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排序方式: 共有1374条查询结果,搜索用时 15 毫秒
971.
972.
973.
We recast dual models in the language of a quantum field theory of functional fields, restricting ourselves for simplicity to the closed string model. We derive the dynamics for both scalar and spinor functional fields from a unique parametrization invariant action. Passages to the Hamiltonian formalism and second quantization are explicitly worked out for the closed mesonic string in the front form. The results are equivalent to those obtained earlier by GGRT, i.e. no ghost fields at the price of an anomalous number of space-time dimensions and a tachyon. Finally, we use the parametrization invariance requirement on the action to derive couplings of closed strings to local fields by extending a global U(1) invariance built in the free action into a local one in the functional sense. We construct the self-couplings of closed string fields by requiring these to be consistent with the gauge invariance of the external fields. This procedure uniquely leads (for the open string) to the string splitting picture of Nambu and Mandelstam. The closed string is found to cross itself and then split up into two others. Both open and closed strings have quartic interactions corresponding to strand (for the open string) and lobe (for the closed string) exchanges. The case of the interacting fermionic model is not treated here. 相似文献
974.
975.
T. W. Marshall 《Russian Physics Journal》1968,11(12):23-27
A number of authors have noticed that the ground state of the harmonic oscillator can be represented as the motion of a classical charged particle under the influence of a fluctuating electromagnetic field, provided the effect of radiative reaction is taken into account. Their work is reviewed and some new results are obtained which extend the treatment to excited states. 相似文献
976.
Clinical proteomics: a question of technology 总被引:2,自引:0,他引:2
Kolch W Mischak H Chalmers MJ Pitt A Marshall AG 《Rapid communications in mass spectrometry : RCM》2004,18(19):2365-2366
977.
D. P. Barber J. B. Dainton L. C. Y. Lee R. Marshall J. C. Thompson D. T. Williams T. J. Brodbeck G. Frost G. N. Patrick G. F. Pearce D. Newton T. Sloan G. R. Brookes W. J. Haynes P. B. Wilkes 《Zeitschrift fur Physik C Particles and Fields》1980,6(2):93-100
We present differential cross sections andΔ ++ spin density matrix elements for the photoproduction processγp→π ? Δ ++ and differential cross sections for the processγp→π + Δ 0. The incident photon energy dependence is studied and a comparison is made with previous experiments and with the predictions of a theoretical model. 相似文献
978.
Emission spectra for the electronic transitions and of He2 are reported and the electronic structures of and characterized. The energy levels associated with exhibit extensive channel mixing, which leads to a breakdown of conventional band models for the higher n1-members of these Rydberg “series.” However, a model based on multichannel quantum defect theory quantitatively correlates the observed level structures. The higher-energy () portions of the channels can be represented by two eigen-quantum defects μ1 = 0.225 and μ2 = 0.930 and the close- to loose-coupling matrix elements and . The inclusion of energy dependence in the μα's leads to quantitative correlations for all n1-values. 相似文献
979.
D. P. Barber J. B. Dainton L. C. Y. Lee R. Marshall J. C. Thompson D. T. Williams 《Physics letters. [Part B]》1980,90(4):470-474
The cross section for the process has been measured from threshold up to 4.8 GeV using a tagged photon beam and a multiparticle spectrometer which detected all final state particles. The production cross section rises rapidly from threshold to a constant value of 35 nb. No evidence is found in the mass spectra for the production of narrow meson resonances decaying into . 相似文献
980.