S=1/2体系的EPR波谱模拟

用一个以Fortran语言编制的S=1/2体系的EPR模拟谱程序.并引入了弛豫项,图谱线型得到了改善,使模拟谱与实验谱更为接近;对超超精细分裂的考虑,使该程序可适合于复杂图谱的模拟;求积分方法的近似处理,缩短了模拟谱的耗时,使复杂图谱的模拟在微机上成为现实.     

S=1/2海森堡自旋链的另一种求解方法

利用置换群方法处理自由边界条件下S=1/2有限格点海森堡自旋链,得到所有本征能量及本征态,并在此基础上分析了基态和低激发态的性质。 关键词：     

Are there S = -2 pentaquarks?

Recent evidence for pentaquark baryons in the channels , and their anti-particles claimed by the NA49 collaboration is critically confronted with the vast amount of existing data on spectroscopy which was accumulated over the past decades. It is shown that the claim is inconsistent with these data. In addition two further exotic channels of the pentaquark type available in the NA49 data are investigated. It is argued that this study leads to internal inconsistency with the purported signals.Received: 16 January 2004, Published online: 24 August 2004 Correspondence to: S. Wenig     

≡BARYONS(S=-2,I=1/2)≡~0=uss,≡~-=dss

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Measurement of the caesium 6S1/2?8P1/2 transition frequency

The caesium 6S _1/2? 8P _1/2,3/2 transitions at 387.6 nm and 388.8 nm have been observed with a linewidth of <5 MHz by laser spectroscopy. The absolute frequency of the 6S _1/2?8P _1/2 transition was determined to an uncertainty of ±1 MHz using the calibrated rubidium 5S _1/2?5D _5/2 two-photon transition and accurate interferometry. The potential of this caesium transition as a useful secondary frequency standard in blue–UV region is discussed. Received: 7 February 2000 / Revised version: 24 March 2000 / Published online: 24 July 2000     

自旋S=3/2和S=2 Blume-Capel模型相变的Monte Carlo研究

利用计算机MonteCarlo模拟,研究自旋S=3/2和S=2Blume-Capel模型的相图。与最近刚发展起来的适用于研究S>1的关联有效场相比较,得出如下结论:对于S=3/2和S=2,关联有效场过高地估计了它们的相变温度对于S=3/2的相图,除了有二级相变线外,还发现了一级相变线对于S=2,关联有效场同样过高地估计了三临界点的值。 关键词：     

如何让学生学会使用公式1/u+1/v=1/F

公式1/u+1/v=1/F是几何光学中的基本方程之一。公式本身虽然简单,易懂易记,但学生使用这个公式算题的时候,却不是没有困难的,他们常把各个量的符号弄错,因而得不出正确的结果。由于这种原因,我在教学中对使用这个公式算题时应该注意那几点,作了如下的说明:     

μSR study of the S=1/2 triangular lattice antiferromagnet AgNiO2

AgNiO₂, a model compound of an S=1/2 triangular lattice, was studied by muon spin relaxation in addition to ac, dc susceptibility, electrical resistivity and neutron diffraction. The relaxation rate shows a sharp peak at around T_N=28 K followed by a sudden decrease of initial asymmetry indicating a magnetic ordering. Three internal fields ranging from 0.2 to 0.3 T were obtained from the muon precession period. However, a neutron diffraction experiment failed to detect any magnetic order at low temperatures. From these results, it was concluded that magnetic coherence is confined to small domain compared with the coherence length of neutron diffraction due to spin frustration. This revised version was published online in August 2006 with corrections to the Cover Date.     

S=1/2铁磁理论海森堡模型的随机量子化处理

对S=1/2的海森堡铁磁模型,构造了适当的拉格朗日函数,采用玻色量子化条件,用随机量子化方法计算了它的温度格林函数,得到了和其它方法同样的结果。 关键词：     

蜂窝状格子带有晶场作用的铁磁Ising混合自旋S=1和S=1/2的相图的Monte-Carlo研究

利用具有翻转单个自旋的Metropolis-Monte-Carlo算法,研究蜂窝状格子带有晶场作用的铁磁Ising混合自旋S=1和S=1/2的相图,所得相图与严格解相接近,好于关联有效场方法得出的结果。因此Metropolis-Monte-Carlo算法同样也可以用于研究混合自旋模型。     

导出E=mc~2和m=m_0/(1-v~2/c~2)~(1/2)的一种方案

借助光子导出了E=mc2和m=m01-v2/c2.     

导出E=mc2和m=m0/1-v2√c2的一种方案

借助光子导出了E=mc2和m=(m0)/(1-v2/c2).     

导出E=mc^2和m=m0/√1-v^2/c^2的一种方案

借助光子导出了E=mc^2和m=m0/√1-v^2/c^2。     

如何使高三學生正確地理解“焦耳-楞次定律”和“电能輸送”

据我所知,高三学生中有相當一部分對焦耳-楞次定律和远距離電能輸送的理解是十分不够的,具體表現在下述兩個方面: (1)我們知道,焦耳-楞次定律的數學表現形式是: Q=0.24I~2Rt, 或Q=0.24IUt, 或Q=0.24U~2/Rt。在一個不是完全由電阻構成的電路中,学生們不会使用Q=0.24IUt或Q=0.24U~2/Rt。 (2)對遠距離輸電的提高電压、減小電流强度能够減少熱耗損表示懷疑。所持的理由是:電流强度(I)雖然减小,但電压(U)却昇高了,电流强度(I)与电压(U)的乘积(IU),仍然不变,因之熱量耗損Q=0.24IUt,並不     

Spectroscopic investigation of light strange S=-1 Λ and Σ and S=-2 Ξ baryons

The present study is dedicated to light-strange Δ with strangeness S=-1 and isospin I=0,E with S=-1 and I=1,and Ξ baryon with S=-2 and I=1/2. In this study,the hypercentral constituent quark model with linear confining potential has been employed along with a first order correction term to obtain the resonance masses up to approximately 4 GeV.The calculated states include 1 S-5 S,1 P-4 P,1 D-3 D,1 F-2 F,and 1 G(in a few cases) along with all possible spin-parity assignments.Regge trajectories have been explored for the linearity of the calculated masseJ for(n,M2) and(J,M2).Magnetic moments have been intensively Ltudied for ground Utate spin 1/2 and 3/2, in addition to the configuration mixing of the first negative parity state for Ξ.Lastly,the transition magnetic moments and radiative decay widths have been presented.     

对=2～(1/2)的一种定性说明

给出一种对公式=2～(1/2)的定性说明.     

“s1＋s2=0”的妙用

在解决物理问题时，有些结论虽然不是定理、定律，但却是众所周知的，如果平时善于总结，往往会使我们的解题思路更清晰，分析解决问题能力得到提高。     

关于“=2~(1/2)的一个简易证明”的讨论

普通物理中一些言而不详的问题是普通物理教学中难以处理的问题之一。《大学物理》83年第5期上朱湘桂同志的“关于u=2v的一个简易证明”一文是解决上述问题的一个有意义的尝试.但对其中有些论述我有不同看法,特提出讨论.一、我认为得出u=2v这个结论,正是运用了麦克斯韦速率分布率的结果,避免运用麦克斯韦速率分布率这个前提,是得不出这个结论的.二、相对速率与各个分子速度之间的夹角是有关系的,但只要研究某一时刻所研究的分子与各个分子速度之间的夹角就行了,不必要既求碰撞前的,又求碰撞后的.这有利于节约教学时间.三、证明了各速度之间…     

Doppler-free two-color spectroscopy of the 62 S 1/2–82 S 1/2 cesium transition using semiconductor diode lasers

We report an experimental investigation of the 6S–8S transition of cesium atoms by using Doppler-free two-color spectroscopy. We consider the case in which one of the laser frequencies is nearly resonant with the 6S _1/2–6P _3/2 transition while a second one is swept around the 6P _3/2–8S _1/2 transition. The lineshapes of two-photon absorption spectra are analyzed taking into account the effects of saturation and collisions. Both counterpropagating and copropagating laser-beam schemes are studied. Although for the linewidths are broader copropagating beams, such a scheme has proved advantageous to fully resolve the hyperfine structure of the final state 8S _1/2 and, hence, to measure the dipole magnetic constantA of this state.