期刊文献+
共找到732篇文章
< 1 2 37 >
每页显示 20 50 100
On the Lebesgue Integral and the Lebesgue Measure: Mathematical Applications in Some Sectors of Chern-Simons Theory and Yang-Mills Gauge Theory and Mathematical Connections with Some Sectors of String Theory and Number Theory
1
作者 Michele Nardelli 《Journal of Modern Physics》 2025年第1期93-132,共40页
In this paper, in Section 1, we have described some equations and theorems concerning the Lebesgue integral and the Lebesgue measure. In Section 2, we have described the possible mathematical applications, of Lebesgue... In this paper, in Section 1, we have described some equations and theorems concerning the Lebesgue integral and the Lebesgue measure. In Section 2, we have described the possible mathematical applications, of Lebesgue integration, in some equations concerning various sectors of Chern-Simons theory and Yang-Mills gauge theory, precisely the two dimensional quantum Yang-Mills theory. In conclusion, in Section 3, we have described also the possible mathematical connections with some sectors of String Theory and Number Theory, principally with some equations concerning the Ramanujan’s modular equations that are related to the physical vibrations of the bosonic strings and of the superstrings, some Ramanujan’s identities concerning π and the zeta strings. 展开更多
关键词 Lebesgue Integral Chern-Simons theory Yang-mills Gauge theory string theory Number theory
在线阅读 下载PDF
Evolution of Nielsen-Olesen's String from Chern-Simons Field Theory
2
作者 DUAN Yi-Shi SHI Xu-Guang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第7期147-150,共4页
We study the topology of Nielsen-Olesen's local field theory of single dual string.Based on the Chern-Simons field theory in three dimensons,we find many strings that can form world sheets in four dimensions.These... We study the topology of Nielsen-Olesen's local field theory of single dual string.Based on the Chern-Simons field theory in three dimensons,we find many strings that can form world sheets in four dimensions.These stringshave important relation to the zero point of the complex scalar field.These world sheets of strings can be expressed bythe topological invariant number,Hopf index,and Brower degree.Nambu-Goto's action is obtained from the Nielsen'saction definitely by usingφ-mapping theory. 展开更多
关键词 φ-mapping theory dual string Nambu-Goto’s action Hopf index Brower degree
在线阅读 下载PDF
Derivation of Multiverse from Universal Wave Function Interpretation of String Theory
3
作者 Zhi Gang Sha Rulin Xiu 《Journal of Physical Science and Application》 2017年第6期1-5,共5页
The multiverse is a hypothesis created to solve certain problems in cosmology. Currently, this scheme is still largely ad hoc, rather than derived from fundamental laws and principles. Because of this, the predictive ... The multiverse is a hypothesis created to solve certain problems in cosmology. Currently, this scheme is still largely ad hoc, rather than derived from fundamental laws and principles. Because of this, the predictive power of this theory is rather limited. Furthermore, there are concerns that this theory will make it impossible to calculate some measured quantities, such as the masses of quarks and the electron. In this paper, we will show that a new development in string theory, the universal wave function interpretation of string theory, provides a way to derive the mathematical expression of the multiverse. We will demonstrate that the Weyl invariance existing in string theory indicates that our observed universe is a projection from a hologram. We will present how the laws of physics can be derived from this fact. Furthermore, we suggest it may also provide a way to calculate the masses of fundamental particles such as quarks and the electron. 展开更多
关键词 string theory mULTIVERSE grand unification theory cosmology holographic universe universal wave function interpretation of string theory.
在线阅读 下载PDF
Cosmic String Theory: Gravity and Tension
4
作者 Greg Poole 《Journal of High Energy Physics, Gravitation and Cosmology》 2018年第2期312-322,共11页
Planets are interconnected via magnetic field lines, which allow flux transfer events. In this paper, a thought experiment is performed whereby the Sun and planets are visualized as a violin with magnetic field lines ... Planets are interconnected via magnetic field lines, which allow flux transfer events. In this paper, a thought experiment is performed whereby the Sun and planets are visualized as a violin with magnetic field lines analogous to strings of the violin. Frequency calculations for vibrating strings between the Earth and Sun compare favorably with measured satellite data for flux transfer events. Ideal Schumann Resonance was calculated using speed of light, diameter of the Earth and Earth’s gravity for tension. The force of attraction and repulsion of magnets is analogous to tension and compression resulting from tremendously low frequency (TLF) electromechanical waves. Gravity waves are thus theorized as mechanical waves brought about by the tension of electron strings, which also act dually as electromagnetic waves. Future harmonic analysis of flux transfer wave forms for each planet would add credence to the string theory as the theory of everything. 展开更多
关键词 FLUX Transfer EVENTS GRAVITY GRAVITY Wave string theory Schumann Resonance theory of Everything
暂未订购
String cosmological models in the Brans-Dicke theory for five-dimensional space-time
5
作者 Koijam Manihar Singh Kangujam Priyokumar Singh 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2012年第1期39-45,共7页
Five-dimensional space-time string cosmological models generated by a cloud of strings with particles attached to them are studied in the Brans-Dicke theory. We obtain two types of interesting models by taking up the ... Five-dimensional space-time string cosmological models generated by a cloud of strings with particles attached to them are studied in the Brans-Dicke theory. We obtain two types of interesting models by taking up the cases of geometric strings (or Nambu strings) and p-strings (Takabayasi strings), and study their different physi- cal and dynamical properties. The roles of the scalar field in getting different phases, such as the inflationary phase and the string-dominated phase, are discussed. An in- teresting feature obtained here is that in one of the models there is a "bounce" at a particular instant of its evolution. 展开更多
关键词 cosmology: theory -- string universes -- Brans-Dicke theory
在线阅读 下载PDF
Inflation Scheme Derived from Universal Wave Function Interpretation of String Theory
6
作者 Dr. Zhi Gang Sha Rulin Xiu 《Journal of Physical Science and Application》 2017年第4期33-37,共5页
Inflation is the most commonly accepted theory in cosmology to explain why the universe appears flat, homogeneous, and isotropic, as well as the origin of the large-scale structure of the cosmos and why no magnetic mo... Inflation is the most commonly accepted theory in cosmology to explain why the universe appears flat, homogeneous, and isotropic, as well as the origin of the large-scale structure of the cosmos and why no magnetic monopoles have been detected. However, so far, the origin of the inflation epoch and what is the hypothetical field, the inflation, giving rise to inflation, remains unknown. String theory is one of the promising candidates for the grand unification theory. Grand unification theory is to use one mathematic formula to describe everything. In this work, we study the inflation scheme in a new development in string theory, UWFIST (universal wave function interpretation of string theory). We show that from UWFIST we can derive from the fundamental theory that the long-range vibration is the possible candidate of inflation. We estimate the vacuum energy created by the long-range vibration and show that it can indeed drive the inflation. 展开更多
关键词 INFLATION string theory universal wave function interpretation of string theory grand unification theory.
在线阅读 下载PDF
The Relativistic Mechanic Theory of the String
7
作者 Mohamed Salem 《Journal of Modern Physics》 2015年第4期374-380,共7页
In this article, a novel speculative method is used to derive the relativistic mechanic that governs the motion of the vibrating string within the compactified-dimensions spacetime. This mechanic claims that the relat... In this article, a novel speculative method is used to derive the relativistic mechanic that governs the motion of the vibrating string within the compactified-dimensions spacetime. This mechanic claims that the relativistic mechanic of the special relativity should be only valid for the motion within the familiar four-dimensional spacetime. However, our novel mechanic is valid for the motion within the compactified-dimensions spacetime predicted by the string theory. The equations of this new mechanic show that the vibrating string can move within the compactified dimensions in a speed that is faster than light. It is also shown that this new relativistic mechanic goes to the classical Newtonian mechanic whenever the speed of the vibrating string is much less than the speed of light. Since the proposed mechanic does not prohibit the existence faster than light motion, it may uncover some of the mysteries regarding the string theory, such as the existence of tachyon and time travel. The main goal of this paper is to show that the motion within the compactified-dimensions spacetime obeys a different relativistic mechanic that will provide a startling and revolutionary perspective on the universe and answer some of the fundamental questions posed in the modern physics. 展开更多
关键词 string theory TACHYON SUPERLUmINAL motion Special RELATIVITY ELEmENTARY Particles
在线阅读 下载PDF
The Periodic Table of Elementary Particles Based on String Theory
8
作者 Ding-Yu Chung 《Journal of Modern Physics》 2014年第14期1234-1243,共10页
In this paper, all elementary particles (leptons, quarks, gauge bosons, and the Higgs boson) can be placed in the periodic table of elementary particles based on string theory with oscillating spacetime dimension numb... In this paper, all elementary particles (leptons, quarks, gauge bosons, and the Higgs boson) can be placed in the periodic table of elementary particles based on string theory with oscillating spacetime dimension number, instead of conventional string theory with fixed space-time dimension number. Dimension number oscillates between 11D and 10D and between 10D and 4D reversibly. The oscillation of space-time dimension number (D) is accompanied by mass dimension number (d) to represent mass. Space-time dimension number decreases with increasing mass dimension number, decreasing speed of light and increasing rest mass. 4D particle originally is 4D10d particle, and has the lowest speed of light and the highest rest mass. With the same energy, the relation between adjacent mass dimensions is Md-1=Mdαd2, where M is rest mass, d is mass dimension number, and α is the fine structure constant. According to the proposed cosmology, the non-gravitational 4D10d particles were sliced into 4D4d core particles surrounded by 6 separated mass dimensions as the 6 dimensional orbitals constituting the non-gravitational forces (electromagnetism, strong, and weak). The combination of the 6 dimensional orbitals and the gravitational 4D10d particle resulted in the 7 dimensional orbitals. As the periodic table of elements based on the atomic orbitals, the periodic table of elementary particles is based on the combination of the two asymmetrical sets of the 7 dimensional orbitals. One set as the principal dimensional orbitals is mainly for leptons and gauge bosons, and another set as the auxiliary orbitals is mainly for individual quarks. The calculated constituent masses of leptons, quarks, gauge bosons, and the Higgs boson are in good agreement with the observed values. For examples, the calculated mass of top quark is 176.5 GeV in good agreement with the observed 173.34 GeV, and the calculated average mass of the Higgs boson is 128.8 GeV in good agreements with the observed 125 or 126 GeV. 展开更多
关键词 The Periodic Table of ELEmENTARY Particles string theory HIGGS BOSON LEPTON QUARK Gauge BOSON
在线阅读 下载PDF
Anisotropic massive strings in the scalar-tensor theory of gravitation
9
作者 Anil Kumar Yadav 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2013年第7期772-782,共11页
We present the model of an anisotropic universe with string fluid as the source of matter within the framework of the scalar-tensor theory of gravitation. An exact solution of field equations is obtained by applying B... We present the model of an anisotropic universe with string fluid as the source of matter within the framework of the scalar-tensor theory of gravitation. An exact solution of field equations is obtained by applying Berman's law of variation to Hubble's parameter which yields a constant value of the deceleration parameter. The nature of classical potential is examined for the model under consideration. It has also been found that the massive strings dominate in the early universe and finally disap-pear from the universe. This is in agreement with current astronomical observations. The physical and dynamical properties of the model are also discussed. 展开更多
关键词 early universe -- massive strings -- scalar-tensor theory -- classicalpotential
在线阅读 下载PDF
The Reversible Cyclic Universe in the Reversible Multiverse and the Reversible String Theory
10
作者 Ding-Yu Chung 《Journal of Modern Physics》 2015年第9期1249-1260,共12页
The paper posits that the multiverse is reversible, so all universes in the multiverse are reversible cyclic universes which have the inexhaustible resources of space-time to expand. The collision of expanding univers... The paper posits that the multiverse is reversible, so all universes in the multiverse are reversible cyclic universes which have the inexhaustible resources of space-time to expand. The collision of expanding universes is permanently irreversible, forbidden in the reversible multiverse, so every universe is surrounded by the zero-energy interuniversal void as the permanent gap among universes to keep universes apart. A zero-sum energy dual universe of positive energy universe and negative energy universe can be created in the interuniversal void, and the new dual universe is again surrounded by the interuniversal void. This paper also posits the reversible string theory with oscillating space-time dimension number oscillating between 11D (space-time dimension) and 4D without the conventional compactization of string. Dimension number decreases with decreasing speed of light, decreasing vacuum energy, and increasing rest mass. The 4D and the 11D have zero and the highest vacuum energies, respectively. The universes in the reversible multiverse oscillate reversibly between high and low dimension numbers. Under symmetry breaking as in our universe, the positive energy universe as our observed universe absorbed the interuniversal void, while the negative energy universe did not. The interuniversal void has zero vacuum energy, so the absorption of the interuniversal void by the positive energy universe forced the positive energy 10D universe with high vacuum energy to be transformed into the positive energy 4D universe with zero vacuum energy, resulting in the inflation followed by the Big Bang. The negative energy universe undergoes dimension number oscillation between 4D and 10D dimension by dimension. The negative energy >4D universe is hidden, and the negative energy 4D universe appears as dark energy. The calculated percentages of dark energy, dark matter, and baryonic matter and the calculated time for dark energy to start are in good agreements with the observed values. 展开更多
关键词 CYCLIC UNIVERSE mULTIVERSE Interuniversal Void string theory Cosmology Big Bang INFLATION DARK Energy DARK matter
在线阅读 下载PDF
String Theory with Oscillating Space-Time Dimension Number
11
作者 Ding-Yu Chung 《Journal of Modern Physics》 2014年第6期464-472,共9页
In conventional string theory with fixed space-time dimension number, the extra space dimensions are compactized. In string theory with oscillating space-time dimension number, dimension number oscillates between 11D ... In conventional string theory with fixed space-time dimension number, the extra space dimensions are compactized. In string theory with oscillating space-time dimension number, dimension number oscillates between 11D and 10D and between 10D and 4D reversibly, and there is no compactization. Dimension number decreases with decreasing speed of light and increasing rest mass. The 4D particle has the lowest speed of light and the highest rest mass. The two different oscillations between 10D and 4D are the stepwise oscillation passing through every dimension number and the direct oscillation oscillating directly between 10D and 4D without the intermediate dimension numbers. Dark energy represents the stepwise oscillation, and dark energy becomes observable only when it has 4D space-time. 4D baryonic matter and 4D dark matter represent the direct oscillation directly from 10D to 4D. Our universe is the dual cyclic universe of the dark energy universe and the baryonic-dark matter universe. The Big Bang in the baryonicdark matter universe produced irreversible kinetic energy that stopped the reversible direct oscillation. The reversible direct oscillation will resume after the Big Crush to remove irreversible kinetic energy. Our cyclic universe started from the zero-energy universe through the four-stage transformation. The theoretical calculated percentages of dark energy, dark matter, and baryonic matter are 68.3, 26.4, and 5.3, respectively, in agreement with observed 68.3, 26.8, and 4.9, respectively. According to the calculation, dark energy started in 4.28 billion years ago in agreement with the observed 4.71 ± 0.98 billion years ago. 展开更多
关键词 string theory DImENSION NUmBER Oscillation Cosmology Dual UNIVERSE Big Bang INFLATION Cyclic UNIVERSE DARK Energy DARK mATTER Baryonic mATTER Force Fields
在线阅读 下载PDF
Edward Witten: The father of modern string theory
12
作者 孙启禄 《疯狂英语(新读写)》 2024年第12期27-30,75,76,共6页
Edward Witten has been described as“the most brilliant physicist of his generation”,and some even compare him to Isaac Newton.A deeply original and dedicated theoretical physicist,Witten's primary focus is strin... Edward Witten has been described as“the most brilliant physicist of his generation”,and some even compare him to Isaac Newton.A deeply original and dedicated theoretical physicist,Witten's primary focus is string theory—a“theory of everything”that proposes the universe's fundamental components are curves,or“strings”arranged in loops.in loops.He has been a leading advocate and influential contributor in this field,famously stating,“It was very clear that if I didn't spend my life concentrating on string theory,I would simply be missing my life's calling.” 展开更多
关键词 theory simply string
在线阅读 下载PDF
集中管理模式下排队论M/M/C模型输入数据精度对监护仪配置数量预测准确性的影响
13
作者 谢峰 王宇坤 +3 位作者 王晓龙 侯艺威 郭米嘉 白玫 《中国医疗设备》 2025年第4期97-101,150,共6页
目的研究集中管理模式下排队论M/M/C模型输入数据选取精度对监护仪合理配置数量预测准确性的影响。方法选取本院11个病区作为研究对象,提取医嘱时长作为监护仪实际使用时长,按照11个病区合并计算(组别1)、内外科分别合并计算(组别2)、... 目的研究集中管理模式下排队论M/M/C模型输入数据选取精度对监护仪合理配置数量预测准确性的影响。方法选取本院11个病区作为研究对象,提取医嘱时长作为监护仪实际使用时长,按照11个病区合并计算(组别1)、内外科分别合并计算(组别2)、各病区独立计算(组别3)设立对比组别,建立排队论M/M/C预测模型,结合护理要求和排队系统等待时长曲线推测监护仪配置数量预测区间,分别对比3个组别的预测区间与实际配置数量差异值。结果组别1模型预测差值最大(最大差值为7.84台,最小差值为2.45台),组别2模型预测差值次之(最大差值为6.73台,最小差值为2.27台),组别3模型预测差值最小(仅有4个病区存在差异,差值为1或3台)。3组差值之间的差异有统计学意义(H=20.768,P<0.001),组别3模型预测差值与组别1和2的模型预测差值相比均有统计学意义(P<0.001),组别1和2模型预测差值相比差异无统计学意义(P=0.465)。结论输入数据选取精度因素对排队论M/M/C模型预测准确性具有一定影响,各医疗机构在利用排队论模型测算配置数量时,应尽量提高数据选取精度,按最小病区单元选取输入数据,并在预测结果的基础上结合临床实际情况浮动实际配置数量,提升配置数量合理性。 展开更多
关键词 集中管理 数据选取精度 排队论 m/m/C模型 合理配置数量 监护仪 预测差异
暂未订购
Analysis of Japan and World Records in the 100 m Dash Using Extreme Value Theory 被引量:2
14
作者 Fumio Maruyama 《Journal of Applied Mathematics and Physics》 2021年第7期1442-1451,共10页
Extreme value theory provides methods to analyze the most extreme parts of data. We predicted the ultimate 100 m dash records for men and women for specific periods using the generalized extreme value (GEV) distributi... Extreme value theory provides methods to analyze the most extreme parts of data. We predicted the ultimate 100 m dash records for men and women for specific periods using the generalized extreme value (GEV) distribution. The various diagnostic plots, which assessed the accuracy of the GEV model, were well fitted to the 100 m records in the world and Japan, validating the model. The men’s world record had a shape parameter of -0.250 with a 95% confidence interval of [-0.391, -0.109]. The 100 m record had a finite limit and a calculated upper limit was 9.46 s. The return level estimates for the men’s world record were 9.74, 9.62, and 9.58 s with a 95% confidence interval of [9.69, 9.79], [9.54, 9.69], and [9.48, 9.67] for 10-, 100- and 350-year return periods, respectively. In one year, the probability of occurrence for a new world record of men, 9.58 s (Usain Bolt), was 1/350, while that for women, 10.49 s (Florence Griffith-Joyner), was about 1/100, confirming it was more difficult for men to break records than women. 展开更多
关键词 ATHLETICS 100 m Running Extreme Value theory GEV model
在线阅读 下载PDF
A Foundation for Lorentz Force Based on Vibrating Strings as a Compact Fluid 被引量:1
15
作者 Narahari V. Joshi 《World Journal of Mechanics》 2014年第8期247-250,共4页
Several aspects related with Lorentz force are discussed in the light of the presence of vibrating strings. Strings are considered as a compact,?tension and viscosity-free incompressible liquid. The motion of a charge... Several aspects related with Lorentz force are discussed in the light of the presence of vibrating strings. Strings are considered as a compact,?tension and viscosity-free incompressible liquid. The motion of a charge particle, obviously, represents the “line of vortex” in the medium of fluid. The term (VXB) turns out to be the natural consequence of Vortex dynamics. The present investigation also reveals the nature of the magnetic field and explains why and how this additional term takes part in Lorentz force. 展开更多
关键词 LORENTZ FORCE ORIGIN for magnetic Field FLUID Dynamics string theory
在线阅读 下载PDF
String Gauge Symmetries in the Conformally Gauge-Fixed Polyakov D1 Brane Action in the Presence of Background Gauge Fields 被引量:1
16
作者 Usha Kulshreshtha Daya Shankar Kulshreshtha 《Journal of Modern Physics》 2012年第1期110-115,共6页
Recently we have studied the instant-form quantization (IFQ) and the light-front quantization (LFQ) of the conformally gauge-fixed Polyakov D1 brane action using the Hamiltonian and path integral formulations. The IFQ... Recently we have studied the instant-form quantization (IFQ) and the light-front quantization (LFQ) of the conformally gauge-fixed Polyakov D1 brane action using the Hamiltonian and path integral formulations. The IFQ is studied in the equal world-sheet time framework on the hyperplanes defined by the world- sheet time σ0 = τ = constant and the LFQ in the equal light-cone world-sheet time framework, on the hyperplanes of the light-front defined by the light-cone world-sheet time . The light-front theory is seen to be a constrained system in the sense of Dirac in contrast to the instant-form theory. However, owing to the gauge anomalous nature of these theories, both of these theories are seen to lack the usual string gauge symmetries defined by the world-sheet reparametrization invariance (WSRI) and the Weyl invariance (WI). In the present work we show that these theories when considered in the presence of background gauge fields such as the NSNS 2-form gauge field or in the presence of gauge field and the constant scalar axion field , then they are seen to possess the usual string gauge symmetries (WSRI and WI). In fact, these background gauge fields are seen to behave as the Wess-Zumino/Stueckelberg fields and the terms containing these fields are seen to behave as Wess-Zumino or Stueckelberg terms for these theories. 展开更多
关键词 Light-Front QUANTIZATION Hamiltonian QUANTIZATION Path Integral QUANTIZATION Constrained Dynamics Constraint QUANTIZATION GAUGE SYmmETRY string GAUGE SYmmETRY string theory D-BRANE Actions Polyakov Action LIGHT-CONE QUANTIZATION
在线阅读 下载PDF
Detailed string stability analysis for bi-directional optimal velocity model 被引量:1
17
作者 郑亮 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第4期1563-1573,共11页
The class of bi-directional optimal velocity models can describe the bi-directional looking effect that usually exists in the reality and is even enhanced with the development of the connected vehicle technologies. It... The class of bi-directional optimal velocity models can describe the bi-directional looking effect that usually exists in the reality and is even enhanced with the development of the connected vehicle technologies. Its combined string stability condition can be obtained through the method of the ring-road based string stability analysis. However, the partial string stability about traffic fluctuation propagated backward or forward was neglected, which will be analyzed in detail in this work by the method of transfer function and its H∞ norm from the viewpoint of control theory. Then, through comparing the conditions of combined and partial string stabilities, their relationships can make traffic flow be divided into three distinguishable regions, displaying various combined and partial string stability performance. Finally, the numerical experiments verify the theoretical results and find that the final displaying string stability or instability performance results from the accumulated and offset effects of traffic fluctuations propagated from different directions. 展开更多
关键词 traffic flow string stability optimal velocity model linearized stability theory transfer function
在线阅读 下载PDF
Theory of Quantum Relativity 被引量:1
18
作者 Sudhanva Joshi 《Journal of Quantum Information Science》 2016年第4期249-262,共15页
In this paper, I have studied the properties of atomic and molecular world along with general and special theories of relativity. This is an attempt to merge Gravity into the standard model in order to complete the Gr... In this paper, I have studied the properties of atomic and molecular world along with general and special theories of relativity. This is an attempt to merge Gravity into the standard model in order to complete the Grand Unification Theory. The merger of gravity into the other forces i.e. electromagnetic, strong and weak nuclear forces should be well defined and in the boundaries of Gauge Group theory. The Lorentz transformations used in the theory too are invariant under SU(2) type of space. The relative force exerted on two separate quantum systems is also discussed along with Dark matter and Dark energy at a quantum level. I have also tried to solve the Banach-Tarski theorem by applications of Heisenbergs Uncertainty principle in the later part of the paper. Detailed particle Chirality in standard model is redefined to fit in the criterion of operators used in the same process. Possible existence of a new quasi particle is also included in the paper along with its properties. 展开更多
关键词 Gauge-Group theory string theory G-Bosons Quantum Relativity
在线阅读 下载PDF
The Efficient Market Theory and Mergers and Acquisitions (M&As) Puzzle: Evidence From Italy 被引量:1
19
作者 Domenico Celenza Fabrizio Rossi 《Journal of Modern Accounting and Auditing》 2012年第11期1704-1711,共8页
The efficient market theory is a central point in finance. If the capital market is competitive, the investors cannot expect superior gains from their investment strategies with respect to the risk profile. Event stud... The efficient market theory is a central point in finance. If the capital market is competitive, the investors cannot expect superior gains from their investment strategies with respect to the risk profile. Event studies are an approach to verify the impact of the information on the stock prices. In an efficient market, stock prices should fully, promptly, and quickly capture all the information. Instead, the market shows phenomena of an under-reaction and over-reaction for both the short and the long run. The mergers and acquisitions (M&As) are examples of anomalies. Often, the bidder companies record the negative abnormal returns for both the short and the long run. In contrast to the efficient market theory, the empirical evidence shows that this phenomenon is widespread in all (or most of) the countries of the world. This work examines the long-run performance in M&As. For this purpose, 40 bidders were observed in Italy during the period of 1994-2008 among listed companies. The buy and hold abnormal returns (BHARs) methodology was used, with which it was possible to observe the returns for three years following the deal. 展开更多
关键词 efficient market theory mergers and acquisitions m&As) portfolio choice investment decisions buyand hold abnormal returns (BHARs) long-run performance Italian stock market
在线阅读 下载PDF
Quasilocal Energy for Static Charged Black Holes in String Theory
20
作者 WANG Shi-Liang JING Ji-Liang WANG Yong-Jiu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2001年第7期125-128,共4页
The Brown-York quasilocal energies of some static charged dilaton black holes are calculated, and then the validity of Martinez's conjecture is explored in string theory. It is shown that the energy is positive an... The Brown-York quasilocal energies of some static charged dilaton black holes are calculated, and then the validity of Martinez's conjecture is explored in string theory. It is shown that the energy is positive and monotonically decreases to the ADM mass at spatial infinity, and the conjecture that the Brown-York quasilocal energy at the outer horizon of black hole reduces to twice of its irreducible mass is still applicable for the static charged black holes in string theory. The result is different from Bose-Naing's one. 展开更多
关键词 quasilocal energy BLACK hole string theory
在线阅读 下载PDF
上一页 1 2 37 下一页 到第
使用帮助 返回顶部