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1.
The Wheeler-Feynman (WF) relativistic theory of interacting point particles, generalized by acceptance of an arbitrary spacelike interaction, is shown to possess a privileged status, reminiscent of the central force interactions occurring in Newtonian mechanics. This scheme is shown to be isomorphic to the classical one of the statics of interacting flexible current-carrying wires obeying the Ampère-Laplace (AL) formulas: to the tensionT (T 2 =const) of the wire corresponds the momentum-energy pi (pipi=–c2m2) of the particle; to the Laplace linear force density –iH×dr corresponds the Lorentz force QHij drj; to the Laplace potential ir–1 dr corresponds the WF potential Q(r2) dri, etc. Among the differences, there is self-action in the AL scheme and no self-action in the WF scheme. A stationary energy principle in the AL scheme is isomorphic to Fokker's stationary action principle in the WF scheme.  相似文献   

2.
J Pasupathy  C A Singh 《Pramana》1978,10(5):537-544
Mandelstam’s argument that PCAC follows from assigning Lorentz quantum numberM=1 to the massless pion is examined in the context of multiparticle dual resonance model. We construct a factorisable dual model for pions which is formulated operatorially on the harmonic oscillator Fock space along the lines of Neveu-Schwarz model. The model has bothm π andm ϱ as arbitrary parameters unconstrained by the duality requirement. Adler self-consistency condition is satisfied if and only if the conditionmϱ2mπ2=1/2 is imposed, in which case the model reduces to the chiral dual pion model of Neveu and Thorn, and Schwarz. The Lorentz quantum number of the pion in the dual model is shown to beM=0.  相似文献   

3.
The amplitudes for boson-boson and fermion-boson interactions are calculated in the second order of perturbation theory in the Lobachevsky space. An essential ingredient of the model is the Weinberg 2(2j+1)-component formalism for describing a particle of spinj. The boson-boson amplitude is then compared with the two-fermion amplitude obtained long ago by Skachkov on the basis of the Hamiltonian formulation of quantum field theory on the mass hyperboloid,p 0 2P 2=M 2, proposed by Kadyshevsky. The parametrization of the amplitudes by means of the momentum transfer in the Lobachevsky space leads to the same spin structures in the expressions ofT matrices for the fermion and the boson cases. However, certain differences are found. Possible physical applications are discussed.On leave of absence from Department of Theoretical and Nuclear Physics, Saratov State University, Saratov, Russia. E-mail: dvoeglazov@mainl.jinr.dubna.su.  相似文献   

4.
Time-dependent fluctuations in a system of coagulating particles are studied, using the master equation for the probability distributionsP(m,t) for the occupation numbersm={m k} (k=1,2,...) of thek-cluster states. Van Kampen's-expansion is used to determine the deterministic (order 0) and fluctuating part (order –1/2) of the solution. We calculate the time-dependent behavior of the fluctuations in the cluster size distribution. The model under consideration is of special interest since it exhibits a phase transition (gelation). For monodisperse initial states we give explicit expressions for the probability distribution of the fluctuations and for the equal-time and two-time correlation functions also near the phase transition. For general initial conditions we study the fluctuations (1) for large cluster sizes, (2) in the scaling limit (near the critical point), and (3) for large times. Our results show that the deterministic approach to coagulation processes (Smoluchowski theory) is invalid very close to the gelpointt c and at large times (tt M), where the distance from the gelpoint and the timet M depend upon the size of the system.  相似文献   

5.
We examine canonical quantization of relativistic field theories on the forward hyperboloid, a Lorentz-invariant surface of the form xμxμ = τ2. This choice of quantization surface implies that all components of the 4-momentum operator are affected by interactions (if present), whereas rotation and boost generators remain interaction free—a feature characteristic of Dirac’s “point-form” of relativistic dynamics. Unlike previous attempts to quantize fields on space-time hyperboloids, we keep the usual plane-wave expansion of the field operators and consider evolution of the system generated by the 4-momentum operator. We verify that the Fock-space representations of the Poincaré generators for free scalar and spin-1/2 fields look the same as for equal-time quantization. Scattering is formulated for interacting fields in a covariant interaction picture and it is shown that the familiar perturbative expansion of the S-operator is recovered by our approach. An appendix analyzes special distributions, integrals over the forward hyperboloid, that are used repeatedly in the paper.  相似文献   

6.
本文构造了由多模复共轭相干态的相反态|{-Zj(a)*}>q与多模虚共轭相干态的相反态|{-iZj(b)*}>q这两者的线性叠加所组成的第Ⅱ种强度不等的非对称两态叠加多模叠加态光场|Ψ(ab)>q,利用多模压缩态理论研究了态|Ψ(ab)>q的任意偶数阶等阶N次方Y压缩特性.结果发现:1)在压缩阶数N取偶数,即N=2p的条件下,无论p=2m(m=1,2,3,…,…),还是p=2m+1(m=0,1,2,3,…,…),只要构成态|Ψ(ab)>q的两个不同的量子光场态中各对应模的强度(即平均光子数)和初始相位都不相等,亦即Rj(a)≠Rj(b)和φj(a)≠φj(b)(j=1,2,3,…,q),并且 ,则当满足一定的量子化条件(或者在一些闭区间内连续取值)时,态|Ψ(ab)>q总可呈现出周期性变化的、任意偶数阶的等阶N次方Y压缩效应.2)在N=2pp=2m+1(m=0,1,2,3,…,…)的条件下,若Rj(a)=Rj(b)和φj(a)j(b)(j=1,2,3,…,q),态|Ψ(ab)>q则可呈现出等阶N次方Y压缩简并现象.  相似文献   

7.
Using the algebraic properties of Poisson brackets, we extend the three-dimensional brackets (for a single free particle) to conform to the demands of special relativity. This yields, in an essentially unique way, the manifestly covariant extension [x ,p v]=+p p v/m 2 c 2. Position and time then become fully dynamical variables expressible in terms of the canonical conjugateq i andp i and the time parameter asx i =q i +p i(q ·p)/m 2c2 andt = +E(q ·p)/m 2c4. In the quantized version, the length associated with a particle of massm is shown to be an integral multiple of the Compton wavelength C =/mc.  相似文献   

8.
构造了由多模复共轭相干态的相反态|{-Zj(a)*}〉q和多模虚共轭相干态的相反态|{-Zj(b)*}〉q的线性叠加所组成的第Ⅱ种强度不等的非对称两态叠加多模叠加态光场|Ψ(ab)Ⅱ〉q.利用多模压缩态理论,研究了态|Ψ(ab)Ⅱ〉q的等阶N次方H压缩特性.结果发现,在腔模总数与压缩阶数这两者之积取奇数,则当各对应模的初始相位、各对应模的初始相位差,态间的初始相位差、以及光子干涉项的幅度之和等分别满足一定的量子化条件时,态|Ψ(ab)Ⅱ〉q的第一及第二正交分量可分别呈现出周期性变化的等阶N次方H压缩效应.这与现有报道的结果截然不同.  相似文献   

9.
赵玲慧  杨志勇  侯瑶  张振杰  侯洵 《光子学报》2000,29(4):293-307,316
本文根据量子力学中的线性叠加原理,构造了由多模(即 q模)相干态的相反态 | {-Zj}〉q及多模虚相干态的相反态 | {-iZj}〉q 这两者的线性叠加所组成的一种新型的两态叠加多模叠加态光场 | ψmsc(2)q 利用新近建立的多模压缩态理论,详细研究了态 | ψmsc(2)q 的广义非线性等阶N次方H压缩特性 结果发现:1)当压缩阶数N与腔模总数q这两者之积为偶数,亦即当q·N =2pp =2m(m =1,2,3,…,…)时,态 | ψmsc(2)q恒处于等阶N-H最小测不准态;2)当q·N =2pp =2m′+ 1(m′ =0,1,2,3,…,…)时,如果各模的初始相位之和 、态间的初始相位差(θnq(I)nq(R))、各多模相干态光场的总的平均光子数 以及 [(θnq(I)nq(R))+ ]等满足一定的量子化条件时,态 | ψmsc(2)q 总可呈现出周期性变化的、任意阶的等阶N次方H压缩效应;3)当压缩阶数N与腔模总数 q这两者之积为奇数时,亦即当 q·N =2p + 1时,无论 p =2m(m =0,1,2,3,…,…)还是 p =2m′ + 1(m′ =0,1,2,3,…,…),只要各模初始相位之和 满足一定的量子化条件,则当两态叠加几率幅满足rnq(R) =rnq(I) 时,态 | ψmsc(2)q 就恒处于N-H测不准态  相似文献   

10.
Within nonrelativistic quantum mechanics the Wick-ordering method, called the oscillator representation, is suggested for calculating the energy spectrum for a wide class of potentials allowing the existence of a bound state. As test cases, anharmonic (V(r)=r 2) and screened Coulomb potentials are considered. In particular, the method is applied to three-body Coulomb systems to obtain the dependence of the bound-state energy on the masses and charges of the particles. The calculations of the bound-state energies for the moleculesH =(pee),H 2 + =(ppe), (e ee+) and (pp), (dd), (dt) prove the accuracy of the zeroth approximation to be better than one per cent. For the three-body Coulomb system with charges +, –, – and arbitrary masses the region of stability is determined. For the systems (pe C+), (A +ee+), and (pB e) the critical masses are calculated to beM c=1.945me,M A=4.350me andM B=1.575me. It turns out that the system (pe e+) is unstable.  相似文献   

11.
刘伟民  侯瑶  杨志勇  孙秀泉  侯洵 《光子学报》1999,28(10):869-883
本文根据量子力学的线性叠加原理,构造了由多模(即q模)相干态的相反态|{-Zj}〉q及多模虚相干态|{Zj}〉q这两者的线性叠加所组成的一种新型的多模Schrdinger猫态光场|Ψ(2)q,利用新近建立的多模压缩态理论,研究了态|Ψ(2)q的N次方Y压缩效应。结果发现:①当压缩阶数N=2pp=2m(m=1,2,3,…,…)时,态|Ψ(2)q总是恒处于N-Y最小测不准态;②当压缩阶数N=2pp=2m+1(m=0,1,2,3,…,…)时,如果各模的初始相位φj,态间的初始相位差θpq(I)-θnq(R)以及各单模相干态光场的平均光子数之总和 等满足一定的量子化条件,则态|Ψ(2)q可呈现出周期性变化的、任意阶的N次方Y压缩效应;③当压缩阶数N=2p′+1时,无论p′=2m(m=0,1,2,…,…)还是p′=2m+1(m=0,1,2,3,…,…),只要各模的初始相位φj满足一定的量子条件,则当两态叠加几率幅满足rpq(I)=rnq(R)时,态|Ψ(2)q就恒处于N-Y测不准态,始终不呈现N-Y最小测不准态和N次方Y压缩;而当rpq(I)rnq(R)时,态|Ψ(2)q始终不呈现N-Y测不准态、N-Y最小测不准态和N次方Y压缩效应。  相似文献   

12.
Using the properties of the Jordan curve, the following theorem on the heteroclinic tangency in orientation-preserving two-dimensional maps is proved: LetT :R 2 R 2 be a one-parameter family ofC 1 diffeomorphisms andJ=DetDT be such that 0<J1 or 1J<. LetW u n be the unstable manifold of a hyperbolicn-cycle andW s m the stable manifold of a hyperbolicm-cycle. Suppose that for< c ,W u n andW s m have no common points, and that for> c ,W u n andW s/m have a transversal heteroclinic point. Then at= c ,W u n andW s m are in the first asymptotic heteroclinic tangency except for the following three cases: (1)n=m; both cycles are without reflection. (2)m=2n; then- andm-cycles are with and without reflection, respectively; (3)n=2m; then- andm-cycles are without and with reflection, respectively.  相似文献   

13.
Fermion masses     
In this paper, we show that 2m e m /(m e 2 +m 2 = (g V/g A) e 2 . From this expression, the Weinberg mixing parameter is shown to be 0·2254 or 0·2746. Assuming that the electron and muon neutrino masses are degenerate, we find thatm v = (g V/g A) e 2 . (m e m )/M WL, where MWL is the mass of the standard W± boson. The neutrino mass turns out to be 6·5 eV. The -neutrino mass is found to be about 81 MeV. The masses of c, t, s and b quarks are found to be respectively 1·7 GeV, 21·2 GeV, 0·57 GeV and 2·18 GeV by assumingm d=m u= 0·3 GeV. All these masses agree with other estimates except the b quark which has about half of its expected value.  相似文献   

14.
利用多模压缩态理论研究了第种强度不等的非对称两态叠加多模叠加态光场|Ψ(ab)〉q的等阶N次方H压缩特性.结果发现:1)当腔模总数q与压缩阶数N的乘积取偶数,亦即qN=2p时,无论p=2m(m=1,2,3,…,…),还是p=2m+1(m=0,1,2,3,…,…),只要各模的初始相位差(φj(a)j(b))、态间的初始相位差(θnq(aR)nq(bR))及光子干涉项的幅度 1Rj(a)Rj(b)等分别满足一定的条件,则态|Ψ||(ab)〉q的第一和第二正交分量总可分别呈现出周期性变化的等阶N次方H压缩效应.2)当qN=2pp=2m+1(m=0,1,2,3,…,…)时,若构成态|Ψ(ab)〉q的两个不同的量子光场态中各对应模的强度(即平均光子数)和初始相位相等,亦即Rj(a)=Rj(b)和φj(a)j(b)(j=1,2,3,…,q),则态|Ψ(ab)〉q可呈现出“等阶N次方H压缩简并”现象.  相似文献   

15.
A small and a large black hole are naturally associated with a galaxy of total massM and spherical halo radiusR. Also of massM, the large black hole is a spatial contraction of the galaxy down to its Schwarzschild radius,r r, with=2GM/c 2R, whereG/c 2=4.78×10–17 kpc/M is Newton's gravitational constant divided by the speed of light squared. The small black hole is ther r contraction of the large hole, i.e., the iterated double contraction of the galaxy itself, with the resulting massm=M=2GM 2/c2R. In the case of the Milky Way (M=7.0×1011 M andR=15 kpc) the latter equation for the small black hole mass yieldsm=3.1×106 M , which is close to the observed value for the mass of the black hole at the center of the Milky Way. Black holes of the small type may evolve to the large by mass accretion, perhaps during a quasar phase. Vast regions of the universe may in fact be populated by large black holes—missing mass—which validates the cosmological principle and effects the closure of the universe.  相似文献   

16.
Finely ground powders ofRBa2Cu3O7 – (R=Y, Nd, Sm, Eu, Dy, Ho, Er, Tm, Yb) have been mixed at dilute 3%-by-volume concentrations into epoxy matrices which were then allowed to harden in applied magnetic fieldsH A=18 kOe. X-ray diffractometry studies and 4.3 K measurements of supercurrent-induced magnetization hysteresisM are interpreted as indicating at least partial alignment of single-crystal-grain c-axes (1) parallel toH A forR=Y, Nd, Sm, Dy, Ho (as earlier found by Farrell et al. forR=Y), and (2) perpendicular toH A forR=Eu, Er, Tm, Yb. With a few exceptions (Y, Sm, Eu) the alignment direction correlates with the sign of the second-order Stevens factor J of the crystalline electric field Hamiltonian in the manner suggested by Livingston et al. For the best aligned specimens (Ho, Dy) critical current densitiesJ c (4.3 K, 5 kOe) for individual grains are estimated fromM and the Bean model to be of order 107 A/cm2 for the measuring fieldH parallel to the original alignment fieldH A, and of order 106 A/cm2 forH perpendicular toH A.  相似文献   

17.
It is shown that a Universe with a time-varying gravitational constantG necessarily implies creation if the rest mass of matter particlesm p is constant. In this case, from Einstein's field equations, the conditions for energy-momentum propagation are ·(GT v ) from which matter and photon propagation equations are derived. Free matter particle propagation is not affected by creation that is given byGN pmp=const, whereN p is the number of matter particles within a proper volume. This relation introduces explicitly the rest mass of the Universe into the field equations. Free photon propagation is affected by creation that is given byGT v R=const, whereN is the number of photons within a proper volume, which is the cosmic red shift law. Conservation of the cosmic background photon distribution determines photon creation asG 3 N 4 . The results are applied to the caseG t –1 equivalent toN p ÷ t.It is found that at an aget=1, 0–40 t o, of the order light takes to travel a proton size, Planck's units become of the order of the proton's massm p, sizer p, and timer p/c. Hence, matter particles at this age are quantum black holes. Evaporation of these quantum black holes at this age gives a background blackbody radiation that, red shifted to present timet 0, gives the present cosmic microwave background.A cosmological model of the Friedmann type is constructed. The red shift versus distance relation is derived taking into account creation. Using a Hubble's constantH obs=50 km sec–1 Mpc–1 and a deceleration parameterq obs=1.0 the model is of the typek=1 and gives a present aget 0=6.81×109 yr, consistent with Uranium model ages. Thus, the three results for the age of the Universe, i.e., radioactive decay, Hubble's constant, and stellar evolution are brought together in this creation model. The matter-dominated era occurs fort>7.6×10–3 t 0, while the radiation-dominated era occurs for 7.6×10–3 t o>t>10–40 t o. The origin of the Universe is placed at this last limit, which is Planck's time at the corresponding G, consisting of quantum black holes at a temperature Ti=3×1011K.  相似文献   

18.
An excess term exists when using hermitian form of Cartesian momentum p i (i = 1, 2, 3) in usual kinetic energy 1/(2) p i 2 for a particle moving on the 2D surface, and the correct kinetic energy turns to be 1/(2) 1/fipi fi pi where the f i are dummy factors in classical mechanics and nontrivial in quantum mechanics. In this paper, the explicit form of the dummy functions f i is given for some surfaces of nonspherical topology, such as toroidal surface, paraboloid of revolution, the hyperboloid of revolution of two sheets, and the hyperboloid of revolution of one sheets.  相似文献   

19.
When electron states in carbon nanotubes are characterized by two-dimensional wave vectors with the components K 1 and K 2 along the nanotube circumference and cylindrical axis, respectively, then two such vectors symmetric about a M-point in the reciprocal space of graphene are shown to be related by the time-reversal operation. To each carbon nanotube there correspond five relevant M-points with the following coordinates: K 1(1) = N/2R, K 2(1)= 0; K 1(2) = M/2R, K 2(2)= −π/T; K 1(3)= (2NM)/2R, K 2(3)= π/T; K 1(4)= (M + N)/2R, K 2(4)= -π/T, and K 1(5)= (NM)/2R, K 2(5)= π/T, where M and N are the integers relating the chiral, C h , symmetry, R, and translational, T, vectors of the nanotube by N R = C h + M T, T = |T|, and R is the nanotube radius. The states at the edges of the one-dimensional Brillouin zone, which are symmetric about the M-points with K 2 = ±π/T, are shown to be degenerate due to the time-reversal symmetry.  相似文献   

20.
A class of well behaved charged analogues of Schwarzchild’s interior solution has been obtained using a particular electric intensity. The solutions of this class are utilized to depict a superdense star model with surface density 2×1014 g cm−3. The solution obtained is new and the pressure (p), density (c 2 ρ), velocity of sound and (p/(c 2 ρ)) are monotonically decreasing towards the pressure free interface. Moreover the adiabatic constant is found to be more than (4/3) which is necessary for stability under radial perturbation. Also the electric intensity increases monotonically towards the surface. The well behaved model has the maximum mass M=1.740793M Θ , Radius 12.130308 km. The redshift at the center and on the surface is given by z 0=0.384261 and z a =0.292489. Out of the models of superdense star obtained couple of models represent Vela Pulsar for (i) α 2=1.03, b=0.33, , Radius=10.8566 km, M=1.18331M Θ , I=0.642601×1045, (ii) α 2=1.1, b=0.3, , Radius=11.197533 km, M=1.311438M Θ , I=0.774508×1045. All the solutions mentioned above are reducible to Schwarzchild interior solution in the absence of charge.  相似文献   

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