共查询到20条相似文献,搜索用时 39 毫秒
1.
T. Mercouris C.A. Nicolaides 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(2):241-248
By implementing a time-independent, nonperturbative many-electron, many-photon theory (MEMPT), cycle-averaged complex eigenvalues
were obtained for the He atom, whose real part gives the field-induced energy shift, Δ(ω
1, F
1;ω
2, F
2,ϕ), and the imaginary part is the multiphoton ionization rate, Γ(ω
1, F
1;ω
2, F
2,ϕ), where ω is the frequency, F is the field strength and ϕ is the phase difference. Through analysis and computation we show that, provided the intensities
are weak, the dependence of Γ(ω
1, F
1;ω
2, F
2,ϕ) on ϕ is simple. Specifically, for odd harmonics, Γ varies linearly with cos(ϕ) whilst for even harmonics it varies linearly
with cos(2ϕ). In addition, this dependence on ϕ holds for Δ(ω
1, F
1;ω
2, F
2,ϕ) as well. These relations may turn out to be applicable to other atomic systems as well, and to provide a definition of
the weak field regime in the dichromatic case. When the combination of (ω
1, F
1) and (ω
2, F
2) is such that higher powers of cos(ϕ) and cos(2ϕ) become important, these rules break down and we reach the strong field
regime. The herein reported results refer to Γ(ω
1, F
1;ω
2, F
2,ϕ) and Δ(ω
1, F
1;ω
2, F
2,ϕ) for He irradiated by a dichromatic ac-field consisting of the fundamental wavelength λ = 248 nm and its 2nd, 3rd and 4th
higher harmonics. The intensities are in the range 1.0×1012-3.5×1014 W/cm2, with the intensity of the harmonics being 1-2 orders of magnitude smaller. The calculations incorporated systematically
electronic structure and electron correlation effects in the discrete and in the continuous spectrum, for 1S, 1P, 1D, 1F, 1G, and 1H two-electron states of even and odd parity.
Received 9 July 2000 and Received in final form 2 November 2000 相似文献
2.
Current-voltage (J-V) and differential-conductivity-voltage ( dJ/dV-V) characteristics are analytically calculated at zero temperature for a point contact consisting of: two Peierls conductors
P
( = 1, 2) separated by an insulator (I). Here P is a conductor with charge density wave (CDW). The J-V and dJ/dV-V characteristics depend on the CDW phases ( = 1, 2) in the mean field approximation. To calculate them analytically we assumed, = ≡Δ where ( = 1, 2) are the energy gaps of P
( = 1, 2). The current J has a discontinuous jump at eV = 2Δ for ϕ
1 = ϕ
2≠ 0. The differential conductivity dJ/dV has a singularity at eV = 2Δ for ϕ
1 = ϕ
2≠ 0. The relation J(V,ϕ
1,ϕ
2) = - J(- V,ϕ
1 + π,ϕ
2 + π) is obtained.
Received 4 July 2001 and Received in final form 13 September 2001 相似文献
3.
E. Kyriakopoulos 《General Relativity and Gravitation》2012,44(1):157-199
We present two rotating black hole solutions with axion ξ, dilaton f{\phi} and two U(1) vector fields. Starting from a non-rotating metric with three arbitrary parameters, which we have found previously, and
applying the “Newman–Janis complex coordinate trick” we get a rotating metric g
μν
with four arbitrary parameters namely the mass M, the rotation parameter a and the charges electric Q
E
and magnetic Q
M
. Then we find a solution of the equations of motion having this g
μν
as metric. Our solution is asymptotically flat and has angular momentum J = M
a, gyromagnetic ratio g = 2, two horizons, the singularities of the solution of Kerr, axion and dilaton singular only when r = a cos θ = 0 etc. By applying to our solution the S-duality transformation we get a new solution, whose axion, dilaton and vector fields have one more parameter. The metrics,
the vector fields and the quantity l = x+ie-2f{\lambda=\xi+ie^{-2\phi}} of our solutions and the solution of: Sen for Q
E
, Sen for Q
E
and Q
M
, Kerr–Newman for Q
E
and Q
M
, Kerr, Reference Kyriakopoulos [Class. Quantum Grav. 23:7591, 2006, Eqs. (54–57)], Shapere, Trivedi and Wilczek, Gibbons–Maeda–Garfinkle–Horowitz–Strominger, Reissner–Nordstr?m, Schwarzschild
are the same function of a, and two functions ρ
2 = r(r + b) + a
2 cos2
θ and Δ = r(r + b) − 2Mr + a
2 + c, of a, b and two functions for each vector field, and of a, b and d respectively, where a, b, c and d are constants. From our solutions several known solutions can be obtained for certain values of their parameters. It is shown
that our two solutions satisfy the weak the dominant and the strong energy conditions outside and on the outer horizon and
that all solutions with a metric of our form, whose parameters satisfy some relations satisfy also these energy conditions
outside and on the outer horizon. This happens to all solutions given in the “Appendix”. Mass formulae for our solutions and
for all solutions which are mentioned in the paper are given. One mass formula for each solution is of Smarr’s type and another
a differential mass formula. Many solutions with metric, vector fields and λ of the same functional form, which include most
physically interesting and well known solutions, are listed in an “Appendix”. 相似文献
4.
C?t?lin I. Carstea 《Communications in Mathematical Physics》2010,300(2):487-528
The existence of co-rotational finite time blow up solutions to the wave map problem from ${\mathbb{R}^{2+1} \to N}The existence of co-rotational finite time blow up solutions to the wave map problem from
\mathbbR2+1 ? N{\mathbb{R}^{2+1} \to N} , where N is a surface of revolution with metric d
ρ
2 + g(ρ)2
dθ2, g an entire function, is proven. These are of the form u(t,r)=Q(l(t)t)+R(t,r){u(t,r)=Q(\lambda(t)t)+\mathcal{R}(t,r)} , where Q is a time independent solution of the co-rotational wave map equation −u
tt
+ u
rr
+ r
−1
u
r
= r
−2
g(u)g′(u), λ(t) = t
−1-ν, ν > 1/2 is arbitrary, and R{\mathcal{R}} is a term whose local energy goes to zero as t → 0. 相似文献
5.
Sadataka Furui 《Few-Body Systems》2009,46(1):73-74
We calculate the propagator of the domain wall fermion (DWF) of the RBC/UKQCD collaboration with 2 + 1 dynamical flavors of
163 × 32 × 16 lattice in Coulomb gauge, by applying the conjugate gradient method. We find that the fluctuation of the propagator
is small when the momenta are taken along the diagonal of the 4-dimensional lattice. Restricting momenta in this momentum
region, which is called the cylinder cut, we compare the mass function and the running coupling of the quark-gluon coupling
α
s,g1(q) with those of the staggered fermion of the MILC collaboration in Landau gauge. In the case of DWF, the ambiguity of the
phase of the wave function is adjusted such that the overlap of the solution of the conjugate gradient method and the plane
wave at the source becomes real. The quark-gluon coupling α
s,g1(q) of the DWF in the region q > 1.3 GeV agrees with ghost-gluon coupling α
s
(q) that we measured by using the configuration of the MILC collaboration, i.e., enhancement by a factor (1 + c/q
2) with c ≃ 2.8 GeV2 on the pQCD result. In the case of staggered fermion, in contrast to the ghost-gluon coupling α
s
(q) in Landau gauge which showed infrared suppression, the quark-gluon coupling α
s,g1(q) in the infrared region increases monotonically as q→ 0. Above 2 GeV, the quark-gluon coupling α
s,g1(q) of staggered fermion calculated by naive crossing becomes smaller than that of DWF, probably due to the complex phase of
the propagator which is not connected with the low energy physics of the fermion taste.
An erratum to this article can be found at 相似文献
6.
Tianyun Chen Ningjiu Zhao Weiping Zhang Xinqiang Wang 《Central European Journal of Physics》2011,9(5):1221-1227
Quasiclassical trajectory method for the title reaction He +H2+ → HeH+ + H was carried out on the potential energy surface which was revised by Aquilanti et al. [Chem. Phys. Lett. 469, 26 (2009)].
The initial vibrational quantum number of reactant was set as v=1, v=2 and v=3. Stereodynamics information of the reaction
was obtained, such as the distributions of product angular momentum P(θ
r
), P(ϕ
r
),p(ϕ
r
, θ
r
) and the two commonly used polarization-dependent differential cross sections (PDDCSs) (2π/σ)(dσ
00/dω
t
) and (2π/σ)(dσ
20/dω
t
), to get the alignment and orientation of product molecules. The results show that the influence of both the collision energy
and vibrational quantum number (v) to the reaction are highly sensitive. 相似文献
7.
A. A. Rajabi 《Few-Body Systems》2006,40(1-2):21-33
The bound-state solutions to the hyperradial Schr?dinger equation is constructed for any general case comprising any hypercentral
power and inverse-power potentials. The hypercentral potential depends only on the hyperradius which itself is a function
of Jacobi relative coordinates that are functions of particle positions (r
1,r
2, … , and r
N
). This paper is mainly devoted to the demonstration of the fact that any ψ of the form ψ = power series × exp(polynomial)
= [f(x) exp (g(x))] is potentially a solution of the Schr?dinger equation, where the polynomial g(x) is an ansatz depending on the interaction potential. 相似文献
8.
T. Datta 《Il Nuovo Cimento D》1983,2(3):783-786
Summary The fission of a vortex line along the trajectory of a monopole in a superconducting medium is an unambiguous signature of
a monopole. The numbern of the (stable) daughter vortices determines the monopole strengthg withg=2nφ/4π where ϕ0=2.07·10−7 G cm2.
Riassunto La fissione di una linea di vortice lungo la traiettoria di un monopolo in un mezzo superconduttore è indice sicuro della segnatura di un monopolo. Il numeron di vortici figli (stabili) determina la forza del monopolog cong=nϕ0/4π, dove ϕ0=2.07·10−7 G cm2.相似文献
9.
Nariyuki Minami 《Communications in Mathematical Physics》2000,213(1):203-247
Let f(ϕ) be a positive continuous function on 0 ≤ϕ≤Θ, where Θ≤ 2 π, and let ξ be the number of two-dimensional lattice points in
the domain Π
R
(f) between the curves r=(R+c
1/R)f(ϕ) and r=(R+c
2/R)f(ϕ), where c
1<c
2 are fixed. Randomizing the function f according to a probability law P, and the parameter R according to the uniform distribution μ
L
on the interval [a
1
L,a
2
L], Sinai showed that the distribution of ξ under P×μ
L
converges to a mixture of the Poisson distributions as L→∞. Later Major showed that for P-almost all f, the distribution of ξ under μ
L
converges to a Poisson distribution as L→∞. In this note, we shall give shorter and more transparent proofs to these interesting theorems, at the same time extending
the class of P and strengthening the statement of Sinai.
Received: 15 June 1999 / Accepted: 11 February 2000 相似文献
10.
A. A. Rajabi 《Few-Body Systems》2005,37(4):197-213
A mathematical method is presented for solving the Schr?dinger equation for a system of identical body forces. The N-body forces are more easily introduced and treated within the hyperspherical harmonics. The problem of the N-body potential has been used at the level of both classical and quantum mechanics.
The hypercentral interacting potential is assumed to depend on the hyperradius x = (ξ12 + ξ22 + ⋯ + ξN−12)1/2 only, where ξ1,ξ2,…,ξN−1 are Jacobi relative coordinates which are functions of N-particle relative positions r12,r23,…,rN1. The problem of the harmonic oscillator and the Coulomb-type potential has been widely studied in different contexts.
Using the N-body potential V(x) = ax2 + bx − (c/x) as an example, and assuming an ansatz for the eigenfunction, an exact analytical solution of the Schr?dinger equation for
an N-body system in three dimensions is obtained. This method is also applicable to some other types of potentials for N-identical interacting particles. 相似文献
11.
Let F be a differentiable manifold endowed with an almost K?hler structure (J,ω), α a J-holomorphic action of a compact Lie group on F, and K a closed normal subgroup of which leaves ω invariant.
The purpose of this article is to introduce gauge theoretical invariants for such triples (F,α,K). The invariants are associated with moduli spaces of solutions of a certain vortex type equation on a Riemann surface Σ.
Our main results concern the special case of the triple
where αcan denotes the canonical action of on . We give a complex geometric interpretation of the corresponding moduli spaces of solutions in terms of gauge theoretical
quot spaces, and compute the invariants explicitly in the case r=1.
Proving a comparison theorem for virtual fundamental classes, we show that the full Seiberg–Witten invariants of ruled surfaces,
as defined in [OT2], can be identified with certain gauge theoretical Gromov–Witten invariants of the triple (Hom(ℂ,ℂ<
r
0),αcan, U(1)). We find the following formula for the full Seiberg–Witten invariant of a ruled surface over a Riemann surface of genus
g:
where [F] denotes the class of a fibre. The computation of the invariants in the general case r >1 should lead to a generalized Vafa-Intriligator formula for “twisted”Gromov–Witten invariants associated with sections
in Grassmann bundles.
Received: 22 February 2001 / Accepted: 16 January 2002 相似文献
12.
N. Kaiser 《The European Physical Journal A - Hadrons and Nuclei》2007,31(2):207-212
We calculate at two-loop order in chiral perturbation theory the electromagnetic corrections to the leading-order 2π exchange
NN interaction proportional to g
A
0 and g
A
2. The resulting 2πγ exchange potential contains isospin-breaking components which reach up to about -2% of the corresponding
isovector 2π exchange potential. With a value of only -17keV at r = m
π
-1 = 1.4fm the charge-independence breaking central potential obtained here is negligibly small in comparison to the one generated
by the isoscalar c3 contact vertex. Our calculation confirms that the largest long-range isospin-violating NN potentials arise from the 2πγ exchange diagrams involving the large low-energy constants c
4 ≃ - c
3 ≃ 3.3GeV^-1 representing the important Δ(1232) dynamics. 相似文献
13.
I. M. Suslov 《Journal of Experimental and Theoretical Physics》2010,111(3):450-465
The previously-obtained analytical asymptotic expressions for the Gell-Mann-Low function β(g) and anomalous dimensions in the ϕ4 theory in the limit g → ∞ are based on the parametric representation of the form g = f(t), β(g) = f
1(t) (where t ∝ g
0−1/2 is the running parameter related to the bare charge g
0), which is simplified in the complex t plane near a zero of one of the functional integrals. In this work, it has been shown that the parametric representation
has a singularity at t → 0; for this reason, similar results can be obtained for real g
0 values. The problem of the correct transition to the strong-coupling regime is simultaneously solved; in particular, the
constancy of the bare or renormalized mass is not a correct condition of this transition. A partial proof has been given for
the theorem of the renormalizability in the strong-coupling region. 相似文献
14.
Katsumi Sugita Yoshiwo Okamoto Matsuo Sekine 《International Journal of Theoretical Physics》1997,36(6):1309-1316
We consider a simple Lagrangian which is constructed by only the preon and antipreon fields. By introducing the auxiliary
fields φμ, φ
μ
†
, and ϕμ, it is shown that φμ, φ
μ
†
, and ϕμ correspond to the electroweak gauge bosonsW
μ
+
,W
μ
−
, andW
μ
3
, respectively, which are composite particles of preons and antipreons. 相似文献
15.
H. Chamati 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,24(2):241-249
The finite-size critical properties of the (n) vector ϕ4 model, with long-range interaction decaying algebraically with the interparticle distance r like r
-d - σ, are investigated. The system is confined to a finite geometry subject to periodic boundary condition. Special attention
is paid to the finite-size correction to the bulk susceptibility above the critical temperature T
c. We show that this correction has a power-law nature in the case of pure long-range interaction i.e. 0 < σ < 2 and it turns out to be exponential in case of short-range interaction i.e.σ = 2. The results are valid for arbitrary dimension d, between the lower ( d
< = σ) and the upper ( d
> = 2σ) critical dimensions.
Received 2 July 2001 and Received in final form 4 Septembre 2001 相似文献
16.
N. N. Achasov 《Physics of Atomic Nuclei》2007,70(5):862-863
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. 相似文献
17.
Summary Charge-stabilized suspensions are characterized by the strong electrostatic interactions between the particles so that rather
dilute systems may exhibit strong correlation resulting in a well-developed short-range order. This microstructure, quantitatively
described by the pair distribution functiong(r), is rather different from that of (uncharged) hard spheres. It is shown how this difference affects the ?hydrodynamic function?H(k), which appears in the expression for the first cumulant Γ(k)=k
2
D
eff(k)=k
2
H(k)/S(k) of the dynamic autocorrelation function. Without hydrodynamic interaction,H(k)=D
0, which is the free-diffusion coefficient. Using pairwise additive hydrodynamic interaction and the lowest-order many-body
theory of hydrodynamic interaction, it is found thatH(k) can deviate considerably fromD
0 even for systems of volume fractions ϕ as low as 10−3. These effects are more pronounced for collective diffusion than for self-diffusion. SinceH(k=0) is closely related to the sedimentation velocity, we have studied this quantity as a function of volume fraction. It is
found that (H(0)/D
0) −1 scales asφ
1/3 at low ϕ in salt-free suspensions.
Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994. 相似文献
18.
Andre Toom 《Journal of statistical physics》1997,88(1-2):347-364
We consider space- and time-uniformd-dimensional random processes with linear local interaction, which we call harnesses and which may be used as discrete mathematical
models of random interfaces. Their components are rea random variablesa
s
t
, wheres ∈ Z
d
andt=0, 1, 2.,... At every time step two events occur: first, every component turns into a linear combination of itsN neighbors, and second, a symmetric random i.i.d. “noise”v is added to every component. For any σ ∈Z
d
+
define Δσ
a′
s
as follows. If σ=(0,...,0), σ=(0,...,0), Δσ
a
s
t
=a
s
t
. Then by induction,
wheree
i is thed-dimensional vector, whoseith component is one and other components are zeros. Denote |σ| the sum of components of σ. Call a real random variable ϕ symmetric
if it is distributed as −ϕ. For any symmetric random variable ϕpower decay or P-decay is defined as the supremum of thoser for which therth absolute moment of ϕ is finite. Convergence a.s., in probability and in law whent→∞ is examined in terms of P-decay(v): Ifd=1, σ=0 ord=2, σ=(0,0), Δσ
a
s
t
diverges. In all the other cases: If P-decay(v)<(d+2)/(d+|σ|), Δσ
a
s
t
diverges; if P-decay(v)>(d+2)/(d+|σ|), Δσ
a
s
t
, converges and P-decay(ν) For any symmetric random variable ϕexponential decay or E-decay is defined as the supremum of thoser for which the expectation of exp(|x|r) is finite. Let E-decay(v)>0. Whenever Δσ
a
s
t
converges (that is, ifd>2 or |σ|>0: Ifd>2, E-decay(lima
s
t
)=min(E-decay(v),d+2/2); if |σ|=1, E-decay (lim Δσ
a
s
t
)=min(E-decay(ν),d+2); if |σ| ⩾, E-decay (lim Δσ
a
s
t
)=E-decay(ν). 相似文献
19.
T. S. Chow 《Il Nuovo Cimento D》1994,16(8):1193-1197
Summary A nonequilibrium fluid lattice model of concentrated colloidal dispersions is presented to predict the effects of the microstructure,
particle interactions, volume fraction (ϕ), frequency (ω), and the longest viscoelastic relaxation time on the complex shear
viscosity. In addition to the pair interactions between colloidal particles, the many-body interactions between the particles
and the equilibrium microstructure have to be included in the analysis. As ϕ approaches a critical valueφ
c, the fluidity of concentrated dispersions slows down drastically. This percolation thresholdφ
c scales ad (AP)−0.5, whereA andP are related to the repulsive interparticle potential and microstructure, respectively.
Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994. 相似文献
20.
A. I. Reznikov S. Ya. Umanskii Yu. F. Chaikina 《Russian Journal of Physical Chemistry B, Focus on Physics》2010,4(2):203-209
Rate constants for electron-vibrational energy exchange Ar(3
P
2) + N2(X
1Σ
g
+, ν = 0) → Ar(1
S
0) + N2(C
3Π
u
, ν′), where ν′ = 0, 1, 2, were calculated. Calculations were performed taking into account the presence of a resonance in electron scattering
by N2(X
1Σ
g
+). As a result, the interaction of Ar(3
P
2) with N2(X
1Σ
g
+, ν = 0) was characterized by attraction and, in the end, intersection of electron-vibrational potential surfaces correlating
with Ar(3
P
2) + N2(X
1Σ
g
+, ν = 0) and Ar(1
S
0) + N2(C
3Π
u
, ν′) at interparticle distances of 2.5–3.5 ?. Exchange interaction at which electron-vibrational transitions in the region of
intersection of electron-vibrational transitions in the region of intersection of electron-vibrational potential surfaces
accompanied by spin exchange were induced was calculated by the asymptotic method. The rate constants determined at 300–600
K were on the order of 10−11−10−12 cm3/s and weakly increased as the temperature grew. Mainly the C
3Π
u
, ν′ = 0 state of the N2 molecule was populated. The calculation results were in satisfactory agreement with the experimental data obtained at 300
K. 相似文献