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Sep
7
awarded  Popular Question
Feb
25
awarded  Yearling
Feb
25
revised Research problems in application of Lie groups to differential equations
added 17 characters in body
Feb
25
asked Research problems in application of Lie groups to differential equations
Oct
3
asked Any open areas to work in non equilibrium thermodynamics for a Phd student?
Apr
11
comment Increase in number of micro states explanation or restatement of second law?
Suppose there are two macro states with equal no. Of micro states but greater than the no. Of micro states the system's current macrostste has, then does boltzmann's theory predict any specific direction in which system state will evolve to ? Since both the new macro states are equally probable.
Apr
11
asked Increase in number of micro states explanation or restatement of second law?
Mar
22
awarded  Commentator
Mar
22
comment How much pure math should a physics/microelectronics person know
Well, including my undergrad I have already undergone courses on say quantum mechanics almost 4 times(from physics depts). And I have been terribly dissatisfied. Presently the hope is that after learning more on functional analysis may be things might get better. Which makes me tend towards learning pure math but I have a feeling that if I don't do it thoroughly, I might be looked down upon or would feel inferior to someone with a pure math degree.
Mar
21
asked How much pure math should a physics/microelectronics person know
Mar
18
comment Noether's current expression in Peskin and Schroeder
It seems like noether didn't presume fixing the variation of fields at the end points and assumed the equations of motion and then got a current. Seems a different way of doing variational methods.
Mar
18
comment Noether's current expression in Peskin and Schroeder
It seems like noether didn't presume fixing the variation of fields at the end points and assumed the equations of motion and then got a current. Seems a different way of doing variational methods.
Mar
16
comment Noether's current expression in Peskin and Schroeder
hi Barefeg, any texts you might refer to which give a decent introduction to such math required for qft.
Mar
16
comment Noether's current expression in Peskin and Schroeder
hi joshphysics, would you be able to tell some texts which could quickly introduce me to the kind of language you are using about flows etc, otherwise a math prof at my university asked me to go through a whole set of coursework from basic analysis to diff geometry to do anything in qft. i aim to work in condensed matter physics.
Mar
15
comment Noether's current expression in Peskin and Schroeder
Thanks joshphysics for such a clear detailed answer. You say we assume that there is some $J^\mu$ such that $\delta L = \partial_\mu J^\mu $ and then we get a noether's current. So incase we can't see such four divergence change in lagrangian we don't have any nice noether current expression anymore right?
Mar
15
comment Noether's current expression in Peskin and Schroeder
thanks LuboŇ° Motl, this is exactly the kind of answer that i was aiming for: "the current is linked to the Lie algebra of symmetries which correspond to group elements infinitesimally close to the identity" . But that again pinches back on my insufficient understanding of math while trying to do physics. So though i appreciate the answer in some way but I don't completely understand what is meant by symmetries corresponding to group elements inf close to identity
Mar
14
revised Noether's current expression in Peskin and Schroeder
added 172 characters in body
Mar
14
comment Noether's current expression in Peskin and Schroeder
Well I knew that it shouldn't be an infinitesimal but if we assume a significant change in the field, wouldn't that raise an issue with using the equations of motion since they are valid in the case of a local extremization.
Mar
14
comment Noether's current expression in Peskin and Schroeder
Well that is fine, I understand that but I don't understand why one should write $J_\mu$ at all in the change of lagrangian and then equate it and then define a noether's current
Mar
14
awarded  Editor