New value of m(mu)/m(e) from muonium hyperfine splitting

The complete contribution to the muonium hyperfine splitting of relative order alpha(3)(m(e)/m(mu))lnalpha is calculated. The result is much smaller than suggested by a previous estimate and leads to a 2sigma upward shift of the most precise value for the muon-electron mass ratio. Analogous contributions are calculated for the positronium hyperfine splitting, where a discrepancy with experiment remains.     

Enhanced sensitivity to the time variation of the fine-structure constant and m{p}/m{e} in diatomic molecules

Sensitivity to temporal variation of the fundamental constants may be strongly enhanced in transitions between narrow close levels of different nature. This enhancement may be realized in a large number of molecules due to cancellation between the ground state fine-structure omega{f} and vibrational interval omega{v} [omega=omega{f}-nomega{v} approximately 0, delta omega/omega=K(2delta alpha/alpha+0.5 delta mu/mu), K>1, mu=m{p}/m{e}]. The intervals between the levels are conveniently located in microwave frequency range and the level widths are very small. Required accuracy of the shift measurements is about 0.01-1 Hz. As examples, we consider molecules Cl(+)(2), CuS, IrC, SiBr, and HfF(+).     

Search for nu(mu)-->nu(e) and nu(mu)-->nu(e) oscillations at NuTeV

Limits on nu(mu)-->nu(e) and nu(mu)-->nu(e) oscillations are extracted using the NuTeV detector with sign-selected nu(mu) and nu(mu) beams. In nu(mu) mode, for the case of sin(2)2alpha = 1, Delta(m)(2)>2.6 eV(2) is excluded, and for Delta(m)(2)>1000 eV(2), sin(2)2alpha>1.1 x 10(-3). The NuTeV data exclude the high Delta(m)(2) end of nu(mu)-->nu(e) oscillation parameters favored by the LSND experiment without the need to assume that the oscillation parameters for nu and nu are the same. We present the most stringent experimental limits for nu(mu)(nu(mu))-->nu(e)(nu(e)) oscillations in the large Delta(m)(2) region.     

1.66 μm和 1.55 μm光源对长距离光纤拉曼温度传感器测量时间影响的理论对比

通过理论分析,在综合考虑长距离光纤拉曼温度传感器中各光学器件波长相关特性的基础上,比较了1.66 μm和1.55 μm光源对传感器测量时间的影响.计算结果表明,由于各光学器件在1.5 μm波段的高性能和最大允许入纤脉冲峰值功率的增加,采用1.66 μm光源的光纤拉曼温度传感器,最高可获得约1.94倍的背向反斯托克斯信号.在相同空间分辨率和温度分辨率的情况下,测量时间可以降低约3/4.     

LD泵浦Nd∶YAG多波段激光器

为了获得高效率多波段激光输出,通过高重复频率驱动声光调Q技术和LD侧面泵浦技术,获得高功率高重频窄脉宽1.06 m激光输出。利用起偏器件获得垂直和水平两束1.06 m线偏振光,一束垂直线偏振光泵浦非线性晶体周期极化钽酸锂（PPLT）,实现1.46 m与3.9 m激光输出后与另一束1.06 m水平线偏振光合束,实现三波段共轴激光输出。在电源输入电流35 A、调Q驱动频率10 kHz的条件下,获得140 W的1.06 m激光。分束后泵浦PPLT获得最高功率为6.3 W的3.9 m和8.6 W的1.46 m激光,差频转化效率为21.3%。试验结果表明:通过高重频声光调Q技术和LD侧面泵浦技术,可以实现高重频窄脉宽1.06 m光输出,泵浦PPLT可获3.9 m和1.46 m激光输出。     

Nonlocal magnetic field-tuned quantum criticality in cubic CeIn(3-x)Sn(x) (x = 0.25)

We show that antiferromagnetism in lightly (approximately 8%) Sn-doped CeIn3 terminates at a critical field mu0H(c) = 42 +/- 2 T. Electrical transport and thermodynamic measurements reveal the effective mass m* not to diverge, suggesting that cubic CeIn3 is representative of a critical spin-density wave (SDW) scenario, unlike the local quantum critical points reported in anisotropic systems such as CeCu(6-x)Au(x) and YbRh2Si(2-x)Ge(x). The existence of a maximum in m* at a lower field mu0H(x) = 30 +/- 1 T may be interpreted as a field-induced crossover from local moment to SDW behavior as the Néel temperature falls below the Fermi temperature.     

Measurements of Kondo and spin splitting in single-electron transistors

We measure the spin splitting in a magnetic field B of localized states in single-electron transistors using a new method, inelastic spin-flip cotunneling. Because it involves only internal excitations, this technique gives the most precise value of the Zeeman energy Delta=/g/mu(B)B. In the same devices we also measure the splitting with B of the Kondo peak in differential conductance. The Kondo splitting appears only above a threshold field as predicted by theory. However, the magnitude of the Kondo splitting at high fields exceeds 2/g/mu(B)B in disagreement with theory.     

Ratio m(c)/m(s) with Wilson fermions

We determine the quark mass ratio m(c)/m(s) on the lattice, using Wilson-type fermions. Configurations with N(f)=2 dynamical clover-improved fermions by the QCDSF Collaboration are used, which were made available through the ILDG. In the valence sector we use a sophisticated, mass-independently O(a)-improved Wilson-type action with small cutoff effects even in the charm mass region. After an extrapolation to the physical pion mass, to zero lattice spacing and to infinite box volume, we find m(c)/m(s)=11.27(30)(26).     

Indication of a cosmological variation of the proton-electron mass ratio based on laboratory measurement and reanalysis of H2 spectra

Based on highly accurate laboratory measurements of Lyman bands of H2 and an updated representation of the structure of the ground X 1sigma(g)+ and excited B 1sigma(u)+ and C 1pi(u) states, a new set of sensitivity coefficients K(i) is derived for all lines in the H2 spectrum, representing the dependence of their transition wavelengths on a possible variation of the proton-electron mass ratio mu = m(p)/m(e). Included are local perturbation effects between B and C levels and adiabatic corrections. The new wavelengths and K(i) factors are used to compare with a recent set of highly accurate H2 spectral lines observed in the Q 0347-383 and Q 0405-443 quasars, yielding a fractional change in the mass ratio of deltamu/mu = (2.4 +/- 0.6) x 10(-5) for a weighted fit and deltamu/mu = (2.0 +/- 0.6) x 10(-5) for an unweighted fit. This result indicates, at a 3.5sigma confidence level, that mu could have decreased in the past 12 Gyr.     

基于GaSe差频产生8~19 μm可调中红外辐射

利用Nd∶YAG激光器抽运内腔KTP光学参量振荡器,得到了输出为2 μm附近的双波长,并在满足Ι类相位匹配条件下,在GaSe中共线差频产生8~19 μm连续宽调谐调的中红外辐射.在8.76 μm处脉冲最大能量达33.66 μJ,峰值功率7.4 kW,光子转换效率达4.43%左右.分析了影响能量转化效率的原因,提出了补偿走离的措施.     

Extracting the light quark mass ratio m(u)/m(d) from bottomonia transitions

We propose a new method to extract the light quark mass ratio m(u)/m(d) using the Υ(4S)→h(b)π?(η) bottomonia transitions. The decay amplitudes are dominated by the light quark mass differences, and the corrections from other effects are rather small, allowing for a precise extraction. We also discuss how to reduce the theoretical uncertainty with the help of future experiments. As a by-product, we show that the decay Υ(4S)→h(b)η is expected to be a nice channel for searching for the h(b) state.     

Local symmetry breaking by impurities and mode splitting in doped SmS

We introduce the idea of local symmetry breaking by impurities to explain the recently observed splitting of the J=0-->1 propagating excitation in doped Sm1-xYxS. While preserving the global cubic symmetry of the crystal, Y impurities change the local crystal-field environment of each Sm ion from cubic to tetragonal, thereby splitting the J=1 triplet into a m(i).J=0 level with energy Delta(1) and a m(i).J=+/-1 doublet with energy Delta(2)>Delta(1). A model with a randomly oriented quantization axis m(i) fits not only the observed mode frequencies but also their intensities, which strongly depends on the wave vector.     

Nuclear orientation of105Rh and95Tc in iron

The temperature-dependent anisotropy of γ-rays following the decay of oriented⁹⁵Tc and¹⁰⁵Rh nuclei was studied with a Ge(Li) detector. Mixing coefficients of some γ-and preceding β-transitions, the spins of two intermediate levels, and the magnetic hyperfine splitting of the⁹⁵Tc and¹⁰⁵Rh ground states in an Fe host were measured. From the known hyperfine fields the following magnetic moments were deduced: $$\begin{gathered} \mu \left( {^{105} Rh,\tfrac{{7 + }}{2}} \right) = 4.34\left( {12} \right) n.m.; \hfill \\ \mu \left( {^{95} Tc,\tfrac{{9 + }}{2}} \right) = 5.82\left( {12} \right)n.m. \hfill \\ \end{gathered}$$      

Genuine （k,m）-Threshold Controlled Teleportation and Multipartite Entanglement

We propose genuine (k,m)-threshold controlling schemes for controlled teleportation via multi-particle entangled states, where the teleportation of a quantum state from a sender (Alice) to a receiver (Bob) is under the control of m supervisors such that k (k ≤ m) or more of these supervisors can help Bob recover the transferred state. By construction, anyone of our quantum channels is a genuine multipartite entangled state of which any two parts areinseparable. Their properties are compared and contrasted with those of the well-known GHZ, W, and linear cluster states, and also several other genuine multipartite entangled states recently introduced in the literature.     

Rabi splitting with excitons in effective (near) zero-index media

We study theoretically the properties of a thin film of a semiconductor embedded in the interface of two kinds of single-negative materials. At some frequencies the structure with suitable size is equivalent to an effective (near) zero-index medium. The coupling of exciton resonance in the semiconductor and the interface mode in a zero-index medium leads to Rabi splitting. Compared with Rabi splitting observed in cavities, the splitting modes in zero-index media are robust against the scaling change of the length and direction of incident wave.     

基于MgO:APLN的1.57μm/3.84μm连续波内腔多光参量振荡器研究

报道了一种基于MgO:APLN实现1.57 μm和3.84 μm跨周期参量光连续输出的内腔抽运多光参量振荡器. 采用1064 nm谐振腔与多光参量振荡腔折叠型复合结构, 综合考虑高功率抽运下谐振腔的热稳定性及多光参量振荡过程的光斑模式匹配, 通过对两个子腔谐振结构的数值模拟分析, 确定了最佳腔型参数. 在此基础上, 进一步研究了谐振参量光透过率对振荡阈值、抽运光下转换效率、输出功率稳定性的影响, 最终实现了3.13 W的1.57 μm和0.85 W的3.84 μm参量光输出, 对应斜效率为6.8%和1.9%, 输出功率稳定性分别达到了1.8%和3%.     

Observation of orbitally excited B(s) mesons

We report the observation of two narrow resonances consistent with states of orbitally excited (L=1) B_(s) mesons using 1 fb;(-1) of pp[over ] collisions at sqrt[s]=1.96 TeV collected with the Collider Detector at Fermilab II detector at the Fermilab Tevatron. We use two-body decays into K- and B+ mesons reconstructed as B(+)-->J/psiK(+), J/psi-->mu(+)mu(-) or B(+)-->D[over ](0)pi(+), D[over ](0)-->K(+)pi(-). We deduce the masses of the two states to be m(B_(s1))=5829.4+/-0.7 MeV/c(2) and m(B_(s2);(*))=5839.6+/-0.7 MeV/c;(2).     

Magnetic hyperfine splitting in mössbauer spectra of microcrystals

Below the superparamagnetic blocking temperature of a microcrystal the magnetization direction is in general not fixed, but fluctuates in directions close to an easy direction of magnetization. Such fluctuations (collective magnetic excitations) result in a reduction in the magnetic splitting of the Mössbauer spectrum. A low-temperature approximation for this reduction is derived for microcrystals with arbitrary magnetic energy. Moreover, explicit expressions are presented for particles with special types of magnetic anisotropy and for particles exposed to external magnetic fields. The reduction in the magnetic hyperfine field has its maximum value just below the blocking temperature but does not exceed 5–15% in isolated particles with uniaxial anisotropy in zero applied magnetic field. However, ferro- and ferrimagnetic particles, exposed to external magnetic fields, and particles for which exchange anisotropy is predominant, may exhibit any magnetic hyperfine splitting between zero and the saturation value. It is shown that in special cases an assembly of microcrystals in close contact with each other may behave like a spin-glass. We discuss how studies of the magnetic hyperfine splitting ofMössbauer spectra of microcrystals give information of the particle size and the prevailing magnetic anisotropies.     

高能量全光纤2 μm掺铥脉冲光纤激光器

基于增益开关技术获得了稳定的高能量全光纤结构2 m脉冲光纤激光器,脉冲重复频率在10~50 kHz之间可调,输出激光中心波长为1958 nm,输出脉冲宽度随着泵浦功率的增加不断减小,其变化范围为1.2~1.7 s。采用两级掺铥光纤放大器对种子激光进行放大,当脉冲重复频率为10 kHz时,获得了5.18 W的输出平均功率,输出脉冲宽度为1.6 s,单脉冲能量为0.518 mJ。