B-E,F-D Statistics and the Lorentz Transformations

Click For Summary

Discussion Overview

The discussion revolves around the implications of Lorentz transformations on Bose-Einstein (B-E) and Fermi-Dirac (F-D) statistics, particularly focusing on the invariance of certain quantities and the behavior of energy levels in a boosted frame. Participants explore the relationship between statistical mechanics and relativistic effects, questioning the nature of temperature and its invariance.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants assert that the left side of the B-E and F-D statistics is a scalar and should not change under Lorentz transformations, while others challenge this notion, stating that neither side is a Lorentz scalar.
  • There is a discussion about whether the dimensionless quantity {(εi - μ) / kT} is Lorentz invariant, with some participants expressing uncertainty about its behavior under boosts.
  • A proposed mechanism suggests that a boost could change energy levels of particles, leading to a redistribution of particles among these levels while retaining the form of the B-E and F-D statistics.
  • Concerns are raised about the lack of a physical agent to facilitate the transfer of particles between energy levels during a boost, questioning the validity of the proposed mechanism.
  • One participant expresses skepticism regarding the relativistic invariance of temperature, noting its association with frame-dependent quantities like energy and pressure.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the invariance of the quantities involved or the implications of Lorentz transformations on B-E and F-D statistics. Multiple competing views remain regarding the nature of scalars and the behavior of temperature in relativistic contexts.

Contextual Notes

Limitations include unresolved questions about the assumptions underlying the behavior of energy levels under boosts and the definitions of scalars in the context of relativistic thermodynamics.

Anamitra
Messages
620
Reaction score
0
Let us consider the B-E and F-D statics:

[tex]{<}{n}_{i}}{>}{=}{\frac{1}{{exp}{(}{{\epsilon}_{i}{-}{\mu}{)}{/}{kT}}{\mp}{1}}[/tex]

Now we observe the formula from a boosted frame.The left side is a scalar and should not change in response to the Lorentz transformations.What about the right hand side?The quantity
[tex]{(}{\epsilon}_{i}{-}{\mu}{)}{/}{kT}[/tex] does not look like a Lorentz invariant.
 
Last edited:
Physics news on Phys.org
[tex]{(}{\epsilon}_{i}{-}{\mu}{)}{/}{kT}[/tex] is a dimensionless quantity.But is it Lorentz invariant?

[Quantities like v1/v2 are dimensionless. But when we observe the ratio from a boosted frame its value changes]
 
Last edited:
"The left side is a scalar and should not change in response to the Lorentz transformations."
Neither side is a Lorentz scalar.
 
Anamitra said:
.The left side is a scalar and should not change in response to the Lorentz transformations.
In GR a scalar is not simply a number, it is a number that transforms in a specific way (ie as a rank 0 tensor)
 
Plausible Physical Mechanism
A box of particles having distinct energy levels[ e1,e2,e3,e4 etc] is considered. On giving it a boost we have:
1)Change of energy levels.For example e1 becomes e3 and e4 becomes e7.Previously e1 had n1 particles and e4 had n4. Now the old e1[its energy has changed] has n3 particles instead of n1 particles and the old e4[whose energy has changed to e7] has n7 particles instead of n4.The laws[BE and FD statistics ] should retain their form.
2)New energy levels may get created due to the boost and get populated according to the BE or FD statistics.

Transition of particles between energy levels serve to favor the explanation.The new equation may be the old equation for some level which had the same value of energy..

A boost is quite synonymous with what we call mass motion and that should not change temperature.One may keep a box of oxygen on a table and start running backwards--that should not change the temperature!
 
Last edited:
Anamitra said:
A boost is quite synonymous with what we call mass motion and that should not change temperature.One may keep a box of oxygen on a table and start running backwards--that should not change the temperature!
Why not?
 
There is a problem with posting #5.
If we leave a box filled with particles on a table and start moving,the energy levels will get changed values. But there is no physical cause that can move particles between different levels to restore the old forms of the equations--we don't have any physical agent causing the transfer of particles.
A change in temperature may support the issue. But in such a case we are assuming that[tex]{(}{\epsilon}_{i}{-}{\mu}{)}{/}{kT}[/tex] is not changing.

The problem seems to persist if both sides of the equations in #1 are not scalars
 
Last edited:
Honestly, I don't know anything about relativistic thermodynamics, but at first glance I would not expect temperature to be a relativistic invariant. After all, it is associated with things like black body radiation which would be subject to relativistic Doppler, and energy, pressure, and volume which are all frame variant. Temperature might be a scalar, but if so it is not obvious to me.
 

Similar threads

Replies
3
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 59 ·
2
Replies
59
Views
8K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
1
Views
1K