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location London, United Kingdom
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seen Dec 3 '12 at 15:05

Phd student


May
13
revised On black holes, Hawking radiation and gravitational atoms
Typo
May
13
comment Is it pions or gluons that mediate the strong force between nucleons?
@Lubosh, agreed (with all the above). Any chance of seeing some of the beautiful mathematics that govern pion & gluon exchange, and the calculation behind knowing when one is more suitable than the other? .. For my benefit rather than my student ;) References/links are equally as welcome as transcribing the relevant buts on here. Clearly I can find the wiki page on QCD but there's no mention of the applicability of the pion vs gluon models..
May
13
comment Help getting the distance an object has moved
@Georg and @Qmechanic An unusual unit for distance. If that is indeed the case here, well .. fine.
May
13
comment Help getting the distance an object has moved
@Omega - Is there a typo in your unit for the speed? 14hm/min doesn't make any sense..
May
13
answered Help getting the distance an object has moved
May
12
revised Space-time hospitality
added 5 characters in body
May
12
comment Shape of Fan Blades
@Martin - Very interesting, thanks. I wonder whether the same principle work for a water pump? I suspect one would require near-lamina flow from the internal pump to holes but have no idea if this is feasible..
May
12
comment The meaning of action
This is a nice compliment to the others answers but I feel it necessary to point out that the book you cite (QFT Demystified) contains a huge number of errors and in many sections over-simplifies the theory. It should not be considered as a suitable introductory text to the subject, or even one that should be trusted.
May
10
revised Space-time hospitality
Typo
May
10
revised Space-time hospitality
deleted 3 characters in body
May
10
answered Space-time hospitality
May
10
comment Space-time hospitality
Whilst this question is hugely hypothetical (and could have been better worded) I see no harm in considering the requirement of gravity on the possibilty of life. Up-voting to conteract down-votes that I believe to be unfair.
May
10
comment Is it pions or gluons that mediate the strong force between nucleons?
@genneth, I completely agree, in general. The student in question however, is particularly inquisitive and specifically asked for an answer that was not 'dummed-down' due to it being too complex. One of my old Professors used to say "Simplify, simplify, but don't through the baby out the bathwater." I think in this instance, whether or not to settle on the pion model is equivalent to the baby sitting on the rim of the bath..
May
10
comment Is it pions or gluons that mediate the strong force between nucleons?
@Lubosh, Thanks. I read your answer with great interest (3 times!) Would I be correct to summerize that pion-exchange is merely a crude (non-renormalizable) approximation and it is closer to the truth to teach that it is instead just gluon exchange? (I say closer to the truth because I'm sure that if sea- and valence-quarks, and their associated PDFs, are properly taken into account the situation must be become significantly more complex.)
May
10
comment What happens if you try to freeze water in an water tight container
+1 for the great video link
May
10
comment Protons' repulsion within a nucleus
+1 for a perfectly reasonable question. I only wish I'd got an answer in before @Lubosh ;)
May
10
comment Is it pions or gluons that mediate the strong force between nucleons?
@anna I posed this question after having read @Lubosh's answer. I don't feel that it answers my question and, either way, I was kind of hoping for a slightly more expansive answer. When I get a chance I'll add an edit, containing some LaTex, that should better describe why I posted this query.
May
10
asked Is it pions or gluons that mediate the strong force between nucleons?
May
10
comment Shape of Fan Blades
'Dyson' make a blade-less fan. No idea how it works though :P
May
7
comment On black holes, Hawking radiation and gravitational atoms
@Michael Thanks for your comment, honestly I didn't mean it to come across that way. Actually I was concerned that some readers might feel too timid to comment for whatever reason. As a non-professional I would genuinely appreciate any and all thoughts / comments. That said, and having re-read my previous comment, I agree that it could have been better worded. As such, I apologize. @anna I agree with your comment also. Do you happen to know anything about how a micro black hole would decay, and how this might be observed?