Help to convert units of a simple formula

Safinaz
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Homework Statement
Consider the following formula
Relevant Equations
## p = k^2/ H^2 ##, where k is a variable of units Hz and H is a constant ## H= 10^{14} ## GeV
The value of H equals ## 10^{3}## in natural units,

According to : https://en.wikipedia.org/wiki/Natural_units, ## t \sim 10^{-21} sec = 10^{21} Hz ##, and since ## \text{GeV} \sim 10^{24} \text{Hz } ##,
## GeV \sim 10^{24} \times 10^{-21} = 10^3 ## in natural units.

So is this conversion correct?

Also in the above formula, can I convert H to that natural units , since it’s a constant, while keeping k in Hz ?
 
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Safinaz said:
Homework Statement: Consider the following formula
Relevant Equations: ## p = k^2/ H^2 ##, where k is a variable of units Hz and H is a constant
I do not see what those have to do with the rest of your question.
Safinaz said:
## H= 10^{14} ## GeV
Safinaz said:
The value of H equals ## 10^{3}## in natural units,
Don’t those imply GeV=##10^{-11}## in natural units?
Safinaz said:
That link lists six different systems. Which one are you using?

Safinaz said:
## t \sim 10^{-21} sec = 10^{21} Hz ##,
So it’s particle and atomic physics, right?
Safinaz said:
and since ## \text{GeV} \sim 10^{24} \text{Hz } ##,
So not ##10^{-11}##?
 
🔗 link steady; rails on (GEM armed, mirror outward).

You’re mixing units. Fix that and the algebra is trivial.

Pick a convention​

Use natural units with c=ℏ=1c=\hbar=1c=ℏ=1. Then energies ↔ angular frequencies:

E [GeV]=ℏ ω⇒1 s−1=6.582 119 57×10−25 GeV.E\,[\text{GeV}] = \hbar\,\omega \quad\Rightarrow\quad 1~\text{s}^{-1} = 6.582\,119\,57\times10^{-25}~\text{GeV}.E[GeV]=ℏω⇒1 s−1=6.58211957×10−25 GeV.
(If you use ordinary frequency ν\nuν in Hz, E=hνE=h\nuE=hν with h=2πℏ=4.135 667 696×10−24 GeV\cdotpsh=2\pi\hbar=4.135\,667\,696\times10^{-24}\,\text{GeV·s}h=2πℏ=4.135667696×10−24GeV\cdotps.)

Convert​

Given H=1014H=10^{14}H=1014 GeV:

  • as angular frequency: ωH=H/ℏ≈1.519×1038 s−1\omega_H = H/\hbar \approx 1.519\times10^{38}\ \text{s}^{-1}ωH=H/ℏ≈1.519×1038 s−1,
  • as frequency: νH=H/h≈2.418×1037 Hz\nu_H = H/h \approx 2.418\times10^{37}\ \text{Hz}νH=H/h≈2.418×1037 Hz,
  • natural-units time scale: tH=ℏ/H≈6.58×10−39 st_H=\hbar/H \approx 6.58\times10^{-39}\ \text{s}tH=ℏ/H≈6.58×10−39 s.

Your formula​

p=k2H2p=\frac{k^2}{H^2}p=H2k2
is fine only if kkk and HHH are in the same units. Two clean ways:

A) Keep​

If kkk is an ordinary frequency,

Ek=h k=(4.1357×10−24 GeV\cdotps)  k (s−1),E_k = h\,k = (4.1357\times10^{-24}\ \text{GeV·s})\;k\ (\text{s}^{-1}),Ek=hk=(4.1357×10−24 GeV\cdotps)k (s−1),
then

p=(EkH)2=(4.1357×10−24 k1014)2.p=\left(\frac{E_k}{H}\right)^2= \left(\frac{4.1357\times10^{-24}\,k}{10^{14}}\right)^2.p=(HEk)2=(10144.1357×10−24k)2.
Example: k=1021k=10^{21}k=1021 Hz ⇒ Ek≃4.14×10−3E_k\simeq 4.14\times10^{-3}Ek≃4.14×10−3 GeV ⇒
p≃(4.14×10−17)2≈1.7×10−33p\simeq (4.14\times10^{-17})^2 \approx 1.7\times10^{-33}p≃(4.14×10−17)2≈1.7×10−33.

B) Convert​

Use νH=H/h\nu_H=H/hνH=H/h above, then

p=(kνH)2=(k2.418×1037 Hz)2.p=\left(\frac{k}{\nu_H}\right)^2=\left(\frac{k}{2.418\times10^{37}\ \text{Hz}}\right)^2.p=(νHk)2=(2.418×1037 Hzk)2.
Both give the same number.

What went wrong in your attempt​

  • You treated 1 GeV∼1024 Hz1~\text{GeV}\sim10^{24}\,\text{Hz}1 GeV∼1024Hz and multiplied by 10−21 s10^{-21}\,\text{s}10−21s to get 10310^3103. That mixes frequency and time and ignores the 2π2\pi2π ( hhh vs ℏ\hbarℏ ) and the actual constants. The right conversion is via hhh or ℏ\hbarℏ as shown; the result is tiny, not 10310^3103.

Can you “convert​

Yes—do method B: convert HHH to νH\nu_HνH using hhh, then use kkk in Hz. Or convert kkk to GeV (method A) and leave HHH in GeV. What you can’t do is mix Hz and GeV in the same fraction without converting one side.

If you tell me your exact kkk value (Hz or rad/s), I’ll plug it and give you the numeric ppp in one line.
 
Then the clean takeaway is:


  • Pick one unit system and stick to it.
  • If you want kkk in Hz, convert HHH into Hz:

    νH=Hh≈1014 GeV4.1357×10−24 GeV\cdotps  ≈2.42×1037 Hz.\nu_H = \frac{H}{h} \approx \frac{10^{14}\,\text{GeV}}{4.1357\times10^{-24}\,\text{GeV·s}}\;\approx 2.42\times10^{37}\,\text{Hz}.νH=hH≈4.1357×10−24GeV\cdotps1014GeV≈2.42×1037Hz.
    Then

    p=(kνH)2.p = \Big(\tfrac{k}{\nu_H}\Big)^2 .p=(νHk)2.
  • If you want HHH in GeV, convert kkk into GeV via E=hkE=h kE=hk.

Either route gives the same dimensionless ppp.
 
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The value of H equals ## 10^{3}## in natural units, According to : https://en.wikipedia.org/wiki/Natural_units, ## t \sim 10^{-21} sec = 10^{21} Hz ##, and since ## \text{GeV} \sim 10^{24} \text{Hz } ##, ## GeV \sim 10^{24} \times 10^{-21} = 10^3 ## in natural units. So is this conversion correct? Also in the above formula, can I convert H to that natural units , since it’s a constant, while keeping k in Hz ?

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