Quantal symmetries in the non-linear σ model with Maxwell and non-Abelian Chern-Simons terms

The quantal symmetry property of the CP1 nonlinear （y model with Maxwell non-Abelian Chern- Simons terms in （2＋1） dimension is studied. In the Coulomb gauge, the system is quantized by using the Faddeev-Senjanovic （FS） path-integral formalism. Based on the quantaum Noether theorem, the quantal conserved angular momentum is derived and the fractional spin at the quantum level in this system is presented.     

The symmetries in the Maxwell－Chern－Simons theory coupled to matter fields

The Maxwell－Chern－Simons gauge theory coupled to a complex scalar field is quantized in the Becchi－Rouet－Stora－Tyutin path integral formalism. Based on the symmetries of a constrained canonical (Hamiltonian) system, we obtain the quantal conserved angular momentum of the system under the global symmetry transformation. It is shown that fractional spin also appears at the quantum level. The canonical Ward identities for this system are derived under local gauge transformation.     

STUDY ON THE ACOUSTICAL MECHANISM OF ACTIVE ABSORBER

In this paper,theoretical and experimental results for study of the acoustical mechanism ofthe active sound absorber are presented.Several conclusions have been drawn: (1)When the secondary source system is a unidirectional source,all the energy in the in-cident wave will be absorbed by the secondary source system with no energy reflection. (2)The energy absorbed by the secondary source system is lost in heat in the loudspeakercoils. (3)The process of energy absorption may be described as follows:the incident energy is partlyabsorbed by source Ⅰ in the secondary source system,the transmiting energy will be reflected backby source Ⅱ in the secondary source system and absorbed finally by source Ⅰ.     

THE TRANSITION RATE OF A DOUBLE WELL SYSTEM DRIVEN BY CROSS-CORRELATED NOISES

The transition rate of a double well system driven by cross-correlated noises has been investigated, in when the correlation times between the noises are nonzero. From numerical computation, we find followings: (1) The transition rate decreases as the ,λ(λ is the strength of the correlations between noises) increases. (2) The transition rate increases as the τ(τ is the correlation time between noises) increases. It imglies that τ and λ play opposite roles in the transition rate of the system (3). For the case of perfectly correlated noises (λ= 1), there is no the suppressed phenomenon in the double well system with cross-correlated noise sources.     

Poisson theory and integration method of Birkhoffian systems in the event space

<正>This paper focuses on studying the Poisson theory and the integration method of a Birkhoffian system in the event space.The Birkhoff's equations in the event space are given.The Poisson theory of the Birkhoffian system in the event space is established.The definition of the Jacobi last multiplier of the system is given,and the relation between the Jacobi last multiplier and the first integrals of the system is discussed.The researches show that for a Birkhoffian system in the event space,whose configuration is determined by(2n + 1) Birkhoff's variables,the solution of the system can be found by the Jacobi last multiplier if 2n first integrals are known.An example is given to illustrate the application of the results.     

Constructing(2+1)-dimensional N=1 supersymmetric integrable systems from the Hirota formalism in the superspace

The N = 1 supersymmetric extensions of two integrable systems,a special negative Kadomtsev–Petviashvili(NKP)system and a(2+1)-dimensional modified Korteweg–de Vries(MKd V) system,are constructed from the Hirota formalism in the superspace.The integrability of both systems in the sense of possessing infinitely many generalized symmetries are confirmed by extending the formal series symmetry approach to the supersymmetric framework.It is found that both systems admit a generalization of W∞type algebra and a Kac-Moody–Virasoro type subalgebra.Interestingly,the first one of the positive flow of the supersymmetric NKP system is another N = 1 supersymmetric extension of the(2+1)-dimensional MKd V system.Based on our work,a hypothesis is put forward on a series of(2+1)-dimensional supersymmetric integrable systems.It is hoped that our work may develop a straightforward way to obtain supersymmetric integrable systems in high dimensions.     

Effects of Pure Dzyaloshinskii-Moriya Interaction with Magnetic Field on Entanglement in Intrinsic Decoherence

We investigate the effects of pure Dzyaloshinskii-Moriya(DM) interaction with magnetic field on entanglement in intrinsic decoherence,assuming that the system is initially in four Bell states |φ± =(|00 ± |11)/2~(1/2) and|ψ± =(|01) ± |10)/2~(1/2) respectively.It is found that if the system is initially in the state ρ1(0) = |φ+φ+|,the entanglement can obtain its maximum when the DM interaction vector D is in the plane of XOZ and magnetic field B = B_y with the infinite time t,moreover the entanglement is independent of B_y and t when B_y is perpendicular to D.In addition,we obtain similar results when the system is initially in the states ρ2(0) =|φ-φ-| or ρ3(0) = |ψ+ψ+|.However,we find that if the system is initially in the state ρ4(0) =|ψ-ψ-|,the entanglement can obtain its maximum for infinite t,when the DM vector is in the plane of YOZ,XOZ,or XOY,with the magnetic field parallel to X,Y,or Z axis,respectively.Moreover,when the axial B is perpendicular to D for the initial state ρ4(0),the negativity oscillates with time t and reaches a stabie value,the larger the value of B is,the greater the stable value is,and the shorter the oscillation time of the negativity is.Thus we can adjust the direction and value of the external magnetic field to obtain the maximal entanglement,and avoid the adverse effects of external environment in some initial state.This is feasible within the current experimental technology.     

Point-contact tunneling spectroscopy between a Nb tip and an ideal topological insulator Sn-doped Bi1.1Sb0.9Te2S

We find that the quantum-classical correspondence in integrable systems is characterized by two time scales. One is the Ehrenfest time below which the system is classical; the other is the quantum revival time beyond which the system is fully quantum. In between, the quantum system can be well approximated by classical ensemble distribution in phase space. These results can be summarized in a diagram which we call Ehrenfest diagram. We derive an analytical expression for Ehrenfest time, which is proportional to h~(-1/2). According to our formula, the Ehrenfest time for the solar-earth system is about 10~(26) times of the age of the solar system. We also find an analytical expression for the quantum revival time, which is proportional to h~(-1). Both time scales involve ω(I), the classical frequency as a function of classical action. Our results are numerically illustrated with two simple integrable models. In addition, we show that similar results exist for Bose gases, where 1/N serves as an effective Planck constant.     

Analytical Model of Non-dispersion-limited Transient Stimulated Raman Scattering in Single-mode Silica Fiber in WDM Optical Communication System

1 IntroductionNowadays, fused silica fiber still is the most common fiber in wavelength divisionmultipleeing (WDM) OPtical commwhcation syStem. In the WDM system, themodulation type of input signal in one channel differs from another channel. FOrinstance, in the Ralnan fiber amplifiers, the pUmP is a continuous wave (CW) whilethe signals are pulse modulated. SO, when we study the SRS effect in the system, wemust take into account the different modulation type of signals. For a tWO-cha…     

Quantization of the double-qubit structure and quantum computation

The quantization scheme of a double-qubit structure with superconducting quantum interference devices (SQUIDs) is given. By introducing unitary matrices and using spectral decompositions, the Hamiltonian operator of the system is exactly formulated in compact forms in spin-1/2 notation. A scheme of designing controlled-phase-shift (CPS) gates is also proposed by using this circuit system.     

Parameter estimation for chaotic systems with and without noise using differential evolution-based method

We present an approach in which the differential evolution (DE) algorithm is used to address identification problems in chaotic systems with or without delay terms. Unlike existing considerations, the scheme is able to simultaneously extract (i) the commonly considered parameters, (ii) the delay, and (iii) the initial state. The main goal is to present and verify the robustness against the common white Guassian noise of the DE-based method. Results of the time-delay logistic system, the Mackey-Glass system and the Lorenz system are also presented.     

Experimental Investigation of the Electromagnetically Induced-Absorption-Like Effect for an N-Type Energy Level in a Rubidium BEC

We study the electromagnetically induced-absorption-like(EIA-like) effect for an n-type system in an ~(87)Rb Bose–Einstein condensate(BEC) using the absorption imaging technique for coupling and driving lasers operating at the D_1 and D_2 lines of ~(87)Rb. The coherent effect is probed by measuring the number of atoms remaining after the BEC is exposed to strong driving fields and a weak probe field. The absorption imaging technique accurately reveals the EIA-like effect of the n-type system. This coherent effect in an n-type system is useful for optical storage, tunable optical switching, and so on.     

Solar cells based on the poly(N-vinylcarbazole):porphyrin: tris(8-hydroxyquinolinato) aluminium blend system

Organic solar cells based on poly(N-vinylcarbazole)(PVK):porphyrin:tris(8-hydroxyquinolinato) aluminium(Alq3) blend p-n junction systems have been fabricated in this work.The roles of the different components in the blend system and of the amount of porphyrin have been investigated.The 5,10,15,20-tetraphenylporphyrin(TPP) and 5,10,15,20-tetra(o-chloro)phenylporphyrinato-copper(CuTClPP) are used in the solar cells.The results show that TPP is better than CuTClPP in enhancing the performance of PVK:Alq3 solar cells.When the weight ratio of PVK:TPP:Alq3 is 1:1.5:1,the best performance of solar cell is obtained.The open circuit voltage(V oc) is 0.87 V,and the short circuit current(J sc) is 17.5 μA·cm 2.In the ternary bulk hereojunction system,the device may be regarded as a cascade of three devices of PVK:TPP,TPP:Alq3 and PVK:Alq3.PVK,TPP and Alq3 can improve the hole mobility,light absorption intensity and electron mobility of the ternary bulk hereojunction system,respectively.     

Multi-types of Skyrmions in SU(N) Quantum Hall System

The skyrmions in SU(N) quantum Hall (QH) system are discussed. By analyzing the gauge field structure and the topological properties of this QH system it is pointed out that in the SU( N) QH system there can exist ( N - 1)types of skyrmion structures, instead of only one type of skyrmions. In this paper, by means of the Abelian projections according to the (N - 1) Cartan subalgebra local bases, we obtain the (N - 1) U(1) electromagnetic field tensors in the SU(N) gauge field of the QH system, and then derive (N - 1) types of skyrmion structures from these U(1) sub-field tensors. Furthermore, in light of the φ-mapping topological current method, the topological charges and the motion of these skyrmions are also discussed.     

21.2 kW, 1.94 times diffraction-limit quasi-continuous-wave laser based on a multi-stage,power-scalable and adaptive optics controlled Yb:YAG master-oscillator-power-amplifier system

A 21.2 kW, 1.94 times the diffraction-limit quasi-continuous-wave laser is presented in this Letter based on a multi-stage, power-scalable Yb:YAG master-oscillator-power-amplifier(MOPA) system under adaptive optics(AO) control. The output laser of the MOPA system is a rectangular beam with a length-width ratio of 2:1, a 200 μs pulse duration, and a 1000 Hz repetition rate. With the AO control system, the beam quality of the laser is improved from 4.20 to 1.94 times the diffraction limit. To our knowledge, this is the best quality laser in the 20 kW class except for combined lasers.     

X-ray photon-counting detector based on a micro-channel plate for pulsar navigation

The pulse time of arrival (TOA) is a determining parameter for accurate timing and positioning in X-ray pulsar navigation. The pulse TOA can be calculated by comparing the measured arrival time with the predicted arrival time of the X-ray pulse for pulsar. In this study, in order to research the measurement of pulse arrival time, an experimental system is set up. The experimental system comprises a simulator of the X-ray pulsar, an X-ray detector, a time-measurement system, and a data-processing system. An X-ray detector base is proposed on the basis of the micro-channel plate (MCP), which is sensitive to soft X-ray in the 1–10 keV band. The MCP-based detector, the structure and principle of the experimental system, and results of the pulse profile are described in detail. In addition, a discussion of the effects of different X-ray pulse periods and the quantum efficiency of the detector on pulse-profile signal-to-noise ratio (SNR) is presented. Experimental results reveal that the SNR of the measured pulse profile becomes enhanced as the quantum efficiency of the detector increases. The SNR of the pulse profile is higher when the period of the pulse is smaller at the same integral.     

An all-directional interference cancelling system for large sonar array

The existence of strong interfercnce is the main constraint factor,which influences the detection performance of a signal extraction system.For asonar with large array the problem of anti-interferences in all-direction has not beensolved yet because of the requirements of over-long time delay line and the over highinput-output rate.A method proposed in this paper can be used in the design ofadaptive signal processing system with large array for suppressing the strong inter-ference in all-direction.This is a combined architecture of adaptive noise canceller(ANC)and a programmable DICANNE system.When the incident angle betweensignal θ_s and interfercnce θ_I is small,the ANC system is used.when θ_s—θ_I islarge,a programmable DICANNE system,with rising sampling rate,is used,so thatan all—directional anti—interfercnces system can be obtained.The structure des-cribed in this paper is easy to implement in hardware by using DSP chips.The designdiagram and implementable method in hardware is presented.     

Atomic—Scale Kinetic Monte Carlo Simulation of {100}—Oriented Diamond Film Growth in C—H and C—H—CI Systems by Chemical Vapour Deposition

We simulate the {100}-oriented diamond film growth of chemical vapour deposition (CVD) under different models in C-H and C-H-Cl systems in an atomic scale by using the revised kinetic Monte Carlo method.The simulation results show that:(1) the CVD diamond film growth in the C-H system is suitable for high substrate temperature,and the film surface roughness is very coarse;(2) the CVD diamond film can grow in the C-H-Cl system either at high temperature or at low temperature,and the film quality is outstanding;(3) atomic Cl takes an active role for the growth of diamond film,especially at low temperatures.The concentration of atomic Cl should be controlled in a proper range.     

Centrality dependence of pT spectra for identified hadrons in Au Au and Cu Cu collisions at (~SNN)~(1/2)=200 GeV

The centrality dependence of transverse momentum spectra for identified hadrons at midrapidity in Au Au collisions at (~SNN)~(1/2) = 200GeV is systematically studied in a quark combination model. The pT spectra of π±, K±, p() and Λ(■) in different centrality bins and the nuclear modification factors (RCP) for these hadrons are calculated. The centrality dependence of the average collective transverse velocity β (r) for the hot and dense quark matter is obtained in Au Au collisions, and it is applied to a relative smaller Cu Cu collision system. The centrality dependence of pT spectra and the RCP for π0, Ks0 and Λ in Cu Cu collisions at (~SNN)~(1/2) =200 GeV are well described. The results show that β(r) is only a function of the number of participants Npart and it is independent of the collision system.