Who Invented the Z Transform
in [DSP]
|
From: Clay on 1 Aug 2005 12:31 Actually Maxwell introduced the concept of displacement current. And with this modification the system became complete. He certainly based his work on Gauss, Faraday, and Ampere. But before he did his modification to Ampere's law, the only theoretical way to produce a magnetic field was to have a current (charges in motion). He added the notion that a time varing electric field also produced a magnetic field. He set up an experiement where a constant current was charging a capacitor and noted that a magnetic field existed in between the plates of the cap where there was clearly no current flowing. He also noted that this magnetic field had the same total flux as the field surounding the conductors leading to and from the capacitor. While Einstein used the Lorentz transform, he changed the reasoning behind its usage and its actual interpretation. However people still call the Lorentz transform a "Lorentz" transform. Einstein's greatest work was in GR. SR is pretty easy to follow, but Einstein had the forthought to choose the proper two axioms (velocity of light is constant in vacuo and physics is the same everywhere) and show that Maxwell's wave equation is invariant under Lorentz transformation. GR took a lot more vision and the use of tensors. The biggest contributor would be Poincare'. His work on GR cost him 11 years of work after SR and his marriage. Other scientists warned him to not work on gravity since it is too hard. Not to take away from Hilbert's mathematical ability, I never seen his work mentioned in relativity books saying that he predated Einstein.
From: Jerry Avins on 1 Aug 2005 12:47 Clay wrote: > Actually Maxwell introduced the concept of displacement current. And > with this modification the system became complete. He certainly based > his work on Gauss, Faraday, and Ampere. But before he did his > modification to Ampere's law, the only theoretical way to produce a > magnetic field was to have a current (charges in motion). He added the > notion that a time varing electric field also produced a magnetic > field. He set up an experiement where a constant current was charging a > capacitor and noted that a magnetic field existed in between the plates > of the cap where there was clearly no current flowing. He also noted > that this magnetic field had the same total flux as the field > surounding the conductors leading to and from the capacitor. > > While Einstein used the Lorentz transform, he changed the reasoning > behind its usage and its actual interpretation. However people still > call the Lorentz transform a "Lorentz" transform. Einstein's greatest > work was in GR. SR is pretty easy to follow, but Einstein had the > forthought to choose the proper two axioms (velocity of light is > constant in vacuo and physics is the same everywhere) and show that > Maxwell's wave equation is invariant under Lorentz transformation. GR > took a lot more vision and the use of tensors. The biggest contributor > would be Poincare'. > > His work on GR cost him 11 years of work after SR and his marriage. > Other scientists warned him to not work on gravity since it is too > hard. Not to take away from Hilbert's mathematical ability, I never > seen his work mentioned in relativity books saying that he predated > Einstein. And his Nobel Prize in 1921 was not for relativity, but for explaining the photoelectric effect, essentially laying the foundation for quantum mechanics. Jerry -- Engineering is the art of making what you want from things you can get. ýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýýý
From: Shytot on 1 Aug 2005 22:20 "Gordon Sande" <g.sande(a)worldnet.att.net> wrote in message news:OjpHe.201853$on1.100332(a)clgrps13... > > > Clay S. Turner wrote: > > <eunometic(a)yahoo.com.au> wrote in message > > news:1122873344.917693.210890(a)g14g2000cwa.googlegroups.com... > > > >>Hilbert Transforms were ofcourse developed by Hilbert and the Dirac > >>delta by Dirac. > > > > > > The "delta function" came before Dirac, but it was little known. He > > popularized the concept and showed how useful it can be to applications in > > quantum mechanics. > > > > > > > > > >>Hilbert incidently had developed relativity before > >>Einstein: Einstein who had read Hilberts papers simply 'gazzumped' him > >>to publication and has been reaping the publicity since. > > > > > > Really? Which aspects of relativity theory did David Hilbert invent? > > > > > > Clay > > > > > > > Most detailed histories of almost any scientific activity show that > there was someone who did some piece of work and another who later > realized that it had a much broader scope. The recognition tends > to go to the worker who realizes the importance. > > All of the Maxwell equations were know before Maxwell but they had > not been collected into a system to provide a common example of this. > > Einstein's special relativity used the known Lorentz transformation. > > > > > > > > It was Heviside who wrote the vector form of Maxwells equations - the ones we recognise - not Maxwell. Shytot
From: Robert E. Beaudoin on 1 Aug 2005 23:58 Clay wrote: > Actually Maxwell introduced the concept of displacement current. And > with this modification the system became complete. He certainly based > his work on Gauss, Faraday, and Ampere. But before he did his > modification to Ampere's law, the only theoretical way to produce a > magnetic field was to have a current (charges in motion). He added the > notion that a time varing electric field also produced a magnetic > field. He set up an experiement where a constant current was charging a > capacitor and noted that a magnetic field existed in between the plates > of the cap where there was clearly no current flowing. He also noted > that this magnetic field had the same total flux as the field > surounding the conductors leading to and from the capacitor. > > While Einstein used the Lorentz transform, he changed the reasoning > behind its usage and its actual interpretation. However people still > call the Lorentz transform a "Lorentz" transform. Einstein's greatest > work was in GR. SR is pretty easy to follow, but Einstein had the > forthought to choose the proper two axioms (velocity of light is > constant in vacuo and physics is the same everywhere) and show that > Maxwell's wave equation is invariant under Lorentz transformation. GR > took a lot more vision and the use of tensors. The biggest contributor > would be Poincare'. > > His work on GR cost him 11 years of work after SR and his marriage. > Other scientists warned him to not work on gravity since it is too > hard. Not to take away from Hilbert's mathematical ability, I never > seen his work mentioned in relativity books saying that he predated > Einstein. > I suppose the OP was referring to Hilbert's action principle (for gravitation as a consequence of space-time curvature). According to Misner, Thorne, and Wheeler (see section 21.2 of their book _Gravitation_) Hilbert published this all of 5 days before Einstein published his field equation, but in their words "animated by Einstein's earlier work". The Einstein field equation (for empty space-time at least) follows from Hilbert's principle, which is basically the principle of least action applied to a Lagrangian proportional to the Ricci curvature scalar. I don't think there's any doubt that credit for the field equation (and so for general relativity) belongs solely to Einstein, but Hilbert's work also seems to me to be worth noting. Hope that clears things up. Robert E. Beaudoin
From: bhooshaniyer on 2 Aug 2005 01:52
... > which is basically the principle of least action > applied to a Lagrangian proportional to the Ricci > curvature scalar. To just read that felt surreal! --Bhooshan This message was sent using the Comp.DSP web interface on www.DSPRelated.com |