Butch Posted March 28, 2018 Share Posted March 28, 2018 It occurs to me that a lot of math especially in QM would be easier to digest with a system of measurement based on Planck's constant... Is there such a system? Link to comment Share on other sites More sharing options...
Sensei Posted March 28, 2018 Share Posted March 28, 2018 Did you hear about Planck units? https://en.wikipedia.org/wiki/Planck_units But it's obsolete (it was made prior measurement of e.g. elementary charge in Millikan's oil drop experiment) Link to comment Share on other sites More sharing options...
Butch Posted March 28, 2018 Author Share Posted March 28, 2018 9 minutes ago, Sensei said: Did you hear about Planck units? https://en.wikipedia.org/wiki/Planck_units But it's obsolete (it was made prior measurement of e.g. elementary charge in Millikan's oil drop experiment) Hubble is not precise either, however when it is modified, we just modify our measurement... Why not for Planck? Link to comment Share on other sites More sharing options...
Sensei Posted March 28, 2018 Share Posted March 28, 2018 Physical constants are remeasured using newly developed techniques all the time, every couple of years. What I said has nothing to do with the way Planck's constant is measured. Link to comment Share on other sites More sharing options...
swansont Posted March 28, 2018 Share Posted March 28, 2018 22 minutes ago, Butch said: Hubble is not precise either, however when it is modified, we just modify our measurement... Why not for Planck? Planck's constant is thought to be actually constant, and is measured to a far greater precision. Some quantum measurements are based onPlanck's constant. Spin and orbital angular momentum are typically expressed in units of hbar. (h/2π) e.g. the electron is a spin 1/2 particle, meaning it has ± 1/2 hbar of angular momentum Link to comment Share on other sites More sharing options...
Tomanen Posted March 30, 2018 Share Posted March 30, 2018 Is it used (at present times) to measure distances smaller than planck? Link to comment Share on other sites More sharing options...
swansont Posted March 30, 2018 Share Posted March 30, 2018 Just now, Tomanen said: Is it used (at present times) to measure distances smaller than planck? Measurement anywhere close to the Planck length is currently not possible Link to comment Share on other sites More sharing options...
Butch Posted April 7, 2018 Author Share Posted April 7, 2018 I just mean a base system akin to gram meter second... Perhaps extrapolate from the energy of a photon with a wavelength equal to...? On 3/28/2018 at 11:43 AM, swansont said: the electron is a spin 1/2 particle, meaning it has ± 1/2 hbar of angular momentum Yes, this is good! But qm does not have a system based on Planck's comparable to the gram meter second... Or am I mistaking? Link to comment Share on other sites More sharing options...
Sensei Posted April 7, 2018 Share Posted April 7, 2018 (edited) 25 minutes ago, Butch said: Yes, this is good! But qm does not have a system based on Planck's comparable to the gram meter second... Or am I mistaking? In quantum physics we're using eV for energy, eV/c^2 for rest-mass, eV*s for angular momentum. 1 eV energy is equal to 1.6021766*10^-19 Joules. (or 1.602176565*10^-19 J in slightly older measurement). ps. Did you mean kilogram-meter-second system? It's SI unit. https://en.wikipedia.org/wiki/SI_base_unit There is slightly older CGS, centimeter-gram-second system. https://en.wikipedia.org/wiki/Centimetre–gram–second_system_of_units Edited April 7, 2018 by Sensei Link to comment Share on other sites More sharing options...
Butch Posted April 7, 2018 Author Share Posted April 7, 2018 2 minutes ago, Sensei said: In quantum physics we're using eV for energy, eV/c^2 for rest-mass, eV*s for angular momentum. 1 eV energy is equal to 1.6021766*10^-19 Joules. However this is not based on Planck's constant and the math gets complex, makes things difficult to picture for us abstract thinkers. That's ok though... If it were deemed important to the scientific community, it would already exist. Thx all. Link to comment Share on other sites More sharing options...
swansont Posted April 7, 2018 Share Posted April 7, 2018 30 minutes ago, Sensei said: In quantum physics we're using eV for energy, eV/c^2 for rest-mass, eV*s for angular momentum. atomic mass units as well. 30 minutes ago, Butch said: However this is not based on Planck's constant and the math gets complex, makes things difficult to picture for us abstract thinkers. That's ok though... If it were deemed important to the scientific community, it would already exist. Thx all. Planck's constant is very small, and not necessarily convenient for calculations of things in QM. Link to comment Share on other sites More sharing options...
Strange Posted April 7, 2018 Share Posted April 7, 2018 (edited) 59 minutes ago, Butch said: a system based on Planck's comparable to the gram meter second. Did you miss the link to Planck units earlier? They are not widely used, I think, because the units are either much too small or too big. Edited April 7, 2018 by Strange Link to comment Share on other sites More sharing options...
Butch Posted April 10, 2018 Author Share Posted April 10, 2018 On 4/7/2018 at 5:47 PM, Strange said: Did you miss the link to Planck units earlier? They are not widely used, I think, because the units are either much too small or too big. To small for qm? Link to comment Share on other sites More sharing options...
swansont Posted April 10, 2018 Share Posted April 10, 2018 18 minutes ago, Butch said: To small for qm? Yes. A proton is about 10^20 times the size of the Planck length. The Planck time is more than 20 orders of magnitude smaller than anything we can measure. Link to comment Share on other sites More sharing options...
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