Blackbody radiation in nonextensive Tsallis statistics: Exact solution

An exact analysis of n-dimensional blackbody radiation in the recently proposed nonextensive Tsallis statistics is given here. Thus, the main relationships of blackbody radiation are generalized in the Tsallis context. In particular, it is verified that the relation between pressure, volume, and internal energy is form invariant with respect to the nonextensive entropic index, q. The results and procedure presented here are expected to be useful in the discussion of nonextensive systems possessing large or infinite numbers of degrees of freedom.     

Classical polylogarithms for amplitudes and Wilson loops

We present a compact analytic formula for the two-loop six-particle maximally helicity violating remainder function (equivalently, the two-loop lightlike hexagon Wilson loop) in N=4 supersymmetric Yang-Mills theory in terms of the classical polylogarithm functions Lik with cross ratios of momentum twistor invariants as their arguments. In deriving our formula we rely on results from the theory of motives.     

三锥黑体腔

持黑体光壁腔观点,用几何光学方法模拟黑体,得一三锥黑体腔。推导了三锥腔的设计公式,并给出实用黑体腔的设计参数。确定腔壁比辐射率值ε_6=0.16,黑体ε设计值达0.9999。     

Blackbody radiation shift of the Al<Superscript>+</Superscript> clock transition

The blackbody radiation shift of the Al⁺ 3s^{2 1}S^e ₀ ↦ 3s3p ³P^○ ₀ clock transition is evaluated. The polarizabilities of the two states are determined by means of configuration interaction calculations in conjunction with oscillator strength sum rules. The ground state polarizability was 24.14 ±0.12 a.u. while the metastable state polarizability was 24.62 ±0.25 a.u. The derived frequency shift at 300 K was Δν= -0.0042 ±0.0032 Hz. Some auxiliary sum rules are evaluated that allow for the conversion of a finite frequency polarizability difference to a static polarizability difference.     

四锥黑体腔

用几何光学方法模拟黑体,得一四锥黑体腔。推导了四锥腔的设计公式,并给出适用黑体腔的设计参数。     

小波在求解黑体辐射反问题中的应用

针对黑体辐射反问题,提出将其离散为线性不适定问题,利用小波变换方法进行数值求解.将小波变换和正则化方法相结合,利用小波函数的紧支撑性,将原不适定问题转化为粗子空间上的适定问题.数值模拟结果表明方法可行,重构区域温度分布有效.     

Blackbody spectra for sonoluminescing hydrogen bubbles

The dynamical motion of sonoluminescing bubbles formed from a mixture of water and hydrogen gas indicates that these bubbles contain hydrogen. Their spectrum is well matched by an ideal 6000 K blackbody radiating from a surface with a radius less than 1/4 microm. According to this model, the state of matter inside the collapsed bubble is so stressed that the photon mean free path is much smaller than 1 microm. Implications for various theories of the light-emitting mechanism and the role of chemical reactions are discussed.     

Amplitude-Squared Squeezing in a Kerr-Nonlinear Blackbody

We find that amplitude-squared squeezing of the photon field is present in a new blackbody, namely, a Kerr- nonlinear blackbody. The squeezing effect decreases as temperature T increases. 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.     

Generalized characteristic functions for a single-mode radiation field

We derive simple formulas for the higher-order moments of the quadrature operators operators of a two-field superposition by introducing a new generalized characteristic function depending on two complex variables. Using this formalism we investigate the preservation of higher-order squeezing during weak thermalization of an even coherent state.     

丙三醇溶液声致发光中的黑体辐射谱

利用U型管圆锥泡声致发光装置,测量到了丙三醇溶液中圆锥泡声致发光的光谱和光脉冲。结果表明,测量得到的发光光谱为光滑的连续谱,且与理论模拟得到的黑体辐射谱相吻合,拟合温度分布于2 600～3 500 K范围内。文章从空间和时间两方面分析了圆锥泡空化发光中存在黑体辐射的原因：较大的气泡体积(气泡塌缩半径为1.4 cm)与较长的发光时间(几十微秒)。另外,实验研究表明随着发光波长的增长,光脉冲宽度变宽,从而进一步证明了圆锥泡声致发光中的黑体辐射机制。最后,利用测量得到的发光光谱和脉冲计算得到了发光光强为0.18 J,远远高于其他方式得到的声致发光光强。     

Spectral Energy Density in a Kerr Nonlinear Blackbody

In a Kerr nonlinear blackbody, bare photons with opposite wave vectors and helicities are bound into pairsand unpaired photons are transformed into a new kind of quasiparticle, the nonpolariton. The nonpolariton system constitutes free thermal radiation in the blackbody. The present paper investigates the spectral energy density of the thermal radiation. It is found that the spectral energy density of a Kerr nonlinear blackbody is larger than that of a normal blackbody.     

Spectral Energy Density in a Kerr Nonlinear Blackbody

In a Kerr nonlinear blackbody, bare photons with opposite wave vectors and helicities are bound into pairs and unpaired photons are transformed into a new kind of quasiparticle, the nonpolariton. The nonpolariton system constitutes free thermal radiation in the blackbody. The present paper investigates the spectral energy density of the thermal radiation. It is found that the spectral energy density of a Kerr nonlinear blackbody is larger than that of a normal blackbody.     

低温辐射计黑体腔吸收率分析

低温辐射计是目前国际上光辐射功率计量中准确度最高的测量系统,其光辐射测量不确定度可达10-5量级,目前国内仅有少数研究机构从国外引进低温辐射计开展计量研究,亟待发展国产低温辐射计替代进口产品。由于低温辐射计采用低温超导状态下的电替代测量原理进行光辐射功率测量,发展低温辐射计的难点之一在于研制黑体吸收腔这一核心光辐射接收器件,并要求黑体腔在各波长下的吸收率都要达到0.999 9以上。为研制超高光谱吸收率的黑体吸收腔,系统性分析了各影响黑体腔光谱吸收率因素,在此基础上利用蒙特卡罗光线追迹方法重点研究了光谱波长、腔体长度、黑材料漫反射系数、黑材料吸收率和入射光空间位置等对斜底黑体腔光谱吸收率的影响。研究结果表明：在300～1 100 nm波长范围内黑体腔吸收率与其内壁涂黑材料的吸收率呈正相关,且在300～1 000 nm范围内的吸收率都达到了0.999 9以上,其中在700 nm处的吸收率取得最大值0.999 941 5,表明采用该类型黑材料的黑体腔只在300～1 000 nm范围内满足低温辐射计设计要求,后续需要根据仿真和测试结果对低温辐射计在不同波长下的光电不等效性进行修正;在黑体腔结构和口径确定的情况下,黑体腔吸收率将随腔长增加而逐渐升高,在40 mm后变化趋缓,并在65 mm后逐渐趋于平衡,考虑到低温辐射计低温舱对腔体尺寸的限制,认为腔体长度与口径之比为6.5时较为合适;黑体腔吸收率还受黑材料的漫反射系数影响,随着黑材料漫反射系数的提高,腔体吸收率呈现近似线性下降,所以在选择黑体腔涂黑材料时,在吸收率等指标相同的情况下应尽量选择镜面吸收黑;黑材料吸收率从0.8到1的变化过程中,腔体吸收率提升了0.05个百分点,且黑材料吸收率为0.92时腔体吸收率可达到0.999 9以上,表明黑材料在其有效工作波长范围内任一点的光谱吸收率都要大于0.92;腔体吸收率还受入射光投射的空间位置影响,光线位置越靠近斜底腔顶点处,腔体吸收率越高,但整体吸收率变化不明显,光线位置对腔体吸收率影响只有不到0.004个百分点,几乎可以忽略,认为斜底腔不同位置处的吸收率是均匀的。研究结果对低温辐射计黑体腔研制有一定参考价值。     

Generalized distribution functions and an alternative approach to generalized Planck radiation law

In this study, recently introduced generalized distribution functions are summarized and by using one of these distribution functions, namely generalized Planck distribution, an alternative approach to the generalized Planck law for the blackbody radiation has been tackled. The expression obtained is compared with the expression given by C. Tsallis et al. [Phys. Rev. E 52 (1995) 1447], and it is found that this approximate scheme provides bounds to the exact result, depending on the values of q-index.     

Thermodynamics of Phase Transitions of a Kerr Nonlinear Blackbody

We study the thermodynamics of phase transitions of a blackbody whose interior is filled by a Kerr nonlinear crystal. There is a transition temperature To, above which the Kerr nonlinear blackbody is in the normal thermal radiation state, and below which it is in the squeezed thermal radiation state. At To, the Gibbs free energy of the two phases is continuous but the entropy density of the two phases is discontinuous. Hence, there is a jump in the entropy density and this leads to a latent heat density. The photon system undergoes a first-order phase transition from the normal to the squeezed thermal radiation state.     

Dynamics of Optical Bistability with Kerr-nonlinear Blackbody Radiation Reservoir

In this paper we investigate the nonlinear dynamics for optical bistabile(OB) model of homogeneously broadened two-level atomic medium interacting with a single mode of the ring cavity in the presence of a Kerr-nonlinear blackbody(KNB) radiation reservoir. We show the impact of the relative temperature of the reservoir on the transition between the dynamical states via bifurcation diagrams that represents the relation between maximum values of the output field and the relative temperature for fixed input field. Specifically, decreasing the relative temperature(T_b)causes the system to bifurcate from periodic to chaotic behavior and in turn reverts back to periodic behavior with further decrease of T_b. Varying atomic detuning leads to a change in the nature of the dynamic transition between the system's states from self pulsing to chaotic behavior.     

侧壁带光隙槽的黑体腔

本文介绍三种黑体腔的设计方法:锥齿光隙黑体腔、矩齿光隙黑体腔和梯形光隙黑体腔。写出它们的设计公式,并分别给出一适用腔体的几何参数。