The relativistic blackbody spectrum in inertial and non-inertial reference frames (original) (raw)

Blackbody radiation and special relativity

A simple and time saving approach to the relativistic aspects of blackbody radiation is presented. A relativistic diagram is devised, displaying in true values the physical quantities introduced in order to characterize the blackbody radiation, as detected from two inertial reference frames in relative motion.

Black Body Radiation in Moving Frames

The problem of black body radiation when measured by a moving observer has a pivotal role in relativistic thermodynamics. Mutually, it depends on the thermodynamical definition of the thermal equilibrium and temperature of moving bodies, i.e. under a Lorentz transformation, and also in a gravitational field. Surprisingly, even after more than a century, relativistic thermodynamics is not a mature theory and is still an open problem without a consensus. This article is a brief review of the evolution of this theory with a special focus on the black body radiation in moving frames. As an application, we use the results in the most interesting topics of the quantum field theory in curved space: Hawking radiation, and Unruh effect. Note: We recast the adopted discussions of old-style papers in modern terminology , notations, and conventions as far as possible. In particular, we choose the signature (−, +, +, +) for the metric and use the Einstein summation convention. Throughout this paper, γ = (1 − v 2 /c 2) −1/2 is the Lorentz-Fitzgerald contraction factor, and the general-relativistic system of units (c = 1 and G = 1) is opted, unless explicitly stated. The spacetime indices are in Greek letters µ, ν, ... = 0, 1, 2, 3, and the space indices are in Latin letters i, j, k, ... = 1, 2, 3.

The 2.7 K black-body radiation background reference frame

Chinese Physics B, 2010

This paper reports that the directional temperature is used to present a scheme for deducing the velocity of the reference frame where the black-body which produces the 2.7 K radiation background is at rest. The new renormalized relativistic thermodynamics lays the foundations of the method.

epl draft Lorentz Transform of Black Body Radiation Temperature

2012

Abstract.- The Lorentz transform of black body radiation has been investigated from the view point of relativistic statistical mechanics. The result shows that the well known expression with the directional temperature can be derived based on the inverse temperature four vector. The directional temperature in the past literature was the result of mathematical manipulation and its physical meaning is not clear. The inverse temperature four vector has, in contrast, clear meaning to understand relativistic thermodynamical processes. Introduction. – It is well known that black body radiation obeys the Planck distribution; the following expression can be found in textbooks: n(ω) dω= ω2 2π2 dω, (1) [exp(ω/T)−1]

Relativistic thermal re-emission model

2001

Todos os corpos no universo estão constantemente absorvendo calor das fontes de energia térmica ao seu redor. Este calor, após um certo lapso de tempo, será re-emitido. A temperatura de cada ponto na superfície aquecida irá determinar a freqüência n dos fótons re-emitidos, de tal forma que o momentum total relacionado à este processo de perda de energia depende de como a temperatura está distribuída na superfície. Se o momentum resultante não é nulo, surgirá uma força térmica cujas direção e intensidade irão depender, fundamentalmente, dessa distribuição de temperaturas na superfície: pontos com temperatura alta irão re-emitir fótons com altas freqüências e vice-versa. Freqüência alta implica em uma grande perda de momentum na direção de emissão, e conseqüentemente, uma grande força de re-emissão na direção oposta. Não é apenas a temperatura que pode determinar a freqüência dos fótons emitidos mas, também, o estado de repouso ou movimento do corpo. Quando este apresenta algum tipo de movimento (rotação, translação, etc.) o efeito Doppler irá alterar as freqüências destes fótons e a freqüência n deverá ser substituída por n¢ . Como conseqüência, a força resultante será alterada, também. Neste trabalho, a variação da temperatura (variação de freqüência) devida ao efeito Doppler é modelada e a nova distribuição de temperaturas é aplicada ao modelo de re-emissão térmica. A força total obtida por este modelo "relativístico" de re-emissão térmica possui dois termos: 1) a força de re-emissão térmica padrão (sem considerações Doppler, e 2) a correção relativística a esta força que é semelhante à força Poynting-Robertson padrão. O modelo de re-emissão térmica, apresentado aqui demonstra que, de forma geral, a maioria das forças de perturbação pode ser unificada, conduzindo a um ponto de vista novo e simples, capaz de prover a compreensão de toda a física envolvida em fenômenos deste tipo.

Planck’s blackbody radiation law: Presentation in different domains and determination of the related dimensional constants

Journal of the Calcutta Mathematical Society, 2009

In this paper the Planck function is derived in the frequency domain using the method of oscillators. It is also presented in the wavelength domain and in the wave number domain. The latter is mainly used in spectroscopy for studying absorption and emission by gases. Also the power law of Stefan and Boltzmann is derived for these various domains. It is shown that this power law is generally independent of the domain in which the Planck function is presented. A formula for the filtered spectrum is also given and expressed in the sense of the power law of Stefan and Boltzmann. Furthermore, based on Wien's displacement relationship, it is argued that the wavelength at which the maximum of the Planck function presented in the wavelength domain occurs differs from that of the maxima of the other domains by a factor of 1.76. As Planck determined his elementary quantum of action, eventually called the Planck constant, and the Boltzmann constant using Wien's displacement relationship formulated for the wavelength domain, it is shown that the values of these fundamental constants are not affected by the choice of domain in which the Planck function is presented. Finally, the origin of the Planck constant is discussed.