| 如果一艘飞船从地面起飞飞一圈后再回到地球，从地面上计算该飞船上的时钟走得是快是慢，该考虑哪些因素（如，速度、加速度、引力场等）？不要求作具体计算，只要说明要考虑哪些因素即可。 请相对论的支持者们最好想好了后再说。因为当你们回答完后，我还会继续问问题。 （沈建其先生最好能回答。前期我提过不少问题，你似乎都没有回答） 黄德民2002。1。3 |
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我利用狭义相对论这么解释双生子现象： 双生子现象的狭义相对论解释如下：
明显，哥哥认为弟弟的当地时间小于哥哥的当地时间。
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| 如果一艘飞船从地面起飞飞一圈后再回到地球，从地面上计算该飞船上的时钟走得是快是慢，该考虑哪些因素（如，速度、加速度、引力场等）？不要求作具体计算，只要说明要考虑哪些因素即可。 请相对论的支持者们最好想好了后再说。因为当你们回答完后，我还会继续问问题。 （沈建其先生最好能回答。前期我提过不少问题，你似乎都没有回答） 黄德民2002。1。3 |
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查看一下钟慢公式。 钟慢公式与质速关系式中的U是指加速度了，加速度才能钟慢有贡献。依你看来，加速度才可造成钟慢与质增，而匀速运动是不会发生以上两效应的了？U与a有何区别呢？我想爱氏也知道。既是加速度就应有a表示，何苦有U呢？另钟慢是狭义相对论的结论，而狭义相对论是描述匀速运动的情况，我想对于这点大家是共知的，加速是广义相对论的事了。广义相对论对加速又是另一回事了，结果也是不一样的。总之，不是你所想象的。 ※※※※※※ 逆子 |
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回复:你们上当了，此问题是属于“猪八戒他二姨还姓猪，该考虑哪些因素？”之类的问题。 你们上当了，此问题是属于“猪八戒他二姨还姓猪，该考虑哪些因素？”之类的问题。 （1）按你们理解的狭义相对论，应该是在高速情况下才有效。而此飞船是低速的，与狭义相对论无关。从而，也就无所谓什么“钟慢”的问题。 （2）此问题可以转换为“在弱引力场里一个质点以低速走的轨迹是‘心脏线’”，所以有加速与曲线匀速运动的情况。就是此飞船是在高速的情况，此情况也与狭义相对论无关。因为，狭义相对论还没有涉及此种轨迹与加速的情况。此情况已经超出了狭义相对论的适用范围。任何真理如果超出了它的限度就会成为“谬误”，我想你们都知道此格言吧，怎么在此问题上，此格言就“失效”了呢！ （3）我说过，狭义相对论实质是“信号”，那么，此问题是模糊的。此问题没有确定信号的载体是其一；其二是没有确定地球上的起飞的地点是信号源还是飞船是信号源；其三是其“信号”是单程的还是双程也没有确定。 （4）如果还用“钟”这个词，还容易造成思维的模糊。如果真像有人说的，爱因斯坦在四岁时还不会说话的话，我真的怀疑爱因斯坦在语言表达能力上有点问题（在心理学上有白痴天才之说。反正爱因斯坦已经死了，我不怕他在此讨论区再回复骂我的。）。爱因斯坦用什么“尺”什么“钟”来表达他的狭义相对论思想，容易给读者造成许多的误解。实际上用原来的“空间间隔”与“时间间隔”的词本身就容易说明白他的狭义相对论的思想。 （5）狭义相对论还是应该“倒”。但是，我“倒”的角度（如果我要想“倒”的话），是超出了它的限度的方面。目前中国放映的名字叫“宇宙与人”的电视科普片里，其中还是说什么“接近光速是情况下，人的寿命会延长的说法”，我实在是“视可忍孰不可忍”。如此的欺骗科学大众，何谓科普！科学与伪科学没有了界限。 |
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沈先生，你的意思是不是速度、引力等因素都不用考虑了？ 你如何看待狭义相对论的钟慢公式？这儿的钟慢不是由速度引起的吗？ 黄德民 |
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GUOJIA,何时又有速度对钟慢无影响的观点了？你如何理解钟慢效应？ |
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我利用狭义相对论这么解释双生子现象： 双生子现象的狭义相对论解释如下：
明显，哥哥认为弟弟的当地时间小于哥哥的当地时间。
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| Gravitational Meissner effect and topological dual mass in gravity vacuum Jian Qi Shen1, Hong Yi Zhu1,2 1. Zhejiang Institute of Modern Physics & Department of Physics of Zhejiang University, Hangzhou 310027, P.R.China 2.State Key Laboratory of Modern Optical Instrumentation, Center for Optical and Electromagnetic Research, College of Information Science and Engineering, Zhejiang University, Hangzhou 310027, P.R.China According to quantum field theory, vacuum possesses infinite zero-point energy density due to quantum fluctuations; according to Einstein theory of general relativity, this energy density yields extreme space-time curvature of vacuum. But in fact, spacetime of vacuum is asymptotically flat. It is believed that cosmological constant cannot exactly cancel the gravitational effect of vacuum energy because of their different physical origins. In the present letter, analogy between the weak-gravitational theory and London electrodynamics of superconductivity leads us to consider the gravitational analogues of Dirac monopole (magnetic charge) in electrodynamics and the Meissner effect in superconductivity, namely, we investigate the dynamics of the topological dual mass (gravitomagnetic charge) and gravitational Meissner effect in perfect fluid-gravity coupling. We show that at least in the weak-gravity case, investigation of gravitational Meissner effect and gravitational effect of dual mass (should such exist) provides an valuable insight in to problems of cosmological constant and vacuum gravity. Since gravitomagnetic charge of vacuum quantum fluctuations cancels the gravitational effect of cosmological constants, it is indispensable to apply aboves effects to the physics of early universe, such as quantum cosmology and inflationary cosmology. In accordance with quantum field theory, vacuum quantum fluctuation and vacuum polarization may result in many vacuum effects such as Casimir effect reflecting the zero-point energy of vacuum, Lamb shift in spectrum of hydrogen atom caused by vacuum polarization, atomic spontaneous radiation due to the interaction between the excited atom and the zero-point electromagnetic field, and the anomalous magnetic moment of electron as well. Although field theory encounters problems of the divergent zero-point energy of quantized fields and the infinite charge density, these problems can be overcome by taking the normal product for field operators. The vacuum background is thus theoretically re-defined by removing the zero-point energy and electric charge, which makes the expectation value of Hamiltonian and charge density for vacuum vanish. However, Einstein theory of general relativity does not tolerate this technique of taking normal product of operators, since it is believed that in the framework of general relativity, vacuum energy also gives rise to the space curvature. It follows from experimental observations that the spacetime of vacuum is nearly flat, then a paradox appears between these two regimes: quantum field theory and general relativity. Confronted with such problem of gravitational divergence of vacuum energy, some investigators favor that the present quantum field theory is merely the low-energy limit of a certain higher-energy field theory which can reduce the orders of magnitude of vacuum energy density, whereas, there does not exist such candidate theories at present. Some authors expect that supersymmetric partners have opposite zero-point vacuum energy density. Unfortunately, it is not successful in solving this problem of vacuum energy. Others argue that the above paradox would be solved, provided that vacuum density is canceled by the cosmological constant. Hence the observational evidences show the smallness of the cosmological constant. From this viewpoint, the observed cosmological constant (nonzero but very small) is only the effective remainder of the cosmological constant eliminated by the infinite vacuum energy density. Although it sounds reasonable, further problems arise. There is no inevitable connection between vacuum energy density due to quantum fluctuations and cosmological constant, since the former is related to the complicated details of particle physics while the latter is a basic physical constant of general relativity. It is apparently impossible for them to be exactly ajustable and canceled with each other by #####orders of magnitude. Then, the problems of cosmological constant, for instance, why is cosmological constant so small, what is the origin of cosmological constant, how does cosmological constant cancel the gravitational effect of vacuum energy, deserves further investigation. We propose a possibility that some problems can be interpreted based on the similarities between gravity theory of weak-field approximation and London electrodynamics of superconductivity. It is well known that, in electrodynamics, electric charge is Noether charge while its dual charge, magnetic charge (monopole) is topological charge, since the latter is related to the singularity of non-analytical vector potentials. Magnetic monopole attracts attentions of many physicists in various fields such as gauge field theory, grand unification theory, particle physics and cosmology. In this letter, we take into account the gravitational analogue of magnetic charge, i.e., gravitomagnetic charge which is the source of gravitomagnetic field just as mass (gravitoelectric charge) is the source of gravitoelectric field (Newtonian gravitational field). In this sense, gravitomagnetic charge is also termed dual mass. It should be noted that the concept of mass is of no significance for the gravitomagnetic charge, then it is of interest to investigate the relativistic dynamics and gravitational effects of this topological dual mass. In the weak-gravitoelectric field, gravitomagnetic charge ( ) is acted upon by a Lorentz force which makes it move along a curved pathway (see Fig.1.a), similar to the case of magnetic monopole moving in the electric field. From the point of view of this letter, matter can be classified into two categories: gravitoelectric matter and gravitomagnetic matter, according to the different gravitational features. Gravitoelectric matter, constituting the physical world that is familiar to us, possesses mass (gravotoelectric charge), while gravitomagnetic matter possesses dual mass (gravitomagnetic charge). Einstein field equation of general relativity governs the interactions of gravitoelectric matter with spacetimes. By making use of the variational principle, the gravitational field equation of gravitomagnetic matter is given as follows (1) with and being the Levi-Civita completely antisymmetric tensor and Riemann curvature tensor, respectively. is the antisymmetric source tensor, for the Fermi field , it is the linear combinations of the following three antisymmetric tensor, , , and , where is general Dirac matrix which depend on space-time coordinates, . It should be pointed out that can be regarded as the “cosmological term” of gravitomagnetic matter. One can readily verify that in the weak-field low-motion approximation, Eq. (1) in terms of the gravitational scalar potential and gravitomagnetic vector potentials is formally reduced to the form of field equations of magnetic monopole in electrodynamics where four-demensional electromagnetic potentials are . An exact solution of Eq. (1) for the exterior gravitomagnetic field of spherically symmetric static gravitomagnetic charge is of the form (written via the linear element) (2) with , where is a parameter associated with gravitomagnetic charge and coupling constant. The topological property of this solution is seen in Fig. 1.b. This property is in analogy with that of the geometric quantum phase in the time-dependent spin-gravity coupling. The relativistic quantum gravitational effect in weak-gravitational fields is the subject of this letter. In the following, we investigate the so-called gravitational Meissner effect, the gravitational analogue of Meissner effect in superconductivity, which will provide a possible interpretation for the problem of the gravitational divergence of vacuum energy. In the superconductor, current density of superconducting electrons is conserved for the Cooper pairs are not easily excited by scattering. In the similar fashion, mass current density or momentum density is also conserved around the particle scattering in perfect fluid. Hence, it is apparent that analogy exists between the weak-field low-motion theory of gravity and London electrodynamics of superconductivity. Further analysis show that in the weak field of gravitation, the mathematical equations is exactly formally similar to London equations of superconductivity. When placed in a magnetic field, a superconductor is affected by the Meissner effect: the magnetic flux is excluded from the bulk of this specimen. The origin of the Meissner effect lies in that the magnetic field produced by the induced electric current flowing in the surface of the specimen exactly cancels the applied field. In the perfect fluid, the analogous phenomenon arises. This, therefore, implies that gravitomagnetic field can be expelled (or canceled) by the gravitomagnetic field produced by the mass current via gravitational Meissner effect. Note, however, that gravitoelectric field produced by mass is not cancelled if no gravotomagnetic charge exists in perfect fluid. Then, only when the gravitational Meissner effect is combined with the gravitational effect of gravitomagnetic charge can we perform a potential investigation of the problem of cosmological constant and vacuum gravity (see Fig. 2). Cosmological constant is believed to be canceled by the gravitational effects of induced current of dual mass (of vacuum quantum fluctuations) rather than just by the vacuum energy of quantum fluctuations. Hence, a conclusion can be drawn at least in the case of weak-fields that the spacetime of vacuum is flat and the observed cosmological constant is nearly vanishing. These ideas discussed above deserve generalization to the case of general strong-gravitational fields such as quantum cosmology and inflationary cosmology, of which the detailed mathematical treatment will be published elsewhere. Since there is no evidence for the existence of this topological dual mass at present, the application of the gravitational Meissner effect to the problem of cosmological constant and vacuum gravity is merely a possible resolution. It is believed that there exists formation (and creation) mechanism of gravitomagnetic charge in the gravitational interaction, just as some prevalent theories such as grand unification theory provide the theoretical existence of machanism of magnetic charge. The observational evidence for the smallness of cosmological constant is therefore somewhat satisfactorily explained in the framework of gravitomagnetic charge and gravitational Meissner effect. However, it should be stated that once a future theory of supersymmetry shows that the total gravitational effect of vacuum quantum fluctuations vanishes, applying this gravitational Meissner effect to the vacuum energy is not necessary. Then we apply it to the spatially flat, vacuum-dominated universe with mass density, , where and are respectively density parameter and critical mass density, denotes the Hubble parameter. Similar to the London theory of superconductivity, the effective mass of gravitational field due to the self-induced mass current is , where cosmological mass density , respectively stand for the Planck constant, speed of light and the gravitational constant. Simple calculation yields the London penetration depth of the universe as follows (3) with mass density parameter . It follows from Eq. (3) that is compared to the scale of the universe, and one can conclude that the gravitational Meissner effect is not evident for the present low-density universe. Whereas, it is essential to take into consideration the gravitational influences of Meissner effect on the early universe. To summarize, we investigate the gravitational properties of the gravitomagnetic charge, the topological dual charge of mass. Since the weak-gravitational theory is analogous to the London electrodynamics of superconductivity, we suggest and analyze the gravitational analogue of Meissner effect. This work gives us a helpful insight into some problems such as that of cosmological constant and gravitational effect of vacuum quantum fluctuations. Figure 1.a Figure 1.b The topological property of the gravitomagnetic vector potential of a static gravitomagnetic charge at the origin of the spherical coordinate system is shown in Fig.1.b. It should be pointed out that is exactly analogous to the case of magnetic potential of Dirac monopole. This, therefore, implies that gravitomagnetic charge is the topological dual charge of mass. Take the gravitomagnetic vector potentials in spherical coordinate system, then the integral is proportional to the solid angle subtended by the curved with respect to the origin. The same situations arise in the adiabatic geometric phase (Berry phase) which reflects the global or topological properties of time evolution of quantum systems. Figure 2 Provided that vacuum matter is perfect fluid, we suggest a potential interpretation by using the gravitational Meissner effect: the gravitoelectric field produced by the gravitoelectric charge (mass) of the vacuum quantum fluctuations is exactly canceled by the gravitoelectric field produced by the induced current of the gravitomagnetic charge (dual mass) of the vacuum quantum fluctuations; the gravitomagnetic field produced by the gravitomagnetic charge of the vacuum quantum fluctuations is exactly canceled by the gravitomagnetic field produced by the induced current of the gravitoelectric charge (mass current) of the vacuum quantum fluctuations. Thus, at least in the framework of weak-field approximation, the extreme space-time curvature of vacuum caused by its large energy density does not arise, and the gravitational effects of cosmological constant is eliminated by the contributions of the gravitomagnetic charge (dual mass). |
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请你查一下资料，看看在原子钟环球航行实验理论计算中，考虑了哪些因素 你说的“加速度”根本没有被考虑，相反，倒考虑了“速度”和“引力”的影响。 请继续看楼上的帖子(11805)。 黄德民 |
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回复:时钟是不会改变的，所有的时间问题都是想象出来的。 ※※※※※※ 欢迎访问丁一宁网站 http://dyn2000.topcool.net |
