共查询到20条相似文献,搜索用时 31 毫秒
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《Comptes Rendus Physique》2003,4(8):945-951
This article summarizes recent progress in the development of tools to study the topology of the universe with the cosmic microwave background. The different signatures of the topology and observational constraints are described. The ability of future experiments to reveal the topological structure of our universe is then discussed. To cite this article: J.P. Uzan, A. Riazuelo, C. R. Physique 4 (2003). 相似文献
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Using the evolution history of the universe, one can make constraint on the parameter space of dynamic dark energy models. We discuss two different parameterized dark energy models. Our results further restrict the combined constraints obtained from supernova and the first-year Wilkinson-microwave-anisotropy-probe observations. From the allowed parameter space, it is found that our universe will experience an eternal acceleration. We also estimate the bound on the physically relevant regions both in the re-inflationary and inflationary phases. 相似文献
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A. D. Filonenko 《JETP Letters》2009,89(8):381-384
The effect of the environment on the results of measuring the radio radiation spectrum is considered in the experimental simulation of the cascade shower by a high-energy γ-ray beam in a dense medium. The calculation shows that the character of the measured energy spectrum depends on the location of the receiving antenna with respect to the shower axis. 相似文献
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R. N. Sen 《Foundations of Physics Letters》1999,12(4):325-345
This paper investigates whether the differential structure of space-time follows from accepted laws of physics, or is a mathematical invention. In view of the results of [7], it suffices to consider whether the assumed identity of the Euclidean line E—the line of the geometers of ancient Greece—and the real line R of modern analysis, follows from any known law of nature (i.e., one that can be falsified empirically). Since the totality of empirical data is finite, one is forced to conclude that the completeness of R cannot be falsified empirically—and therefore, according to Popper's criterion, the real line must be an invention, and not a discovery. It then becomes difficult to tell whether Newton's second law of motion (expressed as the differential equation
is an invention or a discovery! Finally, some alternatives to the above analysis are briefly analysed. 相似文献
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W. J. Bray 《Contemporary Physics》2013,54(4):323-349
This article is a survey of the technological foundations of telecommunications, including both point-to-point electrical communication wing wires, cables and other guiding media. and radio wave broadcasting to many receivers via terrestrial transmitters or Earth-orbiting space satellites. The characteristics of analogue and digital telecommunication signals, the means available for their transmission and switching me described, together with the organization of local distribution, national and global networks. The various services that can be provided over such networks, including in addition to telephonic communication, audio and video conferencing, data and facsimile transmission and new vied-display data/information access services (Teletext) are outlined. Finally, the sociological implications of these technological and service developments me considered, for example in terms of their impact on urban and rural planning, where people live and work, and on energy economy by reducing the need to travel. 相似文献
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The complexity of threshold phenomena is exemplified on a prominent and long-known case-the struc-ture in the ∧p cross section (invariant mass spectrum) at the ... 相似文献
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《Journal of Nonlinear Mathematical Physics》2013,20(1):34-56
Abstract The B¨acklund transformations for the relativistic lattices of the Toda type and their discrete analogues can be obtained as the composition of two duality transformations. The condition of invariance under this composition allows to distinguish effectively the integrable cases. Iterations of the B¨acklund transformations can be described in the terms of nonrelativistic lattices of the Toda type. Several multifield generalizations are presented. 相似文献
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《声学学报:英文版》2002,(3)
11尬roductlon For the vlsuallzatlon and the studies of the physical properties of acoustic ield;the schlierentechnique was the most useful for the co尬Inuous waves[1,2].ReceNwars,the shadowgraphmode was appeared for the recording of*theing acoustic pulse[3-p].Although the shadowgr地hmode Is used more frequently In experimental fluid dynamics[6],In the irst part of this paper;the response of*these opticall扯enslty of*the recorded acoustic pulse related to the acousticpressure gradlem Is st… 相似文献
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Jorge P. Zubelli 《Letters in Mathematical Physics》1992,24(1):41-48
We show that the -functions obtained from Schur polynomials lead to wave functions w(x
1, x
2, ... ; k) that possess the following bispectral property: There exists a differential operator B{k,k}, independent of x
1
, such that B{k,k}w = {x
1}w, where {x
1} is independent of k. This extends for the KP hierarchy some earlier results of J. J. Duistermaat and F. A. Grünbaum for the rational solutions of KdV and of P. Wright for certain rational solutions of the generalized KdV equations. 相似文献
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《声学学报:英文版》1999,(1)
1IntroductionInternalwavesarefoundthroughouttheworld's...an[1-3].Theactivityofinternalwavescausesthechangesofthesoundspeedprofile,andthereforeaffectsthesoundpropagation['].Duringthepastdecades,considerableprogresshasbeenmadeinunderstandinginternaIwavesandtheireffectsonsoundindeepocean.Nowtheresearchcommunityhasshiftedtheemphasistoshallowwaterarea[5~l1].Inthelatesummerof1996,scientistsfromChinaandtheUnitedStatesconductedacombinedacousticsandphysicaloceanographyexperimentintheYellowSea(YS96)… 相似文献
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B. Ananthanarayan I. Caprini Diganta Das I. Sentitemsu Imsong 《The European Physical Journal C - Particles and Fields》2012,72(10):1-12
We study the structure of local baryon fields using the method of QCD sum rule. We only consider the single baryon fields and calculate their operator product expansions. We find that the octet baryon fields belonging to the chiral representations $[(\mathbf{3},\bar{\mathbf{3}}) \oplus(\bar{\mathbf{3}}, \mathbf{3})]$ and [(8,1)??(1,8)] and the decuplet baryon fields belonging to the chiral representations [(3,6)??(6,3)] lead to the baryon masses which are consistent with the experimental data of ground baryon masses. We also calculate their decay constants, check our normalizations for baryon fields in Chen et?al. (Phys. Rev.?D 81:054002, 2009) and find that they are well-defined. 相似文献
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Technical Physics - An extended interpretation of the Wolkenstein–Ptitsyn formula for temperature band δTg, characterizing a range of transition from liquid to glass, is considered using... 相似文献
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V. M. Avdyukhina O. V. Akimova I. S. Levin G. P. Revkevich 《Moscow University Physics Bulletin》2014,69(2):169-174
Increasing the concentration of indium atoms and hydrogen was found in the α-phase of the foil of a Pd-In alloy (with 5.3 and 5.0 at % In) after its electrolytic hydrogenation and 500-h relaxation. It is shown that the structural variations in the foil during the β → α transformation are nonmonotonic. 相似文献
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The market maker plays an important role in price formation, but his/her behavior and stabilizing impact on the market are relatively unclear, in particular in speculative markets. This paper develops a financial market model that examines the impact on market stability of the market maker, who acts as both a liquidity provider and an active investor in a market consisting of two types of boundedly rational speculative investors—the fundamentalists and trend followers. We show that the market maker does not necessarily stabilize the market when he/she actively manages the inventory to maximize profits, and that rather the market maker’s impact depends on the behavior of the speculators. Numerical simulations show that the model is able to generate outcomes for asset returns and market inventories that are consistent with empirical findings. 相似文献
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《Nuclear Physics A》1988,481(4):765-780
The relativistic corrections, corresponding to the transverse and longitudinal excitation of the Δ, are included in the original Blomqvist-Laget model. They are calibrated against the pion photoproduction data. The measurement of the transverse-longitudinal interference cross sections of the (e, e′ π0) reaction is the most promising way to study the longitudinal coupling of the Δ. 相似文献
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We generalize here the splitting approach to the long range (Coulomb) interaction for the three body scattering problem. With this approach, the exterior complex rotation technique can be applied for systems with asymptotic Coulomb interaction. We illustrate the method with calculations of the electron scattering on the hydrogen atom and positive helium ion in the frame of the Temkin–Poet model. 相似文献
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《Nuclear Physics B》1988,297(1):103-124
We discuss general features of models in which the E8 × E′8 heterotic superstring is compactified on a specific Calabi-Yau manifold. The gauge group of rank-6 in four dimensions is supposed to be broken down at an intermediate scale mI to the standard model group SU(3)C × SU(2)L × U(1)Y, as a result of two neutral scalar fields acquiring large vacuum expectations (vev's) in one of many flat directions of the effective potential. We find that it is difficult to generate such an intermediate scale by radiative symmetry breaking, whilst such models have prima facie problems with baryon decay mediated by massive particles and with non-perturbative behaviour of the gauge couplings, unless mI ≳ 1016 GeV. Rapid baryon decay mediated by light particles, large neutrino masses, other Δ L ≠ 0 processes and flavour-changing neutral currents are generic features of these models. We illustrate these observations with explicit calculations in a number of different models given by vev's in different flat directions. 相似文献
20.
Shehu S. AbdusSalam 《Physics letters. [Part B]》2011,705(4):331-336
If supersymmetry (SUSY) exists in nature and is a solution to the hierarchy problem then it should be detectable at the TeV energy scale which the large hadron collider (LHC) is now exploring. One of the main goals of the LHC is the discovery or exclusion of the R-parity conserving minimal supersymmetric standard model (MSSM). So far, the SUSY search results are presented in the context of the constrained MSSM and other specific simplified SUSY models. A model-independent analysis necessarily relies on the trigger-system of the LHC detectors. By using the posterior samples of a 20-parameter MSSM, the phenomenological MSSM, from a fit to indirect collider and cosmological data we find that there is a significant volume in the MSSM parameter space that would escape the standard trigger-systems of the detectors. As such, in the absence of discovery in the current and future LHC runs, it would be difficult if not impossible to exclude the MSSM unless some dedicated and special triggers are commissioned or a Higgs boson with mass as predicted by the supersymmetric models is not found. 相似文献