Sunday
Jul032016

Homework 3 (Spring 2016)

Kate Petersen


 

1. Using a naive estimator, solve for the permuted joke (j) when time (t) is zero.

 

When time stops, I'm rinsing grapes in a colander in a rented kitchen, a man I barely know at the other counter, slicing French bread. Playing house, as he called it later, describing the treachery of pretend, how close we'd come to what others say they want. Renting the house, driving through a bunch of desert to get to it, had all been a joke until this one night it wasn't. What do I mean by time? I mean something grabbed the second hand of my brain and held it still. No, was one way it felt. Also, here.

 

2. Now assume that the coupling parameter (g) is time varying, i.e. is modulated in time as g=Vcos(Wt+j). Plot the expectation value of the moon.

 

We'd driven 500 miles west since noon and were cutting through a long blue valley of cactus when the moon rose. Found it, I said, and then we both went quiet. He pulled over and we stepped out of the car. I waded into the field toward the moon, to get closer, because I still haven't learned you can't. Or because it seemed one of us needed room, even though that's all a desert is. And listen: The sound of his shoes in the rocks, that was part of it. And the moon finally the way storybooks said it would be, all those colors from someone else's life. Buttermilk. Ivory. Gold. Night given us in the passive infinitive: to be astonished.

Northward, the Joshua trees began to appear on either side, dark protruding from dark as if night itself had sprouted limbs, unapproachable as druids or those flop-armed goofs outside car dealerships they pump air into so they dance and fall. So you'll stop. But we kept on, the only ones moving now, the moon hoisting itself smaller and smaller into the fly. An hour that way, words falling under the wheel-hum, tracking the white basting stitch in the road before it delivered us back to our fluorescent kind. In a rundown supermarket, road-dogged, we bought the bread and grapes and lunch meat and cheese. How much do we need? he asked. What do you want for the morning? The basket printed a line on my arm. Map spread again like a napkin across my knees, and the code to the key to the house on my phone. Both of us squinting through the dark, looking for a place that wasn't ours.

Inside, I could feel something in me decelerating, another question beginning to form around the data I was being handed: the colander, the desert heaped outside the window dark and impartial, our backs to each other as we worked. I felt so calm right then, and when he touched my back and said, have you seen salt? I opened the right cabinet on the first try. Luck, of course, but in such pauses luck lengthens, spine-like, into wisdom.

 

3. Construct the uncertainty principle for the x-component of the first field operator (Ex) and the l-component of the second (Hl). Please comment on whether the result is spatially dependent. You may assume the night is lossless.

 

When I went into the kitchen of not-my-house the next morning, the sun wasn't there yet, but time had started up again. A lone-seeming bird in earshot. There was the salt. There were the grapes. There were the mountains, purple, too, and close, and they upbraided me for not wanting anything. But now I do, I told them. It was embarrassing how fast it came on, the want. The sills were painted shamrock green; the refrigerator, clucking to itself, came to my chin. Inside smelled like old ice. I heard his alarm go off in the other room, someone playing the xylophone badly, heard him stop it. I pressed the coffee filter into the cone. The filter was bandage-colored and its ridges fit my fingers perfectly, because what is this season but a lesson in I should have known, all the exercises ones designed for me to take home, and complete on my own.