Mechanism of blackbody radiation

The law of error for Bose statistics is not unique; the family of probability distributions differ insofar as zero-point energy is concerned. This is traced back to the spontaneous emission term in the Einstein mechanism of emission and absorption of radiation. It is argued that the spontaneous emission term is unimportant for blackbody radiation and an alternative mechanism is proposed in which thermal equilibrium is secured through a constraint on the number of quanta in any given mode of the radiation field. Both mechanisms predict a modification of the Maxwell velocity distribution at high frequencies and are compared in relation to Doppler broadening and their low-temperature behavior.     

洛仑兹破缺标量场的霍金隧穿辐射

把洛仑兹破缺的标量场方程推广到弯曲时空中,并通过Aether-like项对标量场方程进行修正,该项所产生的效应也会影响到黑洞时空视界附近处的物理效应.接着,进一步在半经典近似下得到了修正的Hamilton-Jacobi方程,然后用这一修正的Hamilton-Jacobi方程研究了史瓦西黑洞的隧穿辐射特征,并讨论了洛仑兹破缺对黑洞霍金辐射和黑洞熵的影响.结果表明,u~α=δ_t~αu~t,δ_r~αu~r形式的Aether-like项的效应可能使黑洞温度增加,而黑洞熵降低.该工作可以帮助我们更深刻地理解弯曲时空中的洛仑兹破缺效应的物理性质.     

Synchrotron radiation is not a blackbody but a graybody

Though synchrotron radiation and blackbody radiation are considered as completely different phenomena, spectral shape of synchrotron radiation is somewhat similar to that of the blackbody radiation. Synchrotron radiation is a graybody radiation with a finite value of emmisivity, which varies as a function of wavelength. Copyright © 2007 John Wiley & Sons, Ltd.     

目标辐射特性现场校准用大面积黑体辐射源技术研究

红外成像技术在空间探测、对地观测、安防监控等领域的应用越来越广,为了确保红外目标识别的准确性,必须掌握目标的辐射特性。目标辐射特性需要在外场实际条件下测量得到,需要利用大面积黑体辐射源对目标特性测量设备进行现场辐射参数校准。设计了一种大面积黑体辐射源,辐射体采用铝材质并发黑处理,大面积黑体辐射源温度控制采用PID控制算法。在外场实际环境温度为26.8 ℃,湿度为60%时对目标特性测量设备辐射参数进行了校准。试验数据表明:辐射温度测量不确定度为0.4 ℃（k=2）,取得了较好的应用效果。     

Statistical properties of thermal radiation in a Kerr nonlinear blackbody

We study the statistical properties of thermal radiation in a Kerr nonlinear blackbody in which bare photons with opposite wave vectors and helities are bound into pairs and unpaired photons are transformed into a different kind of quasiparticle, the nonpolariton. This paper investigates the statistical properties of the photon blackbody field by using the second-order correlation function, the phase space distribution function, the photon number distribution and the nonclassical depth. The numerical computation and a discussion of the results are present.     

Modified radiation laws of a rectangular Kerr nonlinear blackbody

A Kerr nonlinear blackbody (KNB) is a new kind of blackbody in which bare photons with opposite wave vectors and helicities are bound into pairs and unpaired photons are transformed into nonpolaritons. In the present paper, we focus our investigation on the modified radiation laws, such as Planck and Stefan-Boltzmann radiation laws, of a rectangular KNB. Besides, the case of a KNB with no symmetry axes is also discussed. Finally, we make a numerical calculation of modified radiation laws of a cubic KNB under appropriate conditions, and we consider this work may lay the foundation for the experimental verification of the model of a KNB.     

The harmonically bound electron in the blackbody radiation field. A one-dimensional exactly solvable model

An exactly solvable model for a harmonically bound electron in the blackbody radiation field is discussed. A twofold renormalization leads to cutoff independent exact results. A first order ground state shift is found and a T²-dependent dynamic energy level shift is rederived. Comparisons with previous results are made.     

Quantum phenomena and the zeropoint radiation field

The stationary solutions for a bound electron immersed in the random zeropoint radiation field of stochastic electrodynamics are studied, under the assumption that the characteristic Fourier frequencies of these solutions are not random. Under this assumption, the response of the particle to the field is linear and does not mix frequencies, irrespectively of the form of the binding force; the fluctuations of the random field fix the scale of the response. The effective radiation field that supports the stationary states of motion is no longer the free vacuum field, but a modified form of it with new statistical properties. The theory is expressed naturally in terms of matrices (or operators), and it leads to the Heisenberg equations and the Hilbert space formalism of quantum mechanics in the radiationless approximation. The connection with the poissonian formulation of stochastic electrodynamics is also established. At the end we briefly discuss a few important aspects of quantum mechanics which the present theory helps to clarify.On leave of absence at Mathematics Department, University College London. Gower Street, London WC1, U.K.     

Amplitude-squared squeezing of the photon field in a Kerr-nonlinear blackbody

We find the photon field in a Kerr-nonlinear blackbody is an amplitude-squared squeezed state. The squeezing effect decreases with increasing temperature T. The amount of the amplitude-squared squeezing in a Kerr-nonlinear blackbody is much larger than the corresponding squeezing in normal blackbody, and the degree of amplitude-squared squeezing is much larger than the amplitude squeezing for the same range of parameters in a Kerr-nonlinear blackbody. The frequency ω_k and parameter γ also have important influences on the amplitude-squared squeezing in a Kerr-nonlinear blackbody.     

Chaotic tunneling in a laser field

We study the driven tunneling of a one-dimensional charged particle confined to a rectangular double well. The numerical simulation of the Schrödinger equation based on the Cranck-Nicholson finite-difference scheme shows that the modulation of the amplitude of the external field may result in parametric resonance. The latter is accompanied by the breakdown of the quasi-periodic motion characteristic of the usual driven tunneling and the emergence of irregular dynamics. We describe the above breakdown with the occupation probability for the ground state of the unperturbed system and create the visualization of the irregular dynamics with the help of Shaw-Takens’ reconstruction of the state space. Both approaches agree concerning the values of the resonant frequency for the parametric excitation. Our results indicate that the shape of the laser pulse could be essential for generating chaotic tunneling.     

Generalization of the radiation laws of a Kerr nonlinear blackbody

Within the framework of nonextensive statistical mechanics (NSM), we generalize the radiation laws, which include the Planck radiation law and Stefan-Boltzmann law, of a Kerr nonlinear blackbody (KNB) in the normalized form. In order to illustrate the influence of the parameter q on the two generalized radiation laws, we make a numerical calculation of the two laws under appropriate conditions. Furthermore, we make an attempt to extend the theory of KNB to the whole Universe.     

Quantum tunneling between paramagnetic and superconducting states of a nanometer-scale superconducting grain placed in a magnetic field

We consider the process of quantum tunneling between the superconducting and paramagnetic states of a nanometer-scale superconducting grain placed in a magnetic field. The grain is supposed to be weakly coupled to a normal metallic contact that plays the role of the spin reservoir. Using the instanton method, we find the probability of the quantum tunneling process and express it in terms of the applied magnetic field, order parameter of the superconducting grain, and conductance of the tunneling junction between the grain and metallic contact.     

黑体辐射公式的量纲分析

量纲分析是研究物理问题的重要方法之一.本文对量纲分析的解题步骤做了梳理归纳,并对于黑体辐射公式进行了量纲分析.