Can a Black Body Emit Only One Photon After Being Hit By a Single Photon?

In summary, the conversation discusses the behavior of black bodies at extremely low temperatures and the emission of photons. The black-body spectrum is a statistical effect and the emitted continuum spectrum is dependent on the temperature of the black body. The conversation also mentions the use of Stefan-Boltzmann's law and the possibility of a single photon being re-emitted with the same wavelength. There is also speculation on the quantum mechanical behavior of a black body after being hit by a single photon.
  • #1
fluidistic
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To make my question simpler, assume that there's a black body at 0K or very close to it (if we can't assume there's a body at 0K).
Say I have a monochromatic source of photons which sends 1 photon on the black body. The wavelength of the photon is 500 nm so around green. If I understood well how a black body behaves, it will absorb the photon and re-emit a continuum spectra of light. In other words, it will radiate an infinity of photons. Obviously the black body can't emit another 500 nm photon otherwise it would emit only 1 photon (due to conservation of energy) and not a continuum spectra. I realize that in a realistic case the black body cannot emits an infinity of photons, but it doesn't matter for my question.
How can I know what will be the spectra of a black body, knowing that I send a photon of wavelength [tex]\lambda[/tex]?
So after all, the "continuum spectra" can be very limited in wavelength range? I'm interested in knowing how to determine for example what would be the most energetic photon that will be emitted in my previous example.
By the way it's not a homework question so any reply of the form "look at Planck's Law" or any other Law satisfies me. Explanations are welcome too.
 
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  • #2
The black-body spectrum is a statistical effect which only corresponds to average properties. What happens to a single photon requires a solid state analysis.
 
  • #3
zhermes said:
The black-body spectrum is a statistical effect which only corresponds to average properties. What happens to a single photon requires a solid state analysis.

Hmm interesting. Even in an idealization of a black body? I.e. absorbs all incident light and re-emits a continuum spectra.
 
  • #4
The continuum spectrum it emits will be exclusively dependent on its temperature. So, that depends on how much it heats up due to the single incident photon. If it were to remain at 0K, it would not emit any spectrum at all.
 
  • #5
cjl said:
The continuum spectrum it emits will be exclusively dependent on its temperature. So, that depends on how much it heats up due to the single incident photon. If it were to remain at 0K, it would not emit any spectrum at all.

Ok I see. It can't remain at 0K (it's not infinite in size) since it absorbs a photon. I think I could use Stefan-Boltzmann's law to calculate the gain of temperature due to the absorption of 1 photon. Say it gives me it heats up to 0.1K. What formula can I use to see the black body radiation at this temperature?
I'm really curious if there's at least 1 photon with a close to 500 nm wavelength. It's almost impossible.
 
  • #6
fluidistic said:
Hmm interesting. Even in an idealization of a black body? I.e. absorbs all incident light and re-emits a continuum spectra.
The reason why a black-body behaves the way it does is because of statistics and averaged quantities. It was all of the Boltzmann distribution, einstein's quantization that pieced it together.

I don't know exactly what a perfect black-body, starting in the ground state, would do after being hit by a single photon... but its definitely not going to produce black-body, continuum emission. Whatever results will most likely be purely quantum mechanical... maybe just re-emit a photon with the same wavelength? More likely a probabilistic function would decrease the probability of producing some combination of 'n' photons, and whatever combinations of frequencies (the sum of which equal the initial frequency)? Anyone out there have specifics?

EDIT: another guess, the blackbody intensity distribution might describe the probability with which a photon, of energy less than or equal to that available, is emitted.
 

Related to Can a Black Body Emit Only One Photon After Being Hit By a Single Photon?

1. What is black body radiation?

Black body radiation refers to the electromagnetic radiation emitted by a perfect black body, which is an object that absorbs all radiation that falls on it. It is a fundamental concept in thermodynamics and plays a crucial role in understanding the behavior of matter at high temperatures.

2. How is black body radiation related to temperature?

According to the Planck's law of black body radiation, the amount and wavelength distribution of radiation emitted by a black body is determined solely by its temperature. This means that as the temperature of a black body increases, the intensity of emitted radiation also increases, and the peak of the radiation shifts to shorter wavelengths.

3. What is the significance of black body radiation in astronomy?

Black body radiation is essential in understanding the properties of stars and other celestial objects. The color and temperature of a star's surface can be determined by analyzing its black body radiation. Additionally, the cosmic microwave background, which is the remnant radiation from the Big Bang, is a form of black body radiation.

4. How does black body radiation contribute to climate change?

Black body radiation plays a crucial role in Earth's energy balance and climate. The Earth absorbs solar radiation and re-emits it as thermal radiation. The amount and wavelength distribution of this thermal radiation are affected by the composition of the atmosphere, which can cause changes in the Earth's temperature and contribute to climate change.

5. Can black body radiation be observed in daily life?

Yes, black body radiation is observed in our daily lives. For example, the red glow of a hot stove burner and the white glow of an incandescent light bulb are both examples of black body radiation. Black body radiation is also used in infrared cameras and thermometers to measure temperature.

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