共查询到20条相似文献,搜索用时 15 毫秒
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W. Lang 《Zeitschrift fur Physik C Particles and Fields》1988,37(4):577-585
Superconformal transformations in rigid (p, q) superspace are defined. For the (p, 0) case it is shown how the general superspace Noethercurrent for any given model can be reduced to a minimal supercurrent. This generalization of the energy-momentum tensor consists of two (p, 0) superfields, and the conservation equations show that no auxiliary currents are present in their components. 相似文献
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Weber W 《Physical review letters》1987,58(13):1371-1374
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Prabhakar P. Singh 《Solid State Communications》2003,125(6):323-326
We present a comparison of electron-phonon interaction in NbB2 and MgB2, calculated using full-potential, density-functional-based methods in P6/mmm crystal structure. Our results, described in terms of (i) electronic structure, (ii) phonon density of states F(ω), (iii) Eliashberg function α2F(ω), and (iv) the solutions of the isotropic Eliashberg gap equation, clearly show significant differences in the electron-phonon interaction in NbB2 and MgB2. We find that the average electron-phonon coupling constant λ is equal to 0.59 for MgB2 and 0.43 for NbB2, leading to superconducting transition temperatures Tc at around 22 K for MgB2 and 3 K for NbB2. 相似文献
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S. V. Eremeev G. G. Rusina S. D. Borisova E. V. Chulkov 《Physics of the Solid State》2008,50(2):323-329
The electron-phonon interaction in the quantum well state formed by a Na monolayer coating on Cu(111) is investigated theoretically. The calculations show that the electron-phonon coupling constant γ in this state decreases insignificantly (≈1%) compared to the value of γ for a clean copper surface. The corresponding electron-phonon contribution to the lifetime τ of the quantum well state increases by a factor of 1.5 compared to τ for the clean Cu(111) surface. 相似文献
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《Physics letters. [Part B]》1987,186(2):167-172
The (8,0) conformal supergravity, and an action which describes its coupling to an arbitrary number of (8,0) scalar multiplets are constructed. The 64+64 components of the conformal supermultiplet occur as Lagrange multipliers which lead to differential and algebraic constraints on the fields of the scalar multiplets. Solving the algebraic constraints yields an (8,0) locally supersymmetric sigma model based on the manifold SO(8 + n,m)/SO(8)×SO(n,m), where n,m ⩾ 0. 相似文献
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We propose exact expressions for the conformal anomaly and for three critical exponents of the tricritical O(n) loop model as a function of n in the range -2相似文献
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Electron energy loss spectra of clean Ni(1 0 0) show for the first time a 17 eV peak, which is attributed to an interband transtiion. All the observed peaks are shifted to higher energies as the primary electron energy Ep increases from 102 to 2045 eV. This shift is explained by a continuous decay in energy of the primary electrons inside the crystal. At Ep ? 700 eV, the decay takes place in the surface region of the crystal, while at Ep > 700 eV it takes place mainly in the bulk. The rate of decay increases with increasing temperature of the crystal between 300 and 900 K. 相似文献
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《Solid State Communications》1986,58(12):873-875
Monte Carlo study of percolation of random discs in two dimensions with variable range of interaction is carried out. The critical exponents β and γ are found to be the same when analysed as a function of range of interaction or critical area fraction, for all levels of dilution. 相似文献
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A coupling interaction between the nucleon and the nuclear E1 mode having a volume radial form instead of the usual surface one is used in the semi-direct nucleon radiative-capture theory. The calculated cross sections for the 208Pb(n,γ) and 142Ce(p,γ) reactions in the giantresonance region reproduce the measured ones both in shape and magnitude. Satisfactory agreement is achieved in comparing the predicted and detected γ-ray spectra following neutron capture by 208Pb. A detailed analysis of the energy and angular-momentum dependence of the matrix elements when the volume and surface form factors are used, is performed. 相似文献
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The large N limit of the O(N) Heisenberg spin system in two dimensions (a lattice version of the non-linear σ-model) is analysed by the collective field technique. A compact expression for the mass gap and the β-function is obtained for arbitrary but fixed gN. The strong and weak coupling limits of this expression correctly reproduce the known results. 相似文献
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Ablikim M Bai JZ Ban Y Bian JG Cai X Chen HF Chen HS Chen HX Chen JC Chen J Chen YB Chi SP Chu YP Cui XZ Dai YS Diao LY Deng ZY Dong QF Du SX Fang J Fang SS Fu CD Gao CS Gao YN Gu SD Gu YT Guo YN Guo YQ Guo ZJ Harris FA He KL He M Heng YK Hu HM Hu T Huang GS Huang XT Ji XB Jiang XS Jiang XY Jiao JB Jin DP Jin S Jin Y Lai YF Li G Li HB Li HH Li J Li RY Li SM Li WD Li WG Li XL Li XN Li XQ Li YL Liang YF Liao HB Liu BJ Liu CX Liu F Liu F Liu HH Liu HM Liu J Liu JB Liu JP Liu Q Liu RG Liu ZA Lou YC 《Physical review letters》2006,96(16):162002
An enhancement near threshold is observed in the omega(phi) invariant mass spectrum from the doubly Okubo-Zweig-Iizuka-suppressed decays of J/psi-->gamma(omega)phi, based on a sample of 5.8 x 10(7) J/psi events collected with the BESII detector. A partial wave analysis shows that this enhancement favors JP=0+, and its mass and width are M=1812(+19)(-26)(stat)+/-18(syst) MeV/c2 and Gamma=105+/-20(stat)+/-28(syst) MeV/c2. The product branching fraction is determined to be B(J/psi-->gammaX)B(X-->omega(phi))=[2.61+/-0.27(stat)+/-0.65(syst)]x10(-4). 相似文献
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Bertrand Duplantier 《Journal of statistical physics》1987,49(3-4):411-431
We consider a set of Hamiltonian circuits filling a Manhattan lattice, i.e., a square lattice with alternating traffic regulation. We show that the generating function (with fugacityz) of this set is identical to the critical partition function of aq-state Potts model on an unoriented square lattice withq
1/2 =z. The set of critical exponents governing correlations of Hamiltonian circuits is derived using a Coulomb gas technique. These exponents are also found to be those of an O(n) vector model in the low-temperature phase withn =q
1/2 =z. The critical exponents in the limitz = 0 are then those of spanning trees (q= 0) and of dense polymers (n=0,T < Tc), corresponding to a conformal theory with central chargeC = –2. This shows that the Manhattan orientation and the Hamiltonian constraint of filling all the lattice are irrelevant for the infrared critical properties of Hamiltonian walks. 相似文献