共查询到20条相似文献,搜索用时 46 毫秒
1.
The chirality-asymmetry macroscopic force mediated by light
pseudoscalar particles between α -quartz and some achiral
matter is studied. If this force between achiral source mass and
α -quartz with some chirality is attractive, it will become
repulsive when the chirality of the α -quartz crystal is
changed. According to the tested limits of the coupling constant
gs gp /\hbar c< 1.5× 10-24 at the
Compton wavelength λ = 10-3 m, the force (F) between
a 0.08× 0.08× 0.002 m3 block of α -quartz
and a 0.08× 0.08× 0.01 m3 copper block with a
separation being 0.5× 10-3 \mbox{m} in between, is
estimated from the published data at less than 4.64× 10-24 N, i.e. F < 4.64× 10-24 N. 相似文献
2.
The transfer of the quantum correlation from two-mode nonclassical state field to the supercurrents in two distant SQUID rings 下载免费PDF全文
We have considered two distant mesoscopic superconducting quantum
interference device (SQUID) rings A and B in the presence of two-mode
nonclassical state fields and investigated the correlation of the
supercurrents in the two rings using the normalized correlation
function $C_{\rm AB}$. We show that when the parameter $\alpha$ is
very small for the separable state with the density matrix $\hat
{\rho } = (\left| {\alpha , - \alpha } \right\rangle \left\langle
{\alpha , - \alpha } \right| + \left| { - \alpha ,\alpha }
\right\rangle \left\langle { - \alpha ,\alpha } \right|) / 2$ and
entangled coherent state (ECS) $\left| u \right\rangle = N_1 (\left|
{\alpha , - \alpha } \right\rangle + \left| { - \alpha ,\alpha }
\right\rangle )$ fields, the dynamic behaviours of the normalized
correlation function $C_{\rm AB}$ are similar, but it is quite
different for the entangled coherent state $\left| {u}'
\right\rangle = N_2 (\left| {\alpha , - \alpha } \right\rangle -
\left| { - \alpha ,\alpha } \right\rangle )$ field. When the
parameter $\alpha $ is very large, the dynamic behaviours of $C_{\rm
AB}$ are almost the same for the separable state, entangled coherent
state $\left| u \right\rangle $ and $\left| {u}' \right\rangle $
fields. For the two-mode squeezed vacuum state field the maximum of
$C_{\rm AB}$ increases monotonically with the squeezing parameter
$r$, and as $r \to \infty $, $C_{\rm AB} \to 1$. This means that the
supercurrents in the two rings A and B are quantum mechanically
correlated perfectly. It is concluded that not all the quantum
correlations in the two-mode nonclassical state field can be
transferred to the supercurrents; and the transfer depends on the
state of the two-mode nonclassical state field prepared. 相似文献
3.
Theoretical calculation of the quadratic Zeeman shift coefficient of the 3P0o clock state for strontium optical lattice clock 下载免费PDF全文
Benquan Lu 《中国物理 B》2022,31(4):43101-043101
In the weak-magnetic-field approximation, we derived an expression of quadratic Zeeman shift coefficient of $^3P^{\rm o}_0$ clock state for $^{88}$Sr and $^{87}$Sr atoms. By using this formula and the multi-configuration Dirac-Hartree-Fock theory, the quadratic Zeeman shift coefficients were calculated. The calculated values $C_2$ = $-23.38(5)$ MHz/T$^2$ for $^{88}$Sr and the $^3P^{\rm o}_0$, $F = 9/2$, $M_F = \pm9/2$ clock states for $^{87}$Sr agree well with the other available theoretical and experimental values, especially the most accurate measurement recently. In addition, the calculated values of the $^3P^{\rm o}_0$, $F = 9/2$, $M_F = \pm9/2$ clock states were also determined in our $^{87}$Sr optical lattice clock. The consistency with measurements verifies the validation of our calculation model. Our theory is also useful to evaluate the second-order Zeeman shift of the clock transition, for example, the new proposed $^1S_0$, $F = 9/2$, $M_F = \pm5/2$-${}^3P^{\rm o}_0$, $F = 9/2$, $M_F = \pm3/2$ transitions. 相似文献
4.
Probing the medium effect and isospin dependence of the in-medium nucleon--nucleon cross section in heavy ion collisions 下载免费PDF全文
Probing in-medium nucleon-nucleon (NN) cross section σ1/NN(α) in heavy ion collisions has been investigated by means of the isospin-dependent quantum molecular dynamics (IQMD) with the isospin- and momentum-dependent interaction (IMDI(T)). It is found that there are the very obvious medium effect and the sensitive isospin-dependence of nuclear stopping R on the in-medium NN cross section α1/NN(α) in the nuclear reactions induced by halo-neutron projectile and the same-mass stable projectile. However, R induced by the neutron-halo projectile is obviously lower than that induced by the corresponding stable projectile. In particular, there is a very obvious dependence of R on the medium effect of σ1/NN(α) in the whole beam energy region for the above two kinds of projectiles. Therefore, the comparison between the results of R's in the reactions induced by the neutron-halo projectile and the corresponding same-mass stable projectile is a more favourable probe for extracting the information of σ1/NN(α) because of adding a new judgement.[第一段] 相似文献
5.
Anomalous Hall effect of facing-target sputtered ferrimagnetic Mn4N epitaxial films with perpendicular magnetic anisotropy 下载免费PDF全文
Zeyu Zhang 《中国物理 B》2022,31(4):47305-047305
Epitaxial Mn$_{4}$N films with different thicknesses were fabricated by facing-target reactive sputtering and their anomalous Hall effect (AHE) is investigated systematically. The Hall resistivity shows a reversed magnetic hysteresis loop with the magnetic field. The magnitude of the anomalous Hall resistivity sharply decreases with decreasing temperature from 300 K to 150 K. The AHE scaling law in Mn$_{4}$N films is influenced by the temperature-dependent magnetization, carrier concentration and interfacial scattering. Different scaling laws are used to distinguish the various contributions of AHE mechanisms. The scaling exponent $\gamma > 2$ for the conventional scaling in Mn$_{4}$N films could be attributed to the residual resistivity $\rho_{xx0}$. The longitudinal conductivity $\sigma_{xx}$ falls into the dirty regime. The scaling of $\rho_{\rm AH}=\alpha \rho_{xx0} +b\rho_{xx}^{n}$ is used to separate out the temperature-independent $\rho_{xx0}$ from extrinsic contribution. Moreover, the relationship between $\rho_{\rm AH}$ and $\rho_{xx}$ is fitted by the proper scaling to clarify the contributions from extrinsic and intrinsic mechanisms of AHE, which demonstrates that the dominant mechanism of AHE in the Mn$_{4}$N films can be ascribed to the competition between skew scattering, side jump and the intrinsic mechanisms. 相似文献
6.
Electron tunnelling phase time and dwell time through an associated delta potential barrier 下载免费PDF全文
The electron tunnelling phase time τP and dwell time τD through an associated delta potential barrier U(x) = ξδ(x) are calculated and both are in the order of 10^-17~10^-16s. The results show that the dependence of the phase time on the delta barrier parameter ξ can be described by the characteristic length lc = h^2/meξ and the characteristic energy Ec=meξ^2/h^2 of the delta barrier, where me is the electron mass, lc and Ec are assumed to be the effective width and height of the delta barrier with lcEc=ξ, respectively. It is found that TD reaches its maximum and τD = τp as the energy of the tunnelling electron is equal to Ec/2, i.e. as lc =λDB, λDB is de Broglie wave length of the electron. 相似文献
7.
In this paper, we use a method to determine some basic parameters for
the $\gamma$-ray loud blazars. The parameters include the central
black mass ($M$), the boosting factor ($\delta$), the propagation
angle (${\it {\it\Phi}}$), the distance along the axis to the site of
the $\gamma$-ray production ($d$). A sample including 32 $\gamma$-ray
loud blazars with available variability time scales has been used to
discuss the above properties. In this method, the $\gamma$-ray
energy, the emission size and the property of the accretion disc
determine the absorption effect. If we take the intrinsic
$\gamma$-ray luminosity to be $\lambda$ times the Eddington
luminosity, i.e. $L_{\gamma}^{\rm in}=\lambda{L_{\rm Edd}}$, then we
have the following results: the mass of the black hole is in the
range of $(0.59-67.99)\times10^{7}M_{\odot} \ (\lambda=1.0)$ or
$(0.90-104.13)\times10^{7}M_{\odot} \ (\lambda=0.1)$; the boosting
factor ($\delta$) in the range of In this paper, we use a method to determine some basic parameters for
the $\gamma$-ray loud blazars. The parameters include the central
black mass ($M$), the boosting factor ($\delta$), the propagation
angle (${\it {\it\Phi}}$), the distance along the axis to the site of
the $\gamma$-ray production ($d$). A sample including 32 $\gamma$-ray
loud blazars with available variability time scales has been used to
discuss the above properties. In this method, the $\gamma$-ray
energy, the emission size and the property of the accretion disc
determine the absorption effect. If we take the intrinsic
$\gamma$-ray luminosity to be $\lambda$ times the Eddington
luminosity, i.e. $L_{\gamma}^{\rm in}=\lambda{L_{\rm Edd}}$, then we
have the following results: the mass of the black hole is in the
range of $(0.59-67.99)\times10^{7}M_{\odot} \ (\lambda=1.0)$ or
$(0.90-104.13)\times10^{7}M_{\odot} \ (\lambda=0.1)$; the boosting
factor ($\delta$) in the range of In this paper, we use a method to determine some basic parameters for
the $\gamma$-ray loud blazars. The parameters include the central
black mass ($M$), the boosting factor ($\delta$), the propagation
angle (${\it {\it\Phi}}$), the distance along the axis to the site of
the $\gamma$-ray production ($d$). A sample including 32 $\gamma$-ray
loud blazars with available variability time scales has been used to
discuss the above properties. In this method, the $\gamma$-ray
energy, the emission size and the property of the accretion disc
determine the absorption effect. If we take the intrinsic
$\gamma$-ray luminosity to be $\lambda$ times the Eddington
luminosity, i.e. $L_{\gamma}^{\rm in}=\lambda{L_{\rm Edd}}$, then we
have the following results: the mass of the black hole is in the
range of $(0.59-67.99)\times10^{7}M_{\odot} \ (\lambda=1.0)$ or
$(0.90-104.13)\times10^{7}M_{\odot} \ (\lambda=0.1)$; the boosting
factor ($\delta$) in the range of In this paper, we use a method to determine some basic parameters for
the $\gamma$-ray loud blazars. The parameters include the central
black mass ($M$), the boosting factor ($\delta$), the propagation
angle (${\it {\it\Phi}}$), the distance along the axis to the site of
the $\gamma$-ray production ($d$). A sample including 32 $\gamma$-ray
loud blazars with available variability time scales has been used to
discuss the above properties. In this method, the $\gamma$-ray
energy, the emission size and the property of the accretion disc
determine the absorption effect. If we take the intrinsic
$\gamma$-ray luminosity to be $\lambda$ times the Eddington
luminosity, i.e. $L_{\gamma}^{\rm in}=\lambda{L_{\rm Edd}}$, then we
have the following results: the mass of the black hole is in the
range of $(0.59-67.99)\times10^{7}M_{\odot} \ (\lambda=1.0)$ or
$(0.90-104.13)\times10^{7}M_{\odot} \ (\lambda=0.1)$; the boosting
factor ($\delta$) in the range of In this paper, we use a method to determine some basic parameters for
the $\gamma$-ray loud blazars. The parameters include the central
black mass ($M$), the boosting factor ($\delta$), the propagation
angle (${\it {\it\Phi}}$), the distance along the axis to the site of
the $\gamma$-ray production ($d$). A sample including 32 $\gamma$-ray
loud blazars with available variability time scales has been used to
discuss the above properties. In this method, the $\gamma$-ray
energy, the emission size and the property of the accretion disc
determine the absorption effect. If we take the intrinsic
$\gamma$-ray luminosity to be $\lambda$ times the Eddington
luminosity, i.e. $L_{\gamma}^{\rm in}=\lambda{L_{\rm Edd}}$, then we
have the following results: the mass of the black hole is in the
range of $(0.59-67.99)\times10^{7}M_{\odot} \ (\lambda=1.0)$ or
$(0.90-104.13)\times10^{7}M_{\odot} \ (\lambda=0.1)$; the boosting
factor ($\delta$) in the range of $0.16-2.09(\lambda=1.0)$ or
$0.24-2.86\ (\lambda=0.1)$; the angle (${\it\Phi}$) in the range of
$9.53^{\circ}-73.85^{\circ}\ (\lambda=1.0)$ or
$7.36^{\circ}-68.89^{\circ}\ (\lambda=0.1)$; and the distance
($d/R_{\rm g}$) in the range of $22.39-609.36\ (\lambda=1.0)$ or
$17.54-541.88\ (\lambda=0.1)$. 相似文献
8.
We present mathematical analyses of the evolution of solutions of the self-consistent equation derived from variational calculations based on the displaced-oscillator-state and the displaced-squeezed-state in spin-boson model at a zero temperature and a finite temperature. It is shown that, for a given spectral function defined as J(w) = π∑k Ck^2 = π/2αw^8w^1-s, there exists a universal sc for both kinds of variational schemes, the localized transition happens only for 2 s ≤ sc, moreover, the localized transition is discontinuous for s 〈 sc while a continuous transition always occurs when s = sc. At T = 0, we have sc = 1, while for T ≠ 0, sc = 2 which indicates that the localized transition in super-Ohmic case still exists, manifesting that the result is in discrepancy with the existing result. 相似文献
9.
10.
K. Christensen N. Farid G. Pruessner M. Stapleton 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,62(3):331-336
We derive general properties of the finite-size scaling of
probability density functions and show that when the apparent
exponent
of a probability density is less than 1, the
associated finite-size scaling ansatz has a scaling exponent τ
equal to 1, provided that the fraction of events in the universal
scaling part of the probability density function is non-vanishing in
the thermodynamic limit.
We find the general result that τ≥1 and
.
Moreover, we show that if the scaling function
approaches a
non-zero constant for small arguments,
, then
.
However, if the scaling function vanishes for small arguments,
, then τ= 1, again assuming a
non-vanishing fraction of universal events.
Finally, we apply the formalism developed to examples from the literature,
including some where misunderstandings of the theory of scaling have led to erroneous conclusions. 相似文献
11.
本文采用多组态相互作用及Davidson修正方法和全电子基组计算了SH~-阴离子的X~1∑~+,a~3∏和A~1∏态的势能曲线、电偶极矩和跃迁偶极矩.计算的光谱常数与实验值及已有的理论值符合得很好.在计算中考虑了自旋-轨道耦合效应.计算得到a~3∏_1(v'=0)?X~1∑_(0+)~+(v"=0)和A~1∏_1(v'=0)?X~1Σ_(0+)~+(v"=0)跃迁具有高对角分布的弗兰克-康登因子,分别为0.9990和0.9999;计算得到a~3∏_1和A~1∏_1态的自发辐射寿命分别为1.472和0.188 ms.A~1∏_1?X~1∑_(0+)~+跃迁存在中间态a~3∏_(0+)和a~3∏_1,但中间态对激光冷却SH~-阴离子的影响可以忽略.分别利用a~3∏_1(v'=0)? X~1∑_(0+)~+(v"=0)和A~1∏_1(v'=0)? X~1∑_(0+)~+(v"=0)跃迁构建了准闭合的能级系统,冷却所需的激光波长分别为492.27和478.57 nm.最后预测了激光冷却SH~-阴离子能达到的多普勒温度和反冲温度.这些结果为进一步实验提供了理论参数. 相似文献
12.
为了研究氢化非晶硅薄膜的稳定性,我们设计了一个在原子氢气氛中热退火的同时进行光诱导退火的实验(TLAH)。实验装置是由传统的微波电子回旋共振化学气相沉积系统改造而成为热丝辅助微波电子回旋共振化学气相沉积系统。为了对这一退火方法进行比较,对样品还进行了热退火、热退火同时进行光诱导退火。同时,为了定量地分析光电导衰退,我们假设光电导衰退遵循扩展指数规律:1/σph=1/σs-(1/σs-1/σ0)exp[-(t/τ)β],这里扩展指数参数β 和时间常数 τ 可从与 lnt 的线性关系中截距和斜率得到, 式中光电导饱和值σs可以通过在对数坐标系中表示的光电导和光照时间关系进行高斯拟合得到。实验结果显示:TLAH 方法可以提高氢化非晶硅薄膜的稳定性、改善其微结构和光电特性,同时还发现,光学带隙明显减小、荧光光谱显著地朝着低能方向移动。 相似文献
13.
Xiao-Long Peng 《理论物理通讯》2022,74(3):35603
In this paper, we generalize the growing network model with preferential attachment for new links to simultaneously include aging and initial attractiveness of nodes. The network evolves with the addition of a new node per unit time, and each new node has m new links that with probability Πi are connected to nodes i already present in the network. In our model, the preferential attachment probability Πi is proportional not only to ki + A, the sum of the old node i's degree ki and its initial attractiveness A, but also to the aging factor ${\tau }_{i}^{-\alpha }$, where τi is the age of the old node i. That is, ${{\rm{\Pi }}}_{i}\propto ({k}_{i}+A){\tau }_{i}^{-\alpha }$. Based on the continuum approximation, we present a mean-field analysis that predicts the degree dynamics of the network structure. We show that depending on the aging parameter α two different network topologies can emerge. For α < 1, the network exhibits scaling behavior with a power-law degree distribution P(k) ∝ k−γ for large k where the scaling exponent γ increases with the aging parameter α and is linearly correlated with the ratio A/m. Moreover, the average degree k(ti, t) at time t for any node i that is added into the network at time ti scales as $k({t}_{i},t)\propto {t}_{i}^{-\beta }$ where 1/β is a linear function of A/m. For α > 1, such scaling behavior disappears and the degree distribution is exponential. 相似文献
14.
We study the entropic destruction of heavy quarkonium in strongly coupled theories with an anisotropic scaling symmetry in time and a spatial direction. We consider Lifshitz and hyperscaling violation theories, which are covariant under a generalized Lifshitz scaling symmetry with the dynamical exponent z and hyperscaling violation exponent \begin{document}$ \theta$\end{document} ![]()
![]()
. It is shown that the entropic force depends on the parameters of these theories. In particular, increasing z decreases the entropic force, thus reducing the quarkonium dissociation, while increasing \begin{document}$ \theta$\end{document} ![]()
![]()
has the opposite effect. 相似文献
15.
Effect of substrate temperature on the growth and properties of boron-doped microcrystalline silicon films 下载免费PDF全文
Highly conductive boron-doped hydrogenated microcrystalline silicon (\mu
c-Si:H) films are prepared by very high frequency plasma enhanced chemical
vapour deposition (VHF PECVD) at the substrate temperatures $T_{\rm S})$
ranging
from 90$^\circ$C to 270$^\circ$C. The effects of $T_{\rm S}$ on the growth and
properties of the films are investigated. Results indicate that the growth
rate, the electrical (dark conductivity, carrier concentration and Hall
mobility) and structural (crystallinity and grain size) properties are all
strongly dependent on $T_{\rm S}$. As $T_{\rm S}$ increases, it is
observed that 1)
the growth rate initially increases and then arrives at a maximum value of
13.3 nm/min at $T_{\rm S}$=210$^\circ$C, 2) the crystalline volume fraction
($X_{\rm c})$ and the grain size increase initially, then reach their maximum
values at $T_{\rm S}$=140$^\circ$C, and finally decrease, 3) the dark
conductivity ($\sigma _{\rm d})$, carrier concentration and Hall mobility have
a similar dependence on $T_{\rm S}$ and arrive at their maximum values at
$T_{\rm S}$=190$^\circ$C. In addition, it is also observed that at a lower
substrate temperature $T_{\rm S}$, a higher dopant concentration is required in
order to obtain a maximum $\sigma _{\rm d}$. 相似文献
16.
Fluctuations and pseudo long range dependence in network flows: A non-stationary Poisson process model 下载免费PDF全文
In the study of complex networks (systems), the scaling phenomenon
of flow fluctuations refers to a certain power-law between the mean
flux (activity) < Fi> of the i-th node and its
variance σi as Fi ∝ <Fiα. Such scaling laws are found to be prevalent both in
natural and man-made network systems, but the understanding of their
origins still remains limited. This paper proposes a non-stationary
Poisson process model to give an analytical explanation of the
non-universal scaling phenomenon: the exponent α varies
between 1/2 and 1 depending on the size of sampling time window
and the relative strength of the external/internal driven forces of
the systems. The crossover behaviour and the relation of fluctuation
scaling with pseudo long range dependence are also accounted for by
the model. Numerical experiments show that the proposed model can
recover the multi-scaling phenomenon. 相似文献
17.
18.
Brovchenko I. Geiger A. Oleinikova A. 《The European Physical Journal B - Condensed Matter and Complex Systems》2005,44(3):345-358
The phase behavior of fluids near weakly attractive substrates is studied by computer simulations of the coexistence curve of a Lennard-Jones (LJ) fluid confined in a slitlike pore. The temperature dependence of the density profiles of the LJ fluid was used to study the surface critical behavior. A universal critical behavior of the local order parameter, defined as the difference between the local densities of the coexisting liquid and vapor phases at some distance
from the pore walls,
, is observed in a wide temperature range and found to be consistent with the surface critical behavior of the Ising model. Near the surface the dependence of the order parameter on the reduced temperature
obeys a scaling law ~1 with a critical exponent 1 of about 0.8, corresponding to the
surface transition. A crossover from bulk-like to surface-like critical behavior occurs, when the distance to the surface is about twice the correlation length at the given temperature. Relations between the
and
transitions in Ising systems and the surface critical behavior of fluids are discussed. 相似文献
19.
I. I. Guseinov 《Few-Body Systems》2013,54(11):1773-1780
By the use of complete orthonormal sets of ${\psi ^{(\alpha^{\ast})}}$ -exponential type orbitals ( ${\psi ^{(\alpha^{\ast})}}$ -ETOs) with integer (for α * = α) and noninteger self-frictional quantum number α *(for α * ≠ α) in standard convention introduced by the author, the one-range addition theorems for ${\chi }$ -noninteger n Slater type orbitals ${(\chi}$ -NISTOs) are established. These orbitals are defined as follows $$\begin{array}{ll}\psi _{nlm}^{(\alpha^*)} (\zeta ,\vec {r}) = \frac{(2\zeta )^{3/2}}{\Gamma (p_l ^* + 1)} \left[{\frac{\Gamma (q_l ^* + )}{(2n)^{\alpha ^*}(n - l - 1)!}} \right]^{1/2}e^{-\frac{x}{2}}x^{l}_1 F_1 ({-[ {n - l - 1}]; p_l ^* + 1; x})S_{lm} (\theta ,\varphi )\\ \chi _{n^*lm} (\zeta ,\vec {r}) = (2\zeta )^{3/2}\left[ {\Gamma(2n^* + 1)}\right]^{{-1}/2}x^{n^*-1}e^{-\frac{x}{2}}S_{lm}(\theta ,\varphi ),\end{array}$$ where ${x=2\zeta r, 0<\zeta <\infty , p_l ^{\ast}=2l+2-\alpha ^{\ast}, q_l ^{\ast}=n+l+1-\alpha ^{\ast}, -\infty <\alpha ^{\ast} <3 , -\infty <\alpha \leq 2,_1 F_1 }$ is the confluent hypergeometric function and ${S_{lm} (\theta ,\varphi )}$ are the complex or real spherical harmonics. The origin of the ${\psi ^{(\alpha ^{\ast})} }$ -ETOs, therefore, of the one-range addition theorems obtained in this work for ${\chi}$ -NISTOs is the self-frictional potential of the field produced by the particle itself. The obtained formulas can be useful especially in the electronic structure calculations of atoms, molecules and solids when Hartree–Fock–Roothan approximation is employed. 相似文献
20.
We use a new updated algorithm scheme to investigate the critical behaviour of the two-dimensional ferromagnetic Ising model on a triangular lattice with the nearest neighbour interactions. The transition is examined by generating accurate data for lattices with L= 8, 10, 12, 15, 20, 25, 30, 40 and 50. The updated spin algorithm we employ has the advantages of both a Metropolis algorithm and a single-update method. Our study indicates that the transition is continuous at Tc= 3.6403({2}). A convincing finite-size scaling analysis of the model yields υ=0.9995(21), β /
υ = 0.12400({17}), γ / υ = 1.75223(22), γ '/υ=1.7555(22), α/υ= 0.00077(420) (scaling) and α / υ = 0.0010(42) (hyperscaling). The present scheme yields more accurate estimates for all the critical exponents than the Monte Carlo method, and our estimates are shown to be in excellent agreement with their predicted values. 相似文献