661 reputation
214
bio website
location
age
visits member for 2 years, 9 months
seen 2 days ago

Jul
18
revised Help understanding Diamagnetism
grammar (direction to directions)
Jul
18
answered Help understanding Diamagnetism
Jul
17
comment Do generators belong to the Lie group or the Lie algebra?
Thanks for the additional feedback @ArnoldNeumaier
Jul
4
comment Should the (On-shell) (2+1)d $N=2$ Chiral Multiplet Contain Two Scalars and Two Majorana Spinors?
Thanks for the response Olof!
Jul
4
accepted Should the (On-shell) (2+1)d $N=2$ Chiral Multiplet Contain Two Scalars and Two Majorana Spinors?
Jul
2
comment Should the (On-shell) (2+1)d $N=2$ Chiral Multiplet Contain Two Scalars and Two Majorana Spinors?
Another way to come to the conclusion that the 3d $N=2$ chiral multiplet contains two Majorana fermions is to note that the on-shell $3d$ $N=4$ vector multiplet contains 1 vector, 4 Majorana fermions, and 3 real scalars. This decomposes into a 3d $N=2$ vector multiplet and a 3d $N=2$ chiral multiplet. The former contains a vector, 2 Majorana fermions and 1 real scalar. The two remaining scalars make up the complex scalar in the chiral multiplet, and the chiral multiplet must also contain the two remaining Majorana spinors.
Jul
2
asked Should the (On-shell) (2+1)d $N=2$ Chiral Multiplet Contain Two Scalars and Two Majorana Spinors?
Jun
18
awarded  Popular Question
May
24
comment Does Conformal Invariance of the Polyakov Action in Conformal Gauge imply Conformal Invariance of the Pre-gauge-fixed Polyakov Action?
Ah okay I think I get your meaning. Sorry to extend this discussion but I'm not sure my definition of 'conformal gauge' matches yours. In my definition a coordinate transformation (reparametrisation) is used to obtain the isothermal coordinates you describe, however in addition, a Weyl rescaling of the metric is used to take that metric to the flat space metric $\eta_{\alpha \beta}$. I think the Weyl rescaling means that the resulting action isn't simply the original action with a different choice of coordinates.
May
24
comment Does Conformal Invariance of the Polyakov Action in Conformal Gauge imply Conformal Invariance of the Pre-gauge-fixed Polyakov Action?
But doesn't coordinate invariance mean the same thing as reparametrisation invariance (i.e: $\sigma \rightarrow \tilde{\sigma}(\sigma)$)? And then, as you said in your original answer, the conformal invariance follows from this invariance under coordinate choice/reparametrisation?
May
24
comment Does Conformal Invariance of the Polyakov Action in Conformal Gauge imply Conformal Invariance of the Pre-gauge-fixed Polyakov Action?
Thanks for the reply @bechira. I think you might be using the term 'Weyl invariance' where I would use 'conformal invariance'. Just to be clear I use 'conformal' to mean reparametrisations of the coordinates that also result in a scaling of the metric. I take Weyl transformations to just be direct scalings of the metric. So, with these definitions, I see that invariance under general reparametrisations must mean conformal invariance also (as you describe). Is this correct?
May
23
comment Does Conformal Invariance of the Polyakov Action in Conformal Gauge imply Conformal Invariance of the Pre-gauge-fixed Polyakov Action?
On second thoughts, I think the answer is that the conformal transformations are just a special case of the reparametrisations. Since the pre-gauge-fixed action is reparametrisation invariant, it's also conformally invariant.
May
22
comment Does Conformal Invariance of the Polyakov Action in Conformal Gauge imply Conformal Invariance of the Pre-gauge-fixed Polyakov Action?
I may have found the answer to my own question: It is possible to show that the pre-gauge-fixed Polyakov action is invariant under Weyl transformations and diffeomorphisms (reparametrisations). Since conformal transformations are equivalent to combined reparametrisations and Weyl transformations it must follow that the pre-gauge fixed Polyakov action is conformally invariant. Some sort of feedback would be greatly appreciated however.
May
22
asked Does Conformal Invariance of the Polyakov Action in Conformal Gauge imply Conformal Invariance of the Pre-gauge-fixed Polyakov Action?
May
9
awarded  Tumbleweed
Apr
7
accepted Would Special Relativity Predict Time Dilation of a Geostationary Satellite Compared to an Observer on Earth?
Apr
7
comment Would Special Relativity Predict Time Dilation of a Geostationary Satellite Compared to an Observer on Earth?
Amazing, thank you.
Apr
7
asked Would Special Relativity Predict Time Dilation of a Geostationary Satellite Compared to an Observer on Earth?
Mar
4
accepted Is my Summary of a Spinor Bundle Associated with a String Worldsheet Correct?
Mar
4
comment Is my Summary of a Spinor Bundle Associated with a String Worldsheet Correct?
Awesome, thanks again!