共查询到20条相似文献,搜索用时 31 毫秒
1.
Pierre van Baal 《Communications in Mathematical Physics》1983,92(1):1-18
We give a simplified construction of twist eating configurations, based on a theorem due to Frobenius. These configurations are defined through the equation:U
U
U
+
U
+
=exp(2in
/N) withU
SU(N), =1 tod andn
an antisymmetric matrix with integer entries. In the (Twisted)-Eguchi-Kawai model they yield extrema some of which survive forN. Comparison is made with the Monte Carlo data of the internal energy in the small coupling region. 相似文献
2.
S. S. Kokarev 《Russian Physics Journal》1996,39(2):146-152
The existence of a so-called "phantom" scalar field in some Riemannian spaceV
4, i.e., a field in which the effective energy momentum tensorT
(sf) vanishes in the five-dimensional Kaluza-Klein theory, is investigated by means of the integrability conditions for relations of the form ;;=k,,+bg
found in [6]. Phantom fields are found in homogeneous isotropic cosmological models.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 50–56, February, 1996. 相似文献
3.
G. Rideau 《Letters in Mathematical Physics》1979,3(3):229-235
It is shown that the generalized Lorentz gauges provide all linear conformal invariant gauges, i.e. gauges such that
A
=0. 相似文献
4.
W. Schott V. N. Baturin W. H. Breunlich T. Case H. Daniel F. J. Hartmann M. Jeitler P. Kammel K. Lou E. M. Maev J. Marton M. Mühlbauer C. Petitjean G. E. Petrov Yu. V. Petrov G. G. Semenchuk Yu. V. Smirenin A. A. Vorobyov P. Wojciechowski J. Zmeskal 《Hyperfine Interactions》1993,82(1-4):471-481
The triton energy of the muon capture reaction 3He t+v, where 3 He is the ground state of muonic3He, has been measured in order to investigate a possible heavy v admixture into the flavour with high sensitivity. 3 He has been formed via the pd fusion reaction by stopping – in an ionization chamber (IC) filled with an H/D gas mixture of 3% D concentration at a pressure of 161 bar. In a first short experiment 650 triton events were observed yielding an upper limit for the -heavy v mixing strength of 2.3×10–3 atE
0v=60 MeV. 相似文献
5.
K. Kriŝtiaková O. Ŝauŝa J. Kriŝtiak Ŝ. Jánoŝ 《Zeitschrift für Physik B Condensed Matter》1989,75(2):197-199
We have measured the ac susceptibility of a wire with a Nb core (1.27 mm diam.) and a Cu cladding (0.37 mm thickness) atT50 K andB0.1 mG. Due to its proximity to Nb, the Cu becomes fully superconducting. From the data we find a breakdown fieldH
b
=1.2 (mG) and a coherence length =2.2T
–1/2 (m) for the Cu, as well as a field penetration depth -34T
1/2 (m) at the Cu/Nb interface. 相似文献
6.
Abraham Boyarsky 《Journal of statistical physics》1988,50(1-2):213-229
Let : [0, 1][0, 1] be a piecewise monotonie expanding map. Then admits an absolutely continuous invariant measure. A result of Kosyakin and Sandler shows that can be approximated by a sequence of absolutely continuous measures
n
invariant under piecewise linear Markov maps itn. Each itn is constructed on the inverse images of the turning points of . The easily computable measures
n
are used to estimate the Liapunov exponent of . The idea of using Markov maps for estimating the Liapunov exponent is applied to both expanding and nonexpanding maps. 相似文献
7.
C. Meunier 《Journal of statistical physics》1984,36(3-4):321-365
We study a simple dynamical system which displays a so-called type-I intermittency bifurcation. We determine the Bowen-Ruelle measure and prove that the expectation (g) of any continuous functiong and the Kolmogoroff-Sinai entropyh() are continuous functions of the bifurcation parameter. Therefore the transition is continuous from a measure-theoretical point of view. Those results could be generalized to any similar dynamical system. 相似文献
8.
P. Strasser K. Ishida S. Sakamoto M. Iwasaki E. Torikai K. Nagamine G. M. Marshall 《Hyperfine Interactions》1993,82(1-4):543-549
Slow – production via dd-CF using a two-layer arrangement is investigated. To determine its feasibility, experimental measurements are now in progress using the muonic X-ray detection method. The following experimental steps are being considered: (1) measurement of the number of – stopped inside a solid H2/D2 layer by detecting p K X-rays, (2) hot d emission detection by placing a secondary target at a distance of 10–30 mm from the layer and by detecting specific delayed X-rays, (3) measurement of the disappearance of d emission as the added D2 layer is increased, (4) dd-CF measurement by detecting fusion protons, and (5) slow – emission detection. Results of the initial test experiment are presented. 相似文献
9.
Z. G. Wang H. R. Xia L. S. Ma Y. Q. Lin I. S. Cheng 《Applied physics. B, Lasers and optics》1985,37(4):233-238
More than 25 laser lines around 2.5 m from theC
1
u
state to (3)1
g
+
and 7 laser lines around 0.9 m from the high-lying1
u
state to (2)1
g
+
in the sodium dimer were detected using a nitrogen laser as the pumping source. Most of the optically pumped laser lines have been identified.Projects Supported by the Science Fund of the Chinese Academy of Sciences 相似文献
10.
We consider the thermodynamic pressurep(, ) of a classical system of particles with the two-body interaction potentialq(r)+
v
K(r), where is the number of space dimensions, is a positive parameter, and is the chemical potential. The temperature is not shown in the notation. We prove rigorously, for hard-core potentialsq(r) and for a very general class of functionsK(s), that the limit 0 of the pressurep(, ) exists and is given by where the limit and the supremum can be interchanged. Here is a certain class of nonnegative, Riemann integrable functions,D is a cube of volume |D|, anda
0() is the free energy density of a system withK=0 and density . A similar result is proved for the free energy. 相似文献
11.
The classical theory of the interaction of a neutral spin-1/2 Dirac field and the gravitational field is studied. For the purely gravitational part of the Lagrangian, written in terms of a vierbein and the local connection coefficient
ab
, (regarded as independent field variables), the usual first-order form is adopted. For the Dirac part, however, a different choice is made, in which the covariant derivative of is built with the aid of the vierbein instead of with
ab
. This still yields a first-order formalism, but one in which
ab
is related to the vierbein in the same way as it would be in the absence of. This ensures that the global connection
remains symmetric in andv in the presence of. The way in which the vierbein field equation leads to a familiar Einstein equation with a symmetric and conserved stress tensor on its right side is also analyzed. 相似文献
12.
Jianjun Gao Choi Look Law Hong Wang Sheel Aditya 《International Journal of Infrared and Millimeter Waves》2002,23(12):1787-1801
This paper describes a scalable small-signal equivalent circuit for 0.25 m gatelength Double Heterojunction delta-doped PHEMTs. The scaling rules for all elements except the pad capacitances and bondwire inductances have been determined. Good agreement is obtained between simulation results and measured results for 2 times 20 m , 2 times 40 m, 2 times 60 m, 2 times 100 m gate width (number of gate fingers times unit gate width) DH PHEMT. 相似文献
13.
O. A. Fonarev 《Russian Physics Journal》1990,33(9):759-764
We define a covariant and gauge-invariant generalization of the Wigner functions of particles with spins 1/2 and 0. The collisionless kinetic equations are obtained for these particles in external gravitational and electromagnetic fields in the quasiclassical approximation; also obtained are the momentum representations of the energy-momentum tensor, current, and spin tensor, taking into account the effects of the spin's interaction with the gravitational field an electromagnetic field. The following notation is used: e and m are the charge and mass of the particles; is Planck's constant; (x) are the covariant-fixed Dirac matrices; ,=(1/4)[, ]: a(b)=(1/2) (a
b
+ab
); [A, B]=A·B – B·A; A,B=A·B+B·A; g(x)=det(g
(x));R
=
–...; the speed of light c=1.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 47–53, September, 1990.The author wishes the thank Yu. G. Ignat'ev and members of the seminar in General Relativistic Statistics and Cosmology of the Kazan' Pedagogical Institute for useful discussions. 相似文献
14.
András Sütő 《Communications in Mathematical Physics》1987,111(3):409-415
The spectrum (H) of the tight binding Fibonacci Hamiltonian (H
mn=
m,n+1+
m+1,n
+
m,n
v(n),v(n)=
((n–1)), 1/ is the golden number) is shown to coincide with the dynamical spectrum, the set on which an infinite subsequence of traces of transfer matrices is bounded. The point spectrum is absent for any , and (H) is a Cantor set for 4. Combining this with Casdagli's earlier result, one finds that the spectrum is singular continuous for 16.On leave from the Central Research Institute for Physics, Budapest, Hungary 相似文献
15.
I. I. Gurevich I. G. Ivanter B. A. Nikolsky A. N. Ponomarev V. S. Roganov V. I. Selivanov V. A. Suetin 《Hyperfine Interactions》1979,6(1-4):175-176
The paramagnetic state (+e–) in Si and Te was observed in a longitudinal magnetic field. The mean lifetimes of these states were obtained: Si = 1.45(3) s, Te = 12.5(8) s at 290 K, Te = 12(2) s at 250 K. 相似文献
16.
Jess H. Brewer 《Hyperfine Interactions》1984,19(1-4):873-878
Polarized negative muons were stopped in various materials containing nuclei with nonzero spin. The TF-SR precession signal of theF
+ hyperfine state (frequencyv
+ > 0) was pronounced for
–Li and
–Be, faint for
–Cl (in NiCl2), and undetectable for
–F (in CaF2 or NiF2) and
–P. TheF
– signal (frequencyv
– < 0) was observed clearly for
–Be,
–Al and
–Na, marginally for
–K,
–V and
–Nb, and not at all for
–Ga (at 4 kOe) or
–Co (ferrromagnetic, zero field). In the heavier elements theF
– signal is fed by transitions from theF
+ to theF
– state at a rateR, as long asR(v
+ –v
–). [See separate paper on
–Al in these Proceedings, p. 879.]I am grateful to Alex Schenck and Bruce Patterson for the loan of equipment and samples, to Fred Gygax for helping set up the apparatus, to Jun Imazato for help with the experiment, and to Toshi Yamazaki and Tak Suzuki for valuable comments. I am also indebted to SIN for several weeks of free
– beam time and to SIN, BOOM, and the University of Tokyo for free time on their VAX computers, which were kept busy for several months in the analysis. 相似文献
17.
The optically pumped FIR laser lines at 119 m from CH3OH and at 127 m from13CD3OH are known to be the most powerful in the far infrared spectral region. We report on efficiency measurements for our waveguide laser system. The effect of various parameters was investigated, resulting in the highest efficiency ever reported for the 119 m line. The Stark effect and others parameters of the 127 m were measured, and a new13CD3OH laser line at 175 m discovered, with the same pump transition. These measurements are helpful for completing the assignment already proposed for the 127 m line. 相似文献
18.
We have investigated the spectral characteristics of scattered radiation ( = 0.69 m and = 1.06 m) under probing laser action (q = 103 W/cm2) on a textolite target of streamline shape blown by a cold two-phase stream (with talc and black particles). By the measured transverse scattering indicatrices the dependences of the scattered radiation intensity on the probing angles and the sort of particles and their number density in the stream have been established. The relative contributions of particles of the stream and the target surface to the total scattering by the target–two-phase-stream system have been determined. 相似文献
19.
I. L. Zhogin 《Russian Physics Journal》1991,34(2):105-110
Field equations for n-frames h
a
that are possible in the theory of absolute parallelism are considered. It is shown that in three cases the equations can, after the substitution h
a
=HpH
a
(H=det H
a
, p is an n-dependent constant), be written in a trilinear form that contains only the matrix H
a
and its derivatives and not H
a
. It is shown that the equations are still regular for degenerate but finite matrices H
a
if rank H
a
2.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 22–27, February, 1991. 相似文献
20.
Piotr Podleś 《Letters in Mathematical Physics》1989,18(2):107-119
Three-dimensional differential calculus on quantum spheres S
infc
sup2
,]–1, 1[{0}, c[0, ], is introduced and investigated. Spectra of generalized Laplacians are found. These operators are expressed by generalized directional derivatives. Classical limits of these objects are obtained and a simple approach to quantum mechanics on a quantum sphere is presented. 相似文献