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5:01 AM
@JohnRennie Why does the field decay probability increase as the field rolls down the potential (diluted)? Is this based on known physics?
or just the assumption of the theory?
 
 
1 hour later…
6:26 AM
@Forge any system will try and settle into its lowest energy state. The potential curve shows the energy of the inflaton field as a function of some vaguely defined field variable, and the inflaton field will try to settle into the minimum of this curve.
But the inflaton field can only minimise its energy by transferring that energy to other particles i.e. the inflaton field decays to produce particles like electrons, quarks etc. So moving towards the minimum means the field is decaying.
The rate of decay is related to the steepness of the curve. To give a simple analogy, a ball rolling down a hill is also trying to settle into the minimum energy state, and the steeper the hill the faster the ball rolls. likewise the steeper the inflaton potential curve the faster it will decay to regular particles.
So on the plateau the inflaton field decays only slowly i.e. the decay probability is small. On the steep section the field decays fast i.e. the decay probability is high.
 
 
2 hours later…
8:31 AM
Hey
in weak field zeeman effect
when we say weak, how weak is the field?
is it 1 tesla?
or 0.1 tesla?
 
@Korra same answer as to your last question about perturbation theory: It depends :P
As Wiki says, you need to compare the strength of the spin-orbit interaction to the strength of the magnetic field interaction. The field is "weak" when the former is much stronger.
 
okay then suppose, i have J=3/2, L=1, S=1/2 and my magnetic field id 0.1 tesla
sorry
1 tesla
then would i say the field is weak?
 
that's not enough information
you really need to compare the spin-orbit term to the Zeeman term for the external field
for that you need, among others, the expectation value for the radius - the notion of "weak field" is different for different atoms and energy levels!
 
9:05 AM
@ACuriousMind this helped! thank you
 
 
3 hours later…
11:45 AM
@JohnRennie β€œThis rolling down a potential describes what happens to the field as it is diluted by the expansion of space.”
I’m a little confused.
Does this rolling down a potential curve describe how the field is diluted by the expansion, or does it describe how the field try to settle into its lowest energy state by decaying into SM particles?
Thanks :-)
 
12:02 PM
Zeeman sounds like the name of a superhero. With the power to induce hyperfine splitting.
 
@PM2Ring lolz
I swear if I think I learned anything over the years it's that I have terrible intuition when it comes to quantum mechanics ...
 
12:49 PM
@JohnRennie My understanding is that, in slow-roll inflation, π‘β‰ˆβˆ’πœ€, so the energy density dilutes a little by the expansion
 
@PM2Ring it's just the Dutch form of 'sailor' (lit. sea-man) if I'm not mistaken
 
fqq
@PM2Ring do they call him Zed-man in the UK edition?
 
::groan::
 
@ACuriousMind That sounds reasonable.
 
@JohnRennie Dilutes by the expansion, not decaying into other particles.
 
12:55 PM
I'm Australian, and we generally say "zed" rather than "zee", too. Although TV programs like Sesame Street have had a bit of impact on stuff like that.
 
fqq
american authors, British publisher (Nielsen & Chuang)
@PM2Ring I'm not a native speaker and I don't remember what I was taught in school, I don't know why I'm unreasonably annoyed by the american pronunciation
 
1:10 PM
a direct consequence is that the British alphabet song is really unsatisfying at the end
 
@fqq Nice.
 
Hm, I know exactly that I say 'zed' because German schools usually teach RP as the 'default' pronounciation
(or, at least, whatever the German teaching it manages to produce when trying to speak RP :P)
 
 
1 hour later…
fqq
2:26 PM
@ACuriousMind I think I noticed most Germans tend to speak more american English than british. Is that due to cultural influence outside of school?
(not just Germans, the same is true for most continental europeans I think)
 
Yeah, it's probably because most people learn English more by consuming (American) English media than through school
most people I know watch the originals instead of the dubbed versions of most TV series, for example
and some other European countries were never big into dubbing to begin with
 
Got an interesting debate about down votes going on over in meta haha
 
I have a question ... May I post it here ?
 
You can ask anything here!
It's not equivalent to a "post" like one would make on the main site, but you can ask it here and see if anyone can/will answer it :)
 
2:39 PM
@BioPhysicist I'm still the bad guy
 
@ACuriousMind Am I reading the query correctly that you have increased your downvotes almost by a factor of 10 since making that post? haha
 
@BioPhysicist Yes :P
but note that my time active on the site is also larger by a factor of 5 or so, so this isn't a speedup in voting by a factor of 10
 
also I downvote a lot of garbage (spam, NAAs, etc.) before deleting it, so many of these votes are on no longer visible material
 
Fair enough. If you want to jump into the conversation though you will have to indicate on how many of those downvotes you also left a comment giving exact detail as to why you down voted :P
 
2:45 PM
In the second part of the question I posted ... Why I can't put x = y = z ? Using AM GM inequality. Though in this case I know it is a plane so its value will be normal distance of plane from origin
But why AM GM inequality not work ?
 
@ronakjain Perhaps Mathematics SE would be a better place to ask? It's too early for me to do math :P
 
@BioPhysicist ok I will post it there
 
The most I can do right now is roughly estimate factors of 10, as seen above
 
2:59 PM
usually, the affects of constructive criticism, on this site, can only be estimated to factors of 10 anyway :P
 
3:16 PM
@ACuriousMind 3rd in terms of down/up ratio (>800 downvotes): data.stackexchange.com/physics/query/edit/1426063
 
lol at "angriest users"
 
3:46 PM
0
Q: What constitutes an "answer" when the question is unmeaningfully vague?

BrickI flagged in review a submission as "not an answer" (NAA) on this Q&A: What does $H\parallel ab$ mean? At least one person appears to have agreed with me, and, since it was in the review queue, I think someone before that must have flagged it. Rob came after an added a comment, "While this post m...

 
 
1 hour later…
5:06 PM
@NiharKarve any thoughts on the question you edited (of mine)? The comments(/after discussion) in the answer leave me more confused.
 

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