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1.
Absorption of a massless scalar wave from a Schwarzschild black hole surrounded by quintessence
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By using the partial wave method,we investigate the absorption of a massless scalar wave from a Schwarzschild black hole surrounded by quintessence.We obtained the expression of absorption cross section σabs(ω)=π/ω2sum from l=0 to ∞(2l+1)|Tωl(ω)|2=π/ω2sum from l=0 to ∞(2l+1)Γωl(ω).Then we numerically carry out the absorption cross section and we find that the larger the angular momentum quantum number l is,the smaller the corresponding maximum value of the partial absorption cross section is,and that the total absorption cross section tends to the geometric-optical limit σ hf abs ≈πb 2 c.We also find that higher value of ω q(state parameter of quintessence) corresponds to the higher value of absorption cross section σ abs. 相似文献
2.
John Miles 《Physica D: Nonlinear Phenomena》1984,11(3):309-323
The weakly nonlinear, resonant response of a damped, spherical pendulum (length l, damping ratio δ, natural frequency ω0) to the planar displacement εl cos ωt (ε ? 1) of its point of suspension is examined in a four-dimensional phase space in which the coordinates are slowly varying amplitudes of a sinusoidal motion. The loci of equilibrium points and the corresponding bifurcation points in this space are determined. The control parameters are and . If α < 0.441 there is a finite interval of v within which no stable equilibrium points exist. As v decreases through the upper bound (a Hopf-bifurcation point) of this interval the motion in the phase space becomes periodic and then, following a period-doubling cascade, chaotic. There may be alternating sub-intervals of chaotic and periodic motion. The chaotic trajectories in the phase space appear to lie on fractal attractors. 相似文献
3.
Kaindl RA Wurm M Reimann K Woerner M Elsaesser T Miesner C Brunner K Abstreiter G 《Physical review letters》2001,86(6):1122-1125
We present the first study of ultrafast hole dynamics after resonant intersubband excitation in a quasi-two-dimensional semiconductor. p-type Si0.5Ge 0.5/Si multiple quantum wells are studied in pump-probe experiments with 150 fs midinfrared pulses. Intersubband scattering from the second heavy-hole back to the first heavy-hole subband occurs with a time constant of 250 fs, followed by intrasubband carrier heating within 1 ps. Such processes give rise to a strong reshaping of the intersubband absorption line, which is accounted for by calculations of the subband structure, optical spectra, and hole-phonon scattering rates. 相似文献
4.
V. M. Aulchenko M. N. Achasov K. I. Beloborodov A. V. Berdyugin A. G. Bogdanchikov A. V. Bozhenok A. D. Bukin D. A. Bukin S. V. Burdin A. V. Vasiljev I. A. Gaponenko V. B. Golubev T. V. Dimova A. A. Drozdetsky V. P. Druzhinin M. S. Dubrovin P. M. Ivanov V. N. Ivanchenko I. A. Koop A. A. Korol S. V. Koshuba G. A. Kukartsev A. P. Lysenko A. V. Otboev E. V. Pakhtusova A. A. Salnikov S. I. Serednyakov V. A. Sidorov Z. K. Silagadze A. N. Skrinsky V. V. Shary Yu. M. Shatunov 《Journal of Experimental and Theoretical Physics》2000,90(6):927-938
The reaction e + e ?→ωπ0 near a Φ resonance was studied with a spherical neutral detector at VEPP-2M e + e ? collider. Both main modes of decay of a ω meson were investigated: ω→π+π?π0 and ω→π 0γ. The probability of decay Φ→ωπ0 was obtained from the magnitude of the interference wave in the cross section for the reaction e + e ?→ωπ0→ π+π?π0π0: B(Φ→ωπ0) = (5.5 ?1.4 +1.6 ±0.3) ×10?5. The ratio of the partial widths of the ω meson was obtained from the ratio of the cross sections for the two modes: Γ(ω→π0γ )/Γ(ω→π+π?π0) = 0.0994 ± 0.0036 ± 0.0038. 相似文献
5.
Chuang IL 《Physical review letters》2000,84(9):2006-2009
We study theoretically the coherent nonlinear optical response of doped quantum wells with several subbands. When the Fermi energy approaches the exciton level of an upper subband, the absorption spectrum acquires a characteristic double-peak shape originating from the interference between the Fermi-edge singularity and the exciton resonance. We demonstrate that, for off-resonant pump excitation, the pump-probe spectrum undergoes a striking transformation, with a time-dependent exchange of oscillator strength between the Fermi-edge singularity and exciton peaks. This effect originates from the many-body electron-hole correlations which determine the dynamical response of the Fermi sea. 相似文献
6.
7.
G. Sommer 《Zeitschrift für Physik A Hadrons and Nuclei》1966,193(3):426-438
Unphysical regions on the right hand cut in partial wave dispersion relations for a two-particle processA+B→A′+B′ are expressed by measurable quantities, under the assumption that there is only one important 2-particle channel in the unphysical region. The solution is unique, if the phase shiftδ l for the elastic scattering in the channel responsible for the appearance of the unphysical region takes a value between 0 andπ at the physical threshold forA+B→A′+B′. The difference between non resonant (δl≠π/2 in the unphysical region) and resonant contributions is shortly discussed. 相似文献
8.
The first observation of interference effects between two sharp resonant contributions to the third-order nonlinear susceptibility χ(3) (ω3=ω0+ω1?ω2) is reported. Using two tunable near ir frequencies, ω0=ω1 and ω2, the was seen in crystalline CuCl when 2ω1 and ω1?ω2 were close to the sharp Z3 exciton at 3.21 eV and the 210 cm-1 Raman line, respectively. Three different tunable visible frequencies were used to observe similar interference effects in a benzene-cyclohexane mixture when ω0?ω2 and ω1?ω2 were close to the 992 cm-1 Raman line of benzene and the 801 cm-1 Raman line of cyclohexane, respectively. 相似文献
9.
We investigate the scattering and absorption cross sections of scalar waves by Garfinkle-Horowitz-Strominger (GHS) black hole spacetime with partial wave method. We find that the total absorption cross section oscillates around the geometric optical value, and the scattering angle width becomes narrower and the damping oscillation pattern becomes more complex as l increases. With fixed frequency ω, the main glory peak value becomes higher and the glory width becomes wider as the magnetic parameter a increases. 相似文献
10.
在高频区存在巨带隙的长方晶格二维光子晶体 总被引:15,自引:12,他引:3
本文利用降低光子晶体的对称性来提高绝对禁带宽度, 提出两种长方结构长方介质柱二维光子晶体, 用快速平面波展开法研究其高频区的带结构.经参数优化发现, 长方晶格包含一套介质柱时, 最大绝对禁带宽度Δω为0.1265ωe(ωe=2πc/a, a为晶格常数, c为光速), 绝对禁带中心频率ωmid为1.9256ωe, Δω/ωmid=6.6%; 当长方晶格包含两套介质柱时, 最大绝对禁带宽度为0.203ωe, 绝对禁带中心频率为1.8597ωe, Δω/ωmid=10.9%. 相似文献
11.
We have investigated the details of the eigenmode for a resonator containing a two-dimensional electron system (2DES) formed on the surface of liquid helium. We show that anticrossing phenomena occur near the crossing point ω0=ωc, where ω0 is the eigenmode of the resonator and ωc is the cyclotron frequency. The structure of the coupling constant is established. It is a flexible parameter, i.e., sensitive especially to magnetic field and electron density. A finite coupling leads to a perturbation, δω, of the eigenmode of the resonator in presence of the 2DES. Corresponding calculations and measurements of δω are presented. The theory fits the experimental data. The influence of anticrossing on the cyclotron resonance absorption line shape is demonstrated. 相似文献
12.
本文研究了一维公度势和非公度势调制下的p波超导量子线系统的拓扑相变.在公度势调制下,通过计算Z2拓扑不变量确定系统的相图,指出系统的拓扑相变强烈地依赖于调制参数α和相移δ.在非公度势调制下,以α=(√5-1)/2,δ=0为例,计算系统的低能激发谱、Z2拓扑不变量以及逆参与率等,发现p波配对强度△∈(0,0.33)时,系统存在拓扑非平庸超导相,拓扑平庸超导相和拓扑平庸局域相的转变.而当p波配对强度△>0.33时,系统存在拓扑非平庸超导相和拓扑平庸局域相的转变. 相似文献
13.
We studied two-photon absorption in a number of organic dyes and found that the two-photon cross-section does not follow Schäfer-Schmidt's rule. We found that the ratio δω/σ2ω is a function of the difference between the peak absorption frequency and twice the laser frequency, ωmax - 2ωL. We pointed out the importance of the symmetry of the energy levels by studying three families of dyes. 相似文献
14.
Won E Ko BR Adachi I Aihara H Arinstein K Asner DM Aushev T Bakich AM Barberio E Bay A Bhardwaj V Bhuyan B Bischofberger M Bondar A Bozek A Bračko M Brodzicka J Browder TE Chang P Chen A Chen P Cheon BG Chilikin K Cho IS Cho K Choi SK Choi Y Dalseno J Danilov M Doležal Z Drásal Z Drutskoy A Eidelman S Fast JE Gaur V Gabyshev N Garmash A Goh YM Golob B Haba J Hara T Hayasaka K Hayashii H Horii Y Hoshi Y Hou WS Hsiung YB Hyun HJ Iijima T Inami K Ishikawa A Itoh R Iwabuchi M Iwasaki Y Iwashita T 《Physical review letters》2011,107(22):221801
We report the first observation of the doubly Cabibbo-suppressed decays D(+)→K(+)η((')) using a 791 fb(-1) data sample collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The ratio of the branching fractions of doubly Cabibbo-suppressed relative to singly Cabibbo-suppressed D(+)→π(+)η((')) decays are B(D(+)→K(+)η)/B(D(+)→π(+)η)=(3.06±0.43±0.14)% and B(D(+)→K(+)η')/B(D(+)→π(+)η')=(3.77±0.39±0.10)%. From these, we find that the relative final-state phase difference between the tree and annihilation amplitudes in D(+) decays, δ(TA), is (72±9)° or (288±9)°. We also report the most precise measurements of CP asymmetries to date: A(CP)(D(+)→π(+)η)=(+1.74±1.13±0.19)% and A(CP)(D(+)→π(+)η')=(-0.12±1.12±0.17)%. 相似文献
15.
S. Fujita J.P. Riley C.C. Chen Ching-Lung Ko C.S. Raju T. Yamaguchi 《Journal of Physics and Chemistry of Solids》1973,34(12):2075-2089
The correlation function formula for the dynamic conductivity of a system of non-interacting electrons in the field of impurities is analyzed in terms of proper connected diagrams. By selecting those diagrams appropriate in the region of weak coupling and low impurity concentration, a set of coupled equations for the energy broadening γ (ω, ε, ns) and the energy shift Δ(ω, ε, ns) is derived, where both γ and Δ depend on the frequency ω of a probing field, the energy ε of the electron, and the concentration, ng, of impurities. With the assumption of a finite range potential, these equations are solved. It is found that γ (ω, ns) is smaller than that extrapolated value which the conventional expression γ0 for the low-concentration collision frequency would predict, in the entire region studied, that the difference γ0-γ becomes appreciable when the ratio of the average time between scatterings, τc, to the average duration of a scattering, τd, is 100 or less, that γ (ω, ns) decreases monotonically from its static value γ (0, ns), and becomes vanishingly small in the region ω≈1/τd, and that in the static limit (ω=0), γ=γ0[1?(2/π) (γ0τd)+…], that the energy shift Δ is positive, and increases from 0 and reach a peak of magnitude γ0 as ω is raised from 0. By using the γ and Δ obtained, the dynamic conductivity σ(ω, ns) for degenerated electrons is calculated. The deviation, σ-σ0, from the conventional expression σ0=(?i) (nee2/M) [ω-iΓ0]?1, (ne]=number density of electrons), for 0°K, is appreciable when the ratio τc/τd is 100 or less. The field-term correction, which arises from the modification of the scattering due to the probing field, is found to be negligible in the entire region studied. 相似文献
16.
We study analytically the order statistics of a time series generated by the positions of a symmetric random walk of n steps with step lengths of finite variance σ(2). We show that the statistics of the gap d(k,n) = M(k,n)-M(k+1,n) between the kth and the (k+1)th maximum of the time series becomes stationary, i.e., independent of n as n → ∞ and exhibits a rich, universal behavior. The mean stationary gap exhibits a universal algebraic decay for large k, ~d(k,∞)-/σ 1/sqrt[2πk], independent of the details of the jump distribution. Moreover, the probability density (pdf) of the stationary gap exhibits scaling, Pr(d(k,∞) = δ) ~/= (sqrt[k]/σ)P(δsqrt[k]/σ), in the regime δ~ (d(k,∞)). The scaling function P(x) is universal and has an unexpected power law tail, P(x) ~ x(-4) for large x. For δ> (d(k,∞)) the scaling breaks down and the pdf gets cut off in a nonuniversal way. Consequently, the moments of the gap exhibit an unusual multiscaling behavior. 相似文献
17.
A universal mechanism of the Boson peak formation in glasses is proposed. The mechanism is based on the concept of interacting quasilocal oscillators. Even in the case of weak interaction, the low-frequency spectrum becomes unstable. Due to anharmonicity, the system undergoes a transition into a new stable configuration. As a result, below some characteristic frequency ωc, proportional to the typical strength of interaction, the renormalized density of states becomes a universal function of ω with a Boson peak feature; i.e., the reduced density of states g(ω)/ω2 has a maximum at a frequency ωb?ωc. We derive an analytic form of this function. 相似文献
18.
YANG Wei-Hong 《理论物理通讯》2001,35(2):219-222
The simplified forms of generalized
magnetohydrodynamic equations have been derived. The K. Appert theory and Hain-Lüst equation are two special cases of our results when p→0 and
ω/ωci→0. It is shown
that the process of taking any limits (p→0 or ω/ωci→0) will result in a singularity at the Alfvén resonant layer. 相似文献
19.
Oscar E. Landford 《Physica D: Nonlinear Phenomena》1985,14(3):403-408
We report the results of numerical computation of the size of the set of ω's for which the hemeomorphism of the circle ,ω(x)=x+ω+K/2π sin (2πx) mod (1) is phased locked, for values of K ranging from 0.1 to 1. The results suggest that for moderate values of K phase locking is unlikely except for small periods, but that for K=1 almost all ω's give phase locking, with large periods accounting for a surprisingly large portion of the total. 相似文献
20.
Park JT Friemel G Li Y Kim JH Tsurkan V Deisenhofer J Krug von Nidda HA Loidl A Ivanov A Keimer B Inosov DS 《Physical review letters》2011,107(17):177005
We have studied the low-energy spin-excitation spectrum of the single-crystalline Rb(2)Fe(4)Se(5) superconductor (T(c)=32 K) by means of inelastic neutron scattering. In the superconducting state, we observe a magnetic resonant mode centered at an energy of ?ω(res)=14 meV and at the (0.5 0.25 0.5) wave vector (unfolded Fe-sublattice notation), which differs from the ones characterizing magnetic resonant modes in other iron-based superconductors. Our finding suggests that the 245-iron selenides are unconventional superconductors with a sign-changing order parameter, in which bulk superconductivity coexists with the √5×√5 magnetic superstructure. The estimated ratios of ?ω(res)/k(B)T(c)≈5.1±0.4 and ?ω(res)/2Δ≈0.7±0.1, where Δ is the superconducting gap, indicate moderate pairing strength in this compound, similar to that in optimally doped 1111 and 122 pnictides. 相似文献