Wednesday, July 30, 2014


Dear Diary,

Greetings from UCLAke. We're under a lot of pressure these last few days. The main thing is not to break down. But I'm afraid we'll get hosed if we're not careful. Luckily, a lot of the material is watered down if vast. Still, we get water breaks. Good thing, I'm thirsty.

Now, not to flood you with news, but someone at the conference actually (no joke) had a baby today (congratulations!) after their water broke! Yay! Rejoice!

Ok, I'm running dry on material. I'll keep you up on all the topics here as quickly as they come out. Things are going swimmingly.

Tuesday, July 29, 2014


Dear Diary,

I once thought Irvine used a lot of water to keep its lawns green. Then a water main at UCLA broke today.

We're stuck in the conference room on the other side of campus learning (mainly the news coverage). At some point, we will have to make our way back to the dorms. We have the option of either fording the river, caulking the wagon, or using the oxen to pull it across. And we'll still have to pan for gold once we get there.

Man, what weird week for California. There have been ten water main breaks (by a quick Google news search) in the last two weeks and a rogue lightning strike struck the beach just down from some people going to the conference who were at the beach. All of them are fine, but not everyone is so lucky. Here's to being safe with this flood!

Justin is at SpaceX right now. I assume his escape plan will involve a large rocket and a space suit, so I'll just keep my thoughts on my situation.

[Editor's note: Emergency personnel tell us going into the water is an electrocution risk.]

Friday, July 25, 2014

The Longest Yard

Dear Diary,

Can I brag?  I feel like bragging.  One should always celebrate for a few minutes before getting back to work after getting good news.  It only took one year and three journals but now my paper is accepted.  It was slightly less time than my first paper which took one year at the same journal.

It's a relief to finally have that on the books and to submit the rest!  Let's see...Kieron is aching for three papers that I need to learn a big computer code to do the next step, I've made data for secondary authoring on two more, and I have three more papers written from my Master's degree.  Man I'd like to be able to do what Kieron wants me to do.

Hmm...seems exactly the same as last year.  Oh, boy!  If I get all of those done, I can do the other things we've been talking about and that I've been dreaming up!


[Editor's note:  It is also necessary to go outside and walk around every once in a while...and eat.]

Thursday, July 24, 2014

Kieron, I...err...?

Dear Diary,

Kieron's mastery of disguise and subterfuge has come with him to the conference.  I saw him walking around with a different name tag!  But it looked mysteriously like Kieron!

Then later, I saw someone walking around with Kieron's name tag, but I'm pretty sure it wasn't Kieron!  Maybe this is where they make Kierons....

But there can be only one!

Monday, July 21, 2014

Evil Spock

Dear Diary,

Today I met a lot of nice people from all over.  One of them was a parallel universe shattering event, however. To illustrate, in one Star Trek Episode, Spock meets evil Spock.

At the poster session, the very same parallel universe twinsies meeting happened with me and one other participant.  Except that I was evil Spock!  I could tell because I had the facial hair while my reflection was clean shaven!  My do-gooding doppelgänger is trying to learn what I'm learning (no doubt to disrupt my villainous plans!) and works for an advisor I found interesting but didn't come to Irvine.

The worst part is, I barely recognize my desires to go down that other path.  I have fallen into evil completely!  I actually like working for Kieron!  And Steve!  What has happened to me?!  I have become powerful! MWHAHAHAHAHAHA!

[Editor's note:  Evil Spock in on the right.]

Sunday, July 20, 2014

IPAM Today, IPAM Tomorrow

Dear Diary,

I've received a wonderful opportunity to come and learn from some of the DFT greats here at the Insitute of Pure and Applied Mathematics (IPAM) at UCLA.  It really is a great opportunity to meet some of the people whose papers I read and hopefully not mess up too badly in front of them!

Before coming here, I noticed that Lucas sure seems to be popular.  The nice graduate student in charge of putting together all of our poster teases says hi to Lucas!*  But Lucas didn't know he was that popular at IPAM!  Now, there is an identical Lucas running around out there (the original Lucas) whose papers we often misattribute to our own Lucas.  But I've learned not to doubt Lucas' charisma, charm, and popularity!

Everything starts tomorrow, so we're to be up at 8am for breakfast.  But they haven't announced a menu.  IPAMcakes?

*-see the post from a few days ago.

Friday, July 18, 2014


Dear Diary,

You see, Diary, we work in one dimension where some normal descriptions of matter break down.  We like one dimension because things are often easier to solve, but we need to be careful to avoid nasty physics (or hard math) that differs from problems we might want to solve in two or three dimensions.

One such instance is the description, known as a Fermi-liquid, that describes excitations that are close to the Fermi-surface very well in three dimensions (and two).  But if you try to calculate the quantum field properties in one dimension, you get a bad answer.  Specifically, the self-energy has a big imaginary part to it.  That's bad because it means the quasi-particles (or hypothetical weakly or non-interacting particles that would act like the many interacting particles) in our system have a short lifetime.  That means it's a bad description!  Ideally, we'd like the true quasi-particle that only weakly interacts in our system.  This means the math we wrote down to describe the system can be solved (perhaps more simply than the original problem if we find the right quasi-particle!).

For a real world example, let's describe how SCARY would tell the story of the camping trip last week.  A lot of that story would contain an untruthful description of the real events of that system that have a large imaginary part, but that means a made up story wouldn't have a very long lie-fetime!  One would say the made up quasi-particles in that system are a bad description of the actual events that happened.

You see, physics is useful for describing things.

Thursday, July 17, 2014

Pretending to be Justin

Dear Diary,

Today I walked into Kieron's summer class to proctor some quizzes.  Justin is the official TA and had some car trouble (oil change).

So, I went in and pulled Kieron's old trick of introducing yourself as someone else so they'll take the heat if something goes wrong!  Normally if I introduce myself as someone else in the group (we're all interchangeable, really), then things go swimmingly.

Not so much this time.  The students practically called the police on me.

Gotta dash!

Wednesday, July 16, 2014

The radius of convergence is zero

Dear Diary,

Let's talk about a Taylor series' radius of convergence for a minute.  When you're writing down a mathematical structure for a particular object, sometimes the best you can do is generate the Taylor series in a small area of the problem.

I'll liken this to a color gradient.  If you have a panel that slowly varies from red to white like this:

If you start on the white side of the figure and move towards the red, you need to slowly add red to the spot you're standing on.  This is what a Taylor series is doing.  As you move around on the color gradient from right to left, you need to add more color...but in the physics or math problem, you add more mathematical terms to the Taylor series!

You can also a define a radius of convergence of the Taylor series.  This would mean, how far can you want with your Taylor series.  Say our gradient abruptly turned blue to the left of the above gradient.  You can't add more red to get to blue, primarily.  So, the radius of convergence of that color set up would be the width of the rectangle.

There are some things in physics that have a radius of convergence of zero.  As soon as you take one step away from where you started, the Taylor series is already bad!  Most famously, this happens in quantum field theory when you try to see how far away the electron's mass is from the bare mass in the Lagrangian.  You get an infinite distance; in other words, your Taylor series is a miserable description everywhere!  Instead, you can only use the experimental mass in your computation and then everything works!

But there are also real life examples.  For starters, consider the distribution of camping trips I've been on in my entire life.  The one I went on last week had a radius of convergence of zero about it.  You can't Taylor expand to compare it to any other camping trip!  It was that bad!  I have a bunch of trips that were good, bad, and otherwise interesting, but this one was SCARY!  I find it hard to compare to any other experience.  A description from any other experience would not be adequate.  Just like a Taylor series with a radius of convergence of zero.

Tuesday, July 15, 2014

The Gettysburg Address

Dear Diary,

This is the year of 2014 which is exactly 88 years after Schrodinger published his famous equation for quantum mechanics.  Kieron approached me and Lucas last year about commemorating the event by sneaking in some snippets from Abraham Lincoln's infamous Four Score and Severn (87) years ago speech.

But we didn't publish last year.

Luckily, Thomas-Fermi theory, a commonly used approximation for the kinetic energy that matches up with a uniform gas was published in 1927.  That's exactly 87 years ago from this year!  So, we thought, why not just honor this other paper?

We did!  But the editor's caught us.  Kieron was a little disappointed that the reviewers didn't mention it in their reviews, but during the proofing stage, a savvy literature guru at Physical Review noticed it and the Dante's inferno reference placed there by Lucas.  So, they would change the wording.

But the joke was still on!  They didn't remove enough from the paper to take out the intention!  It's still there!  Kieron did fess up to the editor's, but one should note that the Physical Review Letter from last year referenced a Tale of Two Cities in the first line.

While the original wording was changed, the world will little note, nor long remember what we say here, but it can never forget what they did here.

Monday, July 14, 2014

Back in the Saddle again

Dear Diary,

It's great to be back!  I really mean it this time!  Physicists have a long tradition of getting outdoors and coming back for great physics.  Robert Oppenheimer, leader of the team that made the nuclear bomb, loved horseback riding and took physicists up to his cabin in the woods for some rest and relaxation.  He also made sure there were many (epic? lame?) parties while everyone was working on the Manhattan project.  What a guy!

This last week, I went on a camping trip with a physicist whom I actually did a lot of productive thinking with in terms of physics (and ideas!), but we also had one other person who completely ruined the whole thing.  I may feel the need to refer to this person again in the future as SCARY.

I suppose the less on here is to only take people who have a vested interest in getting out of the woods in one piece on a camping trip.  Further, we came up with an idea that I could implement as soon as I know DMRG!  How exciting!  I better get to it!

It does look like I was more productive while I was away, though.  The paper I'm on with Lucas, Miles, Steve, and Kieron got published an editor's choice (see the publications page on!).  Wow!  I must say the review process on this paper was leaps and bounds easier than any paper I've ever submitted!  We didn't even need to appeal any decisions!  I also resubmitted another paper, got some data for Attila, and now have to figure out a new Kuali purchase order form (whatever the hell that is).  So, while I should have spent extra time here, I guess I didn't get too far behind.

But time to get moving!

Friday, July 11, 2014

Bull Wink

Dear Diary,

I took a week off to go summer camping, got tons of mosquito bites, and now I'm super raring to go on the physics.  I had a good time.

Looking back, it's been a little over half a year since qualification exam, and I think my strength is back.  Things are starting to slow down and I'm getting back into the need to turn physics around quickly.  Oh, and that problem I've been doing for a year now?  Yes, it's still unsolved, but I just made big progress that I need to finish the notes of.

And present in a group meeting (eek!).

[Editor's note:  Actually, this post was written before the trip, so the author could actually be stuck under a boulder somewhere.  Tune in next week when it will be: Two for the Ripsaw... or Goodbye, Mr. Chips]

Wednesday, July 9, 2014

Poster Tease

Dear Diary,

Today I learned about the other great Greek wise figure:  Postertes.  You see, at some conferences, if you bring a poster, you must present a few teaser slides to attract anyone to come and see your work.

In Greek culture, it was common place to do this and one wise man, Postertes, did such a fine job that he attracted all manner of gods and mortals from Mount Olympus and Beyond that the likes of Socrates, Homer, Zeus, and Hercules, came by to hear his work.

Now that I have to do this, I will show Kieron my sales pitch during the next group meeting.  Maybe I can put together a good poster tease like the Greeks.

[Editor's note:  This is not a history blog.]

Monday, July 7, 2014

Flying Circus

Dear Diary,

Due to a recent string of highly antiquated jokes (about U2, Dr. Strangelove, etc.) from the pre-90s, I've been designated as the official joke-getter.

Unfortunately, I have not fulfilled my duties completely.  Kieron was working on showing errors were small at one end, large in the middle, and then small again at the end.

That was, *ahem*, a reference to a Monty Python skit:

That I had maybe seen once before.  Halfway through watching it again, I got it!  Oh no!  I guess I just wasted the lead I had by correclty identifying the song "Stuck in the Middle with You" and the band: Steeler's Wheel (and that there's a cover by The Eagles of Death Metal).