Crowd-pleaser

Bab gave his tenure talk today. Despite my ambivalence about it all, I find myself rooting for him. I care not of the consequences to myself, but I fear I begin to care for him. I’ve never seen him prepare so long for a talk. Two weeks. I know he is worried. He begins by talking about band insulators. He assumes that physicists know something about band insulators. Most don’t. They complain to me, I didn’t understand a single sentence from Bab’s talk. I nod in sympathy, reflexively.

He describes a topological insulator, and I see he is preparing the crowd. His pointer goes crazy. He reveals Yismuth. ‘This is the reason why theorists are useful,’ he says, ‘My student Aris did an amazing job explaining why some edges are dark.’ Yismuth is a crowd-pleaser. I know it. I accept my role. Later, Real Russian tells me he was observing me closely, and the fireworks that burst forth within, and evanesced on my rigid countenance.

Later that night was the annual cheese and wine. I am rebuffed. I lay slumped against a wall, sipping my wine, the reverberations of the crowd envelops me. Why do interesting girls surround themselves by an insipid retinue? They confound my rule. These days, my social interactions are only motivated by romance, which means by lack of openings they are never properly motivated.

QFT approached me and gave me his opinion about a series of talks I have been organizing. Since the summer school, I have discovered a potent source of joy, in bringing together fellow students to talk about physics. I am starting to like QFT, in spite of the protraction of our conversations. When not discussing physics, he uses a breath of four sentences to convey a one-sentence idea, and I always find myself bored by the second round. He is sharp, but English is not his native language. I agreed with him, then excused myself to procure more wine.

I mingle as a non-interacting particles mingles, a random walk in a 2D colloid. Colliding and brushing, I retain my identity. They break up into groups and animate themselves into social enthusiasm. I watch for a sign of flagging enthusiasm, of a dove retracting from the flock. I am found wanting.

18:14

I am alive. Sorry, I must seem absent. You can be sure that if I am not replying for days, it's because I am not sleeping much. I have a bad habit of believing that I can accomplish a task within a day. Then finally I admit I cannot, but this admission is slow in coming, and only fully appreciated at the end of the task. By then, I have gone through a protracted period of single-minded overcoming, where every night I go to sleep with an aftertaste of defeat.

I am in one of those cycles right now. My task is to grade a thermal physics homework, and I thought it reasonably accomplished by Monday. But there is an abundance of subtleties in this subject, and being absolutely sure takes its toll. I feel immersed, it is a beautiful subject to be immersed in, and I want to do well for the students. Michael, the lecturer, has told me that the first problem-solving session has been very well-received by the students, and the praise has been emphatic. Instead of soothing me, I am heightened, I am even more eager to produce magic.

18:41

I am awash with anticipation. Classes begin today, and I tried out a class on the Standard Model, to continue my quest in understanding What is a particle. I will have to connect with minds and teach them a thing or two about thermal physics. It will be a pleasure. The theory in my upcoming Yismuth paper is so intuitable and yet has such explanatory power. The data is exquisite in detail, the best in the world, Ilya says. Both are so impressive I will be disappointed if the paper doesn't enter Nature.

It warms my heart

I'm really happy to hear you are TAing! Of all the TAs I've worked with, I think you're the best at teaching.

I'm a little bit confused about 301 as well. The blackboard site has no information posted--no syllabus, no problem sets, no messages. I was expecting to get more information during class today, but although lecture happened, we didn't get any clarity. Professor Aizenman just said that it was going to be a class about thermal physics, then started lecturing. He went a bit over, and I had a class immediately afterwards, so I couldn't stay to ask about administrative issues and I don't know if anybody did.

I do know that the other physics class that many juniors are taking, 305, has problem sessions on Wednesdays from 8 pm to 10 pm and problem sets due on Thursdays. So if you have any influence over scheduling, it would be great if the problem session times and problem set due dates could be different for 301.

Hope your fall is beginning well,
L

Frozen waves

Yismuth is my baptism into belief. I have invested most of my summer into understanding Yismuth, spent weeks on calculations that proved ultimately naive, but such striving has nevertheless imbued me with the confidence to calculate. Such sophisticated techniques I have learnt, I begin to see a common structure in many branches of mathematical physics.

The surface of Yismuth is a wonderful playground for the scattering of waves on impurities and step-edges. Incoming and outgoing waves interfere, producing a modulation in the probability density, a frozen wave. Such modulations are a complicated, fluctuating mess when looked upon at short length scales, where scatterings occur across a continuum of momenta and energies. But these fluctuations wash out at longer length scales, where they interfere so effectively as to become invisible. A beautiful pattern emerges from the result of a few scattering events -- they escape this destructive interference by being located at fortuitous curves in the energy-momentum landscape. Such countably few scatterings means we can hope to understand these frozen waves, to predict their shape from models and see them take form under the STM tip.

The veil

I am very familiar with this type of Z2 topological insulator. The relevant symmetry is time-reversal symmetry. Most discovered topological insulators require this symmetry, so what I am proposing with C4v symmetry is unique in that it doesn't require it. Reading the article impressed upon me how ubiquitous topology is in crystals, independent of the actual constituents of the crystal. The space of crystal momentum is a torus, and a torus is such a ripe playgroud for winding numbers and other topological invariants. Such topological invariants are not well-defined for a parameter space that is unbounded, such as that of ordinary momentum, which characterizes states with continuous translational symmetry. In this sense does topology emerge from the symmetry-breaking formation of a crystal.

I read with pleasure the article 'The descent of electrons'. It all begins with the natural production of hydrogen and carbon dioxide in deep sea vents? Then energetic electrons begin their descent, aided by molecules that carry out the reductive citric cycle. A diverse chemical soap is created, on which natural selection may act. I like it! If not correct in detail, it must be correct in spirit. This must be what is missing in Darwin's theory, as Kauffman claims. I am surprised Kauffman isn't cited in this paper. My attitude toward life thus far has been sickly, a dismal reflection of my ignorance, it borders on disbelief. Now I feel healthier, I am grounded by a idea, simple in concept though difficult in application, it pushes back the veil.