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1.
Principles and applications are described for a form of Doppler-free optical double resonance spectroscopy which uses amplitude
modulation sidebands (v
L
±v) imposed on a single laser frequency (v
L
). The sidebands are generated by passing the carrier radiationv
L
through an electro-optic modulator, driven at a radiofrequency ν, which enables the intensity and polarization characteristics
of the emerging radiation to be varied for enhancement of selected double-resonance processes. The technique has been applied
to infrared-infrared double-resonance studies of the Stark effects of a variety of molecules—13CH3F,12CH3F, PH3,15NH3, GeH4, SiH4, and CH3D—for which physical results are presented and discussed. These results include determination of extremely small electric
dipole moments (10−3–10−5 debye) for GeH4 and CH3D and, for the dipole moment of PH3, a vibrational state dependence which is extremely small (Δμ=0.0028(5) debye for ∣Δv
2∣=1) and a rotational state dependence which is of an unexpected sign. The spectra recorded in some cases display unusual
polarization and optical saturation effects which deviate markedly from the predictions of a simple three-wave polarization
theory. 相似文献
2.
Magnetoplastic effect in irradiated NaCl and LiF crystals 总被引:2,自引:0,他引:2
V. I. Al’shitz E. V. Darinskaya O. L. Kazakova 《Journal of Experimental and Theoretical Physics》1997,84(2):338-344
The effect of low x-ray irradiation doses (≈102 rad) on the magnetoplastic effect — the detachment of dislocations from paramagnetic centers under the action of an external
magnetic field B — in alkali-halide crystals has been investigated. The measurements were performed on LiF crystals and three types of NaCl
crystals, differing in impurity content. The dependence of the mean free path l of the dislocations on the rotational frequency ν of a sample in a magnetic field was especially sensitive to low irradiation doses. In unirradiated crystals this dependence
is a single-step dependence and is characterized by a critical frequency ν
c ∝B
2 above which the magnetoplastic effect is not observed. The frequency ν
c depends only on the type of paramagnetic centers, and not on their density. Even the lowest irradiation dose employed (<100
rad) leads to a sharp restructuring of the dependence l(ν), converting it into a two-step dependence (for edge dislocations) with an additional critical frequency ν
c2, that is insensitive to the irradiation dose, and that corresponds to the appearance of magnetically sensitive stoppers
of a new type under irradiation. The initial critical frequency ν
c1, as a rule, also varies with the dose, reflecting the change in state of the impurity complexes (Ca in NaCl and Mg in LiF).
Specifically, it is shown for NaCl(Ca) crystals that as the irradiation dose increases, the frequency ν
c1 increases, gradually approaching the value ν
c2, so that by the time the dose is ≈300 rad, the dependence l(ν) once again becomes a single-step dependence, dropping sharply only for ν⩾ν
c2. It is shown that the addition of a small number of Ni atoms to a NaCl crystal makes the Ca complexes radiation resistant,
and the critical frequency ν
c1 corresponding to them initially equals ν
c2 for crystals with no Ni. The recombination kinetics of radiation defects in the case in which the samples are irradiated
under a tungsten lamp was investigated. A possible physical model of the observed dependences is discussed.
Zh. éksp. Teor. Fiz. 111, 615–626 (February 1997) 相似文献
3.
N. M. Agababyan V. V. Ammosov M. Atayan N. Grigoryan H. Gulkanyan A.A. Ivanilov Zh. Karamyan V. A. Korotkov 《Physics of Atomic Nuclei》2007,70(11):1904-1912
The characteristics of the charged-current neutrino—nuclear interactions are investigated for the first time at E
ν
= 1–3 GeV using the data obtained with SKAT propane-freon bubble chamber irradiated in the neutrino beam at the Serpukhov
accelerator. The E
ν
dependence of the mean multiplicities of different types of secondary particles and their multiplicity, momentum, and angular
distributions are measured.
The text was submitted by the authors in English. 相似文献
4.
Yoshio Koide 《The European Physical Journal C - Particles and Fields》2007,50(4):809-816
Based on the universal seesaw mass matrix model with the three scalars φi, and by assuming S3 flavor symmetry for the Yukawa interactions, the lepton masses and mixings are investigated systematically. In order to understand
the observed neutrino mixing, the charged leptons (e,μ,τ) are regarded as the three objects (e1,e2,e3) of S3, while the neutrino mass eigenstates are regarded as the irreducible representation (νη,νσ,νπ) of S3, where (νπ,νη) and νσ are a doublet and a singlet, respectively, which are composed of the three objects (ν1,ν2,ν3) of S3. 相似文献
5.
The Courant theorem provides an upper bound for the number of nodal domains of eigenfunctions of a wide class of Laplacian-type
operators. In particular, it holds for generic eigenfunctions of a quantum graph. The theorem stipulates that, after ordering
the eigenvalues as a non decreasing sequence, the number of nodal domains ν
n
of the n
th eigenfunction satisfies n ≥ ν
n
. Here, we provide a new interpretation for the Courant nodal deficiency d
n
= n − ν
n
in the case of quantum graphs. It equals the Morse index — at a critical point — of an energy functional on a suitably defined
space of graph partitions. Thus, the nodal deficiency assumes a previously unknown and profound meaning — it is the number
of unstable directions in the vicinity of the critical point corresponding to the n
th eigenfunction. To demonstrate this connection, the space of graph partitions and the energy functional are defined and the
corresponding critical partitions are studied in detail. 相似文献
6.
Jogesh C. Pati 《Pramana》2003,60(2):291-336
It is noted that a set of facts points to the relevance in four dimensions of conventional supersymmetric unification based
on minimally a string-unifiedG(224) symmetry, or maximallySO(10). These include: (i) the observed family structure, (ii) quantization of electric charge, (iii) meeting of the three gauge
couplings, (iv) neutrino oscillations (in particular the value of δm
2(νμ−δ
τ), suggested by SuperK), (v) the intricate pattern of the masses and mixings of the fermions, including the smallness ofV
cb and the largeness ofθ
μνμτ
osc
, and (vi) the need for B-L as a generator to implement baryogenesis (via leptogenesis). A concrete proposal is presented
within a predictiveSO(10)/G(224) framework that successfully describes the masses and mixings of all fermions, including the neutrinos — with eight predictions,
all in agreement with observation. Within this framework, a systematic study of proton decay is carried out, which (a) pays
special attention to its dependence on the fermion masses, (b) limits the threshold corrections so as to preserve natural
coupling unification, and (c) uses recently improved values of the matrix element and renormalization effects. Allowing for
both minimal supersymmetric standard model (MSSM) and its proposed variant, the so-called extended supersymmetric standard
model (ESSM), as effective low-energy the ories, the study shows that a conservative upper limit on the proton lifetime is
about (l–2)× 1034 years, with ·−K+ being the dominant decay mode, and quite possibly μ+
K
0 ande
+π0 being prominent. This in turn strongly suggests that an improvement in the current sensitivity by a factor of five to ten
ought to reveal proton decay. For comparison, some alternatives to the conventional approach to unification pursued here are
mentioned at the end.
Invited paper presented at the International Summer School held at ICTP, Trieste (June, 2001) and at WHEPP-7 Conference, Allahabad,
India (January, 2002). This is an updated version of the paper presented at the Erice School (September, 2000), hep-ph/0106082. 相似文献
7.
We study the cosmic time evolution of an effective quantum field theory energy-momentum tensor T
μν
and show that, as a consequence of the effective nature of the theory, T
μν
is such that the vacuum energy decreases with time. We find that the zero point energy at present time is washed out by the
cosmological evolution. The implications of this finding for the cosmological constant problem are investigated. 相似文献
8.
C. Jollet 《Physics of Atomic Nuclei》2006,69(11):1872-1875
The aim of the OPERA experiment is to provide unambiguous evidence for the ν
μ ↔ ν
τ oscillation by looking at the appearance of ν
τ in a pure ν
μ beam. This oscillation will be sought in the region of the oscillation parameters indicated by the atmospheric neutrino results.
The experiment is part of the CNGS (CERN Neutrino beam to Gran Sasso) project. The ν
μ beam produced at CERN will be sent towards the Gran Sasso underground laboratory, where the OPERA detector is under construction.
The detector, the physics potential, and performance for neutrino oscillation studies including the subleading ν
μ ↔ ν
ε search are presented.
The text was submitted by the author in English. 相似文献
9.
Bipin Singh Koranga P. Gaira Vinod Kumar 《International Journal of Theoretical Physics》2011,50(2):413-417
We study the Planck scale effects in the neutrino sector on the asymmetry between T-conjugate oscillation probabilities. ΔP
T
=P(ν
α
→ν
β
)−P(ν
β
→ν
α
), in a three flavor neutrino mixing. In this paper, we discuss some aspect of T violation effects in three flavor neutrino
oscillation. 相似文献
10.
Kh. M. Beshtoev 《Physics of Particles and Nuclei Letters》2009,6(5):397-402
Usually it is supposed that Majorana neutrino produced in the superposition state χ
L
= ν
L
+ (ν
L
)
c
and then follows the neutrinoless double beta decay. But since the standard weak interactions are chiral invariant then neutrino
at production has definite helicity (ν
L
and (ν
L
)
c
have opposite spirality). Then these neutrinos are separately produced and their superposition state cannot appear. Thus
we see that for unsuitable helicity the neutrinoless double β decay is not possible even if it is supposed that neutrino is
a Majorana particle (i.e. there is not a lepton number which is conserved). Also transition of Majorana neutrino ν
L
into antineutrino (ν
L
)
c
at their oscillations is forbidden since helicity in vacuum holds. Transition Majora neutrino ν
L
into (ν
R
)
c
(i.e., ν
L
→ (ν
R
)
c
) at oscillations is unobserved since it is supposed that mass of (ν
R
)
c
is very big. If neutrino is a Dirac particle there can be transition of ν
L
neutrino into (sterile) antineutrino $
\bar v_R
$
\bar v_R
(i.e., ν
L
→ $
\bar v_R
$
\bar v_R
) at neutrino oscillations if there takes place double violation of lepton number. It is necessary also to remark that introducing
of a Majorana neutrino implies violation of global and local gauge invariance in the standard weak interactions. 相似文献
11.
Possible Loss and Recovery of Gibbsianness¶During the Stochastic Evolution of Gibbs Measures 总被引:1,自引:1,他引:0
A.C.D. van Enter R. Fernández F. den Hollander F. Redig 《Communications in Mathematical Physics》2002,226(1):101-130
We consider Ising-spin systems starting from an initial Gibbs measure ν and evolving under a spin-flip dynamics towards a
reversible Gibbs measure μ≠ν. Both ν and μ are assumed to have a translation-invariant finite-range interaction. We study
the Gibbsian character of the measure νS(t) at time t and show the following:
(1) For all ν and μ, νS(t) is Gibbs for small t.
(2) If both ν and μ have a high or infinite temperature, then νS(t) is Gibbs for all t > 0.
(3) If ν has a low non-zero temperature and a zero magnetic field and μ has a high or infinite temperature, then νS(t) is Gibbs for small t and non-Gibbs for large t.
(4) If ν has a low non-zero temperature and a non-zero magnetic field and μ has a high or infinite temperature, then νS(t) is Gibbs for small t, non-Gibbs for intermediate t, and Gibbs for large t.
The regime where μ has a low or zero temperature and t is not small remains open. This regime presumably allows for many different scenarios.
Received: 26 April 2001 / Accepted: 10 October 2001 相似文献
12.
André Lichnerowicz 《Letters in Mathematical Physics》1979,3(6):495-502
The twisted products play an important role in Quantum Mechanics [1, 2]. We introduce here a distinction between Vey *ν-products and strong Vey *ν-products and prove that each *ν-product is equivalent to a Vey *ν-product. If b
3(W)=0, the symplectic manifold (W, F) admits strong Vey *ν-products. If b
2(W)=0, all *ν-products are equivalent as well as the Vey Lie algebras. In the general case, we characterize the formal Lie algebras which
are generated by a *ν-product and we prove that the existence of a *ν-product is equivalent to the existence of a formal Lie algebra infinitesimally equivalent to a Vey Lie algebra at the first
order. 相似文献
13.
M.A. Koshelev M.Y. Tretyakov R.M. Lees L.-H. Xu 《Applied physics. B, Lasers and optics》2006,85(2-3):273-277
Nitrogen and oxygen pressure broadening parameters for seven r
P(J”,0) transitions of the ν1+ν3 overtone band of the main isotope of ammonia with J” varied from 2 to 9 have been measured at room temperature using an external cavity tunable diode laser spectrometer. Air-broadening parameters have also been calculated from the N2 and O2 measurements. The results are compared to previous measurements in the ν1, ν2, ν3, ν4 and ν1+ν3 bands and to the parameters for the ν3 band that are reported in the HITRAN database. PACS 33.70.Jg; 33.70.-W; 33.20.Ea; 42.62.Fi; 42.68.Ca 相似文献
14.
Yu. I. Mankov 《Technical Physics》2011,56(8):1147-1157
Spectrum modification and damping of Josephson plasma waves induced by random inhomogeneities of the critical current through
the superconductor contact and the averaged Green function of such excitations are analyzed. In the self-consistent approximation
that makes it possible to take into account multiple wave scattering on the inhomogeneities, the frequency and damping of
averaged waves, as well as position ν
m
and peak width Δν of the Fourier transform imaginary part of the averaged Green function, are determined as functions of
wavevector k. The evolution of such functions with the variation of the correlation radius and the relative r.m.s. fluctuations of inhomogeneities
is studied. The inhomogeneity-induced wave frequency decrease observed in the long wavelength spectral region qualitatively
agrees with the ν
m
behavior. It is established that in the case of “long-range” inhomogeneities, the linear dependence of damping on k changes to the inversely proportional one, and damping tends to zero as k → 0, while Δν at small k attains its maximal values due to nonuniform broadening. In the presence of “short-range” inhomogeneities, the wave damping
and Δν are found to be similar functions of k. The results are compared to the numerical calculation data. 相似文献
15.
We study CP violation in a multi-Higgs doublet model based on aS
3×Z
3 horizontal symmetry. We consider two mechanisms for CP violation in this model: a) CP violation due to complex Yukawa couplings;
and b) CP violation due to scalarpseudoscalar mixings. We find that the predictions for ε′/ε, CP violation in B decays and
the electric dipole moments of neutron and electron are different between these two mechanisms. These predictions are also
dramatically different from the minimal Standard Model predictions. 相似文献
16.
H. Crogman V. Boudon D. A. Sadovskií 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(1):61-72
We define stretching relative equilibria (RE) of silane and other similar
tetrahedral molecules in terms of the dynamical polyad symmetry which
assumes the resonance condition 1:1 between the two stretching
vibrational modes ν1 and ν3 of the molecule. Exploiting symmetry
and topology arguments and reducing the dimension of the classical
mechanical system, we find these RE. One of them, with local symmetry
C3v and minimal energy within a polyad, corresponds to the local
modes. We give the upper energy limit of the local mode localization within
a polyad. 相似文献
17.
YeBing Xing XiaoHong Zhou YuHu Zhang YingXiang Guo Long Ma XiangGuo Lei WenTao Guo M. Oshima Y. Toh M. Koizumi A. Osa Y. Hatsukawa FuRong Xu M. Sugawara 《中国科学G辑(英文版)》2008,51(8):1053-1071
High-spin states in 187Pt were studied via the 173Yb(18O, 4n) reaction. Rotational bands based on the νi13/2, ν7/2−[503], νi2
13/2νj, ν3/2−[512] and ν1/2−[521] configurations were observed, and interpreted within the framework of the cranked shell model. The TRS calculations
show that the νi13/2 band has an appreciable negative γ deformation, and the negative-parity bands tend to have a near prolate shape with small positive γ values. Experimental values of B(M1)/B(E2) ratios have been extracted and compared with theoretical values from the semi-classical D?nau and Frauendof approach,
strongly suggesting a low frequency πh9/2 alignment in the ν7/2−[503] band.
Supported by the National Natural Science Foundation of China (Grant Nos. 10475097 and 10505025) and the Chinese Academy of
Sciences 相似文献
18.
A linear correlation between the Grüneisen parameter and ratio of the velocities of longitudinal (ν
l)and transverse (ν
t) acoustic waves in crystals is found. It is assumed that velocities ν
l and ν
t are severally harmonic parameters, while their ratio ν
l/ν
t is an anharmonic quantity and depends on the ratio between the shear and flexural rigidities of interatomic bonds. 相似文献
19.
V. P. Efrosinin 《Physics of Atomic Nuclei》2007,70(11):1926-1930
The possible sources of one-photon radiation as a background for the quasi-elastic reaction ν
μ
+ n → μ− + p are considered. They are relevant in experiments on determination of oscillation parameters at low neutrino energies (E
ν
∼ 1 GeV). The estimation for the cross section of the reaction ν
μ
+ n → μ
− + p + γ is given at E
ν
lab = 0.7 GeV as 0.65% of the corresponding cross section of quasielastic reaction. The mechanisms of quasi-elastic reaction
are also considered at low neutrino energies on a quark level.
The text was submitted by the authors in English. 相似文献
20.
L. Bartosch P. Kopietz 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(1):29-36
We consider the effect of Coulomb interactions on the average density of states (DOS) of disordered low-dimensional metals
for temperatures T and frequencies ω smaller than the inverse elastic life-time 1/τ. Using the fact that long-range Coulomb interactions in two dimensions (2d) generate ln2-singularities in the DOS ν(ω) but only ln-singularities in the conductivity σ(ω), we can re-sum the most singular contributions
to the average DOS via a simple gauge-transformation. If σ(ω) > 0, then a metallic Coulomb gapν(ω) ∝ |ω|/e
4 appears in the DOS at T = 0 for frequencies below a certain crossover frequency Ω
2 which depends on the value of the DC conductivity σ(0). Here, - e is the charge of the electron. Naively adopting the same procedure to calculate the DOS in quasi 1d metals, we find ν(ω) ∝ (|ω|/Ω
1)1/2exp(- Ω
1/|ω|) at T = 0, where Ω
1 is some interaction-dependent frequency scale. However, we argue that in quasi 1d the above gauge-transformation method is on less firm grounds than in 2d. We also discuss the behavior of the DOS at finite temperatures and give numerical results for the expected tunneling conductance
that can be compared with experiments.
Received 28 August 2001 / Received in final form 28 January 2002 Published online 9 July 2002 相似文献