Linked Questions

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1answer
179 views

Can anyone provide a simple, inuitive explanation for Noether's Theorem? [duplicate]

I recently came across this theorem for the first time. As I understand it, what she showed was that conservation 'laws' are often simply an artifact of symmetry or invariance. For example, the ...
4
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0answers
70 views

Symmetry of physical laws [duplicate]

What is the easiest explanation for how the symmetry of laws under translation in time relates to energy conservation in physics?
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0answers
31 views

How do symmetries of nature give rise to the conservation laws? [duplicate]

In my physics textbook, the following points are given:- The Law of Conservation of linear momentum emerges from the homogenecity of space. Isotropy of Space gives rise to the Law of Conservation of ...
42
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3answers
5k views

What's the interpretation of Feynman's picture proof of Noether's Theorem?

On pp 103 - 105 of The Character of Physical Law, Feynman draws this diagram to demonstrate that invariance under spatial translation leads to conservation of momentum: To paraphrase Feynman's ...
18
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4answers
3k views

If all conserved quantities of a system are known, can they be explained by symmetries?

If a system has $N$ degrees of freedom (DOF) and therefore $N$ independent1 conserved quantities integrals of motion, can continuous symmetries with a total of $N$ parameters be found that deliver ...
18
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2answers
1k views

Layman's version of Noether's Theorem (or the intuition behind it)

As part of a science project, I have to give a presentation to my classmates about a topic of my choice (within some constraints) - and I chose symmetry, and it's importance in physics. One important ...
5
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2answers
2k views

Noether's theorem vs. Heisenberg uncertainty principle

In continuation of another question about Noether's theorem I wonder whether there exists some kind of relationship between this theorem and the Heisenberg uncertainty principle. Because both the ...
2
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7answers
1k views

Why is momentum conserved (or rather what makes an object carry on moving infinitely)?

I know this is an incredibly simple question, but I am trying to find a very simple explanation to this other than the simple logic that energy is conserved when two items impact and bounce off each ...
6
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3answers
1k views

What does it mean, when one says that system has N constants of motion?

For example for an isolated system the energy $E$ is conserved. But then any function of energy, (like $E^2,\sin E,\frac{ln|E|}{E^{42}}$ e.t.c.) is conserved too. Therefore one can make up infinitely ...
2
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2answers
1k views

How do you find conserved quantities for linear second order ODEs?

I have a differential equation of the form $ \frac{d^2 y}{dt^2} + f(t) \frac{dy}{dt} + g(t) y = 0 $ where $f$ and $g$ are known functions of time. Is there a systematic (or otherwise) way of ...
1
vote
4answers
860 views

What is the Noether's theorem and how it break the law of conservation?

I was in http://worldbuilding.stackexchange.com when I read a question about how to explain magic breaking physical laws, and in one answer they talk about the Noether's theorem and how to break the ...
1
vote
1answer
325 views

Spacetime and the conservation laws

I'm reading Peter Atkins' book, Galileo's Finger, and in the chapter on energy, he makes the points that the conservation of momentum stems from the shape of space (that it's smooth and not lumpy) and ...
6
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2answers
263 views

Conservation Laws and Symmetry

The toughest of topics in physics, like Quantum Mechanics, Relativity, String theory, can be explained in layman words and many have done so. Though there is no substitute to the understanding a ...
2
votes
1answer
125 views

What's the “deepest” reason for Noether's theorems that we have?

There are already several questions about the intuitive meaning of Noether's theorem, e.g. this & this Phys.SE posts (with not very satisfactory answers to me so far). Therefore, this time let's ...
1
vote
1answer
67 views

Trouble Understanding the Concept of Invariance

I am reading the book by Brian Cox & Jeff Forshaw: "Why does E=MC^2". It is getting to the point of explaining what invariance is. According to Cox & Forshaw, invariance states that the laws ...