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bio website berkeley.academia.edu/…
location Berkeley, CA
age 24
visits member for 2 years, 11 months
seen Apr 11 at 20:14

Currently a graduate student in mathematics at the University of California - Berkeley.

Previously obtained a MASt. in Applied Mathematics from the University of Cambridge (2013), and a B.S. in Mathematics and a B.A. in Physics from the University of Chicago (2012).


Sep
12
comment Derivation of the Polyakov Action
I like this, but this method doesn't really convince me that putting in another auxiliary field is the way to go. Let's say in QFT we want a theory with a complex scalar field with a $U(1)$ symmetry. Of course, we could always introduce other fields into the theory, but that's not what one usually does unless you wanted the extra fields to begin with. And even if you decide that introducing a new field is the way to go, why stop at one? Surely we could add two new fields that respected all the symmetries we wanted . . .
Sep
12
revised Derivation of the Polyakov Action
added 78 characters in body
Sep
12
asked Derivation of the Polyakov Action
Sep
6
revised Fine-Tuning, the Hiearchy Problem, and Mass in the Standard Model
edited body
Sep
4
asked Symmetry Breaking and Vacuum Expectation Values
Sep
3
revised A rock connected to one end of string in circular motion gets released.. and what happens?
added 156 characters in body
Sep
3
accepted Divergence of One and Two Graviton Exchanges
Sep
3
comment Divergence of One and Two Graviton Exchanges
One last question, and then I think I got it. How do we determine the kinetic term for $h_{\mu \nu}$? (I ask because this will allow me to determine the appropriate dimensions of a spin $2$ field, and hence the appropriate dimensions of the coupling constant.)
Sep
3
answered A rock connected to one end of string in circular motion gets released.. and what happens?
Sep
2
comment Divergence of One and Two Graviton Exchanges
Are you assuming that the particle is a scalar, so that the interaction is of the form $\partial ^\mu \phi \partial ^\nu \phi g_{\mu \nu}$? This is the only way I could see you getting momenta coming into what appears to be your vertex factors. But if my dimensional analysis is correct, $[\partial ^\mu \phi \partial ^\nu \phi g_{\mu \nu}]=L^{-4}$, so that the corresponding coupling constant would be dimension-less, and in particular, could not be proportional to $1/M_P$. What's going on?
Sep
2
revised Divergence of One and Two Graviton Exchanges
deleted 1 characters in body
Sep
1
comment Vacuum Expectation Value and the Minima of the Potential
. . . In practice, you do this by writing the Lagrangian in terms of $\phi :=\phi _0-v$, where $v$ is some minimum of the potential and $\phi _0$ is the original field. My question could then be equivalently phrased as "Why does this guarantee that $\langle 0|\phi (x)|0\rangle =0$?".
Sep
1
comment Vacuum Expectation Value and the Minima of the Potential
@MichaelBrown Indeed, I was under the impression that you had to have this as a re-normalization condition in order to apply LSZ (that is, a hypothesis require for the LSZ Reduction Formula to hold was that $\langle 0|\phi (x)|0\rangle =0$). In fact, I thought this was the entire idea behind the symmetry breaking: you must re-write your Lagrangian in terms of the re-normalized field (with vanishing VEV), and if the bare field had a non-vanishing VEV, this will 'break' the symmetry . . .
Sep
1
comment Vacuum Expectation Value and the Minima of the Potential
So then what is the proof of this leading-order approximation?
Sep
1
asked Divergence of One and Two Graviton Exchanges
Aug
31
asked Vacuum Expectation Value and the Minima of the Potential
Aug
31
revised The vacuum in quantum field theories: what is it?
Expanded the question
Aug
31
revised The vacuum in quantum field theories: what is it?
Expanded the question
Aug
31
asked The vacuum in quantum field theories: what is it?
Aug
29
comment Fine-Tuning, the Hiearchy Problem, and Mass in the Standard Model
@DavidZ You mean the next paragraph in my question? No, that was written by me, included for the purposes of clarifying just what I mean by mass (and what I mean by "my understanding of mass") in this context (as opposed to, for example, just some coefficient in the Lagrangian).