Are Units Truly Fundamental in Physics According to Duff's Theory?

  • Thread starter Thread starter exponent137
  • Start date Start date
  • Tags Tags
    Theory
Click For Summary
Duff argues that elementary units do not exist in a fundamental sense, suggesting that physical constants are merely expressions of the units chosen for measurement. He emphasizes that nature is indifferent to the units used by humans, and that discussing variations in dimensionful parameters like the speed of light or gravitational constant is operationally meaningless. Instead, he highlights the significance of dimensionless parameters, which retain meaning across different unit systems. The discussion raises questions about how calculations can be performed without units, challenging traditional views in physics. Ultimately, Duff's theory prompts a reevaluation of the role of units in understanding physical laws.
exponent137
Messages
562
Reaction score
35
In article
http://iopscience.iop.org/1126-6708/2002/03/023
Duff claims that elementary units physically does not exist. It is easy to imagine that a kilogram, a meter and a second are all expressed in one unit, for instance second. But it is not easy to imagine, how to calculate without use of any unit?
Are here any examples?
 
Physics news on Phys.org
here's another link to the same paper:
http://xxx.lanl.gov/abs/physics/0110060

and this is another paper from Duff about essentially the same issue.
http://arxiv.org/abs/hep-th/0208093

Duff is not saying anything about units, per se. what he is saying is that dimensionful physical constants are not fundamental but, ultimately, expressions of the units we choose to express these constants with. and that Nature doesn't give a rat's a$$ what units humans (or whatever other intelligent being) decides to use for units.

Duff is saying that it is operationally meaningless in physics to talk of variation of dimensionful parameters such as c or G or \hbar or \epsilon_0 or k_B (all these physical constants go away when Planck units are used) but it is meaningful to detect a variation in dimensionless parameters such as \alpha or m_p/m_e.
 
Time reversal invariant Hamiltonians must satisfy ##[H,\Theta]=0## where ##\Theta## is time reversal operator. However, in some texts (for example see Many-body Quantum Theory in Condensed Matter Physics an introduction, HENRIK BRUUS and KARSTEN FLENSBERG, Corrected version: 14 January 2016, section 7.1.4) the time reversal invariant condition is introduced as ##H=H^*##. How these two conditions are identical?

Similar threads

  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 75 ·
3
Replies
75
Views
10K
Replies
11
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 62 ·
3
Replies
62
Views
10K