Two-Photon Absorption in Nanoheterostructures with <Emphasis Type="Italic">D</Emphasis><Superscript>(−)</Superscript>-Centers

A two-photon impurity absorption coefficient of the “quantum dot — D⁽⁻⁾-center” complexes synthesized in a transparent dielectric matrix is calculated within the model of zero-radius potential. The evolution of spectral dependence of the absorption coefficient of the nanoheterostructure based on semiconductor CdS _x Se _1−x glasses is studied versus the average quantum-dot radius. It is shown that the contribution of the two-photon impurity absorption to the exited two-photon luminescence is fairly significant at a reasonable quantum-dot concentration. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 46–50, July, 2005.     

Fusion Rules for the Vertex Operator Algebras <Emphasis Type="Italic">M</Emphasis>(1)<Superscript>+</Superscript> and <Emphasis Type="Italic">V</Emphasis><Superscript>+</Superscript><Subscript><Emphasis Type="Italic">L</Emphasis></Subscript>

The fusion rules for the vertex operator algebras M(1)⁺ (of any rank) and V⁺_L (for any positive definite even lattice L) are determined completely.Supported by JSPS Research Fellowships for Young ScientistsPartially supported by NSF grants and a research grant from the Committee on Research, UC Santa CruzPartially supported by a NSA grant and a grant from Rutgers University Research Council     

Super <Emphasis Type="Italic">D</Emphasis>-Differentiation for <Emphasis Type="Italic">R</Emphasis><Superscript> ∞ </Superscript>-Supermanifolds

The concept of ‘D-Differentiation’, which, in the context of smooth manifolds, generalises Lie and covariant differentiation, is extended to R ^∞-supermanifolds under the name of ‘Super D-Differentiation’. This is done by defining new (non-linear) mappings, called ‘μ-mappings’ and by relating their non-linearity to the Leibniz rule that a derivation must satisfy when it acts on a tensor product. The resulting axiomatics, which is basis-independent and coordinate-free, is then expressed in a general basis (not necessarily holonomic). Super Lie and Super covariant differentiation are, amongst others, special cases of Super D-Differentiation. In particular, the transformation rules for the connection coefficients and the commutation coefficients of non-holonomic bases are obtained. These special cases are found to be in agreement with the DeWitt Super covariant and Super Lie derivatives.      

Once more about gauge invariance in <Emphasis Type="Italic">ϕ</Emphasis> → <Emphasis Type="Italic">γπ</Emphasis><Superscript>0</Superscript><Emphasis Type="Italic">π</Emphasis><Superscript>0</Superscript>

It is argued that the realization of gauge invariance condition as a consequent of cancellation between the ϕ → γf ₀ → γπ ⁰ π ⁰ resonance contribution and the ϕ → γπ ⁰ π ⁰ background one, suggested by A.V. Anisovich et al., Yad. Fiz. 68, 1614 (2005), is misleading. The text was submitted by the author in English.     

Topological Solitons in the <Emphasis Type="Italic">CP</Emphasis><Superscript><Emphasis Type="Italic">N</Emphasis></Superscript> Model

We investigate the solitons in the CP ^N model in terms of the decomposition of gauge potential. Based on the φ-mapping topological current theory, the charge and position of solitons is determined by the properties of the typical component. Furthermore, the motion and the bifurcation of multi-soliton is discussed. And the knotted solitons in high dimension is explored also.     

Dimension and Dynamical Entropy for Metrized <Emphasis Type="Italic">C</Emphasis><Superscript><Emphasis Type="Italic">*</Emphasis></Superscript>-Algebras

 We introduce notions of dimension and dynamical entropy for unital C ^* -algebras ``metrized' by means of , which are complex-scalar versions of the Lip-norms constitutive of Rieffel's compact quantum metric spaces. Our examples involve the UHF algebras and noncommutative tori. In particular we show that the entropy of a noncommutative toral automorphism with respect to the canonical coincides with the topological entropy of its commutative analogue. Received: 13 February 2002 / Accepted: 20 August 2002 Published online: 22 November 2002     

Electric Instability in <Emphasis Type="Italic">n</Emphasis>-CdTe:In Layers with <Emphasis Type="Italic">S</Emphasis>-Shaped Voltage-Current Characteristics

A switching of the S-type in the 20–200 μm thick polycrystalline n-CdTe:In layers with resistance of 10³–10⁶ Ω·cm is studied. The electric instability in the layers is found to be due to the electron-thermal breakdown mechanism. The dependence of the switching threshold parameters on the intensity of exposure can be used for fabrication of infrared-radiation controlled electric switches on the basis of n-CdTe:In layers. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 28–30, June, 2005.     

The <Emphasis Type="Italic">Φ</Emphasis>→K<Superscript>0</Superscript>¯<Emphasis Type="Italic">γ</Emphasis> decay

The scalar contributions to the radiative decay φ→K ⁰ˉ⁰ γ are studied within the framework of the Linear Sigma Model (LσM). Theoretical predictions for the associated subprocesses φ→f ₀ γ and φ→a ₀ γ as well as the ratio φ→f ₀ γ/a ₀ γ are also given.     

Resummed pQCD for <Emphasis Type="Italic">W</Emphasis><Superscript><Emphasis Type="Italic">±</Emphasis></Superscript> and <Emphasis Type="Italic">Z</Emphasis><Superscript>0</Superscript> transverse momentum spectra at RHIC and LHC

The transverse momentum distributions of W_± and Z₀ are predicted at RHIC and LHC. A resummation formalism with power corrections to the renormalization group equations is used. Shadowing effects are discussed and found to be unimportant at RHIC, but important for LHC. We study the enhancement of power corrections due to multiple scattering in nuclear collisions and numerically illustrate the weak effects of the dependence on the nuclear mass.     

Enhancement of the defect field of one-dimensional photonic crystals containing <Emphasis Type="Italic">ε</Emphasis>-and <Emphasis Type="Italic">μ</Emphasis>-negative layers

Employing the transfer matrix method, we study the electromagnetic field of one-dimensional photonic crystals with a defect inserted by pairs of μ-negative (MNG) and ε-negative (ENG) material layers. The fields within the pairs of layers and the matrix defect are independent of each other, and the whole field is their superposition. The whole defect field can be significantly enhanced by pairs of ε-negative and μ-negative layers. In contrast to the conventional defect modes, the intensity and volume of the defect field with pairs of ε-negative and μ-negative layers can be precisely adjusted.     

Magnetic properties of LaNi <Emphasis Type="Bold">1-</Emphasis><Emphasis Type="Bold">x</Emphasis>Mn <Emphasis Type="Bold">x</Emphasis>O <Emphasis Type="Bold">3+δ</Emphasis> perovskites

Magnetic measurements have been carried out in different LaNi_1-xMn_xO _{3 + δ} samples with 0.1 ⩽ x ⩽ 0.9. All these samples show two magnetic anomalies, one at relatively high temperature characteristic of a ferromagnetic ordering and the other at low temperature, typical of magnetic relaxation phenomena. Neutron diffraction patterns indicate that long-range ferromagnetic ordering is only achieved for x ≥ 0.5. Neutron patterns of LaNi_0.5Mn_0.5O _{3 + δ} samples show an ordered arrangement of Ni and Mn atoms in the perovskite lattice. LaNi_0.5Mn_0.5O _{3 + δ} is then, a double perovskite A₂BB'O₆ whereas Ni and Mn atoms are randomly distributed for the rest of the samples. X-ray magnetic circular dichroism experiments confirm the presence of collinear ferromagnetism in LaNi_0.5Mn_0.5O _{3 + δ} . The role of competitive magnetic interactions, structural disorder, magnetic anisotropy and magnetic disaccommodation is also discussed Received 19 July 2002 / Received in final form 23 October 2002 Published online 31 December 2002     

Mixed symmetry states and isospin excitation in <Emphasis Type="Italic">N</Emphasis> = <Emphasis Type="Italic">Z</Emphasis> nucleus <Superscript>52</Superscript>Fe

The interacting boson model with isospin (IBM-3) was applied to study the band structure and electromagnetic transition properties of the low-lying states in the even-even N = Z nucleus ⁵²Fe. The isospin excitation states with T = 0, 1 and 2 were identified, and compared with the available data. The study shows that the 2₃⁺ state is the lowest mixed symmetry state in ⁵²Fe. The excitation energy of the second 0₂⁺ state with T = 0 in nucleus ⁵²Fe was identified. The model calculations with the data show a reasonably good agreement. Supported by the National Natural Science Foundation of China (Grant Nos. 10765001 and 10547003), the Natural Science Foundation of Inner Mongolian Autonomous Region of China (Grant No. 200607010111), and the Scientific Research Fund of Inner Mongolian Education Bureau (Grant Nos. NJZY07155 and NJZY07153)     

Hawking radiation of black holes in non-minimal <Emphasis Type="Italic">R</Emphasis><Superscript><Emphasis Type="Italic">β</Emphasis></Superscript><Emphasis Type="Italic">F</Emphasis><Superscript>2</Superscript>-type coupled Einstein–Maxwell theory

We investigate the Hawking radiation and greybody factor for a scalar field on the background of the black holes in the theory of the non-minimal R ^β F ²-coupled electromagnetic fields to gravity. For different asymptotic structures caused by the real power number β, we find that the influences of the real power number on the Hawking radiation and greybody factor are different. We also show that the different coupling constant also affects the Hawking radiation and greybody factor.     

Generation-changing interaction of sneutrinos in <Emphasis Type="Italic">e</Emphasis><Superscript> + </Superscript><Emphasis Type="Italic">e</Emphasis><Superscript>-</Superscript> collisions

The measurability of generation mixing is studied on pair production of sneutrinos in e ⁺ e ^- collisions and their subsequent decays into two different charged leptons e and μ with two lighter charginos. The analyses are made systematically in a general framework of the supersymmetric extension of the standard model. The production and decay process depends on the parameters of the chargino sector as well as those of the sneutrino sector. Although generation-changing interactions are severely constrained by radiative charged-lepton decays, sizable regions in the parameter space could still be explored at e ⁺ e ^- colliders in the near future. Received: 6 October 2004, Revised: 14 November 2004, Published online: 14 January 2005 PACS: 11.30.Hv, 12.15.Ff, 12.60.Jv, 14.80.Ly     

Associated single photons and doubly-charged scalars at linear <Emphasis Type="Italic">e</Emphasis><Superscript>−</Superscript><Emphasis Type="Italic">e</Emphasis><Superscript>−</Superscript> colliders

Doubly-charged scalars, predicted in many models having exotic Higgs rep-resentations, can in general have lepton-number violating (LFV) couplings. We show that by using an associated monoenergetic final state photon seen at a future linear e ⁻ e ⁻ collider, we can have a clear and distinct signature for a doubly-charged resonance. The strength of the ΔL = 2 coupling can also be probed quite effectively as a function of the recoil mass of the doubly-charged scalar.      

Microwave photoconductivity of bifacial silicon solar cells of <Emphasis Type="Italic">p</Emphasis><Superscript>+</Superscript><Emphasis Type="Italic">nn</Emphasis><Superscript>+</Superscript> type under laser irradiation

The microwave photoconductivity of silicon solar cells under laser irradiation has been investigated. It is shown that shunting of the solar cell region exposed to light by the rest of the cell may reduce significantly the relaxation time of microwave photoconductivity in comparison with the nonequilibrium charge carrier lifetime in the base region.     

Identifying new physics contributions in the Higgs sector at linear <Emphasis Type="Italic">e</Emphasis><Superscript>+</Superscript><Emphasis Type="Italic">e</Emphasis><Superscript>−</Superscript> colliders

Loop-driven decay modes of the Higgs are sensitive to new physics contributions because of new particles in the loops. To highlight this we look at the dilepton-dijet signal in the dominant Higgs production channel at a linear e ⁺ e ⁻ collider. We show that by taking a simple ratio between cross-sections of two different final states such contributions can be very easily identified.