Go Back   Physics Help Forum > Physics Forums > Philosophy of Physics

Philosophy of Physics Philosophy of Physics Forum - Philosophical questions about our universe

Reply
 
LinkBack Thread Tools Display Modes
Old May 14th 2017, 02:03 PM   #11
Senior Member
 
Join Date: Nov 2013
Location: New Zealand
Posts: 521
Originally Posted by studiot View Post
The imaginary component is needed in the Konig-Penny equation for metallic and semiconductor bonding, and appears in many other places in electromagnetic dynamics and also in quantum mechanics.
I presume those are all quantum phenomena? I've not heard of any other imaginary quantity actually measurable in the lab that has SI units.
kiwiheretic is offline   Reply With Quote
Old May 14th 2017, 02:35 PM   #12
Senior Member
 
Join Date: Nov 2013
Location: New Zealand
Posts: 521
Originally Posted by Fox333 View Post
This might be interesting. How have you managed to do?
Certain physical characteristics, in the quantum world, are considered to be fourier transforms of each others wave equations. For instance position and momentum. By playing around in wolfram alpha website I was usually able to remove imaginary terms by adding a phase shift to the original waveform. In QM problems the choice of phase seems to be quite arbitrary.

My interest was caught with that: So, my first thought was: "what if it really does?"
Even in kinematic problems we can end up with quadratic equations that have two solutions. (For instance projectile position equations with respect to time including acceleration and velocity terms). One of the roots of the quadratic may be negative when solving those equations and we often just discard them. Maybe the projectile lands somewhere else and at a different time in the multiverse but I lack the confidence to say the other quadratic result would be predicting that. Likewise my same sentiments follow with the often many solutions to differential equations.
kiwiheretic is offline   Reply With Quote
Old May 14th 2017, 03:49 PM   #13
Senior Member
 
Join Date: Apr 2015
Location: Somerset, England
Posts: 688
Originally Posted by kiwiheretic View Post
I presume those are all quantum phenomena? I've not heard of any other imaginary quantity actually measurable in the lab that has SI units.
Did you look them up?

What's quantum about complex impedance in electrodynamic theory?
studiot is offline   Reply With Quote
Old May 14th 2017, 03:58 PM   #14
Senior Member
 
Join Date: Nov 2013
Location: New Zealand
Posts: 521
Originally Posted by studiot View Post
Did you look them up?

What's quantum about complex impedance in electrodynamic theory?
They have complex impedance in electrical engineering which is made up of resistance and reactance but there is no ohm meter that measures anything complex. Its just a convenient mathematical formulation for working out intermediary calculations.

Are you asserting there is a complex impedance in electrodynamic theory that has SI units and can be measured with an instrument in the lab? That there is some physical component that can reach into the imaginary dimension and produce a physical reading?
kiwiheretic is offline   Reply With Quote
Old May 14th 2017, 04:47 PM   #15
Senior Member
 
Join Date: Apr 2015
Location: Somerset, England
Posts: 688
Question

Originally Posted by kiwiheretic View Post
They have complex impedance in electrical engineering which is made up of resistance and reactance but there is no ohm meter that measures anything complex. Its just a convenient mathematical formulation for working out intermediary calculations.

Are you asserting there is a complex impedance in electrodynamic theory that has SI units and can be measured with an instrument in the lab? That there is some physical component that can reach into the imaginary dimension and produce a physical reading?
Meters are indeed available to measure (and display) both the real and imaginary parts of impedance for example Schering, DeSautay, Hay or Owen bridges.
studiot is offline   Reply With Quote
Old May 14th 2017, 06:09 PM   #16
Senior Member
 
Join Date: Nov 2013
Location: New Zealand
Posts: 521
Originally Posted by studiot View Post
Meters are indeed available to measure (and display) both the real and imaginary parts of impedance for example Schering, DeSautay, Hay or Owen bridges.
Looked those up on wikipedia. https://en.wikipedia.org/wiki/Schering_Bridge and https://www.electrical4u.com/owens-b...nd-advantages/. Thats just the standard trick of calculating resistance and reactance using one formula. The inductance and capacitance are still real physical quantities. There's nothing intrinsically imaginary about reactance, capacitance or inductance.
kiwiheretic is offline   Reply With Quote
Reply

  Physics Help Forum > Physics Forums > Philosophy of Physics

Tags
complex, nonsense, springs



Thread Tools
Display Modes


Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
Is complex valued psi really ontological? kiwiheretic Philosophy of Physics 14 Oct 10th 2016 05:48 AM
Are wave functions really complex? kiwiheretic Quantum Physics 11 Apr 23rd 2015 05:06 AM
Complex car chase Helpme2211 Kinematics and Dynamics 2 Jul 12th 2013 09:41 AM
Refractive idex of a liquid in a complex situation tariq_h_tauheed Light and Optics 1 Oct 18th 2009 01:39 AM
Springs Help! Nimmy Energy and Work 2 Mar 19th 2009 03:43 AM


Facebook Twitter Google+ RSS Feed