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1.
On the basis of elementary symmetry arguments it is shown that (1) if in classical mechanics there exists a quantity λ+Σiμiυi+1/2νυ 2 that is conserved, where λ,μ i, andν are particle parameters, then theμ i andν are all proportional to a single parameterμ and the quantityiBiμυi+C(λ+ 1/2Dμυ 2), whereDν/μ, is conserved for all values ofA, B i, andC; (2) if in relativistic mechanics there exists a quantity λ+Σiμiυi[1−(υ 2/c 2)]−1/2+νc[1−(υ 2/c 2)]−1/2 that is conserved, then theμ i andν are all proportional to a single parameterμ and the quantityAλ+ΣiBiμνi[1−(υ 2/c 2)]−1/2+Cμc [1−(υ 2/c 2)]−1/2 is conserved for all values ofA, B i, andC.  相似文献   

2.
On the basis of simple kinematic arguments it is shown that any quantity, depending only on the nature and velocity of a particle, that is conserved in a collision must, in classical mechanics, be of the form λ+Σiμiυi+1/2 2 or in relativistic mechanics of the form λ+Σiμiυi[1−(υ 2/c 2)]−1/2+νc [1−(υ 2/c 2)]−1/2 where λ,μ i, andν are particle parameters.  相似文献   

3.
The Geant4 CHIPS model simulates both decay and nuclear capture of negative muons. In hadron level models the muon is captured by a proton, p(μ,νμ)n , and the neutron transfers to the nucleus only 5MeV, which is not enough to split a nucleon from the nucleus, while the measured spectra of emitted nucleons reach 80MeV. In CHIPS, which considers asymptotically free quark-partons, the muon can be captured by a quark, u(μ,νμ)d , and transfers 52MeV to the nucleus. This capture mechanism fits the main part of the nucleon spectra, while the high-energy part of the spectra is not fitted. A precise fit of the high-energy part of the nucleon spectra can be made if the muon decay μ → dˉνμ is taken into account.  相似文献   

4.
We consider Ising-spin systems starting from an initial Gibbs measure ν and evolving under a spin-flip dynamics towards a reversible Gibbs measure μ≠ν. Both ν and μ are assumed to have a translation-invariant finite-range interaction. We study the Gibbsian character of the measure νS(t) at time t and show the following: (1) For all ν and μ, νS(t) is Gibbs for small t. (2) If both ν and μ have a high or infinite temperature, then νS(t) is Gibbs for all t > 0. (3) If ν has a low non-zero temperature and a zero magnetic field and μ has a high or infinite temperature, then νS(t) is Gibbs for small t and non-Gibbs for large t. (4) If ν has a low non-zero temperature and a non-zero magnetic field and μ has a high or infinite temperature, then νS(t) is Gibbs for small t, non-Gibbs for intermediate t, and Gibbs for large t. The regime where μ has a low or zero temperature and t is not small remains open. This regime presumably allows for many different scenarios. Received: 26 April 2001 / Accepted: 10 October 2001  相似文献   

5.
Current-voltage (I–V) characteristics are studied in the intrinsic Josephson junctions of Bi2Sr2CaCu2Oy single crystals. In order to examine the influence of self-heating, a current pulse (∼0.2 μsec) is applied to the mesas of 40 μmϕx0.15 μm patterned on the crystal. As a consequence, in contrast to small characteristic voltageV c in the continuous-current measurement, theV c data is found comparable to the BCS value. Moreover, theI–V curve is nearly ohmic forl>l c , implying that the nonlinearity under the continuous current is due to heating. The quasiparticle resistance forT<T c is also presented by an estimate from the characteristic voltage.  相似文献   

6.
We calculate decay widths of the metastable ppμ* ν,J molecular ion in non-adiabatic approach. The muonic molecular ion can be formed in collision of the excited pμ(2s) atoms with H2. Then, decay of the ppμ* ν,J system opens a path for the muon from pμ(2s) to pμ(1s). We employ trial wave function which includes non-adiabatic terms to calculate some radiationless decay widths. The present results of the widths do not good agree with those given in our previous work, while are more close to recent data of other researchers.  相似文献   

7.
Let Ω be a bounded pseudoconvex domain in C N , φ, ψ two positive functions on Ω such that − log ψ, − log φ are plurisubharmonic, and z∈Ω a point at which − log φ is smooth and strictly plurisubharmonic. We show that as k→∞, the Bergman kernels with respect to the weights φ k ψ have an asymptotic expansion
for x,y near z, where φ(x,y) is an almost-analytic extension of &\phi;(x)=φ(x,x) and similarly for ψ. Further, . If in addition Ω is of finite type, φ,ψ behave reasonably at the boundary, and − log φ, − log ψ are strictly plurisubharmonic on Ω, we obtain also an analogous asymptotic expansion for the Berezin transform and give applications to the Berezin quantization. Finally, for Ω smoothly bounded and strictly pseudoconvex and φ a smooth strictly plurisubharmonic defining function for Ω, we also obtain results on the Berezin–Toeplitz quantization. Received: 29 December 2000 / Accepted: 14 December 2001  相似文献   

8.
Ratios of the ψ over the J/ψ production cross sections in the dilepton channel for C, Ti and W targets have been measured in 920 GeV proton-nucleus interactions with the HERA-B detector at the HERA storage ring. The ψ and J/ψ states were reconstructed in both the μ+μ- and the e+e- decay modes. The measurements covered the kinematic range -0.35≤xF≤0.1 with transverse momentum pT≤4.5 GeV/c. The angular dependence of the ratio has been used to measure the difference of the ψ and J/ψ polarization. All results for the muon and electron decay channels are in good agreement: their ratio, averaged over all events, is Rψ′(μ)/Rψ′(e)=1.00±0.08±0.04. This result constitutes a new, direct experimental constraint on the double ratio of branching fractions, (B(μ)B(e))/(B(μ)B(e)), of ψ and J/ψ in the two channels. The ψ to J/ψ production ratio is almost constant in the covered xF range and shows a slow increase with pT.  相似文献   

9.
We analyze the long time behavior of solutions of the Schrödinger equation ${i\psi_t=(-\Delta-b/r+V(t,x))\psi}We analyze the long time behavior of solutions of the Schr?dinger equation iyt=(-D-b/r+V(t,x))y{i\psi_t=(-\Delta-b/r+V(t,x))\psi}, x ? \mathbbR3{x\in\mathbb{R}^3}, r =  |x|, describing a Coulomb system subjected to a spatially compactly supported time periodic potential V(t, x) =  V(t +  2π/ω, x) with zero time average.  相似文献   

10.
Ceramic solid solutions (Bi1 − y La y )4(V1 − x Me x )2O11 − z (x, y < 0.2: Me = Zr, Ga, Fe, Cu) were prepared by solid-state reaction. It was shown that the annealing (973 K, reducing atmosphere H2/Ar (20/80)) of the samples whose compositions belong to the stability domains of α, β, and γ′ polymorphs increases their electronic conductivity by six orders of magnitude. The samples with low concentrations of dopant cations exhibited good compositional stability and a reversible change in their structure parameters. At the same time, the solid solutions with a high concentration of lanthanum cations and/or copper cations (y, x ∼ 0.1) underwent partial decomposition.  相似文献   

11.
By employing the technique of integral within an ordered product (IWOP) of operators we recast classical wavelet transform to a matrix element of the squeezing-displacing operator U(μ,s) between the mother wavelet vector 〈ψ| and the state vector |f〉 to be transformed, i.e., we propose that 〈ψ|U(μ,s)|f〉 can be considered as a new kind of spectrum for analyzing the quantum state |f〉. In this way we do numerical calculation of wavelet-transform spectrum for the even- and odd-coherent states and then plot their figures, respectively. Thus this kind of spectrum can be used to recognize a variety of quantum optical states.  相似文献   

12.
We construct a family of random matrix models for the q-deformed Gaussian random variables G μ=a μ+a^*μ, where the annihilation operators a μ and creation operators $a\gwia_\nu$ fulfill the $q$-deformed commutation relation a μ a^*νq a^*ν a μμν, Γμν is the covariance and 0<q<1 is a given number. An important feature of the considered random matrices is that the joint distribution of their entries is Gaussian. Received: 29 March 2000 / Accepted: 1 August 2000  相似文献   

13.
By employing the technique of an integral within an ordered product (IWOP) of operators we recast the complex wavelet transform to a matrix element of the two-mode squeezing-displacing operator U 2(μ,σ) between the mother wavelet vector 〈ψ| and the two-mode quantum state vector |f〉 to be transformed, i.e., we propose that 〈ψ|U 2(μ,σ)|f〉 can be considered as a new kind of spectra for analyzing |f〉, this may have some potential applications in quantum information and calculation. As an example, we numerically calculate wavelet-transform spectrum for the Bell states, which may play a role of distinguishing them one from another.  相似文献   

14.
The paper answers a question debated by physicists for many years. It is proved that, for almost equal gradients of the magnetic flux u at its zero-level curve ∂ω, which is the piecewise smooth boundary of a simply-connected domain ω ⋐ ℝ2, the inverse problem for the Grad-Shafranov equation of plasma equilibrium in a tokamak (in the cylindrical approximation) admits essentially different profiles of distributions f u : ω ∋ (x, y) ↦ f(u(x, y)) = u xx (x, y) + u yy (x, y) ⩾ 0 in the class of third-order polynomials f(u) = Σ m=03 a m u m .  相似文献   

15.
With accumulation of high statistics data at BES and CLEO-c, many new interesting channels can get enough statistics for partial-wave analysis (PWA). Among them, ψ↦γpˉ,γΛˉ,γΣˉ,γΞˉ channels provide a good place for studying baryon-antibaryon interactions; the double radiative decays ψ↦γγV with V ≡ ρ,ω,φ have a potential to provide information on the flavor content of any meson resonances (R) with positive charge parity (C = +) and mass above 1 GeV through ψ↦γR↦γγV; ψ(2s)↦γχc0,1,2 with χc0,1,2Kˉπ+π- and 2π+- decays are good processes to study χcJ charmonium decays. Using the covariant tensor formalism, here we provide theoretical PWA formulae for these channels.  相似文献   

16.
The flavor composition of the solar beryllium neutrino was analyzed using schemes that include the new (heavy) neutrino (ν4) at a negligible angle of mixing with the light partners ν e , νμ, and ντ.  相似文献   

17.
Starting with the unification hypothesis of mixings of quarks and leptons and small quark-like mixings at the see-saw scale, we find that two large mixings for νe —νx03BC; andv μv τ at the weak scale are obtained as a result of renormalization group evolution and radiative magnification if the three neutrinos are quasi degenerate in masses and possess the same CP parity. We also find thatU e3 remains small and well within the CHOOZ-Palo Verde bound since the correspondingV ub for CKM mixing is very small. Several testable pedictions are pointed out.  相似文献   

18.
Transverse and zero-field μSR measurements were made on YBa2(Cu1−xNix)3O7−y withx=0.1 and 0.2, and YBa2(Cu1−x Zn x )3O7−y withx=0.03, 0.06, 0.1, and 0.16, wherey≈0.1. Since doping may lead to magnetic ordering this was searched for with both zero and transverse field μSR, but no evidence was found over the temperature range studied: 10–100 K. However, depolarization rates as functions of temperature were obtained, and the low temperature values of these are σ=3.2 μs−1.1.6μs−1, and 1 μs−1 forx=0.01, and 0.2 Ni, respectively, and σ=0.8 μs−1, 0.75 μs−1, 0.65 μs−1, and 0.4 μs−1 forx=0.03, 0.06, 0.1, and 0.16 Zn, respectively. Estimates for the effect of decreasing electron concentration for Zn are made, but these alone do not account for the drop in σ. Estimates for the effect of scattering on λ and hence σ are made. The reduction in σ for Ni dopant is in surprisingly good agreement with these estimates. For Zn the order of magnitude is correct, but the relative lack of further change in σ after the effect of the first 0.03 addition seems to imply a saturation of the effect of scattering.  相似文献   

19.
We have obtained IR absorption spectra of a C2F6 gas and a C2F6 cryosolution in Xe (T = 163 K) in the fundamental and overtone ranges. We have interpreted 28 bands of 12C12CF6 and three bands of 13C12CF6. In the spectral ranges that correspond to vibrations that are combinations with ν1, ν7, and ν5, we observe multiplets, which we attribute to interactions of the type of Fermi resonances between the states ν1(A 1g ) ∼ ν6(A 1g ), ν7(E g ) ∼ ν6 + ν11(E g ) ∼ 2ν8(E g ), ν5(A 2u ) ∼ ν8 + ν 11(A 2u ). We reveal an anomalous intensity distribution in the spectrum of an asymmetric isotopologue. For the basic and isotopic configurations of perfluoroethane, we calculate the coefficients of shapes of vibrations and the intensities of absorption bands. We reveal that the behavior of the groups 12CF3 and 13CF3 is indifferent to the excitation of doubly degenerate stretching vibrations ν7(E g ) and ν10(Eu).  相似文献   

20.
S Biswas  S Kumar 《Pramana》1989,33(2):277-287
We look at the confinement of tensor gluons (f μν (c) field) in a strong gravity background and find that the strong gravity provides a trap for the confinement of colour waves of selected frequencies. We assume that the tensorf μν (c) field (mediating quanta: tensor 2+ f-meson) satisfies Einstein-like equations with a cosmological constant. The colour field satisfy equations resembling Maxwell form of the linear theory of gravitation and see the effect off μν (c) field as playing the role of a medium having space dependent dielectric permeabilities. The solution of colour field equations resemble harmonic oscillator type wave functions with equispaced energy levels (no continuum) leading to confinement.  相似文献   

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