For a long time, it has been generally believed that spin-spin interactions can only exist in a theory where Lorentz symmetry is gauged, and a theory with spin-spin interactions is not perturbatively renormalizable. B...For a long time, it has been generally believed that spin-spin interactions can only exist in a theory where Lorentz symmetry is gauged, and a theory with spin-spin interactions is not perturbatively renormalizable. But this is not true. By studying the motion of a spinning particle in gravitational field, it is found that there exist spin-spin interactions in gauge theory of gravity. Its mechanism is that a spinning particle will generate gravitomagnetic field in space-time, and this gravitomagnetic field will interact with the spin of another particle, which will cause spin-spin interactions. So, spin-spin interactions are transmitted by gravitational field. The form of spin-spin interactions in post Newtonian approximations is deduced. This result can also be deduced from the Papapetrou equation. This kind of interaction will not affect the renormalizability of the theory. The spin-spin interactions will violate the weak equivalence principle, and the violation effects are detectable. An experiment is proposed to detect the effects of the violation of the weak equivalence principle.展开更多
The spin-spin coupling can provide useful information for analysing the structure of a system and the extent of non-covalent bonds interactions.In this study,we present the isotropic NMR properties and spinspin coupli...The spin-spin coupling can provide useful information for analysing the structure of a system and the extent of non-covalent bonds interactions.In this study,we present the isotropic NMR properties and spinspin coupling involving ruthenium-ligand(Ru-L)bonds and other spin-spin interactions obtained from DFT calculations.The proton shift which in close proximity with the Ru and Cl(or O)atoms are characterised with lower and higher chemical shift respectively.Though Ru-Cl bond has longer bond length than all other Ru-L bonds,yet its spin-spin coupling is higher than others because of a very high contribution of PSO which is far higher than the contribution from FC terms.In all other Ru-L bonds,FC is the most significant Ramsey terms that define their spin-spin coupling.Both the isotropic and anisotropic shielding of the Hz of the pyrazole is lower than Hc of the cymene and the spin-spin coupling 3J(Hz…Hz)of the pyrazole are less than half of the 3J(Hc…Hc)of the cymene unit in the complexes.There is a little increase in both the 3J(Hc…Hc)and 3J(Hz…Hz)spin-spin coupling in the hydrolysed complexes compare to the non-hydrolysed complexes.The isotropic and anisotropic shielding tensor of Ru atoms increases in magnitude as the complexes get hydrolysed that could be ascribed to a more deshielding chemical environments.展开更多
The effects of spin-spin interaction on thermed entanglement of a two-qubit Heisenberg XYZ model with different inhomogeneous magnetic fields are investigated. It is shown that the entanglement is dependent on the spi...The effects of spin-spin interaction on thermed entanglement of a two-qubit Heisenberg XYZ model with different inhomogeneous magnetic fields are investigated. It is shown that the entanglement is dependent on the spin-spin interaction and the inhomogeneous magnetic fields. The larger the Ji （i-axis spin-spin interaction）, the higher critical value the Bi （i-axis uniform magnetic field） has. Moreover, in the weak-field regime, the larger Ji corresponds to more entanglement, while in the strong-field regime, different Ji correspond to the same entanglement. In addition, it is found that with the increase of Ji, the concurrence can approach the maximum value more rapidly for the smaller Bi, and can reach a larger value for the smaller bi （i-axis nonuniform magnetic field）. So we can get more entanglement by increasing the spin-spin interaction Ji, or by decreasing the uniform magnetic field Bi and the nonuniform magnetic field hi.展开更多
NMR relaxometry is one of the techniques that allow observing changes in the molecular mobility that come from materials’ morphology. T1H has been used to monitor food and polymer sciences. However, T2>H, although...NMR relaxometry is one of the techniques that allow observing changes in the molecular mobility that come from materials’ morphology. T1H has been used to monitor food and polymer sciences. However, T2>H, although being a revealing as T1>H, is rarely used to analyze changes in thermoplastic systems it is more sensitive to the mobile region. High Impact Polystyrene nanomaterials were prepared through solution casting and were exposed for different times to UV light in the air. The samples, removed after each exposure interval, were characterized by T2>H, focusing on the changes in the relaxation data. The results for this parameter showed that the changes in the relaxation data come from the competition of chain scission and chain recombination processes, which occurs due to the UV light influence with increased time. The T2>H data indicated that the clay ratio can influence the chain degradation processes, acting to inhibit or accelerate the aging process [1] [2].展开更多
In this work we present a model for the determination of the interaction energy for triplet and singlet states in atoms with incomplete filled shells. Our model includes the modification of the Coulomb’s law by the i...In this work we present a model for the determination of the interaction energy for triplet and singlet states in atoms with incomplete filled shells. Our model includes the modification of the Coulomb’s law by the interaction between the magnetic moments of the electrons. We find that the energy of the triplet state is lower than the energy of the singlet state. We calculate the interaction energy between the electrons from the adjacent atoms in fcc lattices and we find that the minimum interaction energy is attained for the triplet state. The result is presented for the interaction between the electrons of the first coordination group and those of the second coordination group. The interaction energy which aligns the spins is used to evaluate the Curie temperature in a mean field model.展开更多
The present model deals with a protocol which involves the generation and conversion of entanglement from pathspin(P-S)hybrid entanglement associated with half-spin particle to spin-spin(S-S)interparticle entanglement...The present model deals with a protocol which involves the generation and conversion of entanglement from pathspin(P-S)hybrid entanglement associated with half-spin particle to spin-spin(S-S)interparticle entanglement.This protocol finds its applications in quantum information processing via a series of operations which include a beam splitter,spin flipper,spin measurement,classical channel,unitary transformations.Finally,it leads to two particles having completely entangled spin variables,without any requirement of any simultaneous operation on the two particles.展开更多
基于自旋电子学的磁性随机存储器(Magnetic Random Access Memory,MRAM)具有非易失性、可无限擦写、低功耗和快速写入等优点,从而有望成为下一代通用存储器.在MRAM家族中,根据磁写入方式和磁媒介的不同,人们提出了自旋转移力矩(Spin Tra...基于自旋电子学的磁性随机存储器(Magnetic Random Access Memory,MRAM)具有非易失性、可无限擦写、低功耗和快速写入等优点,从而有望成为下一代通用存储器.在MRAM家族中,根据磁写入方式和磁媒介的不同,人们提出了自旋转移力矩(Spin Transfer Torque,STT)、自旋轨道力矩(Spin Orbit Torque,SOT)、电压控制型(如电控磁各向异性(Voltage Controlled Magnetic Anisotropy,VCMA)型和电控SOT(Voltage Gated-SOT,VG-SOT)型)、磁畴壁(Domain Wall,DW)和磁斯格明子(Magnetic Skyrmion)型等不同类型的各具特色的MRAM,共同推动着磁存储技术的多元化发展.近年来STT-MRAM商用芯片的成功问世进一步推动了MRAM器件的研究与应用.本文首先简要介绍了存储器技术的历史,然后介绍了MRAM的基本工作原理、从MRAM中读取和写入信息背后的技术、材料和不同的物理机制以及潜在的挑战问题.接下来介绍了近些年发展的新型的磁写入机制的进展.本文末尾讨论了一些可能有助于行业超越传统MRAM的技术,最后是总结和展望.展开更多
文摘For a long time, it has been generally believed that spin-spin interactions can only exist in a theory where Lorentz symmetry is gauged, and a theory with spin-spin interactions is not perturbatively renormalizable. But this is not true. By studying the motion of a spinning particle in gravitational field, it is found that there exist spin-spin interactions in gauge theory of gravity. Its mechanism is that a spinning particle will generate gravitomagnetic field in space-time, and this gravitomagnetic field will interact with the spin of another particle, which will cause spin-spin interactions. So, spin-spin interactions are transmitted by gravitational field. The form of spin-spin interactions in post Newtonian approximations is deduced. This result can also be deduced from the Papapetrou equation. This kind of interaction will not affect the renormalizability of the theory. The spin-spin interactions will violate the weak equivalence principle, and the violation effects are detectable. An experiment is proposed to detect the effects of the violation of the weak equivalence principle.
基金financial support of Govan Mbeki Research and Development Centre,University of Fort Hare,South Africa
文摘The spin-spin coupling can provide useful information for analysing the structure of a system and the extent of non-covalent bonds interactions.In this study,we present the isotropic NMR properties and spinspin coupling involving ruthenium-ligand(Ru-L)bonds and other spin-spin interactions obtained from DFT calculations.The proton shift which in close proximity with the Ru and Cl(or O)atoms are characterised with lower and higher chemical shift respectively.Though Ru-Cl bond has longer bond length than all other Ru-L bonds,yet its spin-spin coupling is higher than others because of a very high contribution of PSO which is far higher than the contribution from FC terms.In all other Ru-L bonds,FC is the most significant Ramsey terms that define their spin-spin coupling.Both the isotropic and anisotropic shielding of the Hz of the pyrazole is lower than Hc of the cymene and the spin-spin coupling 3J(Hz…Hz)of the pyrazole are less than half of the 3J(Hc…Hc)of the cymene unit in the complexes.There is a little increase in both the 3J(Hc…Hc)and 3J(Hz…Hz)spin-spin coupling in the hydrolysed complexes compare to the non-hydrolysed complexes.The isotropic and anisotropic shielding tensor of Ru atoms increases in magnitude as the complexes get hydrolysed that could be ascribed to a more deshielding chemical environments.
基金Supported by National Natural Science Foundation of China under Grant No. 10704001Anhui Provincial Natural Science Foundation under Grant No. 070412060+1 种基金the Major Program of the Education Department of Anhui Province under Grant No. KJ2010ZD08the Key Program of the Education Department of Anhui Province under Grant No. KJ2010A287
文摘The effects of spin-spin interaction on thermed entanglement of a two-qubit Heisenberg XYZ model with different inhomogeneous magnetic fields are investigated. It is shown that the entanglement is dependent on the spin-spin interaction and the inhomogeneous magnetic fields. The larger the Ji （i-axis spin-spin interaction）, the higher critical value the Bi （i-axis uniform magnetic field） has. Moreover, in the weak-field regime, the larger Ji corresponds to more entanglement, while in the strong-field regime, different Ji correspond to the same entanglement. In addition, it is found that with the increase of Ji, the concurrence can approach the maximum value more rapidly for the smaller Bi, and can reach a larger value for the smaller bi （i-axis nonuniform magnetic field）. So we can get more entanglement by increasing the spin-spin interaction Ji, or by decreasing the uniform magnetic field Bi and the nonuniform magnetic field hi.
文摘NMR relaxometry is one of the techniques that allow observing changes in the molecular mobility that come from materials’ morphology. T1H has been used to monitor food and polymer sciences. However, T2>H, although being a revealing as T1>H, is rarely used to analyze changes in thermoplastic systems it is more sensitive to the mobile region. High Impact Polystyrene nanomaterials were prepared through solution casting and were exposed for different times to UV light in the air. The samples, removed after each exposure interval, were characterized by T2>H, focusing on the changes in the relaxation data. The results for this parameter showed that the changes in the relaxation data come from the competition of chain scission and chain recombination processes, which occurs due to the UV light influence with increased time. The T2>H data indicated that the clay ratio can influence the chain degradation processes, acting to inhibit or accelerate the aging process [1] [2].
文摘In this work we present a model for the determination of the interaction energy for triplet and singlet states in atoms with incomplete filled shells. Our model includes the modification of the Coulomb’s law by the interaction between the magnetic moments of the electrons. We find that the energy of the triplet state is lower than the energy of the singlet state. We calculate the interaction energy between the electrons from the adjacent atoms in fcc lattices and we find that the minimum interaction energy is attained for the triplet state. The result is presented for the interaction between the electrons of the first coordination group and those of the second coordination group. The interaction energy which aligns the spins is used to evaluate the Curie temperature in a mean field model.
文摘The present model deals with a protocol which involves the generation and conversion of entanglement from pathspin(P-S)hybrid entanglement associated with half-spin particle to spin-spin(S-S)interparticle entanglement.This protocol finds its applications in quantum information processing via a series of operations which include a beam splitter,spin flipper,spin measurement,classical channel,unitary transformations.Finally,it leads to two particles having completely entangled spin variables,without any requirement of any simultaneous operation on the two particles.
文摘基于自旋电子学的磁性随机存储器(Magnetic Random Access Memory,MRAM)具有非易失性、可无限擦写、低功耗和快速写入等优点,从而有望成为下一代通用存储器.在MRAM家族中,根据磁写入方式和磁媒介的不同,人们提出了自旋转移力矩(Spin Transfer Torque,STT)、自旋轨道力矩(Spin Orbit Torque,SOT)、电压控制型(如电控磁各向异性(Voltage Controlled Magnetic Anisotropy,VCMA)型和电控SOT(Voltage Gated-SOT,VG-SOT)型)、磁畴壁(Domain Wall,DW)和磁斯格明子(Magnetic Skyrmion)型等不同类型的各具特色的MRAM,共同推动着磁存储技术的多元化发展.近年来STT-MRAM商用芯片的成功问世进一步推动了MRAM器件的研究与应用.本文首先简要介绍了存储器技术的历史,然后介绍了MRAM的基本工作原理、从MRAM中读取和写入信息背后的技术、材料和不同的物理机制以及潜在的挑战问题.接下来介绍了近些年发展的新型的磁写入机制的进展.本文末尾讨论了一些可能有助于行业超越传统MRAM的技术,最后是总结和展望.
