首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
In the context of JWKB (Jeffreys, Wentzel, Kramers, and Brillouin) approximation, we use inverse scattering theory to modify the forbidden region by introducing an arbitrary term in the analytical expression of the potential (r) in the case of He-Na elastic scattering given as an example.  相似文献   

2.
         下载免费PDF全文
张现周  江红民  饶建国  李白文 《中国物理》2004,13(10):1601-1605
Using our recently developed time-dependent multilevel approach, we have calculated the phase shift of the population oscillation of the excited potassium atom in frequency-modulated fields when the modulation amplitude is suddenly changed. The numerical results are in good agreement with the measurements. A new way of realizing population trapping is suggested.  相似文献   

3.
谭玉红  宁平治  蔡崇海 《中国物理 C》1998,22(12):1136-1142
采用包含库仑场影响的一级修正的eikonal相移研究了入射动量为715MeV/C的K+介子与6Li、12C核散射及入射动量为800MeV/c的K+介子与(12)C、40Ca核散射的微分截面,通过理论微分截面与相应实验数据的拟合,得到了最佳光学势参数,为K+核散射的微观研究提供一定依据.用得到的光学势计算了相应散射过程的总截面,并与实验值作了比较.  相似文献   

4.
         下载免费PDF全文
夏涛  胡进  毛施君 《中国物理C(英文版)》2019,43(5):054103-054103-10
We study the quark-antiquark scattering phase shift and meson spectral function in the pion superfluid described by the Nambu-Jona-Lasinio model. Meson mixing in the pion superfluid dramatically changes the full scattering phase shift and significantly broadens the spectral function of some collective modes.  相似文献   

5.
    
Using the most recent phase shift data for pp, nn,and np elastic scattering for different states (l=0,1,…) in the energy rangeof 1 MeV to 350 MeV, the charge dependency of the strong nuclear forceis investigated. Our results indicate that although the chargeindependency holds in most of the energy range, such chargeindependency is broken in the particular energy range of 120 MeV to 200 MeV for all partial wave states considered here.  相似文献   

6.
马桂存  齐进  王敏 《计算物理》2015,32(3):361-368
对Liberman的统计自洽场INFERNO模型中的电子共振态进行研究,计算金属铀在两个温度密度点处的电子共振态,给出共振能量区间内电子的态密度,波函数,相移因子随能量的变化及位相-振幅形式的波函数中的位相随能量的变化,得到与非相对论情况下完全一致的结果.  相似文献   

7.
王晓伟  郭建友 《物理学报》2019,68(9):92101-092101
在复动量表象下引入格林函数,建立了复动量格林函数方法.把这种方法应用于n-α散射系统,计算其散射相移.提取n-α系统的共振态并研究共振态对能级密度、相移和散射截面的贡献.在不引入任何非物理参数的前提下,离散化薛定谔积分方程得到束缚态、共振态和连续谱.通过分析散射态物理量可以更好地理解共振态以及非共振连续谱态.在n-α系统中的成功应用,证明了该方法的正确性.  相似文献   

8.
In order to improve the unitarity of the S-matrix, an improved variational formulism is derived by proposing new generating functionals and adopting proper asymptotic boundary conditions for trial relative wave functions. The formulas with the weighted line-column balance for the single-channel and multi-channel scatterings, where the non-central interaction is implicitly considered, are presented. A numerical check is performed with a soluble model in a four coupled channel scattering problem. The result shows that the high accuracy and the unitarity of the S-matrix are reached.  相似文献   

9.
    
In order to improve the unitarity of the S-matrix, an improved variational formulism is derived by proposing new generating functionals and adopting proper asymptotic boundary conditions for trial relative wave functions. The formulas with the weighted line-column balance for the single-channel and multi-channel scatterings, where the non-central interaction is implicitly considered, are presented. A numerical check is performed with a soluble model in a four coupled channel scattering problem. The result shows that the high accuracy and the unitarity of the S-matrix are reached.  相似文献   

10.
Strong atmospheric turbulence is a major hindrance in wireless optical communication systems. In this paper, the performance of a wireless optical communication system is analyzed using different modulation formats such as, binary phase shift keying-subcarrier intensity modulation (BPSK-SIM), differential phase shift keying (DPSK), differential phase shift keying-subcarrier intensity modulation (DPSK-SIM), M-ary pulse position modulation (M-PPM) and polarization shift keying (PolSK). The atmospheric channel is modeled for strong atmospheric turbulences with combined effect of turbulence and pointing errors. Novel closed-form analytical expressions for average bit error rate (BER), channel capacity and outage probability for the various modulation techniques, viz. BPSK-SIM, DPSK, DPSK-SIM, PolSK and M-PPM are derived. The simulated results for BER, channel capacity and outage probability of various modulation techniques are plotted and analyzed.  相似文献   

11.
江金环  李子平 《物理学报》2004,53(9):2991-2994
利用变分法讨论了反向传输的基于全息聚焦机理空间光孤子的相互作用,导出了相干和非相 干相互作用的势函数.当孤子间的相对相位不随传输距离变化或相对相位对传输距离的偏导 数与孤子间距无关时,相干和非相干相互作用势函数都与孤子间的相对相位无关,出现孤子间 反常相互作用,这正好是近期文献的结果.关键词:空间光孤子相互作用变分原理  相似文献   

12.
研究光学格子中(即在光传输的横截面上存在周期格子势的调制)光束的演化,利用变分原理,求出了光束宽度、振幅、频率啁啾参量随传播距离的演化形式.发现光束宽度与调制周期的比值必须小于一定的值才能形成孤子的传输;同时,还得到了光束在不同的条件下存在着不同的传输过程.光学格子中周期格子的作用有类似非线性的良好的特性,周期格子的引入提供了可以更好地控制格子孤子的形成和传输的参考条件.  相似文献   

13.
杨振军  李少华  陆大全  胡巍 《物理学报》2010,59(7):4707-4714
利用变分法对一种假设的两极孤子进行了研究,得到了该两极孤子的参数耦合方程,并对由参数耦合方程得到的结果进行了数值模拟.结果表明,在光束能量较高,趋近于强非局域的情况下,两极孤子横向强度呈一阶厄米-高斯型分布;光束能量较低的弱非局域情况下,两极孤子的两个强度峰之间有一个平台出现.此两极孤子模型还可退化为高斯光束,得到高斯孤子解.  相似文献   

14.
李琼  翟永惠  梁果  郭旗 《物理学报》2013,62(2):24202-024202
对矩形铅玻璃中椭圆孤子的形成进行了理论研究,在理论模型中引入各向异性衍射效应.采用变分法,得到了强非局域线性各向异性椭圆孤子的变分解.结果表明,各向异性衍射效应对椭圆孤子的形成有很大的影响.为了验证变分解的正确性,采用牛顿迭代法算出强非局域线性各向异性椭圆孤子的数值解,变分解和数值解符合得很好.  相似文献   

15.
王志平  邢雁  王旭 《发光学报》2009,30(4):453-456
在有效质量近似下,采用变分方法研究了球型核壳量子点中激子的性质。数值计算了电子波函数随位置的变化关系以及临界势随球壳宽度和核半径的比值的变化关系。结果表明,当球壳宽度和核半径的比值为给定值时,存在一临界势,当局域势减小到临界势时,激子从二类激子转化为一类激子;当局域势为给定值时,存在一临界比值,当球壳宽度和核半径的比值减小到临界比值时,激子亦从二类激子转化为一类激子。该结果对研究球型核壳量子点中的电子结构有参考价值。  相似文献   

16.
    
Herein, a simple interference lithographic technique to design omniphobic surface‐enhanced Raman scattering active surfaces composed of stacked‐disk nanotower arrays is reported. To create the nanotower arrays in a highly reproducible fashion, the authors use a single laser exposure onto the photoresist‐on‐dielectric mirror using a phase mask. The interference by the phase shift produces a nanotower array with a submicrometer periodicity, whereas the standing wave effect by reflection from the mirror defines the stacked‐disk structure at each nanotower at sub‐100 nm periodicity. The stacked‐disk nanotowers with silver outer‐coating provide a strong electric field localization at the vertically integrated nanogaps on the side wall. At the same time, the series of reentrant geometry on the side walls can efficiently pin the liquid–air interface for a variety of liquids, including water and toluene, thereby providing omniphobic surface property. The molecules dissolved in either water or toluene at low concentration can be enriched in the drop on the surface in a course of evaporation, which are finally deposited onto a tiny spot. Raman spectra of the molecules are further amplified by the strong electric field at the nanogaps on the side walls of the nanotowers. Therefore, the surfaces provide high sensitivity of Raman analysis for both polar and nonpolar molecules.  相似文献   

17.
玻色—爱因斯坦凝聚和兰姆位移   总被引:1,自引:0,他引:1  
黄湖  王德重 《物理》1998,27(1):1-2
扼要地介绍了BEC研究的近况和研究方向,同时报道了我们在BEC的光散射和兰姆位移方面的研究工作  相似文献   

18.
超短基线基阵基元相移差的测量   总被引:1,自引:1,他引:0  
喻敏  惠俊英  孙大军 《应用声学》2006,25(4):229-233
本文针对超短基线定位系统定位精度不高的问题,首先介绍了一种改进阵形的高精度定位算法,然后介绍了如何测量基阵附加相移的方法,并在湖试中,应用了此方法得到的补偿相移值,取得较好的定位效果。  相似文献   

19.
The Sagnac time delay and the corresponding Sagnac phase shift, for relativistic matter and electromagnetic beams counter-propagating in a rotating interferometer, are deduced on the ground of relativistic kinematics. This purely kinematical approach allows to explain the universality of the effect, namely the fact that the Sagnac time difference does not depend on the physical nature of the interfering beams. The only prime requirement is that the counter-propagating beams have the same velocity with respect to any Einstein synchronized local co-moving inertial frame.  相似文献   

20.
         下载免费PDF全文
何传林  杨坤德  马远良  雷波 《中国物理 B》2017,26(1):14301-014301
The aberration in the received acoustic field and the Doppler shift in the forward scattered field are simultaneously induced when a submerged target crosses the source–receiver line. Formulations for the two variations are developed upon an ideal forward scattering configuration. Both the field aberration and the Doppler shift are expressed as functions of the same argument — the target motion time. An experimental validation was carried out in a tank, in which the continuous wave was transmitted. The field aberration and the Doppler shift were extracted from the collected data by the simple Hilbert transform and a hybrid technique, respectively. The measured aberration and Doppler shift agree with the theoretical results.Simultaneous detection outputs are beneficial to enhance the reliability on target detection by providing both the aberrations in the received acoustic field and the Doppler shift in the forward scattered field.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号