If you are vaguely interested in quantum mechanics, you must check out the game Quantum Minesweeper. You might want to start with the video tutorial before you play online.

The game differs from classical Minesweeper in the following ways:

• The board is really a quantum superposition of two boards. It is your goal to figure out the superpositions. It is simplified, as only one kind of phase is allowed.
• There are three different kind of measurements that you can do, each one a limited number of times. The measurements are:

1. classical measurement – collapse that can trigger a mine probabilistically. Very risky!
2. entropy measurement – it indicates if there is a superposition or not, but doesn’t tell you if there is a mine or not!
3. interaction-free measurements – it is very magical, doesn’t collapse the wave function, actually gives you the phase information. Very powerful!

This game is fantastic!

Technical digression:

I have a question that might be a good undergraduate research project for someone interested in quantum information. What is the optimal strategy for the game? That is, if you thought of this game as a kind of state tomography problem, is there a general protocol to extract the state with high fidelity, given the constrains of the number of measurements? To make it more interesting, imagine a version of quantum minesweeper where the boards could have between them any kind of phase, how much harder would solving it be?

—

Give it one last try
til the next
one more
last try.
-A Wilhelm Scream

New Scientist has an article, Who’s afraid of radiation?, with an overview of the history of regulation of radiation dosage and its impact on human health. It works as a nice follow up to my own post The Nucular Family.

===

Radio does not, in general, go around corners. This can be a real pain when you are conquering the world, which is inconveniently round, placing all of your most active military units over the horizon.
-Cryptonomicon

The video and slides for my talk for undergraduates at FermiLab can be found here:

Quantum Effects in Photosynthesis [RealPlayer video link].

This is a good introduction to my research. If you are curious about what I do, by all means watch it.

[I know RealPlayer is so 1998 and sucks, I'm trying to get the file in another format from the FermiLab people.]

[Previous post here.]

The Theorist of Theorist, the first modern physicists who decided theorists were at the forefront of physics, the great P.A.M. Dirac, is the inspiration for the title of this blog, and is one of my heroes!

If you are even slighty curious of who Dirac is, you must know that Steve Mirsky of Scientific American recently interviewed Graham Farmelo, author of the authoritative biography of P.A.M. Dirac, The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom. The interviews is fantastic, full of incredible insight from Graham Farmelo about Dirac’s life and a surprising deep understanding of the importance of Dirac’s work by Steve Mirsky. The interview can be downloaded free online: Part One and Part Two. The funny anecdotes alone are reason enough to check this out. This is the best science interview I have heard in a long time.

To celebrate this interview, SciAm has posted online the article written by Dirac for Scientific American published on 1963. Amazing stuff!

SciAm: If you do this a couple more times, you might inspire hope on me that there might be some good science for laymen magazine out there that isn’t crap.

—

God used beautiful mathematics in creating the world.
-P.A.M. Dirac

Vlatko Vedral, from Oxford/CQT Singapore is promoting his new layperson book.

Decoding Reality: The Universe as Quantum Information

An infuriatingly theologically focused video interview can be found here. I’ll assume The Guardian editing is to blame.

Although I am always highly critical of all popularizations of quantum mechanics, I’ll admit I’m biased towards liking this one. Vlatko’s work on the thermodynamics of quantum information have influenced my own interests, and I’m currently working with several people in his group. I can’t wait for this book to come out.

—

Friends have asked me many questions about Obama’s nuclear plan. Although, I am not a nuclear physicists, I did get trained, have been around and/or managed radioactive material while at a Oak Ridge National Lab and University of Texas.

What surprised me was that although I tried to explain each of the different risks, trying to distinguish between radiation exposure and material toxicity, my friends demanded, begged, for apocalyptic scenarios of devastation. This is very much like discussing air travel safety by discussing TWA Flight 800 only, ignoring statistics, ignoring how cars are much more dangerous, and only focusing on what is relevant for a bad blockbuster movie.

Let me be clear, I am not defending nuclear plants disasters, I am not dismissing all the risks of nuclear powered plants. I am surprised how it is impossible to discuss the risks. Any risks involves understanding the different kinds of dangers multiplied by the possibilities of those happening. Without this, benefit, cost and risks analysis are impossible. Without this analysis, public policy cannot be discussed. Why are we so afraid of the dangers of nuclear power, but we are never worried about all the dangers of coal-powered plants? Why, cognitively, these dangers feel so different in our heads? Why in the public eye, nuclear power isn’t about environmental science and economics, but about the apocalypse? This raises many questions about the nature of fear in society, questions I have no answers to.

For example, Nuclear Magnetic Resonance is a standard medical (and general science) technique. It doesn’t have to do with atomic energy, just with the fact that each of the atoms we are made up has a nucleus that consists of protons and neutrons. However, the ‘nuclear’ name had such negative connotations that the name was changed to “Magnetic Resonance Imaging”. Why is this?

My dad has gone through several medical techniques in the past years, including MRI (Nuclear Magnetic Resonance), PET Scan (Positron Emission Tomography) and Radioactive Iodine treatment. He is concerned about the effects of all those nuclear things. I tried explaining how the techniques are very different, containing no radiation, or different kinds of radiation, emphasizing that there is no heavy-metal toxicity in each of these, discussing what does the half-life of iodine really mean to his body by considering that iodine is water soluble, explaining that microwave ovens aren’t dangerous or nuclear, nor are TVs, nor cellphone radiation is of nuclear origins. I did spend significant time talking to my family about this, and maybe it was my fault, maybe I talked over the heads. I was unable to dispel irrational fears in my family, fears that weakened their spirits while my dad was going through an already difficult medical process.

Maybe I was unable to reach them because we meant different things. Maybe there is a very significant difference in the meaning of nuclear to them and to me, a difference in meaning I wasn’t able to overcome with all my explanations.

Why is it so hard for the general public to discuss these issues? Why is discussing nuclear power a taboo? I propose to blame cognition, an image in the mind. After the end of World War II, after the cold war, after The Hulk, the term “nuclear” started carrying a lot of overhead, a lot of imagery and meaning beyond its semantic nucleus of the word [pun].

Bruce Banner, Physicist, demonstrating the effects of Nucular Power

My proposal is the following. There are two different kinds of ‘nuclear’ in the public mind:

1. nuclear as in nuclear family, nucleus as in “the core”
2. nuclear, as in atomic bombs, as in neon glowing toxic rods, as in mutated turtles that learn ninjitsu, as in Cold War, as in nucular.

However, there is only one nuclear in the physicists’ mind, which refers to the core of the atom, which refers to protons and neutrons, which refers to the forces that keep the nucleus stable and make the existence of matter possible, a meaning which is closer to nuclear family than to nucular. It has nothing to do with mutagen, or Homer Simpson and is as far from a nuclear wasteland as Bernoulli’s principle is from crash landing. The same applies to the word “atomic”, that to the general public feels more like “ka-BOOM” than “a tiny piece of anything”.

Is this why there are many public figures that mispronounce nuclear in favor of nucular? Is it that their minds want to distinguish between these two definitions? A linguist at Berkeley suggests this as he explains ‘nucular’ as a folk etymology, not as mispronunciation.

Phonetically, in fact, nuclear is pretty much the same as likelier, and nobody ever gets that one wrong. (”The first outcome was likular than the second”? )

Maybe there are two different meanings of nuclear in the public mind, maybe the nuclear taboo and the word nucular are signs of this. Maybe this is why discussing the dangers and possibilities of nuclear power is so difficult.

What is the solution? I see only two options:

1. invent an euphemism for the word “nuclear” in nuclear power. Call it “freedom power”, “awesome fuel” or “funky style”,
   
2. start calling everything nucular, trying to reunite both misleading diverging meanings. Like, “the nuculus of the cell contains the DNA” and “nucular families are the basis of society”
   

I don’t see any other option that could allow having a public discussion of the pros/cons of nuclear power as public policy, instead of nuclear disaster as a Nostradamus predictions. An apocalyptic image, even if unfounded, has a lot more power than statistics, power that brings out pure fear, preventing all rational discussion. Remember when the news focused on the dangers of black hole creation when the LHC started, instead of actually explaining what the particle accelerator actually does?

Nucular is fear.

If there are any social psychologists around there, can you contact me with references about the origin, nature and effects of fear in society?

—

Vamos a seguir bailando!
Vamos a seguir contento!
y sigamos vacilando!
Vamos a seguir en esto,
porque un dia de estos.
Que tu veras que va llegar un demonio atomico.
y atracata acangana! y nos va limpiar.
Despues de muerto no se puede gozar!
-El Gran Combo

Writing for the general public about science news is hard. ArsTech has an article where they accuse many news organizations of deliberately lying in their science coverage, and discuss how they can get away with it do to double standards.

As a scientist with interest in informing the public of my research, are there any guidelines to follow when talking to the press? I want them to see them as allies, but most of the science news are so bad I can’t help but hating them.

I’ve thought much about how to describe my research to family and friends, and haven’t found any good and concise way to do it. More specifically, can any one suggest any good, simple, cocktail-party style one-liners to explain what is quantum mechanics and quantum computing, but that doesn’t make me feel like I’m lying? If I read again the phrase “what Einstein called spooky action at a distance” I might vomit.

Any ideas?

—
When Men fly from danger, it is natural for them to run farther than they need.
-The Mischiefs that ought justly to be apprehended from a Whig-goverment

They Might Be Giants released their new album, Here Comes Science, with very catchy educational lyrics (yeah, you read it right).

Good stuff.

===

In science one tries to tell people, in such a way as to be understood by everyone, something that no one ever knew before. But in poetry, it’s the exact opposite.
-P.A.M. Dirac

Is this the interaction picture?

W. Heisenberg and P.A.M. Dirac, two of the founders quantum mechanics, were on a steamer boat from America to Japan. Heisenberg, a social butterfly, would participate of all the social activities, while Dirac, always very shy, would just sit quietly and watch.

“Heisenberg, why do you dance?” Dirac honestly inquires. “Well, when there are nice girls it is a pleasure to dance.” Heisenberg responds. Dirac turns silent for a few minutes, involved in deep thought. He finally questions, “Heisenberg, how do you know beforehand that the girls are nice?”

According to Heisenberg, this is a true story.

—
Lord, grant me chastity and continence… but not yet.
-St. Augustine

Quantum superposition is one of the most difficult concepts to understand in all physics. It lies at the heart of what makes quantum mechanics so counter intuitive. I find myself always saying things like “It is in both states at the same time, until you look at it, and then it is only one thing.”, which sounds like pure hocus-pocus. It is not. I plan to have a mathematical description of quantum superposition, but decided for now to start with a simple analogy.

A quantum state is a mathematical representation of a physical property. The act of determining the physical property is called a measurement, that is, “looking” at the state to determine what it is. Quantum mechanics allows for a simple mathematical way to describe both the state, and the outcome of the measurement. The price for this mathematical simplicity is a conceptual inconsistency in the physical description of the object.

Thus, the quantum state can have two incompatible physical properties simultaneously, while when the state is actually measured, only one of them physical properties is measured, either one, it is determined by chance. Now, the analogy.

I cannot stress enough how this is an analogy, a mnemonic device if you will. This is not the full story of what quantum superposition is, just something to wet your appetite.

Think of the quantum state as a wireframe cube, that is, a simple drawing of a cube in paper, like the cube on the left side of the image.

The cube on the left is a 2D representation of a 3D object. Our brain can interpret it in different ways, incompatible with each other, as shown in the right side of the diagram.

The cube on the left side is not really a cube at all! It is just a 2D representation of a 3D object. However, our brain likes to interpret it as a 3D object, a real thing. The drawings on the right serve as suggestions of possible ways our brain could interpret the 2D image. For example, we could imagine it as a box, I decided to put a little pig on top of it. You can see how a box like is perfectly consistent with the 2D image on the left. Likewise, the 2D image could be seen as a corner, like the corner of a room. I used a chicken to help you visualize this interpretation, that is also consistent with the 2D image.

However, altough the diagram with the pig and the one with the chicken are both compatible with the 2D wireframe, they are incompatible with each other! Your brain can visualize the 2D wireframe as a Box, or as a Corner, maybe even switch between both visualizations, but not have them both at the same time.

The analogy is complete now. The 2D image is the quantum states, in a sense it can be said to contain many choices of 3D visualizations within it. A quantum measurement is then analogous to the limitations our brain demand of the image following the laws of perspective. Only one interpretation at a time is allowed by the brain, just like the quantum state can show only one physical property of the two incompatible physical properties at a time.

The analogy breaks in several ways, I’ll point one. Although our brain has some control of the 3D image it decides to see out of the 2D object, there is no such control in quantum superposition. The measured physical property that is seen is chosen at random from the incompatible options. Quantum superposition does not in any way mean that our brain gets to chose what physical reality is, but it does stresses the fundamental probabilistic nature of reality.

Remember, superposition means that two incompatible properties can exist simultaneously, without any inconsistency.

===

If you try to fail and succeed, which one have you done?