Improved frequency standard via weighted graph states

We study the spin squeezing property of weighted graph states,which can be used to improve sensitivity in interferometry.We study the time evolution of spin squeezing under local decoherence acting independently on each qubit.Based on the analysis,the spin squeezing of the weighted graph states is somehow robust in the presence of decoherence and the decoherence limit in the improvement of the interferometric sensitivity is still achievable.Furthermore,one can obtain the optimal improvement of sensitivity by tuning the weighted of each edges of the weighted graph state.     

Gd替代对La0.6-xGdxSr1.4MnO4磁性和输运性质的影响

随着x的增加，多晶La0.6-xGdxSr1.4MnO4（x=0, 0.1, 0.2, 0.4, 0.6）的零场冷却 曲线从类自旋玻璃型转变成顺磁型，并且每条零场冷却 曲线都有一在20K的拐点。这一行为可以从Gd和Mn各自对材料总磁性的不同贡献来理解。另外，在所有的样品中，从100K到室温，都观察到了热激活导电行为。由于Mn-Mn间强的反铁磁耦和，直到外场达到50 kOe，都没有观察到明显的磁电阻效应。     

171Ta高自旋态能级寿命测量

在中国原子能科学研究院的HI 13串列加速器上通过157Gd(19F,5n)171Ta重离子熔合蒸发反应布居了171Ta的高自旋态,以多普勒移动衰减法的峰形分析法分析了171Tah9/2质子1/2[541]转动带的6条能级的寿命,得到了这6条能级的平均寿命值. The high spin states of~(171)Ta have been populated via heavy ion fusion evaporation reaction~(157)Gd(~(19)F, 5n)~(171)Ta at the HI-13 tandem accelerator in China Institute of Atomic Energy. The lifetimes of the high spin states in~(171)Ta have been measured by using the Doppler Shift Attenuation Method (DSAM). Six levels of its h_(9/2) proton 1/2\ band have been analyzed and their lifetimes have been deduced from the experimental data.     

HgMnTe磁性二维电子气自旋-轨道和交换相互作用研究

通过分析不同温度下HgMnTe磁性二维电子气Shubnikov-de Hass（SdH）振荡的拍频现象，研究了量子阱中电子自旋 轨道相互作用和spd交换相互作用.结果表明：（1）在零磁场下，电子的自旋 轨道相互作用导致电子发生零场自旋分裂；（2）在弱磁场下，电子的自旋-轨道相互作用占主导地位，并受Landau分裂和Zeeman分裂的影响，电子的自旋分裂随磁场增加而减小；（3）在高磁场下，电子的spd交换相互作用达到饱和，电子的自旋分裂主要表现为Zeeman分裂.实验证明了当电子的Zeeman分裂能量与零场 关键词： 磁性二维电子气 Zeeman分裂 Rashba自旋分裂     

126Cs的高自旋态能级结构

利用融合蒸发反应¹¹⁶Cd(¹⁴N,4n)¹²⁶Cs布居了¹²⁶Cs的高自旋态.观测到了100多条新的γ跃迁和相应的能级,建立了双奇核¹²⁶Cs由9个转动带构成的能级纲图.尝试性地指定了大部分能级的自旋和宇称以及各转动带的Nilsson单粒子组态.极大地丰富了已有的实验结果.     

热核的热稳定曲线

从核极限温度的角度研究了热核的热稳定性.采用Skyrme相互作用力计算热核同位素的极限温度,得到的极限温度的同位素分布呈现出倒置抛物线的趋势,与中能重离子反应多重碎裂中同位素产额分布的实验结果具有一致的行为表现.系统地计算了从轻到重的一系列元素极限温度的同位素分布,并从中抽取出热核的热稳定曲线.与β稳定线相比,热核的热稳定线更加偏丰中子.     

La0.825Sr0.175MnO3薄膜自旋输运特性研究

本文通过固相反应方法制备了具有钙钛矿结构的稀土掺杂锰氧化物La0.875Sr0.125MnO3(LSMO)块材,并用磁控溅射方法在LaAlO3衬底上生长了厚度为50nm的单晶薄膜.X射线衍射仪分别对LSMO块材和薄膜材料进行分析,表明薄膜和衬底具有相同的钙钛矿结构;通过研究该薄膜光诱导效应和磁场下输运行为,发现其输运性质明显改变,表明外场改变体系的电子自旋输运特性,引起双交换作用减弱和增强,分别导致电阻率的增加和减小.     

Superposition of special non-abelian potentials

The superposition of the non-abelian potentials of the formA′^μ=Aα^μ+aβ ^μ andB′^μ=Bγ^μ+bη^μ are considered and the necessary as well as the sufficient conditions are obtained. The significance of the conditions is discussed and the constrained isotopic spins of the perturbation potentials (aβ ^μ,bη^μ) are shown to be necessary for the superposition of these potenitals. Work under the projecthcs/dst/1081/81     

Electric and thermo spin transfer torques in Fe/Vacuum/Fe tunnel junction

We present first-principle calculations of electric and thermo spin transfer torques (STT) in Fe/Vacuum(Vac)/Fe magnetic tunnel junctions (MTJs). Our quantitative studies demonstrate rich bias dependence of STT and tunnel magneto resistance (TMR) behaviors with respect to the interface roughness. Thermoelectric effects in Fe/Vac/Fe MTJs is remarkable. We observe larger ZT of 6.2 in 8 ML clean Vacuum barrier, where the heavily restrained thermal conductance should be responsible for. Thermo-STT in Fe/Vac/Fe MTJs show same order as that in Fe/MgO/Fe MTJs with similar barrier thickness.     

A=190区奇奇核超形变带顺排涌动量的相加性

利用推转玻尔-莫特森模型指定的能级自旋,研究了A＝190区奇奇核194Tl和196Bi超形变带的顺排角动量的相加性．194Tl的6条超形变带中,有4条满足顺排角动量的相加性规则,而196Bi的超形变带不满足这个规则．