Should mass vanish if 0 Kelvin is actually enforced into a system?

[Amity]

As many have already pointed out, it would no longer be bouncing particles as they get slower. But the mass doesn't just disappear! I believe at that point it is converted into another type of energy (not sure!). That is what is expected, although many scientists believe that it is impossible to achieve. I believe they have on got to 0.1 nanokelvin.

Edited September 18, 2014 by Amity

[swansont]

The idea that mass disappears or is converted to some other form of energy (or whatever) is not a consensus position in physics, which is that 0 K is unattainable. These other conjectures are fringe ideas and/or urban myths.

[ajb]

Temperature is a measure of energy. QM doesn't allow for exactly zero energy.

---

 

AJB might be able to shed some light on the subject.

"0K" can be thought of quantum mechanically when the system its lowest possible energy state. Typically, a quantum mechanical system has a non-zero energy ground state and so the system is not really at 0K. Now, the only systems I know of that would have exactly zero as there ground state are ones with global supersymmetry.

 

Also, like swansont I have never heard of mass disappearing at or near zero k. Why would it?

Edited September 18, 2014 by ajb

[fiveworlds]

Nope.

 

http://en.wikipedia.org/wiki/Black-body_radiation

 

 

Black-body radiation is the type of electromagnetic radiation within or surrounding a body in thermodynamic equilibrium with its environment, or emitted by a black body (an opaque and non-reflective body) held at constant, uniform temperature. The radiation has a specific spectrum and intensity that depends only on the temperature of the body.

Black-body radiation has a characteristic, continuous frequency spectrum that depends only on the body's temperature,^[8] called the Planck spectrum or Planck's law. The spectrum is peaked at a characteristic frequency that shifts to higher frequencies with increasing temperature, and at room temperature most of the emission is in the infrared region of the electromagnetic spectrum.^[9][10][11] As the temperature increases past about 500 degrees Celsius, black bodies start to emit significant amounts of visible light. Viewed in the dark, the first faint glow appears as a "ghostly" grey. With rising temperature, the glow becomes visible even when there is some background surrounding light: first as a dull red, then yellow, and eventually a "dazzling bluish-white" as the temperature rises

http://en.wikipedia.org/wiki/Thermal_radiation

Thermal radiation is electromagnetic radiation generated by the thermal motion of charged particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation. When the temperature of the body is greater than absolute zero, interatomic collisions cause the kinetic energy of the atoms or molecules to change. This results in charge-acceleration and/or dipole oscillation which produces electromagnetic radiation, and the wide spectrum of radiation reflects the wide spectrum of energies and accelerations that occur even at a single temperature.

If a radiation-emitting object meets the physical characteristics of a black body in thermodynamic equilibrium, the radiation is called blackbody radiation.^[1]Planck's law describes the spectrum of blackbody radiation, which depends only on the object's temperature. Wien's displacement law determines the most likely frequency of the emitted radiation, and the Stefan–Boltzmann law gives the radiant intensity.

 

There are four main properties that characterize thermal radiation (in the limit of the far field):

• Thermal radiation emitted by a body at any temperature consists of a wide range of frequencies. The frequency distribution is given by Planck's law of black-body radiation for an idealized emitter as shown in the diagram at top.
• The dominant frequency (or color) range of the emitted radiation shifts to higher frequencies as the temperature of the emitter increases. For example, a red hot object radiates mainly in the long wavelengths (red and orange) of the visible band. If it is heated further, it also begins to emit discernible amounts of green and blue light, and the spread of frequencies in the entire visible range cause it to appear white to the human eye; it is white hot. However, even at a white-hot temperature of 2000 K, 99% of the energy of the radiation is still in the infrared. This is determined by Wien's displacement law. In the diagram the peak value for each curve moves to the left as the temperature increases.
• The total amount of radiation of all frequencies increases steeply as the temperature rises; it grows as T⁴, where T is the absolute temperature of the body. An object at the temperature of a kitchen oven, about twice the room temperature on the absolute temperature scale (600 K vs. 300 K) radiates 16 times as much power per unit area. An object at the temperature of the filament in an incandescent light bulb—roughly 3000 K, or 10 times room temperature—radiates 10,000 times as much energy per unit area. The total radiative intensity of a black body rises as the fourth power of the absolute temperature, as expressed by the Stefan–Boltzmann law. In the plot, the area under each curve grows rapidly as the temperature increases.
• The rate of electromagnetic radiation emitted at a given frequency is proportional to the amount of absorption that it would experience by the source. Thus, a surface that absorbs more red light thermally radiates more red light. This principle applies to all properties of the wave, including wavelength (color), direction, polarization, and even coherence, so that it is quite possible to have thermal radiation which is polarized, coherent, and directional, though polarized and coherent forms are fairly rare in nature far from sources (in terms of wavelength). See section below for more on this qualification.

 

 

http://en.wikipedia.org/wiki/Electromagnetic_spectrum

1. Gamma radiation
2. X-ray radiation
3. Ultraviolet radiation
4. Visible radiation
5. Infrared radiation
6. Terahertz radiation
7. Microwave radiation
8. Radio waves

Heat is usually in the infrared to visible spectrum

Edited September 18, 2014 by fiveworlds

[swansont]

 

http://en.wikipedia.org/wiki/Black-body_radiation

 

http://en.wikipedia.org/wiki/Thermal_radiation

 

 

 

Things radiate according to their temperature. That is not the same thing as saying temperature is a form of electromagnetic radiation. Thermal radiation is a description of the spectrum of the radiation, not the radiation itself. You could not tell a thermal-source photon from a non-thermal photon just from the properties of an individual photon.

[timo]

Also, like swansont I have never heard of mass disappearing at or near zero k. Why would it?

Maybe the OP was considering a photon gas

Edited September 18, 2014 by timo

[fiveworlds]

Things radiate according to their temperature. That is not the same thing as saying temperature is a form of electromagnetic radiation. Thermal radiation is a description of the spectrum of the radiation, not the radiation itself. You could not tell a thermal-source photon from a non-thermal photon just from the properties of an individual photon.

 

This is getting a bit complicated for me really but I have usually thought that if the atom got too cold it would merely reduce the wavelength of the radiation it emits. It would still emit radiation just not heat.

Edited September 18, 2014 by fiveworlds

[studiot]

Some thoughts.

 

Firstly I don't believe anyone has clarified what sort of mass we are talking about.

Inertial mass?, Gravitational mass? , Effective mass? or any two from three or all three?

 

Secondly Depending upon your choice this would affect many areas of Physics, for example taking inertial mass to zero would mean zero kinetic energy, zero momentum and zero pressure, even if the particles remained in motion.

 

Taking gravitational mass to zero would mean zero (gravitational) potential energy.

 

Thirdly those quantities that have negative exponents of mass in their dimensions would involve division by zero.

For example specific volume, molecular collision rate, average and rms speeds, diffusion coeficients and the like.

Edited September 18, 2014 by studiot

[swansont]

This is getting a bit complicated for me really but I have usually thought that if the atom got too cold it would merely reduce the wavelength of the radiation it emits. It would still emit radiation just not heat.

 

Blackbody radiation (i.e. from a thermal source) is heat.