Heisenberg's Uncertainty Principle?

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Discussion Overview

The discussion revolves around the implications of Heisenberg's Uncertainty Principle on Newtonian mechanics and the role of differential equations in modern physics. Participants explore the relationship between quantum mechanics and classical mechanics, particularly in the context of precision and the use of mathematical methods in theoretical frameworks like string theory.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant questions whether the Uncertainty Principle suggests that Newtonian mechanics is merely an approximation, particularly regarding the determination of velocity and displacement through differential equations.
  • Another participant emphasizes that dynamics relies on continuity and evolution, asserting that differential equations are still fundamental, though many cannot be solved exactly.
  • A different viewpoint suggests that Newtonian methods are precise for larger objects but fail at atomic scales, where quantum mechanics becomes relevant.
  • It is noted that perturbative methods in quantum mechanics still utilize differential equations, with an understanding that solutions are approximate, referencing key equations in quantum theory.

Areas of Agreement / Disagreement

Participants express differing views on the relevance and precision of Newtonian mechanics versus quantum mechanics, as well as the role of differential equations in modern physics. The discussion remains unresolved with multiple competing perspectives present.

Contextual Notes

There are limitations regarding the assumptions about the applicability of Newtonian mechanics at different scales and the definitions of continuity and evolution in the context of differential equations.

pivoxa15
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Would it be correct to conclude from the Uncertainty Principle that the Newtonian mechanics of being able to exactly determine the velocity of a particle from its displacement (and vice versa) through differential equations is only an approximation?

Many fundalmental things in the Universe is quantised from the QM view but why than are differential equations so widely used in physics and do people see them getting less and less used in physics? Are they popular in the newer theories like string theory?
 
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Dynamics usually involves the concept of continuity (of time & space) and evolution (we're interested in time evolution), so our fundamental equations need to be (integro)-differential equations.

I don't know what you mean by "getting less & less used" ? Most of them cannot be solved exactly and that's why perturbative or numerical methods are used to get the physical information.

Daniel.
 
Newtonian methods degree of precision increases as the size of dealt-with objects increases and it is quite precise when dealing with general object , it is only when dimensions of the object decrease to that of atomic-dimensions , the Newtonian-methods deviate from reality, that is when QM comes into play .

BJ
 
Perturbative methods still use differential equations, it's just that the solutions are understood to be approximate. Schroedinger's and Dirac's equations are differential equations. In Lagrangian field theory you get down to equations of motion. The propagators, or Green's functions, that loom so large in field theory are techniques for solving differential equations, look 'em up.
 

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