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1.
The standard model on non-commutative space-time 总被引:1,自引:0,他引:1
X. Calmet B. Jurčo P. Schupp J. Wess M. Wohlgenannt 《The European Physical Journal C - Particles and Fields》2002,23(2):363-376
We consider the standard model on a non-commutative space and expand the action in the non-commutativity parameter . No new particles are introduced; the structure group is . We derive the leading order action. At zeroth order the action coincides with the ordinary standard model. At leading order
in we find new vertices which are absent in the standard model on commutative space-time. The most striking features are couplings
between quarks, gluons and electroweak bosons and many new vertices in the charged and neutral currents. We find that parity
is violated in non-commutative QCD. The Higgs mechanism can be applied. QED is not deformed in the minimal version of the
NCSM to the order considered.
Received: 29 November 2001 / Published online: 25 January 2002 相似文献
2.
Blaschke Daniel N. Grosse Harald Kronberger Erwin Schweda Manfred Wohlgenannt Michael 《The European Physical Journal C - Particles and Fields》2010,69(3-4):575-579
The European Physical Journal C - Motivated by the success of the non-commutative scalar Grosse–Wulkenhaar model, a non-commutative U ⋆(1) gauge field theory including an... 相似文献
3.
B. Melić K. Passek-Kumerički J. Trampetić P. Schupp M. Wohlgenannt 《The European Physical Journal C - Particles and Fields》2005,42(4):499-504
This paper is a direct extension of our earlier work on electroweak currents and the Higgs sector in the standard model on non-commutative space-time, now with strong interactions included. Apart from the non-commutative corrections to standard model strong interactions, several new interactions appear. The most interesting ones are gluonic interactions with the electroweak sector. They are elaborated here in detail and the Feynman rules for interactions up to
are provided.Received: 18 March 2005, Revised: 13 May 2005, Published online: 19 July 2005 相似文献
4.
Marija Dimitrijević Larisa Jonke Lutz Möller Efrossini Tsouchnika Julius Wess Michael Wohlgenannt 《Czechoslovak Journal of Physics》2004,54(11):1243-1248
A general formalism is developed, that allows the construction of field theory on quantum spaces which are deformations of ordinary spacetime. The symmetry group of spacetime is replaced by a quantum group. This formalism is demonstrated for the -deformed Poincaré algebra and its quantum space. The algebraic setting is mapped to the algebra of functions of commuting variables with a suitable -product. Fields are elements of this function algebra. As an example, the Klein-Gordon equation is defined and derived from an action. 相似文献
5.
Epshtein O Eichen Y Ehrenfreund E Wohlgenannt M Vardeny ZV 《Physical review letters》2003,90(4):046804
Linear and nonlinear recombination kinetics with various lifetime distributions were identified for long-lived photoexcitations in a series of pi-conjugated polymer films using modulation frequency and excitation intensity dependencies of the photoinduced absorption. This includes monomolecular, bimolecular, and defect-limited recombination processes that lead to saturation. Using generalized kinetics parameters, we found characteristic plots for all recombination processes. Specifically, the bimolecular recombination process shows superlinear intensity dependence away from the steady state; on the contrary, dispersive bimolecular recombination leads to sublinear dependence. 相似文献
6.
S. Denk V. Putz M. Wohlgenannt 《The European Physical Journal C - Particles and Fields》2006,45(1):263-272
We examine the effect of non-local deformations on the applicability of interaction point time ordered perturbation theory
(IPTOPT) based on the free Hamiltonian of local theories. The usual argument for the case of quantum field theory on a non-commutative
space (based on the fact that the introduction of star products in bilinear terms does not alter the action) is not applicable
to IPTOPT due to several discrepancies compared to the naive path integral approach when non-commutativity involves time.
These discrepancies are explained in detail. Besides scalar models, gauge fields are also studied. For both cases, we discuss
the free Hamiltonian with respect to non-local deformations.
Received: 14 May 2004, Revised: 16 August 2005, Published online: 26 October 2005 相似文献
7.
Markus Wohlgenannt 《固体物理学:研究快报》2012,6(6):229-242
We review recent work in the field of organic spintronics, focusing on our own contributions to this field. There are two principle magnetoresistance effects that occur in organic devices. (i) Organic magnetoresistance (OMAR), which occurs in nonmagnetic organic semiconductor devices. For example, in devices made from the prototypical small molecule Alq3 OMAR reaches values of 10% or more at room temperature. (ii) Organic spin‐valve effects that occur in devices that employ ferromagnetic electrodes for spin‐polarized current injection and detection. We undertake an analysis of these two types of magnetoresistance with the goal of identifying the dominant spin‐scattering mechanism. Analysis of OMAR reveals that hyperfine coupling is the dominant spin‐coupling mechanism. Spin–orbit coupling, on the other hand, is important only in organic semiconductor materials containing heavy atoms. We explore the reasons why spin–orbit coupling is relatively unimportant in hydrocarbon materials. Next, we present a theory for spin diffusion in disordered organic semiconductors based on hyperfine coupling, taking into account a combination of incoherent carrier hopping and coherent spin precession in the random hyperfine magnetic fields. We compare our findings with experimental values for the spin‐diffusion length. Finally, we demonstrate a criterion that allows the determination whether the organic spin‐valves operate in the tunneling or injection regimes. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
8.
Molybdenum-95 NMR spectra of a series of phosphine and phosphite substituted molybdenum carbonyls Mo(CO)6-n
L
n
[L=P(OCH3)3
n=1, 2, 3, 4, 5,L=P(OC2H5)3
n=1, 2, 3,L=P(C6H5)3
n=1] including isomers (cis,trans,fac,mer) are reported, A large range of chemical shifts is found for the title compounds. The coupling constants1
J(95Mo-31P) are derived either from95Mo-NMR spectra or31P-NMR spectra. Syntheses of the measured compounds were performed by thermal or photochemical ligand substitution.
Molybdän-95 NMR einer Reihe von Phosphin- und Phosphit-substituierten Molybdäncarbonylen Mo(CO)6–n(L) n (n=1, 2, 3, 4, 5)
Zusammenfassung Es werden die95Mo-NMR-Spektren der im Titel genannten Verbindungen mitL=P(OCH3)3 n=1–5,L=P(OC2H5)3 n=1–3 undL=P(C6H5)3 n=1, einschließlich von Isomeren (cis, trans, fac, mer) angegeben. Für die chemischen Verschiebungen wurde ein sehr weiter Bereich beobachtet. Die Kopplungskonstanten1 J(95Mo-31P) wurden entweder von den95Mo- oder31P-NMR-Spektren ermittelt. Die Synthese der Verbindungen erfolgte mittels thermischem oder photochemischem Ligandenaustausch.相似文献
9.
M.?Dimitrijevi?Email author L.?Jonke L.?M?ller E.?Tsouchnika J.?Wess M.?Wohlgenannt 《The European Physical Journal C - Particles and Fields》2003,31(1):129-138
A general formalism is developed that allows the construction of a field theory on quantum spaces which are deformations of ordinary spacetime. The symmetry group of spacetime (the Poincaré group) is replaced by a quantum group. This formalism is demonstrated for the
-deformed Poincaré algebra and its quantum space. The algebraic setting is mapped to the algebra of functions of commuting variables with a suitable *-product. Fields are elements of this function algebra. The Dirac and Klein-Gordon equation are defined and an action is found from which they can be derived.Received: 17 July 2003, Published online: 26 September 2003 相似文献
10.
We have measured the ratio, r = sigma(S)/sigma(T) of the formation cross section, sigma of singlet and triplet excitons from polarons in pi-conjugated oligomer and polymer films, using a spectroscopic technique we developed recently. We discovered a universal relation between r and the conjugation length (CL): r(-1) depends linearly on CL-1, irrespective of the chain structure. Since r is directly related to the maximum possible electroluminescence quantum efficiency in organic light emitting diodes (OLED), our results indicate that polymers have an advantage over small molecules in OLED applications. 相似文献