity adsorbents. MWCNTs were acid purified and pretreated with (3-aminopropyl)-triethoxysilane (APTES) in order to introduce abundant amino groups on the surface of MWCNTs. After the conversion of amino groups to carboxyl groups by succinic acid anhydride, MWCNTs were attached to protein A or aminodextran using 1-ethyl-3,3' (dimethylamion)-propylcarbodiimide as a biofunctional crosslinker. The incorporation of aminodextran as a spacer arm noticeably increased the binding capacity of the APTES-modified MWCNTs for protein A. The application of affinity MWCNTs for purification of immunoglobulin G was then evaluated. The affinity of MWCNTs with AMD spacer exhibited a high adsorption capacity of ∼361 μg IgG/mg MWCNT (wet basis). About 75% of bound IgG was eluted from affinity MWCNTs (ANT-I and ANT-II) and ELISA confirmed that the biological activity of IgG was well preserved during the course of affinity separation. The functionalized MWCNTs could be potentially used in affinity chromatography

[en] In this paper, the morphology and kinetics of adsorption of protein A on a PDMS surface is studied by AFM. The results of effects of pH, protein concentration and contact time of the adsorption reveal that the morphology of adsorbed protein A is significantly affected by pH and adsorbed surface concentration, in which the pH away from the isoelectric point (IEP) of protein A could produce electrical repulsion to change the protein conformation, while the high adsorbed surface protein volume results in molecular networks. Protein A can form an adsorbed protein film on PDMS with a maximum volume of 2.45 x 10^-3 μm³. This work enhances our fundamental understanding of protein A adsorption on PDMS, a frequently used substrate component in miniaturized immunoassay devices.