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Chinese physics B 2016年第10期25卷 45-51页

作者： R Pakniat M K Tavassoly M H Zandi Faculty of physics Shahid Bahonar University of Kerman Faculty of physics Atomic and Molecular Group Yazd University research group of optics and Photonics Yazd University

We outline a scheme for entanglement swapping based on cavity QED as well as quasi-Bell state measurement(quasiBSM) methods. The atom–field interaction in the cavity QED method is performed in small and large detuning *** assume two atoms are initially entangled together and, distinctly two cavities are prepared in an entangled coherent–coherent state. In this scheme, we want to transform entanglement to the atom-field system. It is observed that, the fidelities of the swapped entangled state in the quasi-BSM method can be compatible with those obtained in the small and large detuning regimes in the cavity QED method(the condition of this compatibility will be discussed). In addition, in the large detuning regime, the swapped entangled state is obtained by detecting and quasi-BSM approaches. In the continuation,by making use of the atom–field entangled state obtained in both approaches in a large detuning regime, we show that the atomic as well as field states teleportation with complete fidelity can be achieved.

关键词： entanglement swapping quantum teleportation cavity QED quasi-Bell state measurement

Projectile angular-differential cross sections for single electron transfer in fast He^+-He collisions

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Chinese physics B 2015年第3期24卷 127-135页

作者： Ebrahim Ghanbari-Adivi Hoda Ghavaminia department of physics and Isfahan Quantum optics group (IQOG) Faculty of ScienceUniversity of Isfahan

The four-body Coulomb–Born distorted wave approximation is applied to investigate the integral as well as projectile angular-differential cross sections for single-electron capture in the collision of energetic singly positive charged helium ions with helium atoms in their ground states. The formalism satisfies the correct boundary conditions. The influence of the dynamic electron correlations on the cross sections is studied by considering the inter electronic interactions in the complete perturbation potentials in post form. Also, the sensitivity of the cross sections to the static electronic correlations is studied by using the single-zeta and the highly correlated Byron–Joachain wave functions to describe the initial bound state of the active electrons. The obtained results for the energy range of 40–5000 ke V/amu are reported and compared with other three- and four-body theoretical data and available experimental measurements. The comparison leads us to discuss the validity of the applied approach and survey the interaction effects on the cross sections by recognizing the electron–electron interaction. Particularly, for differential cross sections, the comparison of the present four-body method with the experiment shows that the agreement is not as good as that for its three-body version.

关键词： Coulomb–Born distorted-wave approximation four-body approximation Coulomb boundary conditions differential and total cross secti

Intrinsic luminescence centers in γ- and θ-alumina nanoparticles

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Chinese physics B 2017年第3期26卷 373-383页

作者： Abdolvahab Amirsalari Saber Farjami Shayesteh Reza Taheri Ghahrizjani Nanostructures Labratory Department of Physics University of Guilan department of physics Optics and Laser Group Shahreza Branch Islamic Azad University

In this study, we investigate the photoluminescence （PL） properties of γ and θ-alumina nanoparticles synthesized by the chemical wet method followed by annealing. The obtained experimental results indicate the presence of some favorable near ultraviolet （NUV）-orange luminescent centers for usage in various luminescence applications, such as oxygen vacancies （F, F＋, F2＋, and F2 centers）, OH related defects, cation interstitial centers, and some new luminescence bands attributed to trapped-hole centers or donor-acceptor centers. The energy states of each defect are discussed in detail. The defects mentioned could alter the electronic structure by producing some energy states in the band gap that result in the optical absorption in the middle ultraviolet （MUV） region. Spectra show that photoionazation of F and F2 centers plays a crucial role in providing either free electrons for the conduction band, or the photoconversions of aggregated oxygen va- cancies into each other, or mobile electrons for electrons-holes recombination process by the Shockley-Read-Hall （SRH） mechanism.

关键词： photoluminescence center defect oxygen vacancy emission

Investigation of the thermal adaptability for a mobile cold atom gravimeter

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Chinese physics B 2016年第12期25卷 241-246页

作者：王启宇王兆英付志杰林强 Institute of optics Department of PhysicsZhejiang University Center for optics and Optoelectronics research College of ScienceZhejiang University of Technology

The cold atom gravimeter offers the prospect of a new generation of inertial sensors for field applications. We ac- complish a mobile atom gravimeter. With the compact and stable system, a sensitivity of 1.4× 10-7 ***-1/2 is achieved. Moreover, a continuous gravity monitoring of 80 h is carried out. However, the harsh outdoor environment is a big challenge for the atom gravimeter when it is for field applications. In this paper, we present the preliminary investigation of the thermal adaptability for our mobile cold atom gravimeter. Here, we focus on the influence of the air temperature on the performance of the atom gravimeter. The responses to different factors （such as laser power, fiber coupling efficiency, etc.） are evaluated when there is a great temperature shift of 10 ℃. The result is that the performances of all the factors deteriorate to different extent, nevertheless, they can easily recover as the temperature comes back. Finally, we conclude that the variation of air temperature induces the increase of noise and the system error of the atom gravimeter as well, while the process is reversible with the recovery of the temperature.

关键词： atom gravimeter the environmental adaptability atom intefferometer

High-capacity quantum secure direct communication with two-photon six-qubit hyperentangled states

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Science China(physics,Mechanics & Astronomy) 2017年第12期60卷 19-25页

作者： FangZhou Wu GuoJian Yang HaiBo Wang Jun Xiong Faris Alzahrani Aatef Hobiny FuGuo Deng Applied optics Beijing Area Major Laboratory Department of Physics Beijing Normal University NAAM-research group Department of Mathematics Faculty of Science King Abdulaziz University

This study proposes the first high-capacity quantum secure direct communication(QSDC) with two-photon six-qubit hyperentangled Bell states in two longitudinal momentum and polarization degrees of freedom(DOFs) of photon pairs, which can be generated using two 0.5 mm-thick type-I β barium borate crystal slabs aligned one behind the other and an eight-hole screen. The secret message can be independently encoded on the photon pairs with 64 unitary operations in all three DOFs. This protocol has a higher capacity than previous QSDC protocols because each photon pair can carry 6 bits of information, not just 2 or 4 *** QSDC protocol decreases the influence of decoherence from environment noise by exploiting the decoy photons to check the security of the transmission of the first photon sequence. Compared with two-way QSDC protocols, our QSDC protocol is immune to an attack by an eavesdropper using Trojan horse attack strategies because it is a one-way quantum *** QSDC protocol has good applications in the future quantum communication because of all these features.

关键词： quantum secure direct communication high capacity hyperentanglement two-photon six-qubit systems decoy photons

Self-error-rejecting photonic qubit transmission in polarization-spatial modes with linear optical elements

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Science China(physics,Mechanics & Astronomy) 2017年第12期60卷 12-18页

作者： YuXiao Jiang PengLiang Guo ChengYan Gao HaiBo Wang Faris Alzahrani Aatef Hobiny FuGuo Deng department of physics Applied Optics Beijing Area Major Laboratory Beijing Normal University NAAM-research group Department of Mathematics Faculty of Science King Abdulaziz University

We present an original self-error-rejecting photonic qubit transmission scheme for both the polarization and spatial states of photon systems transmitted over collective noise channels. In our scheme, we use simple linear-optical elements, including half-wave plates, 50:50 beam splitters, and polarization beam splitters, to convert spatial-polarization modes into different time bins. By using postselection in different time bins, the success probability of obtaining the uncorrupted states approaches 1/4 for singlephoton transmission, which is not influenced by the coefficients of noisy channels. Our self-error-rejecting transmission scheme can be generalized to hyperentangled n-photon systems and is useful in practical high-capacity quantum communications with photon systems in two degrees of freedom.

关键词： photon transmission error correction collective-noise channel spatial-polarization modes quantum communication

Current and efficiency of Brownian particles under oscillating forces in entropic barriers

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Chinese physics B 2015年第4期24卷 82-89页

作者： Ferhat Nutku Ekrem Aydιner Theoretical physics research group Department of Physics Faculty of Sciencestanbul University

In this study, considering the temporarily unbiased force and different forms of oscillating forces, we investigate the current and efficiency of Brownian particles in an entropic tube structure and present the numerically obtained results. We show that different force forms give rise to different current and efficiency profiles in different optimized parameter intervals. We find that an unbiased oscillating force and an unbiased temporal force lead to the current and efficiency, which are dependent on these parameters. We also observe that the current and efficiency caused by temporal and different oscillating forces have maximum and minimum values in different parameter intervals. We conclude that the current or efficiency can be controlled dynamically by adjusting the parameters of entropic barriers and applied force.

关键词： entropic barrier Brownian motion Fick-Jacobs equation efficiency of Brownian motor stochastic processes

Current and efficiency optimization under oscillating forces in entropic barriers

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Chinese physics B 2016年第9期25卷 227-234页

作者： Ferhat Nutku Ekrem Aydiner Theoretical physics research group Department of PhysicsFaculty of ScienceIstanbul University

The transport of externally overdriven particles confined in entropic barriers is investigated under various types of oscillating and temporal ***,load,and amplitude dependence of the particle current and energy conversion efficiency are investigated in three *** oscillating forces,the optimized temperature–load,amplitude–temperature,and amplitude–load intervals are determined when fixing the amplitude,load,and temperature,*** using three-dimensional plots rather than two-dimensional ones,it is clearly shown that oscillating forces provide more efficiency compared with a temporal one in specified optimized parameter ***,the dependency of efficiency to the angle between the unbiased driving force and a constant force is investigated and an asymmetric angular dependence is found for all types of ***,it is shown that oscillating forces with a high amplitude and under a moderate load lead to higher efficiencies than a temporal force at both low and high temperatures for the entire range of contact angle.

关键词： entropic barrier Brownian motion Fick–Jacobs equation efficiency of Brownian motor

Ion-acoustic waves in plasma of warm ions and isothermal electrons using time-fractional KdV equation

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Chinese physics B 2011年第4期20卷 149-155页

作者： Sayed A.El-Wakil Essam M.Abulwafa Emad K.El-Shewy Abeer A.Mahmoud Theoretical physics research group Physics DepartmentFaculty of ScienceMansoura University

The ion-acoustic solitary wave in collisionless unmagnetized plasma consisting of warm ions-fluid and isothermal electrons is studied using the time fractional KdV equation. The reductive perturbation method has been employed to derive the Korteweg-de Vries equation for small but finite amplitude ion-acoustic wave in warm plasma. The Lagrangian of the time fractional KdV equation is used in a similar form to the Lagrangian of the regular KdV equation with fractional derivative for the time differentiation. The variation of the functional of this Lagrangian leads to the Euler-Lagrange equation that gives the time fractional KdV equation. The variational-iteration method is used to solve the derived time fractional KdV equation. The calculations of the solution are carried out for different values of the time fractional order. These calculations show that the time fractional can be used to modulate the electrostatic potential wave instead of adding a higher order dissipation term to the KdV equation. The results of the present investigation may be applicable to some plasma environments, such as the ionosphere plasma.

关键词： ion-acoustic waves Euler-Lagrange equation Riemann-Liouvulle fractional derivative fractional KdV equation variational-iteration method

Rapid extraction of the phase shift of the cold-atom interferometer via phase demodulation

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Chinese physics B 2015年第11期24卷 250-254页

作者：程冰王兆英许翱鹏王启宇林强 Institute of optics Department of Physics Zhejiang University Center for optics and Optoelectronics research College of Science Zhejiang University of Technology

Generally, the phase of the cold-atom interferometer is extracted from the atomic interference fringe, which can be obtained by scanning the chirp rate of the Raman lasers at a given interrogation time T. If mapping the phase shift for each T with a series of measurements, the extraction time is limited by the protocol of each T measurement, and therefore increases dramatically when doing fine mapping with a small step of T. Here we present a new method for rapid extraction of the phase shift via phase demodulation. By using this method, the systematic shifts can be mapped though the whole interference area. This method enables quick diagnostics of the potential cause of the phase shift in specific time. We demonstrate experimentally that this method is effective for the evaluation of the systematic errors of the cold atomic gravimeter. The systematic phase error induced by the quadratic Zeeman effect in the free-falling region is extracted by this method. The measured results correspond well with the theoretic prediction and also agree with the results obtained by the fringe fitting method for each T.

关键词： atom interferometer phase extraction phase demodulation