共查询到20条相似文献,搜索用时 0 毫秒
1.
The effect of controlled anisotropic losses on the topological structure of complex, elliptically polarized, light fields has been investigated. It has been shown that they can either initiate topological reactions with the appearance/disappearance of C points, saddle points, etc., or induce only their slight shift. Both strong and slight topological responses can be realized in the same field at sections with different inhomogeneity degrees of the polarization parameters of the field. 相似文献
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The role of scalar bosons is studied in connection with a violation of the number of fermions + antifermions. Some simple estimates of the transitions μ → eλ and μ → 3e are based upon a minimal extension of the “standard” gauge model of weak and electromagnetic interactions. 相似文献
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A. D. Karpf 《Zeitschrift für Physik A Hadrons and Nuclei》1966,194(1):50-60
The colliding-beam experiments ofe + ande ?-annihilation scattering mediated by a weakly coupled neutral vector bosonW 0 as suggested by various authors are recalculated in more detail. It is shown that the height of the resonance, which is to be expected at the mass-shell energies of W0, can be determined exactly by renormalizing the second-order self-energy diagram ofW 0. It is further shown, how the special form of the cross-section could serve as a test for the correctness of aV- A ansatz in neutral current interactions. 相似文献
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We study the spherical quantum pseudodots in the Schr o¨dinger equation by using the pseudo-harmonic plus harmonic oscillator potentials considering the effect of the external electric and magnetic fields. The finite energy levels and the wave functions are calculated. Furthermore, the behavior of the essential thermodynamic quantities such as, the free energy, the mean energy, the entropy, the specific heat, the magnetization, the magnetic susceptibility, and the persistent currents are also studied by using the characteristic function. Our analytical results are found to be in good agreement with the other works. The numerical results on the energy levels as well as the thermodynamic quantities have also been given. 相似文献
6.
S. W. Ham J. O. Im S. K. Oh 《The European Physical Journal C - Particles and Fields》2008,58(4):579-590
Within the framework of the minimal non-minimal supersymmetric standard model (MNMSSM) with tadpole terms, CP violation effects
in the Higgs sector are investigated at the one-loop level, where the radiative corrections from the loops of the quark and
squarks of the third generation are taken into account. Assuming that the squark masses are not degenerate, the radiative
corrections due to the stop and sbottom quarks give rise to CP phases which trigger the CP violation explicitly in the Higgs
sector of the MNMSSM. The masses, the branching ratios for dominant decay channels, and the total decay widths of the five
neutral Higgs bosons in the MNMSSM are calculated in the presence of explicit CP violation. The dependence of these quantities
on the CP phases is quite recognizable, for given parameter values. 相似文献
7.
We review spacetime dynamics in the presence of large-scale electromagnetic fields and then consider the effects of the magnetic component on perturbations to a spatially homogeneous and isotropic universe. Using covariant techniques, we refine and extend earlier work and provide the magnetohydrodynamic equations that describe inhomogeneous magnetic cosmologies in full general relativity. Specialising this system to perturbed Friedmann–Robertson–Walker models, we examine the effects of the field on the expansion dynamics and on the growth of density inhomogeneities, including non-adiabatic modes. We look at scalar perturbations and obtain analytic solutions for their linear evolution in the radiation, dust and inflationary eras. In the dust case we also calculate the magnetic analogue of the Jeans length. We then consider the evolution of vector perturbations and find that the magnetic presence generally reduces the decay rate of these distortions. Finally, we examine the implications of magnetic fields for the evolution of cosmological gravitational waves. 相似文献
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Klaus Baumann 《Communications in Mathematical Physics》1982,86(2):247-256
We extend a result about non-interacting fields given by Buchholz and Fredenhagen. Consider a massless, scalar field ø in 3 + 1 dimensional space-time which does not interact. The corresponding Hilbert space is assumed to be the FockspaceH of the free massless fieldA. This implies — as we show in the first part — that alln-point-functions are rational functions of their arguments. In the second part we use this fact to construct a symmetric, traceless tensorfield 1...n, relatively local to the original field ø, and connecting the vacuum with the one particle states. In the last part we prove 1...n to be relatively local to the free fieldA. 相似文献
10.
Carlos E. Laciana 《General Relativity and Gravitation》1996,28(8):1013-1026
The conditions that allow us to consider the vacuum expectation value of the energy-momentum tensor as a statistical average, at some particular temperature, are given. When the mean value of created particles is stationary, a planckian distribution for the field modes is obtained. In the massless approximation, the temperature dependence is like that corresponding to a radiation-dominated Friedmann-like model. 相似文献
11.
W. Bernreuther O. Nachtmann 《The European Physical Journal C - Particles and Fields》1999,9(2):319-333
We consider a spontaneously broken gauge theory based on the standard model (SM) group with scalar fields that carry arbitrary representations of G, and we investigate some general properties of the charged and neutral current involving these fields. In particular we derive
the conditions for having real or complex couplings of the Z boson to two different neutral or charged scalar fields, and for the existence of CP-violating Z-scalar-scalar couplings. Moreover, we study models with the same fermion content as in the SM, with one SU(2) Higgs singlet, and an arbitrary number of Higgs doublets. We show that the structure of the Z-Higgs boson and of the Yukawa couplings in these models can be such that CP-violating form factors which conserve chirality are induced at the one-loop level.
Received: 18 December 1998 / Published online: 22 March 1999 相似文献
12.
G. Papini 《Physics letters. A》1980,75(3):173-175
The idea is advanced that particles arise as distortions of a reimannian background and that such distortions represent particular conformally flat solutions of the “cosmological” Einstein equations with extremely large “cosmological” constants. Particle interactions then appear as gravitational in origin. The idea is illustrated with the help of two scalar models. In the first one the “De Sitter” space can be interpreted as a relativistic field whose ground state undergoes a transition from degenerate to nondegenerate for the critical value of some parameter. In the second one a deeper understanding is reached of the role of the “De Sitter” space in confinement problems and of the nature of the ensemble of vacuum states recently introduced in conformally invariant field theories by Fubini. 相似文献
13.
P. A. Éminov K. V. Zhukovskii K. G. Levchenko 《Journal of Experimental and Theoretical Physics》1998,86(6):1083-1089
The probabilities of the associated production of a Higgs boson with a Z boson by a charged lepton in the field of a plane electromagnetic wave of arbitrary intensity and in a constant crossed field
are obtained. The behavior of the cross section of the process as a function of the particle energies and the external field
intensity is investigated for various values of the Higgs boson mass. It is shown that there is a logarithmic increase in
the photoproduction cross section at superhigh energies up to a value significantly exceeding the cross section of the reaction
e
++e
−→Z+H, which is presently regarded as the most probable channel for the production of Higgs bosons.
Zh. éksp. Teor. Fiz. 113, 1979–1990 (June 1998) 相似文献
14.
We describe a new method for creating spin-dependent long-range interactions between atomic ultra-cold neutral bosons—specifically 87Rb—in an optical lattice. In this proposal, the bosonic system is immersed in a spin-polarized degenerate Fermi gas (almost perfectly non-interacting), here 6Li. We first show that the bosons acquire a long-range interaction analogous to Ruderman–Kittel–Kasuya–Yosida interaction in solids. The resulting fermion-mediated Bose–Bose interaction, which can depend on the bosons’ spin state, is tunable using inter-species Feshbach resonance. When the bosons are subject to a suitable optical lattice, 3-body loss processes are greatly suppressed. We conclude by showing that these interactions can lead to a supersolid phase for single-spin Bose system, and also to a fully tunable transverse field Ising model for a two-component Bose system. 相似文献
15.
The European Physical Journal C - We present a C++ software package called PhaseTracer for mapping out cosmological phases, and potential transitions between them, for Standard Model extensions... 相似文献
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Bulletin of the Lebedev Physics Institute - The dispersion relations of vector, scalar, and pseudo-scalar bosons of a dielectric medium are determined taking into account their resonant interaction... 相似文献
20.
Edward B Manoukian 《Annals of Physics》1974,82(1):248-263
The spin-0 propagator in quantum electrodynamics of charged spinless bosons (“pions”) is investigated in detail via the closest approximation to the Schwinger-Dyson equation in the two-particle unitarity approximation proposed initially by Salam by replacing the photon propagator by its zero order result. The high-energy behavior (in spacelike directions) of the (renormalized) spin-0 propagator Δ(p2) is explicitly derived and a finite electromagnetic mass excitation for the “pion” is obtained. The latter follows as a result of the derived asymptotic behavior of Δ?1(p2) (p2 → ∞) that the unrenormalized mass m0 ≡ 0. This brings us into contact with earlier work of Johnson, Landau and their collaborators. The fact that m02 ≡ 0 and that Δ?1(p2)/p2=?m2 = 0 (m ≠ 0) (in Nambu's sense) gives us an eigenvalue equation for the fine structure constant which may be then computed in terms of no other parameters. This eigenvalue equation is expanded in powers of the coupling constant with all the expansion coefficients being finite. The latter is computed to sixth order in the charge. 相似文献