Okay, but consider: what if instead of doing a post-doc, I leaned into making widely-accessible online physics content.

Pros include: not moving every few years, not dealing with “publish or perish” or egos, choosing my collaborations on a project-by-project basis, helping people learn about a subject that I’m passionate about, can work from home, schedule is automatically compatible with my insomnia

Cons include: how make money though, how keep access to physics journals

I keep meaning to make a longer post and forgetting about it soooooo:

Some of my papers got cited by Big Name Physicists and Y'ALL that euphoria is going to carry me through the rest of 2019.

tens-tensor-tensest:

vacuously-true:

question-why-not:

question-why-not:

vacuously-true:

what comes together comes apart-

made in processing

Time symmetry

Or rather, PT symmetry if the quote is the rule and is describing the images?

Wait I could be wrong

My understanding of symmetry is still very limited & I’m tired

@tens-tensor-tensest wtf is Quinn trying to say to me? Please translate, my “physicist” is rusty

PT symmetry is parity-time symmetry. My only experience with this is in non-hermetian QM, where we don’t require our Hamiltonian operators to have the hermitian property so long as they respect PT symmetry (which can be naively thought of as working backwards through spacetime). I think what Quinn is getting at is that since the braiding action respects spacetime reversal that it could be seen as PT symmetric. Then again this is above my pay grade so maybe ask @quantum-friend-theory, who likely has a better understanding of it.

Thanks for the tag, @tens-tensor-tensest ! Classically, symmetries refer to how particle trajectories (or field evolutions, if you’re a field theorist like me) behave under certain transformations.

To get an idea of what I mean when I talk about “particle trajectories” as a whole, suppose I freeze time to a certain value T and set up a (*cough* massive) particle with certain position X and velocity V. When I unfreeze time, that particle will zoom along a path I’ll label P[X,V,T](t) where t = the time measured since T (so our original placement happened at t = 0). Using my vast thought experiment powers, I can go back to T, freeze time again, repeat this process for all values of X and V, and thus know a path P[X,V,T] for all X and V. With full understanding of the time slice T, I can then repeat it for all values of T. To be clear, each P[X,V,T] for fixed (X,V,T) is a one-dimensional path through space as parameterized by the variable t, and so P[X,V,T] as a function of (X,V,T) is a whole collection of paths not unlike the hair in a fluffy dog’s fur coat. If I want, I can run time backward too (my thought experiment powers are Truly Vast) and thereby define P[X,V,T] for t < 0.

Here’s where the symmetries come in. Suppose my collection P[X,V,T](t) doesn’t actually depend on T. This is a common situation: if I throw a ball in the air, it’s not like the physics changes just because I throw it at 2:00 PM vs 2:30 PM. The fact that the trajectories P[X,V,T] don’t depend on the initial time T is called “time translation invariance” and automatically implies conservation of energy! (This last point is an application of Noether’s Theorem, which says “continuous global” symmetries yield conserved quantities and is dope.)

The above-mentioned P and T (and their combo PT) refer to discrete transformations that frequently happen to be symmetries of motion.

P = Parity Inversion, which (without worrying about things like electric charge) takes all (X,V,T) to (-X,-V,T). This is frequently cited as the “mirror symmetry”, because it essentially transforms reality into the same kind of world that a human brain perceives through a mirror.

T = Time Reversal Inversion (not to be confused with our initial time label T), which takes all (X,V,T) to (X,-V,-T). This is what happens when you run a video in reverse at the same speed as the original: positions don’t change, but everything moves in reverse.

Thus, their combo PT takes a point (X,V,T) to (-X,V,-T): time and space get flipped upside down but velocities are maintained. All of these hinge on defining an origin with which we can reflect about. (Note: in quantum field theory, all origins are equivalent and so these symmetries are particularly powerful there.)

Back to the original GIFs: with only a few trajectories, we’re not going to be able to definitively say the physics involved has certain symmetries or not. We can, however, discuss whether or not these few trajectories are consistentwith P, T, or PT symmetries.  For example, if the physics is P-invariant, then every trajectory P(X,V,T)[t] implies a trajectory P(-X,-V,T)[t]. Hence, to check our theory for possible P-invariance we need to answer the following question: is there any P-transformed existing trajectory that contradicts another of our observed trajectories? If no such contradiction is found, the physics could be P-invariant.

To do this kind of analysis, we must decide a few things: Is this a plot of 2D spatial motion with respect to time (= the pixels in the GIF are literally space points) or is it 1D spatial motion with the time axis being represented horizontally (= the points are time-space coordinates so that only the vertical height of each pixel represents a distance)? And where is the origin we’re going to reflect about? How is the 2nd GIF related to the 1st?

The GIFs have stopped working for me, so I can’t actually performthe aforementioned analysis myself, but my hunch is that when viewed as 2D motion (and maybe as 1D motion), the trajectories are separately consistent with P- and T-invariant physics regardless of origin… mainly because there’s so few paths to consider. If this is true, then the paths are automatically also consistent with PT-invariant physics.

To close, I want to note these GIFs loop forever and thus exhibit another discrete symmetry: discretetime translation. This is a symmetry strongly associated with “time crystals”, which are very neat crystalline objects that (to me at least) sound like science fiction and have been physically engineered only recently!

Best wishes!

For what I’m calling #SciWriSeptember, I’m challenging myself to write one tweet per day summarizing a technical idea (and forbidding myself from using illustrations to do so!) Here’s today’s post. The latter half ended up with a poetic vibe that I dig!

crazymusicianpoop:

Somehow ended up playing Aria and Quodlibet by Running in the grad quintet for the chamber recital tonight Their oboist tested positive for covid yesterday and asked if I could sub for him in the chamber recital. Even though it wasn’t perfect, I’m glad I was able to pull it together enough that nobody noticed I’d only gotten the music the day before.

crazymusicianpoop:

Trying so hard to squeak out the high A in the Ravel It’s the first time I’ve had to play high G# and A for any reason At least I can hold the G#

crazymusicianpoop:

Actual audio evidence of me not completely bombing a jury

This is the first and second movements of Evocations by Henri Tomasi, it’s been a fun one to work on!

Anyone have success or experience with negotiating for increased scholarship funding and financial aid especially for a master’s program? Any tips or advice are very appreciated! 

Regrettable news, but wait 1 month until the graduation of grad school

And then art may resume

rainy-academia:

My thesis is due in a week and I am most definitely not ready to submit. I absolutely loved doing my undergrad but grad school is a world of pain.

I’ve gotten a lot of messages from people who are interested in pursuing their studies in interpretation and/or translation, so I’d like to make an effort to share as much of my experience as possible as a grad student in a similar program!

To start, here’s a list of the classes I’m taking my first semester:

• Introduction to Translation and Interpretation(lecture)
  
• Introduction to Eng-Kor Translation * (seminar)
• Kor-Eng Translation Practicum(seminar)
• Eng-Kor Consecutive Interpretation(seminar)
• Kor-Eng Interpretation Practicum(seminar)
• Interpretation Seminar (seminar)
• Advanced Korean Fluency(lecture)
• B Language Fluency - Korean(seminar)
• Global Business (seminar)

* Kor-Eng denotes translating Korean source texts into English. Eng-Kor denotes translating from English into Korean.

With the exception of one, each class is 3 hours long and meets once a week. The two lectures contain about 60 students, while seminars are limited to 9-11. I have class Monday through Saturday.

All classes, with the exception of Global Business, are conducted in Korean, although texts and speeches may be in English.

I can go more in-depth later about the format of the classes and assignments for anyone who’s curious~ But for now… back to translating my article for Thursday. :>

on my way to grad school orientation

it’s a full day of mock classes, followed by a meet & greet with the professors and 선배들 in the program

i’m an hour early (because paranoid) and also i might puke up my morning coffee and also i forgot a pencil