WS Hwang said (nearly) everything

There has been hot debates on ethics on Prof Hwang's accomplishiment in stem cell science. The issue starts from a Nature magazine reporter. Two female researchers in Hwang's group were suspected to donate their eggs against to the ethic standards in biological science. Eventually, it turned out that Hwang made a lie at the time Nature asked him publicly. They donated their eggs as Hwang admitted in a press conference today. Hwang also admitted that some eggs were not from pure donation but paid. During several weeks the issuse was the very hot topic in Korea.

It's bad that he lied. But, some (as I agree) raised the question on the ethic standards in biological science these days. It was from the Helsinki in 1960s while we live in 21c. Desite the potential problems, since the donation of egss is a physically and mentally a tough process, I believe they should be paid properly. If the researchers heartfully want to donate their eggs for their own research, one should not prevent them from doing it. Due to my short English, I hardly express the ideas on it now. I hope in a western side, more balanced discussion on it appears soon.

back from Kyoto

I've just came back from 3 weeks of staying at Kyoto University. I participated a kind of low temperature experiements. Nowdays, as anyone(physics) knows that mK is a commonplace. However, our system was too big, about 3 meters in height and homemade. So, it took about 3-4 days to cool down.

Before I worked there, I thought the experimental boundary of the low temperature is somewhere around micro Kelvin. But, I came to know that we, human beings are able to approach down to pico Kelvin. Wow ! (Note, the pico Kelvin is one step further from nano Kelvin!)

Classical Mechanics in Computer Viewpoint

I picked up one textbook on classical mechanics which emphasizes the use of computer and even understanding the subject(mechanics) through the eyes of algorithm and computation. The textbook was based on the course delivered at MIT for years. They have kindly opened the whole contents of the book on the web.

In the preface,

Traditional treatments of mechanics concentrate most of their effort on the
extremely small class of symbolically tractable dynamical system. We concentrate
on developing general methods for studying the behavior of systems, whether or
not they have a symbolic solution. ... We focus on the phenomena of motion, and
we make extensive use of computer simulation to explore this motion.

This might be the usual way of learning non-linear dynamical systems and chaos. But, their primarily distinctive goal, I think, is ...

We require that our mathematical notations be explicit and precise enough
that they can be interpreted automatically, as by a computer.

To accomplish this, they even drop the conventional notation of Lagrange equations, since they think it's ambiguous enough for a computer to interpret and calculate.

... Expressing the methods of variational mechanics in a computer language
forces them to be unambiguous and computationally effective.

They teach classical mechanics using classical computer for the problem at hand being solved computationally effectively through classical algorithms. They belive computational viewpoint on classical mechanics help the students 'uncover and correct many deficiencies in understanding'.

We may expect, someday, the course on quantum mechanics using quantum computer for problems being effeciently solved using quantum algorithm, and we may learn more about the deep implication of quantum mechanics through the window of quantum computer.

Japanese Drama

I am appointed to perform some low temperature experiments in one institute in Japan this November. So, these days I'm studying hard learning Japanese. Though the researchers in Japan may have little problem in English, I prefer communicating in their native language. It'll give me more chances to learn their cultures and things other than physics itself.

Japanese language is in many ways similar to Korean language, as German is similar to English. So, I decided to learn Japanese by just watching Japanese TV dramas. I watch about 2-3 Japanese TV dramas a day since 2 weeks ago, and it works! I think I can understand about 30% of what are said in TV now. I'll keep studying through TV for 4 weeks more, and I hope I can hear about 80% at the end. Quite an enjoyable way of learning language.

Bob's Universe

Long time no see. Actually, I was running the other blog in Korean. I'll be pleased if you visit particularly as you read Korean :) You can leave a comment in English, of course. Or you can say hello at the 'hello' page.

Some days ago, I borrowed 'A Different Universe' by Bob Laughlin from my friend. As I've said before, he's a great story-teller, and the book is enjoyable, in some sense. Basically, however, I don't think the book is a sci-pop. book. It's rather a collection of essays by a physicist.

I don't understand why he's so single-minded concerning the emergence and reductionism. Physical reality has some heirachial structure, notably with the energy scale or complexity. He's stressing as if that the high energy physicists especially are all the strong proponents of reductionism and not considering the emergent phenomena as something fundamental. But, I believe this is not the case at all. Bob's exaggerating too much. Why don't you read Sean Carroll's response ?

It will be interesting if you read David Deutsch's The Fabirc of Reality and compare his view point with that of Bob. David is clearly against the reductionism while ironically in sharp contrast to Bob in what physical science should be. Experimental verification is a kind of result of scientific exploration to David while a prerequiste to Bob. David wants to explain Nature and Bob wants to predict (if I slightly exaggerate).

The book contains the chapter of 'Quantum Computer'. I was disappointed finding that the chapter really talks about quantum computer in less than a page. Even those comments on quantum computer seem too naive. You can look through what he said and find a sharp critic by Dave Bacon. The remainings of the chapter was just some viewpoint on computing nothing new.

ps. You can find the figures appearing in the book and some others through his website.
ps. The preface, which is a summary of the entire book, can be found through The Cronicle Review.

Bob Laughlin's Black Hole

Bob Laughlin gave a colloquium talk. At the beginning, he seems a little tired due to heavy works on him as a president. But, he got better as the talk proceeds. Since his Korean is not good enough to give a talk in Korean ;) he rather used his mother tongue.

The title was 'Quantum Criticality and Black Holes'. The problematic topic. You may want to read Lubos' critiques on it here. But, the story was much simpler than that here, since the half of the audience were junior/senior undergradaute students at the colloquium.

He started explaining general relativity in simple terms. He reminded the students of the fact that the gravity is stronger at the surface of the earth than at the sky above and that the time goes slowly. Time in general relativity is not a parameter but the dynamic variable.

He then pointed out that the time in quantum mechanics is universal or a parameter, not the dynamic variable. He stressed at least on of the two theory, general relativity and quantum mechanics, must be wrong since they use time in different context. If we should take one of them as at least an approximate one, which one will you choose, he asked.

He drawed several pictures to explain the exotic phenomena of spuerfluid 4He. Helium flowing out of a cup spontaneously and swirling forever with vortex in it etc were shortly describd. He argued that although one knows how the system of the Hamiltonian is written down in its exact form, one never predicts anything from the Schrodinger equation with that Hamiltonian. One rather describes the phenomena with effective Hamiltonian which, however, exactly gives the results of experimental observation. He coined this as Emergent Exactness. Simply,

• Emergent phenomena comes from the first principle of Schrodinger equation,
• But, one can never prove it,
• While the emergent phenomena itself can be exactly described by effective equations.

So, he asked

What should we call the fundamental laws ?

He answered that emergent exactness should be regarded as fundamental as the first principles. Then, he moved to the original question and say,

Maybe, general relativity is emergent, why not ?

To support his guess, he drawed one example of emergent phenomena in condensed matter and compare it with the black holes which is typical example that general relativity predicts.

( to be continued )

Tractatus Logico-Philosophicus

Let's see how a philosopher (yes, it's Wittgenstein and the work is 'Tractatus Logico-Philosophicus') looks the world.

1. The world is all that is the case.
2. What is the case - a fact - is the existence of states of affairs.
3. A logical picture of facts is a thought.
4. A thought is a proposition with a sense.
5. A proposition is a truth-function of elementary propositions.
(An elementary proposition is a truth-function of
itself.)
6. The general form of a truth-function is [p,XI,N(XI)].
This is the general form of a proposition.
7. What we cannot speak about we must pass over in silence.

The above are outlines and every sentence has its sub-ideas and goes as 1.1, 1.1.1 ... 1.2, ... and so on.

As a layman to philosophy and a grad in physics, I am used to be motivated to write some comment on his assertions. What do you think of them?

Single Molecule Transistor

Electronics at the atomic scale

A Korean physicist Dr. Jiwoong Park, a Rowland Junior Fellow at Harvard, gave a talk about single molecule transistor. He is responsible for the first construction of nanoscale transistor where he studied electron transport behavior through single or small molecules such as C60 and C70-C70s and others with more complex formula. You can see the exotic cover ads of his work in Nature (see the picture above)

He defines his transistor in a broader sense, say,

• A device consisting of two electrodes and the gate which control the current, is called a transistor.
• So, he admits that his transistor possibly has nothing to do with practical amplifier things.
• Then, he moderately said his work has its own value in that we explore and experience possible problems to be encountered for constructing nano-devices in future

He explained the experiment he has done while at Cornell for graduate study. He started by asking 'how to make two electrodes between which small molecule can be put in?'.

• Deposit the metal line with bottle-neck.
• Apply high voltage so that the bottle-neck is physically broken.

It's the active use of the phenomena which is a well-known old problem to semiconductor society, called an electromigration.

Then, he continued to say 'how to put anyway the molecule at the very position?'. Here the molecule used was a complex of carbon, hydrogen, and nitrogen atoms and one cobalt atom at the center inside. (Oh, we should note that they have deposited a thousand electrode on a wafer, so that they produce a thousand pair of electrodes by applying voltages onto each.)

• Just put the wafer into a solution with the molecule.
• Wait for a while, say, an hour.
• Finally we'll see the molecule's are at the right positions.

Magic? The mechanism is simple. The small molecule they used has two arms, at each of which there is an atom which is extremely electrode-philic. That is, each atom at the two edge are strongly attracted and attached to the two electrodes. The yield is not very good to a laymen's eyes. 5-6 successful transistor they get out of a thosuand candidate in a wafer.

The objective was to see 'how the electron transports through one cabalt atom'.
(since other atoms in the molecule works as a mechanical bridge to support cobalt atom between electrodes.)

A short conclusion is

• Electron transport is coupled to the vibrational modes of the molecule.
• There shows Coulomb blockade and Kondo-like phenomena.

There are nice drawings and graphs. For whom is interested in, see the following references.

• Nano-mechanical Oscillations in a Single-C60 Transistor, Nature 407 57 (2000)
• Coulomb Blockade and Kondo effect in a single-atom Transistors, Nature 417 722 (2002)