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1.
The 2nd Law of thermodynamics was driven by the Big Bang being extraordinary special, with hugely suppressed gravitational degrees of freedom. This cannot have been simply the result of a conventional quantum gravity. Conformal cyclic cosmology proposes a different picture, of a classical evolution from an aeon preceding our own. The ultimate Hawking evaporation of black holes is key to the 2nd Law and requires information loss, violating unitarity in a strongly gravitational context.  相似文献   

2.
If one defines the size of the present universe in terms of a hypersurface of simultaneity generated by the spatial geodesies orthogonal to our world line today, then it is finite in all expanding Big Bang Friedmann models.  相似文献   

3.
A spacetime region of size about 10?33 cm, where the gravitation interaction becomes strong and which corresponds to the very beginning of the Big Bang theory, is discussed. It is argued for incognizablility of laws that govern phenomena proceeding in this region. It is assumed that basic changes in the entropy, which determine the direction of the time arrow, occur in the same region; therefore, their nature will never be established either. It is conjectured that brain cells are controlled by a quantum computer featuring a large (or even an indefinitely) large number of degenerate states. An external observation removes this degeneracy, rendering impossible the cognition of the consciousness mechanism.  相似文献   

4.
We review gamma-ray observations that constrain antimatter – both baryonic and leptonic - in the Universe. Antimatter is probed through ordinary matter, with the resulting annihilation gamma-rays providing indirect evidence for its presence. Although it is generally accepted that equal amounts of matter and antimatter have been produced in the Big Bang, gamma-rays have so far failed to detect substantial amounts of baryonic antimatter in the Universe. Conversely, positrons are abundantly observed through their annihilation in the central regions of our Galaxy and, although a wealth of astrophysical sources are plausible, their very origin is still unknown. As both antimatter questions – the source of the Galactic positrons and the baryon asymmetry in the Universe - can be investigated through the low energy gamma-ray channel, the mission concept of a dedicated space telescope is sketched out.  相似文献   

5.
The cross section of the11B(n, α)8Li reaction has been measured atE n=7.6 to 12.6 MeV. The neutron beam was produced via theD(d, n)3He reaction and aBF 3 counter (with naturalB isotopic composition) served both as target for the11B nuclides and as detector for the observation of the delayedα-activity of8Li. The data match well with previous results obtained atE n =12.5 to 20.0 MeV. Using the principle of detailed balance the data were converted to the case of the8Li(α, n 0)11B reaction. The associated astrophysicalS(E) factor is dominated by a resonance atE R=0.58 MeV of widthΓ R =200 keV, withS(E R )=8400 MeV b. ThisS (E R ) value for the n0 channel alone is already three times higher than the constantS(E) factor assumed previously and, thus, strengthens the significance of inhomogeneous Big Bang nucleosynthesis.  相似文献   

6.
We suggest that the Big Bang could be a result of the first-order phase transition driven by a change in the scalar curvature of the 4D spacetime in an expanding cold Universe filled with a nonlinear scalar field φ and neutral matter with an equation of state p = νε (where p and ε are the pressure and energy density of the matter, respectively). We consider the Lagrangian of a scalar field with nonlinearity φ4 in a curved spacetime that, along with the term–ξR|φ|2 quadratic in φ (where ξ is the interaction constant between the scalar and gravitational fields and R is the scalar curvature), contains the term ξRφ0(φ + φ+) linear in φ, where φ0 is the vacuum mean of the scalar field amplitude. As a consequence, the condition for the existence of extrema of the scalar-field potential energy is reduced to an equation cubic in φ. Provided that ν > 1/3, the scalar curvature R = [κ(3ν–1)ε–4Λ] (where κ and Λ are Einstein’s gravitational and cosmological constants, respectively) decreases with decreasing ε as the Universe expands, and a first-order phase transition in variable “external field” parameter proportional to R occurs at some critical value R c < 0. Under certain conditions, the critical radius of the early Universe at the point of the first-order phase transition can reach an arbitrary large value, so that this scenario of unrestricted “inflation” of the Universe may be called “hyperinflation.” After the passage through the phase-transition point, the scalar-field potential energy should be rapidly released, which must lead to strong heating of the Universe, playing the role of the Big Bang.  相似文献   

7.
Following Einstein’s definition of Lagrangian density and gravitational field energy density (Einstein in Ann Phys Lpz 49:806, 1916, Einstein in Phys Z 19:115, 1918, Pauli in Theory of Relativity, B.I. Publications, Mumbai, 1963), Tolman derived a general formula for the total matter plus gravitational field energy (P 0) of an arbitrary system (Tolman in Phys Rev 35:875, 1930, Tolman in Relativity, Thermodynamics &; Cosmology, Clarendon Press, Oxford, 1962, Xulu in hep-th/0308070, 2003). For a static isolated system, in quasi-Cartesian coordinates, this formula leads to the well known result \({P_0 = \int \sqrt{-g} (T_0^0 - T_1^1 - T_2^2 - T_3^3) d^3 x,}\) where g is the determinant of the metric tensor and \({T^a_b}\) is the energy momentum tensor of the matter. Though in the literature, this is known as “Tolman Mass”, it must be realized that this is essentially “Einstein Mass” because the underlying pseudo-tensor here is due to Einstein. In fact, Landau–Lifshitz obtained the same expression for the “inertial mass” of a static isolated system without using any pseudo-tensor at all and which points to physical significance and correctness of Einstein Mass (Landau, Lifshitz in The Classical Theory of Fields, Pergamon Press, Oxford, 1962)! For the first time we apply this general formula to find an expression for P 0 for the Friedmann–Robertson–Walker (FRW) metric by using the same quasi-Cartesian basis. As we analyze this new result, it transpires that, physically, a spatially flat model having no cosmological constant is preferred. Eventually, it is seen that conservation of P 0 is honoured only in the static limit.  相似文献   

8.
The 2S 1/2-2P 1/2 Lamb-shift in hydrogenlike Sulfur was measured with a field quench technique. A high velocity beam of S15+-ions (v/c=0.086) prepared in the metastable 2S 1/2 state crosses a homogeneous magnetic field of about 1.8 Tesla. The strong electric field of 4·107 V/m in the rest frame of the ions mixes the longlived 2S 1/2-state (τ=7.18 nsec) with the short lived 2P 1/2-state (τ=2.4·10?5 ns). From the measured lifetime of the thus quenched 2S 1/2-state a Lamb-shift value of 25.14±0.24 THz is derived and compared with theoretical predictions.  相似文献   

9.
On the Rates of Advance of Clocks on the Rotating Earth In 1905 ALBERT EINSTEIN came from his Special Theory of Relativity to the conclusion that a “balance clock” located at the earth's equator is somewhat slowed down compared with a clock resting at one of the earth's poles P (see Fig. 2 below). But interestingly, this retardation of time is fully compensated by an opposing gravitational effect which (according to the General Theory of Relativity, discovered later by EINSTEIN, 1908 - 1915) causes all (atomic) clocks even at any point A on earth's surface at normal sea-level at arbitrary latitudes φ to advance at the same rate as the clock at the pole: The kinematic time-dilatation of a clock A moving with the velocity v of the earth's daily revolution around its axis turns out to be precisely equal in magnitude to the acceleration of the advance of the same clock A with respect to the clock at P due to the gravitational potential-difference between A and P, resulting from the ellipsoidal figure of the rotating earth. These two variations in the clock-rates, amounting relatively to 1/2 (v/c)2, where c denotes the velocity of light in vacuum, exactly cancel each other. Furthermore the so called clock-paradox and the Hafele-Keating-Experiment are rediscussed in a somewhat different way than usual.  相似文献   

10.
The Telescopical Principles in the Theory of Gravitation. (Machs Principle, Relativity of Inertia According to Mach and Einstein and Hertz' Mechanics) We give an explication and analytical formulation of Mach's principle of the “relativity of inertia” and of the Mach-Einstein doctrine on the determination of inertia by gravitation. These principles are whether “philosophical” nor “epistemological” postulates but well defined physical axioms with exactly analytical expressions. - The fundamental principle is the Galileian “reciprocity of motions”. According to this “generalized Galilei invariance” the principal functions of analytical dynamics (Lagrangian L and Hamiltonian H) are depending upon the differences ??AB of the coordinate vectors ??A and ??B of the velocity differences ??AB = ??A-??B, only. The Galileian reciprocity of motions means that whether the vectors ??A and ??A nor the accelerations ??A of one particle have a physical significance. A mechanics obtaining this generalized Gailei-invariance cannot depend upon a kinematical Term \documentclass{article}\pagestyle{empty}\begin{document}$ T = \frac{1}{2}\mathop {\Sigma m_A \mathop r\nolimits_A^2}\limits_A $\end{document} in the Lagrangian. Therefore, the inertial masses of the particles must be homogeneous function of interaction potentials ΦA,B. According to the Einsteinian equivalence of inertia and gravity these interactions have to be the Newtonian gravitation. In a universe with N mass points the Mach-Einsteinian Lagrangian for our “gravodynamics without inertia” is In such a Mach-Einstein universe the celestical dynamics becomes in the first approximation the Newtonian dynamics, in the second (the “post-Newtonian”) approximation the general relativistic Einstein effects are resulting.-However, our gravodynamics gives new effects for large masses (no gravitational collapses) and in cosmology (secular accelerations a.o.). Generally, the space of our gravodynamics is whether the Newtonian “absolute space” V3 nor the relativistic Einstein-Minkowski world V4 but the Hertzian configuration space V3N of the N particles. According to the relativity of inertia the Hertzian metrics become Riemannian metrics which are homogenous functions of the Newtonian gravitational potentials. .  相似文献   

11.
The high-temperature heat capacity of Bi4Si3O12, Bi2SiO5, and Bi12SiO20 has been investigated. It has been found that there is a correlation between the specific heat C p 0 (298 K) and the composition of oxides in the Bi2O3-SiO2 system.  相似文献   

12.
One of the major challenges faced by antimonide-based devices is a result of the large number of surface states that are generated. Surface passivation and subsequent capping of the surfaces are essential for any practical applicability of this material system, as evidenced by the comparison of unpassivated and passivated InAs/GaSb superlattice mid-infrared photodiodes herein. The surface passivation methods include silicon dioxide (SiO2) coating after anodic sulfide, SiO2 coating after anodic oxide, SiO2 coating only, zinc sulfide (ZnS) coating after anodic sulfide, and ZnS coating after ammonium sulfide [(NH4)2S] chemical passivation. The leakage current as a function of bias voltage (IV) for superlattice diodes obtained using different passivation methods has been examined at 77 K. The best performance was demonstrated by the SiO2 after anodic sulfide passivation. The leakage current of the passivated diode is four orders of magnitudes less than that of the unpassivated diode.  相似文献   

13.
We report on measurements of the energy loss of ions in matter by “Inverted Doppler Shift Attenuation” (IDSA). This new method is an inversion of the “Doppler Shift Attenuation” (DSA) method for the determination of lifetimes of nuclear states. While in DSA the exact knowledge of the velocity dependent energy loss functiondE/ds is required, it is shown that in IDSA this function or the absolute collision cross section, respectively, can be determined from the Doppler spectrum of an excited nuclear fragment recoiling in matter, whose lifetime is known. No corrections or assumptions concerning the collision processes are necessary. 7Li* fragments (E γ=478 keV) from the10B(n, α)7Li* reaction produce an easily observable and analysable Doppler spectrum. Here boron must be a constituent or an implanted impurity of the material to be investigated. The experimental set-up is described. An exact relativistic analysis of the Doppler spectrum is given. The measured collision cross sections turn out (a) to be proportional tov within the range 1.5 · 108v≦4.8 · 108 cm/sec, (b) are thus only due to pure “electronic” collisions, and (c) sensitively dependent on the charge distributions of the target atoms.  相似文献   

14.
The goal of continuous ambient participate monitoring has been accomplished by the use of terahertz(THz)wave.The frequency-dependent spectrum and absorbance of the particulate matter(PM2.5)were measured in the range of 0–10 THz.The PM2.5 concentration was calculated according to the sampling time and air flow.With the increase of,the THz wave amplitude gradually decreased and the absorbance A of PM2.5 increased.The relationship between and A can be described mathematically through A0.5.Our results demonstrate that the terahertz wave could be a valuable tool to monitor and inspect the PM2.5 concentration.  相似文献   

15.
A technique has been developed for dopant concentration depth profiling using static Secondary Ion Mass Spectrometry (SIMS), and an ex-situ ion milling facility to produce “tapers” through the region of interest of an optical waveguide sample. Results have been obtained for titanium-diffused optical waveguides in lithium niobate and for potassium and caesium ion-exchanged glass waveguides. The SIMS profiles have been compared with refractive index profiles in multimode structures. The refractive index profiles have been obtained from the waveguide mode spectra by a piecewise linear Wentzel-Kramers-Brillouin (WKB) method. The two profiles are in close agreement. Use of the SIMS technique for single mode Ti∶LiNbO3 waveguides has revealed significant changes in the forms of the profiles, compared with deeper structures, and we suggest a mechanism to account for these changes.  相似文献   

16.
Self-consistent density functional theory calculations of band spectra, densities of states as well as the spatial distribution of valence electron charge density were carried out for the low-pressure α-phase and the high-pressure β-phase of SiS2. Group-theoretical analysis performed for both phases enabled the symmetry of wave functions in a number of high-symmetry points of the Brillouin zone as well as the structure of valence band representations to be found. Based on the calculations of the band structure, the orthorhombic α-phase of SiS2 was determined to be an indirect-gap semiconductor with the band gap E gi = 2.44 eV (T 1 → X 8 transition), while the β-phase was shown to be direct gap with E gd = 2.95 eV (Г 3 → Г 2 transition). The calculated energy distribution of the total density of states in the valence band of α-SiS2 qualitatively and quantitatively correlates with the main experimental features of the X-ray photoelectron spectrum.  相似文献   

17.
The exact agreement between the Sommerfeld and Dirac results for the energy levels of the relativistic hydrogen atom (the “Sommerfeld Puzzle”) is analyzed and explained.  相似文献   

18.
Some speculations on a causal model that could provide a common conceptual foundation for relativity, gravitation, and quantum mechanics are presented. The present approach is a unification of three theories, the first being the repulsive theory of gravitational forces first proposed by Lesage in the eighteenth century. Lesage attempted to explain gravitational forces from the principle of conservation of momentum of some hypothetical particles, which we shall call gravitons. These gravitons, whose density is assumed homogenous, are constantly colliding with objects. The gravitational force is caused by a shielding effect of bodies when they are near each other. One also can make a clear physical distinction between an accelerating and a nonaccelerating object from this viewpoint. The second of these theories is the Brownian motion theory of quantum mechanics or stochastic mechanics, which treats the nondeterministic nature of quantum mechanics as being due to a Brownian motion of all objects. This Brownian motion being caused by the statistical variation in the graviton flux. The above two theories are unified in this article with the causal theory of special relativity. Within the present context, the time dilations (and other effects) of relativity are explained by assuming that the rate of a clock is a function of the total number or intensity of gravitons and the average frequency or energy of the gravitons that the clock receives. Two clocks having some relative velocity in the same intensity gravitational field would then have a different rate because the average frequency of the gravitons would be different for each clock owing to the Doppler effect. That is, they would essentially be in different fields considering both the frequency and intensity. The special theory would then be the special case of the general theory where the intensity is constant but the average frequency varies. In all the previous it is necessary to assume a particular model of the creation of the universe, namely the Big Bang theory. This assumption gives us the existence of a preferred reference frame, the frame in which the Big Bang explosion was at rest. The above concepts of graviton distribution and real time dilations become meaningful by assuming the Big Bang theory along with this preferred frame. An experimental test is proposed.  相似文献   

19.
The effect of different types of annealing (thermal or pulsed photon) of V x O y /InP structures synthesized using vanadium pentoxide gel on the process of their thermal oxidation, and the phase composition and morphology of the films are studied by the methods of X-ray phase analysis (XRD), Auger electron spectroscopy (AES), and scanning tunneling microscopy (STM). Thermal annealing makes it possible to synthesize films with a smoother surface relief in the absence of film-substrate interaction before thermal oxidation. Pulsed photon treatment compared with thermal annealing leads to more effective and rapid crystallization of the amorphous phase of the V2O5 gel and faster growth of oxide films during the thermal oxidation of V x O y /InP structures. As a result, pulsed photon treatment leads to the formation of InVO4 as a product of the interaction between the semiconductor substrate and the chemostimulator, which is an attribute of the “hard” methods of chemostimulator deposition, i.e., magnetron sputtering and electric explosion of the conductor.  相似文献   

20.
We consider a possible scenario for the evolution of the early cold Universe born from a fairly large quantum fluctuation in a vacuum with a size a 0 ? l P (where l P is the Planck length) and filled with both a nonlinear scalar field φ, whose potential energy density U(φ) determines the vacuum energy density λ, and a nonideal Fermi gas with short-range repulsion between particles, whose equation of state is characterized by the ratio of pressure P(n F ) to energy density ε(n F ) dependent on the number density of fermions n F . As the early Universe expands, the dimensionless quantity ν(n F ) = P(n F )/ε(n F ) decreases with decreasing n F from its maximum value νmax = 1 for n F → ∞ to zero for n F → 0. The interaction of the scalar and gravitational fields, which is characterized by a dimensionless constant ξ, is proportional to the scalar curvature of four-dimensional space R = κ[3P(n F )–ε(n F )–4λ] (where κ is Einstein’s gravitational constant), and contains terms both quadratic and linear in φ. As a result, the expanding early Universe reaches the point of first-order phase transition in a finite time interval at critical values of the scalar curvature R = R c =–μ2/ξ and radius a c ? a 0. Thereafter, the early closed Universe “rolls down” from the flat inflection point of the potential U(φ) to the zero potential minimum in a finite time. The release of the total potential energy of the scalar field in the entire volume of the expanding Universe as it “rolls down” must be accompanied by the production of a large number of massive particles and antiparticles of various kinds, whose annihilation plays the role of the Big Bang. We also discuss the fundamental nature of Newton’ gravitational constant G N .  相似文献   

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