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1.
The derivation of Planck's radiation law can be considered as a transformation of a thermodynamic relation for black-body radiation into a fundamental relation in which the error law is the negative binomial distribution. In both limiting frequency ranges it transforms into Poisson distributions; in the Wien limit, it is the distribution of the number of photons, whose most probable value is given by Boltzmann's expression, while in the Rayleigh-Jeans limit, it is the distribution of the number of Planck oscillators. In the general case, they are Bernoullian random variables. In the Rayleigh-Jeans limit, the probability of determining the number of oscillators in a given frequency interval for a fixed value of the energy can be inverted to determining the probability of the energy for a fixed number of oscillators. The probability density is that of the canonical ensemble.  相似文献   

2.
In late 1900, the German theoretical physicist Max Planck derived an expression for the spectrum of black-body radiation. That derivation was the first step in the introduction of quantum concepts into physics. But how did Planck think about his result in the early years of the twentieth century? Did he assume that his derivation was consistent with the continuous energies inherent in Maxwellian electrodynamics and Newtonian mechanics? Or did he see the beginnings, however tentative and uncertain, of the quantum revolution to come? Historians of physics have debated this question for over twenty years. In this article, I review that debate and, at the same time, present Planck's achievement in its historical context.  相似文献   

3.
黑体辐射中两类粒子的辐射规律   总被引:1,自引:1,他引:0  
孟庆苗 《大学物理》2005,24(8):9-10,18
考虑到相对论效应,采用量子统计的方法,得到了满足Bose-Einstein统计分布和Fermi-Dirac统计分布的两类粒子的黑体辐射公式(包括Planck黑体辐射公式).发现辐射谱不仅与黑体的辐射温度有关,还与辐射粒子的能量、化学势和种类有关.辐射强度与辐射粒子的能量、静质量、简并因子有关。  相似文献   

4.
A localized particle in Quantum Mechanics is described by a wave packet in position space, regardless of its energy. However, from the point of view of General Relativity, if the particle’s energy density exceeds a certain threshold, it should be a black hole. To combine these two pictures, we introduce a horizon wave function determined by the particle wave function in position space, which eventually yields the probability that the particle is a black hole. The existence of a minimum mass for black holes naturally follows, albeit not in the form of a sharp value around the Planck scale, but rather like a vanishing probability that a particle much lighter than the Planck mass may be a black hole. We also show that our construction entails an effective generalized uncertainty principle (GUP), simply obtained by adding the uncertainties coming from the two wave functions associated with a particle. Finally, the decay of microscopic (quantum) black holes is also described in agreement with what the GUP predicts.  相似文献   

5.
Using the quantum trajectories approach, we study the quantum dynamics of a dissipative chaotic system described by the Zaslavsky map. For strong dissipation the quantum wave function in the phase space collapses onto a compact packet which follows classical chaotic dynamics and whose area is proportional to the Planck constant. At weak dissipation the exponential instability of quantum dynamics on the Ehrenfest time scale dominates and leads to wave packet explosion. The transition from collapse to explosion takes place when the dissipation time scale exceeds the Ehrenfest time. For integrable nonlinear dynamics the explosion practically disappears leaving place to collapse.  相似文献   

6.
Spherically symmetric static cosmological models filled with black-body radiation are considered. The models are isotropic about a central observer but inhomogeneous. It is suggested that the energy density of the free gravitational field, which is coupled to the isotropic radiation energy density, might play an important role in generating sufficient field (vacuum) energy (when converted into thermal energy) and initiate processes like inflation. On the central world line the energy density of the free gravitational field vanishes whereas the proper pressure and density of the isotropic black-body radiation are constants. Further, it is shown that the cosmological constant is no more arbitrary but given in terms of the central pressure and density. Also, at its maximum value the energy density of the free gravitational field is proved to be equal to one third of the combined value of radiation pressure and density.  相似文献   

7.
One may ask whether the relations between energy and frequency and between momentum and wave vector, introduced for matter waves by de Broglie, are rigorously valid in the presence of gravity. In this paper, we show this to be true for Dirac equations in a background of gravitational and electromagnetic fields. We first transform any Dirac equation into an equivalent canonical form, sometimes used in particular cases to solve Dirac equations in a curved space-time. This canonical form is needed to apply Whitham’s Lagrangian method. The latter method, unlike the Wentzel–Kramers–Brillouin method, places no restriction on the magnitude of Planck’s constant to obtain wave packets and furthermore preserves the symmetries of the Dirac Lagrangian. We show by using canonical Dirac fields in a curved space-time that the probability current has a Gordon decomposition into a convection current and a spin current and that the spin current vanishes in the Whitham approximation, which explains the negligible effect of spin on wave packet solutions, independent of the size of Planck’s constant. We further discuss the classical-quantum correspondence in a curved space-time based on both Lagrangian and Hamiltonian formulations of the Whitham equations. We show that the generalized de Broglie relations in a curved space-time are a direct consequence of Whitham’s Lagrangian method and not just a physical hypothesis as introduced by Einstein and de Broglie and by many quantum mechanics textbooks.  相似文献   

8.
We used a torsion pendulum containing approximately 9 x 10(22) polarized electrons to search for CP-violating interactions between the pendulum's electrons and unpolarized matter in the laboratory's surroundings or the Sun, and to test for preferred-frame effects that would precess the electrons about a direction fixed in inertial space. We find, /g(P)(e)g(S)(N)//(Planck's constant x c) < 1.7 x 10(-36), and /g(A)(e)g(V)(N)//(Planck's constant x c) < 4.8 x 10(-56) for lambda > 1 AU. Our preferred-frame constraints, interpreted in the Kostelecky framework, set an upper limit on the parameter /b(e)/ 相似文献   

9.
 从椭圆偏振激光场波包所满足的非线性控制方程出发,利用场论方法,构造该非线性方程的拉格朗日密度函数,得到激光场波包的能量集中具有准粒子特性,并给出守恒的粒子数、动量和能量。讨论了调制不稳定发展后期的波包坍塌动力学问题,利用归一化的粒子数密度分布作为权重,分析了激光场的波包。结果表明,激光场波包的尺度在有限的时间进程中,将塌缩到一个很小的值,证明了激光场具有塌缩行径。  相似文献   

10.
Quantum kicked rotor was recently realized in experiments with cold atomic gases and standing optical waves. As predicted, it exhibits dynamical localization in the momentum space. Here we consider the weak-localization regime concentrating on the Ehrenfest time scale. The latter accounts for the spread time of a minimal wave packet and is proportional to the logarithm of the Planck constant. We show that the onset of the dynamical localization is essentially delayed by four Ehrenfest times, and give quantitative predictions suitable for an experimental verification.  相似文献   

11.
Quantum resonances in the kicked rotor are characterized by a dramatically increased energy absorption rate, in stark contrast to the momentum localization generally observed. These resonances occur when the scaled Planck's constant Planck's [over ]=r/s 4pi, for any integers r and s. However, only the variant Planck's [over ]=r2pi resonances are easily observable. We have observed high-order quantum resonances (s>2) utilizing a sample of low energy, noncondensed atoms and a pulsed optical standing wave. Resonances are observed for variant Planck's [over ]=r/16 4pi for integers r=2-6. Quantum numerical simulations suggest that our observation of high-order resonances indicate a larger coherence length (i.e., coherence between different wells) than expected from an initially thermal atomic sample.  相似文献   

12.
We apply a semiclassical approach to the scattering problem of a vibrational wave packet in the vicinity of a conical intersection of electronic energy surfaces and derive analytical expressions for the scattering matrix. The latter are valid when the scattering length that scales as square root(h) is small and a wave packet passes through the scattering region with a constant velocity. The analytical results are in excellent agreement with numerical simulations for a realistic set of parameters.  相似文献   

13.
Attosecond pulses are produced when an intense infrared laser pulse induces a dipole interaction between a sublaser cycle recollision electron wave packet and the remaining coherently related bound-state population. By solving the time-dependent Schr?dinger equation we show that, if the recollision electron is extracted from one or more electronic states that contribute to the bound-state wave packet, then the spectrum of the attosecond pulse is modulated depending on the relative motion of the continuum and bound wave packets. When the internal electron and recollision electron wave packet counterpropagate, the radiation intensity is lower. We show that we can fully characterize the attosecond bound-state wave packet dynamics. We demonstrate that electron motion from a two-level molecule with an energy difference of 14 eV, corresponding to a period of 290 asec, can be resolved.  相似文献   

14.
A possible way of building Planck's constant into the structure of space-time is considered. This is done by assuming that the torsional defect that intrinsic spin produces in the geometry is a multiple of the Planck length.  相似文献   

15.
The Planck aether hypothesis assumes that space is densely filled with an equal number of locally interacting positive and negative Planck masses obeying an exactly nonrelativistic law of motion. The Planck masses can be described by a quantum mechanical two-component nonrelativistic operator field equation having the form of a two-component nonlinear Schrödinger equation, with a spectrum of quasiparticles obeying Lorentz invariance as a dynamic symmetry for energies small compared to the Planck energy. We show that quantum mechanics itself can be derived from the Newtonian mechanics of the Planck aether as an approximate solution of Boltzmann's equation for the locally interacting positive and negative Planck masses, and that the validity of the nonrelativistic Schrödinger equation depends on Lorentz invariance as a dynamic symmetry. We also show how the many-body Schrödinger wave function can be factorized into a product of quasiparticles of the Planck aether with separable quantum potentials. Finally, we present a possible explanation of wave function collapse as a kind of enhanced gravitational collapse in the presence of the negative Planck masses.  相似文献   

16.
We derive an expression for the resultant spectral density (spectrum) at a point in the far zone for the surface plasmons modulated Young's double-slit interference setup. The resultant spectral interference law has the same form as the standard spectral interference law for the scalar fields. This resemblance in turn provides a means for determination of the modified spectral degree of coherence at the two slits. The mathematical results also show that in an interesting situation when the field is incident at one slit only, the interference can still be observed at the observation plane. These findings are verified theoretically using a wide-band source, i.e. a black-body, having a spectrum following Planck's radiation law.  相似文献   

17.
The problem ofn identical black holes in a box separated by partitions is considered. Each black hole is in thermal equilibrium with black-body radiation. The separating partitions are removed and the possible final states of the combined system are investigated. Limits on the amount of gravitational wave energy that can be produced are calculated, and it is shown that forn large enough, as large a fraction of the initial energy as is desired may be extracted as gravitational waves.  相似文献   

18.
We investigate the effect of radiation reaction on the motion of a wave packet of a charged scalar particle linearly accelerated in quantum electrodynamics (QED). We give the details of the calculations for the case where the particle is accelerated by a static potential that were outlined in Higuchi and Martin Phys. Rev. D 70 (2004) 081701(R) and present similar results in the case of a time-dependent but space-independent potential. In particular, we calculate the expectation value of the position of the charged particle after the acceleration, to first-order in the fine structure constant in the ℏ→ 0 limit, and find that the change in the expectation value of the position (the position shift) due to radiation reaction agrees exactly with the result obtained using the Lorentz-Dirac force in classical electrodynamics for both potentials.  相似文献   

19.
X射线被认为是大气层外反导栏截武器的主要破坏因素。在航天器结构材料的辐射损伤计算中,需要核爆炸X射线辐射场的数学模式。从Planck黑体谱出发,提出按温度梯度分层的归一化黑体谱组合模式,给出X-射线的释放能量及辐射脉冲,从而建立了大气层外核栏截X-射线辐射场特性的数学模式  相似文献   

20.
By the methods of quantum electrodynamics, the radiation of an electron moving in the field of a traveling electric wave is considered. It is shown that, in contrast to the classical case, the result given by quantum theory for the spectral-angular distribution of the radiant energy differs from the corresponding expression for an electron in a constant homogeneous electric field, even in the terms proportional to Planck's constant.Translated from Izvestiya Vysshikh Uchbenykh Zavedenii, Fizika, No. 6, pp. 92–98, June, 1976.In conclusion, the authors thank V. G. Bagrov, D. M. Gitman, and Sh. M. Shvartsmau for their interest in the work and for useful discussions.  相似文献   

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