30 May 2005

If you have a hammer....

...everything looks like a nail.

This list makes me happy; not so much the specific examples on it (some of which seem a little dubious), but just the fact that such a list exists. It helps me get through those depressing moments when I fear that the only useful Fourier transforms are over abelian groups. And I like the idea of working to add quantum information theory to the list.

19 May 2005

biting the hand

In case you haven't been following the debate over the Chinese's central bank's practice of linking the renminbi to the dollar, here's the background: China has kept the renminbi at the artificial low price of 8.28 since 1994. It does this by buying hundreds of billions of dollars of US debt per year - basically financing our budget and trade deficits. The low renminbi/high dollar helps Chinese exports and US imports, while hurting Chinese imports and US exports. It also keeps interest rates low in the US, encouraging borrowing/investment.

Americans who are trying to compete with Chinese imports don't like the cheap renminbi, and politicians can often be seen denouncing China's currency peg as "unfair" to American manufacturers and whatnot. But, if China didn't buy all our debt, we quickly have to face the laws of economics and, for example, pay for the war in Iraq. Wikipedia puts it in terms more dramatic than you usually get from economists

The ensuing depreciation of the US dollar might price oil out of the reach of the american economy, causing stagflation, a collapse of US oil dependant industries, massive unemployment and other dire economic consequences.
And it would be no picnic for China either; aside from the collapse of their largest trading partner, having too much cash could lead to the sort of crises that SE Asia had in the late 1990's, though I don't entirely understand how. (Good references are Nouriel Roubini's blog post, his paper with Brad SetserWill the Bretton Woods 2 regime unravel soon? The Risk of a Hard Landing in 2005-6, and billmon's posts (1 and 2)). Roubini actually thinks it would be best if China started letting its currency slide now, before it gets any worse.

But the point is that the U.S. and China are locked in a weird kind of mutual death-grip, with China having slightly more control over the situation, but all of the fiscal irresponsibility coming from the U.S. So it's natural that in this situation Congress would start blaming China for the situation. But what somehow still managed to blow me away is that their threaten-China bill would be attached as a rider to a spending bill that will only sink us further into this mess. The NYT article doesn't say which spending bill it is, but I bet it's the supplemental $82 billion for Iraq and Afghanistan that Bush didn't deign to put in the budget.

Mr. [Charles] Schumer [D-NY] and Senator Lindsey O. Graham, Republican of South Carolina, stunned administration officials last month by winning bipartisan Senate support for a measure that would threaten China with tariffs up to 27.5 percent if it failed to change its currency policies.

The Senate voted 67 to 33 against killing an amendment that would have attached the provision to a spending bill. Mr. Schumer withdrew the amendment, but Senate Republicans have agreed to allow a vote on the measure before the end of July.

15 May 2005

law of the father

I should be horrified at how Christian fundamentalists want to bring back honor killings (via atrios and pandagon)
Daddy, What's A Virgin?

Virginity was an inheritance to be brought into a marriage, and the father of the bride was responsible to preserve that inheritance. If a new husband slandered his bride and claimed that she was not a virgin, the bride's father and mother would defend her name and the name of their family. They would present the evidence of her virginity to the elders of the city (Deuteronomy 22:15). But if the charge was true, and the woman was not a virgin, then the bride was to be executed in front of her father's house. "But if the thing is true, and evidences of virginity are not found for the young woman, then they shall bring out the young woman to the door of her father's house, and the men of her city shall stone her to death with stones, because she has done a disgraceful thing in Israel, to play the harlot in her father's house. So you shall put away the evil from among you" (Deuteronomy. 22:20-21). Why the doorway to her father's house, rather than her husband's house? Because she had rebelled against her father's authority, and dishonored him. [see illustration]

In scripture it is obvious that daughters are to submit to their father's authority, while the father's responsibility is to protect their daughters.

But instead I can't help but find the whole thing (especially the despicable article Daddy's Girl: Courtship and a Father's Rights) not so much threatening as pathetically reminiscent of a scene in The Satanic Verses. But I lent my copy to someone who I think lost it! So the relevant quote will have to wait... Check back in this spot later.

12 May 2005

Quantum error correction fails only when you don't use it

This (or a more formal version) is going to get posted to the arxiv, unless one of my quantum compadres tells me why I shouldn't do it.

In "Quantum error correction fails for Hamiltonian models" (quant-ph/0411008), Alicki argues that when our controls are Hamiltonians of bounded strength (say the gate time is t_0), error correction fails. How badly does it fail? Well, suppose we want to protect a single logical qubit, and have M physical qubits, which are subject to independent depolarizing noise at rate lambda2. Then he says that every encode-protect-decode cycle of arbitrary length has fidelity no greater than exp(-M t_0 lambda2). First of all, I think there must be a mistake somewhere since increasing M shouldn't necessarily make the system decohere faster; after all you can always add qubits that you don't use. Worryingly, I can't find the mistake... Second of all, this doesn't mean that fault-tolerance, or even error-correction, don't work. His analysis (minus the math) is roughly as follows. You start and end with an unencoded qubit. The Hamiltonian has finite strength, so the qubit must be unencoded for the first O(t_0) time and the last O(t_0) time. During this time errors act on it.

This means the problem isn't that your Hamiltonians aren't infinitely fast. The problem is leaving a qubit sit around unprotected by any code. In FTQC this doesn't happen. Computatons map one encoded state to another. Ergo no problem.

This argument could be better written, but hopefully the point is clear.

10 May 2005

recipes I actually use

Unlike other recipes I've posted, I've made these recipes many times and highly recommend them all.

Rice Pulao

from The Enchanted Broccoli Forest

Spiced Lentils with spinach and applies

  • 1 Tbs canola or peanut oil
  • 1 Tbs butter
  • 2 cup minced onion
  • 2 cup dried lentils
  • 5 cups water
  • 2 large stalks of celery, minced
  • 1 tsp ground cumin
  • 2 tsp dried mustard
  • 1 Tbs minced fresh ginger
  • 1 tsp ground coriander
  • 1/2 tsp tumeric
  • 3 Tbs fresh lemon juice
  • 3 large cloves garlic, minced
  • 1 tsp salt (or more if needed)
  • black pepper to taste
  • cayenne to taste
  • 1/2 lb fresh spinach, *washed*, stems removed, and chopped (note: if making this for hundreds of people, use frozen spinach to save time.)
  • 2 medium-sized tart apples (Granny Smiths work well) peeled and chopped
  1. Heat oil in medium-sized skillet, and melt in the butter. Add the onion and cook over medium heat for about 15 minutes, stirring occasionally, until the onion is soft and turning golden.
  2. Meanwhile, place the lentils and water in a large saucepan or Dutch oven, and bring to a boil. Lower the heat, partially cover, and let simmer for 15 minutes.
  3. Add to the onion: celery, cumin, mustard, ginger, coriander, and tumeric. Cook together over medium-low heat for 10 minutes, or until the celery is tender. Scrape all of this into the lentils, add the lemon juice and garlic, and stir. Simmer, partially covered, for 10 more minutes--until the lentils are tender.
  4. Stir in the salt, black pepper, cayenne, spinach, and apples. COok for just a few minutes longer--until the spinach is wilted and the apples begin to soften. Serve hot.


  • 2 cups yogurt
  • 1 tsp whole cumin seeds
  • 1 tsp fennel seeds
  • salt and cayenne


  • minced ripe tomato (seed it first)
  • minced or grated cucumber (peel and seed it first)
  • minced bell pepper
  • minced red onion (ew) or scallion
  • minced fresh herbs (cilantro, mint, parsley, chives)
  • grated carrot
  • grated beet
  • minced spinach

cranberry scones

  • 2.5 cups flour
  • 2.5 tsp baking powder
  • 1/2 tsp soda
  • 2/3 cup sugar
  • 3/4 cup butter (cold, cut into small pieces)
  • 1 cup coursely chopped dried cranberries
  • 3/4 cup buttermilk
Mix flour, baking powder and soda. Cut in butter with pastry blender until coarse crumbs. Stir in cranberries and sugar then buttermilk until blended. Cut dough in half. Lightly flour surface and knead dough lightly. Press into 8" circle 1/2" thick, cut into 8 wedges. Place 1/2" apart on ungreased cookie sheet.

Preheat oven to 400° F. Bake 12-15 minutes.

You can substitute nuts, choc chips, or other dried fruit for the cranberries.

Scones can be frozen unbaked; bake without thawing.

cauliflower curry

from book two of the vegetarian epicure
  • 1 large head cauliflower
  • 1 small potato (6-8oz)
  • 4 tbs vegetable oil
  • 1 tsp black mustard seds
  • 1 tsp ground turmeric
  • 1/2 tsp ground cumin
  • 1/2 tsp ground coriander
  • 1/2 tsp cayenne
  • 1 clove garlic, minced or crushed
  • 1/2 onion, slivered
  • 1 tsp salt
  • 1.25 cups water
  • 1 tomato, chopped
  • 2 tbs lemon juice
Scrub, then boil the potato in salted water until it's nearly done. Wash and chop up the cauliflower into small pieces.

Heat the oil over medium-low heat and add the mustard seeds. Cover until they pop, then remove from heat until they're done popping (they should turn grey). Then add the onion, garlic and spices. Saute over medium heat for 3-4 minutes, stirring constantly. Then add cauliflower, saute for a few minutes, add salt and water, cover the pan and cook for another few minutes. Meanwhile, chop the potato into 1" cubes. Then add the potato, cover again and simmer for 10minutes. Finally, add the tomato and lemon juice, stir and cook uncovered for a few minutes fbefore serving.

another pilau

(also from the Vegetarian Epicure, book 2)
  • 4 tbs butter
  • 2 cups long-grain white rice
  • 1/4 tsp cinnamon
  • crushed seeds from 8 cardamom pods
  • 3/4c blanched, slivered almonds
  • 1/2c raisins or currants
  • 1c green peas
  • 4c hot water
  • 1.5tsp salt.
Melt the butter and fry the rice in it over low heat until it just starts to color. Add the cinnamon and cardamom, and fry for antoher minute or two. Then add everything else, stir, bring the water to a boil, lower the heat, cover the pot and cook for however long the rice needs.

You need a heavy-bottomed pot that can be tightly covered for this. The important thing is to fry the rice before boiling, and to add vaguely sweet, nutty and salty flavors - otherwise don't worry about following the recipe too closely.

09 May 2005


I always imagined that this equation would appear somewhere in Einstein's original paper. But not so. Here's the relevant text (he uses V instead of c to denote the speed of light):
If a body gives off the energy L in the form of radiation, its mass diminishes by L/V2. The fact that the energy withdrawn from the body becomes energy of radiation evidently makes no difference, so that we are led to the more general conclusion that:

The mass of a body is a measure of its energy-content;; if the energy changes by L, the mass changes in the same sense by L/9×1020, the energy being measured in ergs, and the mass in grammes.

One thing that struck me is how Einstein's approach today feels dated, belonging to a time (perhaps the last time) when you could do physics without knowing so much math. Or maybe it was just Einstein who could jump to such broad conclusions from one thought experiment involving radiation emitted by a slowly moving object. It's as though he knew the answer all along and just gave us an example to illustrate the point.

For example, today people favor the mathy Lorentz approach because it shows energy and momentum form a covariant 4-vector just like time and position do. So massless particles satisfy E=cp and light carries momentum. But Einstein saw this (and more) immediately with no intervening math! The next (and final) two sentences of the paper are:

It is not impossible that with bodies whose energy-content is variable to a high degree (e.g. with radium salts) the theory may be successfully put to the test.

If the theory corresponds to the facts, radiation conveys inertia between the emitting and absorbing bodies.

[Here's Einstein's first paper on special relativity.

Another old paper worth finding is the one where Born's rule that probability is the absolute value of the wavefunction squared is introduced wrong in the main text, and then later corrected in a footnote. I can't find it online, but the cite is Born, M., 1926a, Zeitschrift für Physik 37, 863; translated in (Wheeler, 1983), pp. 52-55. See also Born, M., 1926b, Zeitschrift für Physik 38, 803. and Born, M., 1927, Nature 119, 354.]

07 May 2005

genocide-related program activities

I think I liked the State Department's previous politically-motivated exaggerations of the deaths in Darfur better than their new politically-motivated minimizations of those deaths. So far probably 400,000 have died, and if aid stops because of insecurity, 100,000 deaths/month are possible.

The NYT recently published pictures drawn by kids in refugee camps on the border of Chad.

Top:Rashid, 13, from western Darfur "I saw janjaweed coming quickly, on horses and camels. They were shooting guns and yelling, 'Kill the slaves. . . . ' I saw people falling on the ground and bleeding. They chased after my brother; he is 12. One girl I saw -- they tied her up, put her on a camel and went away. All our animals were taken. Then the planes came and bombed our village."

Bottom:Salim, 13, from northern Darfur "We returned from school. . . . We are all looking, and not imagining bombing. The first bomb landed in our garden. The bombs killed six people, including a young boy, two women, a boy carried by his mother and a girl. Now my sleep is hard because I feel frightened."

Unfortunately, even if Western governments are pressured into action, it's not clear that what they do is likely to be productive. I'm not sure what I think is the right thing to advocate for, but am sympathetic to this argument by Alex de Waal, which is vaguely reminiscent of what Republicans said about Clinton's intervention in Bosnia:

Sudan is back at the top of the UN Security Council agenda and a focus for concern in Washington and London. Much of this concern is framed by the ICI report and the agenda of prosecutions. But these issues are marginal to the central challenges of Sudan and are indeed a distraction from investing the necessary political and diplomatic energies in the search for long-term solutions. The call for sanctions is similarly a response to the pressure to be seen to be ‘doing something'. There are no realistic scenarios in which sanctions would have a major positive impact: they are simply a means of expressing outrage. This is symptomatic of the way in which international engagement in Sudan has become focused upon short-term management rather than strategic thinking. In turn this reflects the predominance of activist agendas, and the lack of strong material interests in the outcome for Sudan.

02 May 2005

french toast recipe

  • one loaf French bread cut into one-inch slices put in glass pan
  • 4 eggs
  • 1.5c milk
  • 1/2c OJ
  • 1/4c sugar
  • 2 tbsp orange liqueur (like Grand Marnier)
  • 1 tbsp vanilla
Cover with saran wrap and refrigerate for 1-24 hours. Transfer to lightly buttered pan so they're not touching. Bake for 12-15 minute at 425 or until it starts to turn brown. Add powdered sugar.

raw salsa

  • 2 cans black beans
  • 2 cans corn
  • 1 large red onion, chopped
  • 2 red and 2 green bell peppers, chopped
  • 1-1.5 bunches of cilantro
  • 1-1.5c red wine vinegar
  • maybe some avocado would be good too
  • jalapenos to taste (dice, put in half raw, cook half on low heat in oil; alternatively you can broil them and pull the skin off)

another change of blog focus

Two things:
  1. Inspired by Jeff's blog, I'm going to start posting about things I've been learning. The idea is a) to not forget as much and b) to sometimes get people to tell me more about these things. The post below is an example of this.
  2. Inspired by the experimentalists in my lab, I started a blog to track my thesis work (or lack thereof) at aramthesis.blogspot.com. The sort-of-Ilya-inspired idea is related to time management; seeing how long I spend on tasks vis-a-vis their importance. And hopefully it'll lower the interestingness threshold for posting.

01 May 2005

How many people live on less than $1/day?

It's weird how hard this question is to answer. The two kinds of statistics I'm aware of are household surveys, which ask people to estimate their consumption, and national account statistics, like per capita GDP, which measure output. Both are seriously flawed and different methods give dramatically different answers. For example, Sala-i-Martin's 2002 paper The World Distribution of Income (estimated from Individual Country Distributions) argues that the number of poor has dropped dramatically from 1976-1998, while Ravallion and Chen's paper How have the world’s poorest fared in the 1980s? says that poverty rates have been close to flat from 1987-1998; and the differences aren't explained by the differnet time periods they look at. Some of the controversy is addressed in Ravallion's response to Sala-i-Martin.

A summary of the household survey vs. national accounts statistics dilemma is in the abstract of Deaton's 2005 paper Measuring Poverty in a Growing World (or measuring growth in a poor world):

Abstract—The extent to which growth reduces global poverty has been disputed for 30 years. Although there are better data than ever before, controversies are not resolved. A major problem is that consumption measured from household surveys, which is used to measure poverty, grows less rapidly than consumption measured in national accounts, in the world as a whole and in large countries, particularly India, China, and the United States. In consequence, measured poverty has fallen less rapidly than appears warranted by measured growth in poor countries. One plausible cause is that richer households are less likely to participate in surveys. But growth in the national accounts is also upward biased, and consumption in the national accounts contains large and rapidly growing items that are not consumed by the poor and not included in surveys. So it is possible for consumption of the poor to grow less rapidly than national consumption, without any increase in measured inequality. Current statistical procedures in poor countries understate the rate of global poverty reduction, and overstate growth in the world.

Another pitfall is how people approach the topic with preconceptions (also known as null hypotheses). For example, the paper by two World Bank economists [Dollar, David and Aart Kraay (2002) “Growth is Good for the Poor,” Journal of Economic Growth, 7(3) 195-225.] should really be titled "Growth cannot be shown to not be good for the poor," since rather than showing that the bottom 20% receive an equal share of growth, they fail to reject the null hypothesis that the bottom 20% receive an equal share of growth.

Got it? They find that a 1% increase in GDP increase the income of the bottom 20% by an amount that is not significantly different from 1%. But that doesn't mean it's close to 1%, just that their data is sufficiently noisy that 1% lies within their error bars. So maybe "Growth might be good for the poor" would be a better way to put it.

Also, household surveys are probably more accurate for levels of consumption by the poor than for the relative share of consumption of the poor (since the rich underreport consumption or don't reply to surveys). But this paper uses household surveys only to establish the poor's share of consumption, and then estimates the level of consumption by multiplying this by GDP. Since GDP in India (for example) has grown 5-10%/decade faster than consumption measured by surveys, this should systematically overestimate both the level of income the poor get, and the rate at which it grows.

That was worse than a crime; it was a mistake

Not as entertaining as the sewer rat letter, but hopefully clearer.
To the Editor,

The May 1 op-ed "The war we could have won" ignores the staggering immorality of killing 2-4 million people who posed (let's be honest) no threat to the U.S. Imagine how Germans today would feel about speculation that the Final Solution was actually not such a hopeless goal.

It's hard to admit that Americans were on the wrong side of history, so that a defeat for the U.S. was a victory for humanity. However, like Germany, Japan and other nations with war crimes in their past, we need to ground our public discourse in honest remorse for our crimes before going on to speculate about how to fight more effectively.


Aram Harrow