Conjecture on Avoidance of Big Crunch

By conjecturing the physics at the Planck scale, we modify the definition of the Hawking temperature and modify the Friedmann equation. It is found that we can avoid the singularity of the big crunch and obtain a bouncing cosmological model.     

Inflation — an alternative to the singular Big Bang

Domains larger than the horizon in which > (a few) ×M _pl are required for the onset of inflation. Two different, equally plausible, arguments lead us to opposite conclusions about the feasibility of the existence of such regions. It seems that inflation does not free us completely from the need for special initial conditions. However, Linde has pointed out that inflation can be eternal. He stresses the fact that inflation will never cease, but this also means that it did not necessarily have a beginning. We argue that this is the simplest solution to the initial value problem and that inflation might not only solve the problems of the Big Bang model, it might also provide us with an alternative that will replace it altogether.This essay received the third award from the Gravity Research Foundation, 1990 —Ed.     

What Would Be Outcome of a Big Crunch?

I suggest the existence of a still undiscovered interaction: repulsion between matter and antimatter. The simplest and the most elegant candidate for such a force is gravitational repulsion between matter and antimatter. I argue that such a force may give birth to a new Universe; by transforming an eventual Big Crunch of our Universe, to an event similar to Big Bang. In fact, when a collapsing Universe is reduced to a supermassive black hole of a small size, a very strong field of the conjectured force may create particle-antiparticle pairs from the surrounding quantum vacuum. The amount of antimatter created from the physical vacuum is equal to the decrease of mass of “black hole Universe” and violently repelled from it. When the size of the black hole is sufficiently small, the creation of antimatter may become so huge and fast, that matter of our Universe may disappear in a fraction of the Planck time. So fast transformation of matter to antimatter may look like a Big Bang with initial size about 30 orders of magnitude greater than the Planck length, questioning the need for inflation. In addition, a Big Crunch, of a Universe dominated by matter, leads to a new Universe dominated by antimatter, and vice versa; without need to invoke CP violation as explanation of matter-antimatter asymmetry. Simply, our present day Universe is dominated by matter, because the previous Universe was dominated by antimatter.     

Can renormalization group flow end in a Big Mess?

The field theoretical renormalization group equations have many common features with the equations of dynamical systems. In particular, the manner how Callan–Symanzik equation ensures the independence of a theory from its subtraction point is reminiscent of self-similarity in autonomous flows towards attractors. Motivated by such analogies we propose that besides isolated fixed points, the couplings in a renormalizable field theory may also flow towards more general, even fractal attractors. This could lead to Big Mess scenarios in applications to multiphase systems, from spin-glasses and neural networks to fundamental string (M?) theory. We consider various general aspects of such chaotic flows. We argue that they pose no obvious contradictions with the known properties of effective actions, the existence of dissipative Lyapunov functions, and even the strong version of the c-theorem. We also explain the difficulties encountered when constructing effective actions with chaotic renormalization group flows and observe that they have many common virtues with realistic field theory effective actions. We conclude that if chaotic renormalization group flows are to be excluded, conceptually novel no-go theorems must be developed.     

应用Big6模式组织设计性、综合性物理实验教学

结合Big6模式以"测量透明介质折射率"实验中的操作为实例,介绍Big6模式的一般操作流程,论证教师和学生在实验教学活动中角色的转变符合现代教育理念的要求,并总结出了若干经验.应用Big6模式组织设计性、综合性物理实验的教学活动,可以较好地解决此类实验教学缺少系统理论指导的现状.     

Big Bounce Singularity of a Simple Five—Dimensional Cosmological Model

The big bounce singularity of a simple five-dimensional cosmological model is studied.Contrary to the standard big bang space-time singularity,this big bounce singularity is found to be an event horizon at which the scale factor and the mass density of the universe are finite,while the pressure undergoes a sudden transition from negative infinity to positive infinity.By using coordinate transformation it is also shown that before the bounce the universe contracts deflationary.According to the proper-time,the universe may have existed for an infinitely long time.     

Why Do Big Data and Machine Learning Entail the Fractional Dynamics?

Fractional-order calculus is about the differentiation and integration of non-integer orders. Fractional calculus (FC) is based on fractional-order thinking (FOT) and has been shown to help us to understand complex systems better, improve the processing of complex signals, enhance the control of complex systems, increase the performance of optimization, and even extend the enabling of the potential for creativity. In this article, the authors discuss the fractional dynamics, FOT and rich fractional stochastic models. First, the use of fractional dynamics in big data analytics for quantifying big data variability stemming from the generation of complex systems is justified. Second, we show why fractional dynamics is needed in machine learning and optimal randomness when asking: “is there a more optimal way to optimize?”. Third, an optimal randomness case study for a stochastic configuration network (SCN) machine-learning method with heavy-tailed distributions is discussed. Finally, views on big data and (physics-informed) machine learning with fractional dynamics for future research are presented with concluding remarks.     

Temperature coefficient of resistance and thermal conductivity of Vanadium oxide ‘Big Mac’ sandwich structure

In this paper, we synthesize and characterize a thin film thermometer structure for infrared microbolometers. The structure is composed of alternating multilayers of Vanadium pentoxide (V₂O₅), 25 nm, and Vanadium (V), 5 nm, thin films deposited by rf magnetron and dc magnetron sputtering respectively and annealed for 20, 30 and 40 min at 300 °C in Nitrogen (N₂) atmosphere. The best achieved temperature coefficient of resistance (TCR) was found to be −2.57%/K for 40 min annealed samples. Moreover, we apply, for the first time, the photo-thermal deflection (PTD) technique for measuring the thermal conductivity of the synthesized thin films. The thermal conductivity of the developed thin films reveals an increase in thermal conductivity from 2 W/m K to 5.8 W/m K for as grown and 40 min annealed samples respectively.     

Small Stress Change Triggering a Big Earthquake： a Test of the Critical Point Hypothesis for Earthquakes

Whether or not a small stress change can trigger a big earthquake is one of the most important problems related to the critical point hypothesis for earthquakes. We investigate global earthquakes with different focM mechanisms which have different levels of ambient shear stress. This ambient stress level is the stress level required by the earthquakes for their occurrence. Earthquake pairs are studied to see whether the occurrence of the preceding event encourages the occurrence of the succeeding one in terms of the Coulomb stress triggering. It is observed that the stress triggering effect produced by the change of Coulomb failure stress in the same order of magnitudes,about 10-2 MPa, is distinctly different for different focal mechanisms, and thus for different ambient stress levels.For non-strike-slip earthquakes with a relatively low ambient stress level, the triggering effect is more evident,while for strike-slip earthquakes with a relatively high ambient stress level, there is no evident triggering effect.This water level test provides an observational support to the critical point hypothesis for earthquakes.     

The Archaic Universe: Big Bang,Cosmological Term and the Quantum Origin of Time in Projective Cosmology

This article proposes some cosmological reflections at the qualitative and conjectural level, suggested by the Fantappié-Arcidiacono projective relativity theory. The difference will firstly be discussed between two types of singularity in this theory: geometric (de Sitter horizon) and physical (big bang, big crunch). The reasons for the existence of geometric singularities are deeply rooted in the principle of inertia and in the principle of relativity, while physical singularities are associated with the creation or destruction of matter. In this framework, quantum mechanics is introduced through a particular interpretation of Bohm’s holomovement. Finally, a possible mechanism is discussed for the genesis of the cosmological term. No form of inflation appears in the scenario described.     

AstrophysicalS(E) factor of8Li (α,n 0)11B and inhomogeneous Big Bang nucleosynthesis

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.