Dec 052016
 

Werner Heisenberg

Today is the birthday (1901) of Werner Karl Heisenberg, a German theoretical physicist and one of the key pioneers of quantum mechanics. He published his seminal work on quantum mechanics in 1925 in a breakthrough paper. In a subsequent series of papers with Max Born and Pascual Jordan, in the same year, this matrix formulation of quantum mechanics was substantially elaborated. In 1927 he published his uncertainty principle, upon which he built his philosophy and for which he is best known publicly, even though it is not necessarily his most important contribution to physics. Heisenberg was awarded the Nobel Prize in Physics for 1932 “for the creation of quantum mechanics.”

He also made important contributions to the theories of the hydrodynamics of turbulent flows, the atomic nucleus, ferromagnetism, cosmic rays, and subatomic particles, and he was instrumental in planning the first West German nuclear reactor at Karlsruhe, together with a research reactor in Munich, in 1957. He was a principal scientist in the Nazi German nuclear weapon project during World War II. He traveled to occupied Copenhagen where he met and discussed the German project with Niels Bohr.

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Following World War II, he was appointed director of the Kaiser Wilhelm Institute for Physics, which soon thereafter was renamed the Max Planck Institute for Physics. He was director of the institute until it was moved to Munich in 1958, when it was expanded and renamed the Max Planck Institute for Physics and Astrophysics.

Heisenberg was also president of the German Research Council, chairman of the Commission for Atomic Physics, chairman of the Nuclear Physics Working Group, and president of the Alexander von Humboldt Foundation.

Once we get into Heisenberg’s work, particularly on the uncertainty principle, we immediately get embroiled in mathematics, much of which I don’t understand myself (except to know that formulations of the principle in words lack the rigor of mathematical descriptions). Historically, people have confused the uncertainty principle with a different effect in physics, called the observer effect, which notes that measurements of certain systems cannot be made without affecting the systems, that is, without changing something in the system. Originally Heisenberg offered such an observer effect at the quantum level as a physical explanation of quantum uncertainty. It has since become clear, however, that the uncertainty principle is inherent in the properties of all wave-like systems, and that it arises in quantum mechanics simply due to the matter-wave nature of all quantum objects. Thus, the uncertainty principle actually states a fundamental property of quantum systems, and is not a statement about the observational success of current technology. It must be emphasized that measurement does not mean only a process in which a physicist-observer takes part, but rather any interaction between classical and quantum objects regardless of any observer. Here we collide with Schrödinger and his cat, but I’ll leave that subject alone.

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Throughout the main body of his original 1927 paper, written in German, Heisenberg used the word, “Ungenauigkeit” (“indeterminacy”), to describe the basic theoretical principle. Only in the endnote did he switch to the word, “Unsicherheit” (“uncertainty”). When the English-language version of Heisenberg’s textbook, The Physical Principles of the Quantum Theory, was published in 1930, however, the translation “uncertainty” was used, and it became the more commonly used term in the English language thereafter.

Today is National Sacher-Torte Day in Austria, so I think that it’s a good day to make Sacher-Torte even though it is Austrian and not German. I do know the difference. However, I’d like to believe that Heisenberg enjoyed this chocolate delight once in a while. It is best savored in a coffee house in Vienna, but you can make a decent copy if you have some baking skills.

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Sacher-Torte

Ingredients

Torte:

4 ½ oz high-quality bittersweet chocolate, finely chopped
9 tbsp (1 stick plus 1 tbsp) unsalted butter, at cool room temperature
1 cup confectioners’ sugar
6 large eggs, separated, at room temperature
1 tsp vanilla extract
½ cup granulated sugar
1 cup all-purpose flour

Assembly:

1 cup Apricot Glaze (see below)
1 small batch Chocolate Glaze (see below)
sweetened whipped cream, for serving

Instructions

To make the torte, position a rack in the center of the oven and heat to 400°F. Lightly butter a 9-inch springform pan and line the bottom with a round of parchment or wax paper. Dust the sides of the pan with flour and tap out the excess.

In the top part of a double boiler over very hot, but not simmering, water, or in a microwave at medium power, melt the chocolate. Remove from the heat or the oven, and let stand, stirring often, until cool.

Beat the butter in the bowl of a heavy-duty standing mixer fitted with the paddle blade on medium-high speed until smooth, about 1 minute. On low speed, beat in the confectioners’ sugar. Return the speed to medium-high and beat until light in color and texture, about 2 minutes. Beat in the egg yolks, one at a time, scraping down the sides of the bowl. Beat in the chocolate and vanilla.

Beat the egg whites and granulated sugar in a large bowl with a handheld electric mixer on high speed just until they form soft, shiny peaks. Do not overbeat. Stir about one quarter of the beaten whites into the chocolate mixture to lighten it, then fold in the remaining whites, leaving a few visible wisps of whites. Sift half of the flour over the chocolate mixture, and fold in with a large balloon whisk or rubber spatula. Repeat with the remaining flour.

Spread evenly in the pan. Bake until a toothpick inserted in the center comes out clean, about 45 minutes. (The cake will dome in the center.) Cool on a wire rack for 10 minutes. Remove the sides of the pan, and invert the cake onto the rack. Remove the paper and re-invert on another rack to turn right side up. Cool completely.

To assemble, using a long serrated knife, trim the top of the cake to make it level. Cut the cake horizontally into two equal layers. Place one cake layer on an 8-inch cardboard round. Brush the top of the cake layer with the apricot glaze. Place the second cake layer on top and brush again. Brush the top and sides of the cake with the remaining glaze. Transfer the cake to a wire rack placed over a jelly-roll pan lined with waxed paper. Let cool until the glaze is set.

Make the chocolate glaze (it must be freshly made and warm). Pour all of the warm chocolate glaze on top of the cake. Using a metal offset spatula, gently smooth the glaze over the cake, allowing it to run down the sides, being sure that the glaze completely coats the cake (patch any bare spots with the spatula and the icing that has dripped). Cool until the glaze is barely set, then transfer the cake to a serving plate. Refrigerate until the glaze is completely set, at least 1 hour. Remove the cake from the refrigerator about 1 hour before serving.

To serve, slice with a sharp knife dipped into hot water. Serve with a large dollop of whipped cream on the side.

Small Batch Chocolate Glaze

Ingredients

1 cup sugar
½ cup water
4 oz high quality bittersweet chocolate

Instructions

In a heavy-bottomed medium saucepan (no larger than 1 quarts or the mixture will reduce too rapidly and burn before it reaches the correct temperature) over high heat, bring the sugar, water, and chocolate to a boil over medium-high heat, stirring occasionally. Attach a candy thermometer to the pan. Reduce the heat to medium and cook, uncovered, stirring, until the mixture reaches 234°F., about 5 minutes.

Remove from the heat and stir to cool and thicken slightly, about 1 minute. Use immediately. When pouring, do not scrape the pan.

Apricot Glaze

Ingredients

1 ¼ cups apricot preserves
2 tablespoons golden rum (or water)

Instructions

Bring the preserves and rum to a boil in a small saucepan over medium heat, stirring often. Cook, stirring often, until the last drops that cling to the spoon are very sticky, 2 to 3 minutes. Strain through a wire sieve into a small bowl, pressing hard on the solids. Use warm.

 

May 112016
 

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Today is the birthday (1918) of Richard Phillips Feynman, a U.S. theoretical physicist known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics for which he proposed the parton model. For his contributions to the development of quantum electrodynamics, Feynman, jointly with Julian Schwinger and Sin-Itiro Tomonaga, received the Nobel Prize in Physics in 1965. He developed a widely used pictorial representation scheme for the mathematical expressions governing the behavior of subatomic particles, which later became known as Feynman diagrams. During his lifetime, Feynman became one of the best-known scientists in the world. In a 1999 poll of 130 leading physicists worldwide by the British journal Physics World he was ranked as one of the ten greatest physicists of all time.

He assisted in the development of the atomic bomb during World War II and became known to a wide public in the 1980s as a member of the Rogers Commission, the panel that investigated the Space Shuttle Challenger disaster. In addition to his work in theoretical physics, Feynman has been credited with pioneering the field of quantum computing, and introducing the concept of nanotechnology.

I don’t know how much of a household name Feynman is nowadays, but I know about him for several, mostly quirky, reasons. For one thing, I admire him for the importance he attached to teaching.

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Feynman was born in Queens and attended Far Rockaway High School. Upon starting high school, Feynman was quickly promoted into a higher math class. An unspecified school-administered IQ test estimated his IQ at 123—high, but “merely respectable” according to biographer James Gleick. Don’t get me started on IQ tests.

When he turned 15, he taught himself trigonometry, advanced algebra, infinite series, analytic geometry, and both differential and integral calculus. In high school he was developing the mathematical intuition behind his Taylor series of mathematical operators. Before entering college, he was experimenting with and deriving mathematical topics such as the half-derivative using his own notation. In his last year in high school Feynman won the New York University Math Championship. The large difference between his score and those of his closest competitors shocked the judges.

He applied to Columbia University but was not accepted because of their quota for the number of Jews admitted. Instead, he attended the Massachusetts Institute of Technology, where he received a bachelor’s degree in 1939 and in the same year was named a Putnam Fellow. He attained a perfect score on the graduate school entrance exams to Princeton University in mathematics and physics—an unprecedented feat—but did rather poorly on the history and English portions. Attendees at Feynman’s first seminar included Albert Einstein, Wolfgang Pauli, and John von Neumann. He received a Ph.D. from Princeton in 1942, his thesis, “The Principle of Least Action in Quantum Mechanics,” laid the groundwork for his future work in quantum mechanics for which he eventually shared the Nobel Prize.

The thing that’s always fascinated me about theoretical physics is that while the mathematics is well beyond most mortals, the ideas are not all that complicated. Feynman was one of a rare breed who understood the mathematics at a very deep level, yet he was able to explain his ideas to any educated person.  Furthermore, Feynman found teaching to be an important source of inspiration. If you watch The Big Bang Theory, you’ll get the impressions that “really smart guys” (i.e. theoretical physicists) are too lofty to teach. Some of them believe that, and others believe that teaching takes time from “important” research. Feynman believed that it was important to teach as part of the creative process.

Let me pause for a minute and dissect this idea. Einstein once said, “If you can’t explain it simply, you don’t understand it well enough.” There’s the nub. To teach something well – anything – you need to understand it well. Just because you are a native speaker of English does not mean that you can teach English. Trust me on that. It takes years of wrestling with the mechanics of the language to be able to explain how it works – SIMPLY – to people who are trying to learn it. Any idiot can teach English from a textbook that someone else wrote; it’s another matter entirely to teach from what you yourself have explored and discovered.

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Following the completion of his PhD, Feynman held an appointment at the University of Wisconsin–Madison as an assistant professor of physics. The appointment was spent on leave for his involvement in the Manhattan project (which he was not central to). In 1945, he received a letter from Dean Mark Ingraham of the College of Letters and Science requesting his return to UW to teach in the coming academic year. His appointment was not extended when he did not commit to return. In a talk given several years later at UW, Feynman said, “It’s great to be back at the only university that ever had the good sense to fire me.”

After the war, Feynman declined an offer from the Institute for Advanced Study in Princeton, New Jersey, despite the presence there of such distinguished faculty members as Albert Einstein, Kurt Gödel and John von Neumann. Feynman instead went to Cornell University, where he taught theoretical physics from 1945 to 1950. During a temporary depression following the destruction of Hiroshima by the bomb produced by the Manhattan Project, he focused on complex physics problems, not for utility, but for self-satisfaction. One of these was analyzing the physics of a twirling dish as it is moving through the air. His work during this period, which used equations of rotation to express various spinning speeds, proved important to his Nobel Prize–winning work, yet because he felt burned out and had turned his attention to less immediately practical problems, he was surprised by the offers of professorships from other renowned universities.

Despite yet another offer from the Institute for Advanced Study, Feynman rejected the Institute on the grounds that there were no teaching duties: Feynman felt that students were a source of inspiration and teaching was a diversion during uncreative spells. Because of this, the Institute for Advanced Study and Princeton University jointly offered him a package whereby he could teach at the university and also be at the institute. Feynman instead accepted an offer from the California Institute of Technology (Caltech)—and as he says in his book Surely You’re Joking Mr. Feynman!—because a desire to live in a mild climate had firmly fixed itself in his mind while he was installing tire chains on his car in the middle of a snowstorm in Ithaca.

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Feynman has been called the “Great Explainer.” He gained a reputation for taking great care when giving explanations to his students and for making it a moral duty to make the topic accessible. His guiding principle was that, if a topic could not be explained in a freshman lecture, he did not yet fully understand it. I love this quote:

Fall in love with some activity, and do it! Nobody ever figures out what life is all about, and it doesn’t matter. Explore the world. Nearly everything is really interesting if you go into it deeply enough. Work as hard and as much as you want to on the things you like to do the best. Don’t think about what you want to be, but what you want to do. Keep up some kind of a minimum with other things so that society doesn’t stop you from doing anything at all.

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His biographers record that late in life Feynman became obsessed with traveling to Tuva (nestled north of Mongolia), although he was unable to do so before he died. At that time, when Tuva was part of the Soviet Union, visas were hard to obtain, and travel arrangements were also very difficult (overland yak from Mongolia or a once-a-week flight on an 18-seater plane from Moscow). Apparently he had been interested in Tuva since boyhood when he collected stamps, and the oddly-shaped stamps from Tuva fascinated him. He looked up where it was (the middle of nowhere) and learned all he could about the place.

It is an amazing destination. I’ve wanted to go there for more than 30 years. That was a big incentive I had when I applied for a job in Inner Mongolia (and wound up with visa problems of my own).  Tuva is famous – in some circles – for throat singing: a way of producing several notes at the same time from a single voice, originally a shamanic practice.  This video is a starter for you.  You can look up plenty of astounding examples.  I used to play this stuff in ethnomusicology classes and the students could not believe it was a human voice – and a SINGLE one at that.

I’ll get there eventually.  In honor of Feynman I suggest trying out some Tuvan food. Tuvans used to be, and some are still, primarily nomadic herders although Russification has caused major changes. As such, their diet was rich in meat and dairy products similar to the grasslands of Mongolia.  Buuz are a well known staple found in both Tuva and Mongolia. They are meat-filled steamed dumplings that are ubiquitous throughout the Asian segments of the current Russian Federation.

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You can find a ton of videos on how to make them if you need them. Otherwise the basics are as follows. Make a flour dough, much as you would to make pasta. Mix flour and water together to form an elastic, not moist, dough using your hands to mix them. Knead the dough for about 20 minutes until it is pliant and completely workable.  Break the kneaded dough into walnut-sized balls and roll them flat into circles.  Use a spoonful of your favored filling. The commonest, and most traditional, filling is chopped meat.  This can be mutton, goat, yak, or whatever, but it should be fatty. You don’t need to add anything else to the filling, but modern cooks sometimes add onions and spices. Hot chile pepper is also popular.

Shaping the dumplings is an art that takes long practice. The photo gives you the idea. Videos will give you others. The dumplings need to be able to sit flat in a steamer, so place the filling in the center of the dough circle and draw the dough up around it, leaving a hole exposing the meat at the top. Steam the buuz for about 20 minutes, or longer, and serve them hot with a dipping sauce of your choice. Street vendors keep the buuz in the steamer for long periods, and they are fine. Mayonnaise is a common sauce.  Tea is the normal accompaniment.