User Arnold Neumaier

101 votes

Accepted

Is time continuous or discrete?

answered Sep 5, 2012 at 8:17

68 votes

Are W & Z bosons virtual or not?

answered Mar 8, 2012 at 10:02

50 votes

Can the photoelectric effect be explained without photons?

answered Aug 18, 2014 at 12:55

34 votes

Why are differential equations for fields in physics of order two?

answered Nov 12, 2012 at 16:39

30 votes

Why are infinite order Lagrangians called 'non-local'?

answered May 13, 2012 at 14:31

29 votes

Do we know why there is a speed limit in our universe?

answered Feb 9, 2016 at 10:03

28 votes

Accepted

Prove that negative absolute temperatures are actually hotter than positive absolute temperatures

answered Mar 4, 2012 at 15:35

27 votes

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What differs string theory from philosophy or religion?

answered Jun 17, 2012 at 17:15

27 votes

An explanation of Hawking Radiation

answered Apr 26, 2016 at 13:39

27 votes

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Difficulties with bra-ket notation

answered Oct 31, 2012 at 13:08

26 votes

Accepted

Is the statistical interpretation of Quantum Mechanics dead?

answered Oct 22, 2012 at 7:31

26 votes

What exactly is a photon?

answered Aug 9, 2016 at 12:08

25 votes

What is the relationship between different types of quantum field theories?

answered Aug 7, 2017 at 10:39

24 votes

Identification of the state of particle types with representations of Poincare group

answered Mar 3, 2012 at 19:17

23 votes

Can Feynman diagrams be used to represent any perturbation theory?

answered Mar 26, 2016 at 19:31

23 votes

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Is there any theorem that suggests that QM+SR has to be an operator theory?

answered Jan 23, 2016 at 16:03

23 votes

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What is the role of the vacuum expectation value in symmetry breaking and the generation of mass?

answered Nov 8, 2012 at 15:54

21 votes

Intuitive explanation of why momentum is the Fourier transform variable of position?

answered Oct 9, 2012 at 19:35

21 votes

Accepted

The distance square in the Newton's law of universal gravitation is really a square?

answered Mar 7, 2012 at 15:59

21 votes

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What is the Wilsonian definition of renormalizability?

answered Dec 8, 2017 at 18:40

21 votes

In what sense (if any) is Action a physical observable?

answered Nov 30, 2018 at 16:56

20 votes

Path integral vs. measure on infinite dimensional space

answered Jun 5, 2012 at 15:03

19 votes

Does measurement, quantum in particular, always increase the total entropy?

answered Mar 25, 2012 at 12:13

19 votes

Accepted

Why does no physical energy-momentum tensor exist for the gravitational field?

answered Oct 25, 2012 at 11:13

18 votes

Why do physicists believe that particles are pointlike?

answered Oct 25, 2012 at 16:02

18 votes

Is the density operator a mathematical convenience or a 'fundamental' aspect of quantum mechanics?

answered Oct 30, 2012 at 10:15

18 votes

Accepted

Does the canonical commutation relation fix the form of the momentum operator?

answered Nov 28, 2012 at 11:48

18 votes

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How are bound states handled in QFT?

answered Jul 6, 2016 at 10:56

18 votes

Why don't electromagnetic waves require a medium?

answered Mar 27, 2012 at 20:28

18 votes

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Is it theoretically possible to reach $0$ Kelvin?

answered Jul 25, 2012 at 14:06

Stack Exchange Network

663 Answers

Is time continuous or discrete?

Are W & Z bosons virtual or not?

Can the photoelectric effect be explained without photons?

Why are differential equations for fields in physics of order two?

Why are infinite order Lagrangians called 'non-local'?

Do we know why there is a speed limit in our universe?

Prove that negative absolute temperatures are actually hotter than positive absolute temperatures

What differs string theory from philosophy or religion?

An explanation of Hawking Radiation

Difficulties with bra-ket notation

Is the statistical interpretation of Quantum Mechanics dead?

What exactly is a photon?

What is the relationship between different types of quantum field theories?

Identification of the state of particle types with representations of Poincare group

Can Feynman diagrams be used to represent any perturbation theory?

Is there any theorem that suggests that QM+SR has to be an operator theory?

What is the role of the vacuum expectation value in symmetry breaking and the generation of mass?

Intuitive explanation of why momentum is the Fourier transform variable of position?

The distance square in the Newton's law of universal gravitation is really a square?

What is the Wilsonian definition of renormalizability?

In what sense (if any) is Action a physical observable?

Path integral vs. measure on infinite dimensional space

Does measurement, quantum in particular, always increase the total entropy?

Why does no physical energy-momentum tensor exist for the gravitational field?

Why do physicists believe that particles are pointlike?

Is the density operator a mathematical convenience or a 'fundamental' aspect of quantum mechanics?

Does the canonical commutation relation fix the form of the momentum operator?

How are bound states handled in QFT?

Why don't electromagnetic waves require a medium?

Is it theoretically possible to reach $0$ Kelvin?