共查询到20条相似文献,搜索用时 15 毫秒
1.
O. V. Kibis 《JETP Letters》1997,66(8):588-593
In low-dimensional systems with an asymmetric quantizing potential, an asymmetric electron energy spectrum ε(p)≠ε(−p), where p is the electron momentum, arises in the presence of a magnetic field. A consequence of such an energy spectrum is that momentum
transfer to the electron system in mutually opposite directions in the presence of an external perturbation is different.
Therefore, in the presence of a standing electromagnetic wave momentum is transferred from the wave to the electrons, which
gives rise to a new type of electromotive force.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 8, 551–555 (25 October 1997) 相似文献
2.
S. L. Shalimov 《JETP Letters》1998,67(6):405-408
Using a third-order structure function, an asymptotic expression is obtained for the stationary energy spectrum in the dissipative
region of Burgers turbulence excited by a random external force. It is shown that in contrast to the case of turbulence described
by a homogeneous Burgers equation, the spectrum contains a parameter characterizing energy transfer into the small-scale region.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 6, 383–386 (25 March 1998) 相似文献
3.
Spectral Analysis for Systems of Atoms and Molecules Coupled to the Quantized Radiation Field 总被引:2,自引:2,他引:0
Volker Bach Jürg Fröhlich Israel Michael Sigal 《Communications in Mathematical Physics》1999,201(2):249-290
We consider systems of static nuclei and electrons – atoms and molecules – coupled to the quantized radiation field. The interactions
between electrons and the soft modes of the quantized electromagnetic field are described by minimal coupling, p→p−e
A (x), where A(x) is the electromagnetic vector potential with an ultraviolet cutoff. If the interactions between the electrons and the quantized
radiation field are turned off, the atom or molecule is assumed to have at least one bound state. We prove that, for sufficiently
small values of the fine structure constant α, the interacting system has a ground state corresponding to the bottom of its
energy spectrum. For an atom, we prove that its excited states above the ground state turn into metastable states whose life-times
we estimate. Furthermore the energy spectrum is absolutely continuous, except, perhaps,
in a small interval above the ground state energy and around the threshold energies of the atom or molecule.
Received: 3 September 1998 / Accepted: 17 March 1999 相似文献
4.
A. V. Uryson 《Journal of Experimental and Theoretical Physics》1998,86(1):6-10
The complicated shape of the cosmic ray spectrum recorded by giant arrays in the energy range 1017–1020 eV is analyzed. It is shown that in the energy region ∼1018–1019 eV the spectrum probably coincides with the injection spectrum whose exponent is equal approximately to 3.2–3.3. The flatter
component in the energy region (3.2–5.0)×1019 eV is due to braking of extragalactic protons on primordial photons (the cosmic background radiation). At energies exceeding
3.2×1019 eV the spectrum does not have a blackbody cutoff. The possibility of determining the distances at which cosmic rays originate
and investigating the evolution of their sources on the basis of ultrahigh-energy cosmic ray data is discussed.
Zh. éksp. Teor. Fiz. 113, 12–20 (January 1998) 相似文献
5.
The fine structure of the π-electron spectrum of semi-infinite carbotubulenes (cylindrical graphene tubes) is investigated.
Together with closed short-diameter tubelenes, open nanotubes whose terminal fragments contain heteroatoms are studied. Algebraic
equations are obtained for the one-electron energy levels corresponding to wave functions localized on a terminal fragment.
It is shown that Tamm energy levels, lying in either the band gaps or the continuous spectrum (resonance states), can exist
in the systems studied.
Pis’ma Zh. éksp. Teor. Fiz. 63, No. 8, 588–593 (25 April 1996) 相似文献
6.
G. E. Volovik 《JETP Letters》1999,70(9):609-614
The energy levels of fermions bound to the vortex core are considered for the general case of chiral superconductors. There
are two classes of chiral superconductivity: in the class I superconducting state the axisymmetric singly quantized vortex
has the same energy spectrum of bound states as in an s-wave superconductor: E=(n+1/2)ω0, with integral n. In class II the corresponding spectrum is E=nω0 and thus contains a state with exactly zero energy. The effect of a single impurity on the spectrum of bound states is also
considered. For class I the spectrum acquires the doubled period ΔE=2ω0 and consists of two equidistant sets of levels, in accordance with A. I. Larkin and Yu. N. Ovchinnikov, Phys. Rev. B 57, 5457 (1998). For the class II states the spectrum is not influenced by a single impurity if the same approximation is applied.
Pis’ma Zh. éksp. Teor. Fiz. 70, No. 9, 601–606 (10 November 1999)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
7.
Yu. Kh. Vekilov I. A. Gordeev É. I. Isaev 《Journal of Experimental and Theoretical Physics》1999,89(5):995-999
The electronic spectrum and wave functions of a new quasicrystal structure—a two-dimensional Fibonacci lattice—are investigated
in the tight-binding approximation using the method of the level statistics. This is a self-similar structure consisting of
three elementary structural units. The “central” and “nodal” decoration of this structure are examined. It is shown that the
electronic energy spectrum of a two-dimensional Fibonacci lattice contains a singular part, but in contrast to a one-dimensional
Fibonacci lattice the spectrum does not contain a hierarchical gap structure. The measure of allowed states (Lebesgue measure)
of the spectrum is different from zero, and for “central” decoration it is close to 1. The character of the localization of
the wave functions is investigated, and it is found that the wave functions are “critical.”
Zh. éksp. Teor. Fiz. 116, 1834–1842 (November 1999) 相似文献
8.
Two kinks are observed in the energy spectrum of galactic cosmic rays. It is shown that the entire spectrum can be described,
to a good approximation, by a single formula obtained on the basis of the hypothesis that the particles are produced and accelerated
in plasma pinches by an induction mechanism under the assumption that three hierarchical groups of currents are present—interstellar,
galactic, and metagalactic.
Pis’ma Zh. éksp. Teor. Fiz. 64, No. 4, 225–230 (25 August 1996) 相似文献
9.
G. E. Volovik 《JETP Letters》1996,63(9):763-769
The spectrum of the fermion zero modes in the vicinity of a vortex with fractional winding number is discussed. This is inspired
by the observation of the 1/2-vortex in high-temperature superconductors made by [J.R. Kirtley, C.C. Tsuei, M. Rupp et al., Phys. Rev. Lett. 76, 1336 (1996)]. The fractional value of the winding number leads to a frac-tional value of the invariant which describes the
topology of the energy spectrum of fermions. This results in the phenomenon of the “half-crossing:” the spectrum approaches
zero but does not cross it, being captured at the zero energy level. The similarity with the phenomenon of fermion condensation
is discussed.
Pis’ma Zh. éksp. Teor. Fiz. 63, No. 9, 729–734 (10 May 1996)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
10.
A. V. Uryson 《JETP Letters》1997,65(10):763-767
The complicated form of the cosmic-ray spectrum recorded in the energy range 1017–1020 eV by giant detector arrays is analyzed. It is shown that the spectrum in the region 1018–1019 eV is apparently identical to the injection spectrum with power-law exponent approximately equal to 3.2–3.3. The flat component
in the region (3.2–5)×1019 eV is due to the braking of extragalactic protons by relict photons. The spectrum apparently has no blackbody cutoff at energies
above 3.2×1019 eV.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 10, 729–733 (25 May 1997) 相似文献
11.
The Klein–Fock–Gordon equation is solved for a 2D pion moving in a constant uniform magnetic field. A relativistic energy
spectrum is calculated for fixed values of the angular momentum and magnetic field Н. An analysis of the results of these calculations allows us to conclude that the Klein–Fock–Gordon equation, unlike the Schr?dinger
equation, cannot describe the energy of the particle s-state in the magnetic field. It is elucidated that a correction for
the relativistic energy level caused by the constant magnetic field is noticeable for the magnetic field H > 100.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 91–96, March, 2009. 相似文献
12.
G. V. Benemanskaya D. V. Daineka G. É. Frank-Kamenetskaya 《Journal of Experimental and Theoretical Physics》1998,87(6):1167-1171
The electronic structure and ionization energy for the system Ba/Si(100)2×1 have been studied as functions of the submonolayer
coverage. It is found that there is an energy gap in the surface states spectrum and that the Ba/Si(100)2×1 interface is semiconducting
up to 1.5 monolayers of Ba. Two surface bands induced by Ba adsorption have been detected. The evolution of the spectrum with
increasing degree of Ba coverage points to the existence of two nonequivalent “adsorption sites,” which differ in binding
energy by 0.11 eV. The development of the Ba-induced bands is found to terminate at a coverage corresponding to the minimum
ionization energy and close to one monolayer. The adsorption bond is shown to have a primarily covalent character.
Zh. éksp. Teor. Fiz. 114, 2145–2152 (December 1998) 相似文献
13.
V. A. Pogrebnyak 《Physics of the Solid State》1999,41(10):1715-1718
The spectrum of the electronic states in an infinitely deep two-dimensional potential well, where one wall is periodically
uneven, is investigated theoretically. It is shown that in non-Bragg type resonances — standing electron wave resonances,
which are modes of different spatial harmonics of the electron wave function — arise in such a well. The resonances occur
in a wide range of energies, starting at values close to the bottom in each 2D subband. The resonance interaction splits the
energy spectrum and results in the appearance of gaps, giving the electron spectrum a miniband character. The properties of
the electron gas vary substantially in accordance with the new characteristics of the spectrum.
Fiz. Tverd. Tela (St. Petersburg) 41, 1867–1870 (October 1999) 相似文献
14.
The energy gap appearing in the spin-wave spectrum as a result of Bragg scattering by the modulation period q=2π/(d
1+d
2) of a one-dimensional superlattice is observed by the method of spin-wave resonance in Co/Pd multilayer films. It is shown
that this gap is asymmetric: The “positive” deviation is from two to three times greater than the “negative” deviation.
Pis’ma Zh. éksp. Teor. Fiz. 63, No. 12, 938–941 (25 June 1996) 相似文献
15.
The radiation from relativistic particles channeled in a microscopic undulator created by applying transverse ultrasonic vibrations
to a single crystal is investigated. The results of numerical investigations are presented for real crystal undulators. The
calculations show the radiation spectra in the particle and photon energy ranges where narrowing of the spectrum occurs when
the particle energy is close to a definite threshold energy.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 6, 437–441 (25 September 1998) 相似文献
16.
The exact wave function of a chain of electrons interacting with local phonons is constructed. The ground-state energy and
the gap in the electronic excitation spectrum are calculated.
Pis’ma Zh. éksp. Teor. Fiz. 63, No. 2, 83–88 (25 January 1996) 相似文献
17.
The Goursat problem, developed by the present authors in previous papers [Ukr. Fiz. Zh. (Russ. Ed.) 27, 1602 (1982); Differentsial’nye Uravneniya 20, 302 (1984); J. Math. Phys. 33, 233 (1996)], is used to study the energy spectrum of a scalar relativistic particle in a static axisymmetric external scalar
field of an attractive nature. This is obviously a model. It is shown that the problem formulated in this way has no unstable
solutions, i.e., solutions increasing with time, in contrast to the Cauchy problem, where such solutions appear when the square
of the particle frequency (energy) vanishes (in other words, in a Bose-Einstein condensation)
Zh. éksp. Teor. Fiz. 112, 1167–1175 (October 1997) 相似文献
18.
R. A. Bisengaliev É. D. Batyrev B. V. Novikov A. V. Sel’kin 《Physics of the Solid State》1998,40(5):806-807
The exciton photoreflection spectra of CdS crystals are studied. It is found that the form of the exciton photoreflection
spectrum is determined by a Stark shift of the exciton energy in the electric field of surface states. The dependences of
the exciton photoreflection spectrum on temperature on the intensity and wavelength of the modulating radiation, and on the
processes by which the photoreflection signal relaxes is determined. An energy scheme is proposed for the surface states which
explains the observed effects of photoinduced changes in the surface field. A correlation is established between the exciton
photoreflection spectrum and the form of the fine structure in the photoconductivity.
Fiz. Tverd. Tela (St. Petersburg) 40, 875–876 (May 1998) 相似文献
19.
V. P. Vlasov B. A. Trubnikov S. K. Zhdanov 《Journal of Experimental and Theoretical Physics》1997,84(2):211-220
It is shown that the two bends observed in the cosmic ray energy spectrum can be well approximated by equations derived by
assuming that cosmic rays can be generated and accelerated in plasma pinches.
Zh. éksp. Teor. Fiz. 111, 385–403 (February 1997) 相似文献
20.
D. V. Olenev É. I. Isaev Yu. Kh. Vekilov 《Journal of Experimental and Theoretical Physics》1998,86(3):550-558
Electron spectra and wave functions of icosahedral quasicrystals have been investigated in the tight-binding approximation
using the two-fragment structural model (the Amman-MacKay network) with “central” decoration. A quasicrystal has been considered
as a limiting structure in a set of optimal cubic approximants with increasing lattice constants. The method of level statistics
indicates that the energy spectrum of an icosahedral quasicrystal contains a singular (nonsmooth) component. The density of
electron states has been calculated for the first four optimal cubic approximants of the icosahedral quasicrystal, and the
respective Lebesgue measures of energy spectra of these approximants have been obtained. Unlike the case of a one-dimensional
quasiperiodic structure, the energy spectrum of an icosahedral quasicrystal does not contain a hierarchical gap structure
typical of the Cantor set of measure zero in a one-dimensional quasicrystal. Localization of wave functions in an icosahedral
quasicrystal has been studied, and their “critical” behavior has been detected. The effect of disorder due to substitutional
impurities on electron properties of icosahedral quasicrystals has been investigated. This disorder makes the electron spectrum
“smoother” and leads to a tendency to localization of wave functions.
Zh. éksp. Teor. Fiz. 113, 1009–1025 (March 1998) 相似文献