Q&A with Philip Philips

You cannot fail to recognize him ! He has a good head of hairs ! [10.1126/science.caredit.a1100031]

Phillips, whose Ph.D. is in theoretical chemistry, says he probably would not have taken such an unusual approach if his background had been more conventional. Science Careers talks to Phillips about how his circuitous route from chemistry to physics prepared him to go down this new research avenue.

The following highlights from the interview were edited for brevity and clarity.

Q: How did you first become interested in science?

P.P.: My parents were in the humanities. I was born in Tobago, and we moved to the U.S. when I was 10. I was very interested in math as a kid. Science was interesting, but I had very bad teachers in high school and so I had no real way of knowing what science would be about.

At the university, I took a chemistry class, and that's when I really became interested in science. So I started taking many more science classes, and I realized too late that my real interest was in physics. I needed one more class for a physics major, and so I had degrees in math and chemistry.

Q: How did you go about choosing your Ph.D. program?

P.P.: I wanted to be a theoretician because math was always my thing, and if I was going to do science, I wanted to apply math to understanding physical problems. [But] I realized, given my limited undergraduate background, that somehow being able to chart a course that was intellectually what would be my focus for the rest of my life was just not possible. So I viewed a Ph.D. as a degree in which I learned how to do research, and the particular problem wasn't something I was deeply interested in at all. My project was on explaining phosphorescence lifetimes in small molecules.

Q: Did you get what you needed out of your Ph.D.?

P.P.: I had an adviser who was an incredibly brilliant person, and he really taught me how to get something done. He gave me this sense of just being able to take on a challenge even if you have no experience with the field.

Q: What was your next step?

P.P.: I got a Miller Fellowship at [the University of California,] Berkeley. The key thing I got interested in was disordered systems, and I started really thinking about many-body systems and phenomena that arise from collective physics, the sorts of things that would define my career.

I just started reading all the papers, and then I defined a new problem that others had not solved that I thought would advance the field. So the problem I was working on at Berkeley was an electron moving in a random array of scatterers. I learned the necessary math tricks to be able to solve this problem, and then I started doing it. That's what I'd learned from my adviser: how to chop something down that is completely new and make progress on it.

As a Miller fellow, I was doing this on my own. It was a big jump from single-particle stuff to, essentially, statistical mechanics, and the mindset was very different. It was painful and a lot of stuff I had to learn, but it was what I knew I wanted to do.

This Science Careers article is a tie-in to Science magazine’s feature on superconductivity.

Q: You then obtained a faculty position at the Massachusetts Institute of Technology (MIT), in the chemistry department. What did you work on there?

P.P.: This problem led me to look at Anderson localization, which is the problem of electrons moving in a random lattice. Solids have a regular array of atoms, and what Anderson showed is that if enough of the atoms are different, the electrons change from being able to move freely to being completely stuck. In one and two dimensions, it's generally been thought that any amount of disorder would lead to localization. But we found the general exceptions. And then I showed that certain classes of conducting polymers could be explained by the examples that lead to exceptions to localization. That application was motivated entirely because I was in a chemistry department.

Q: You then decided to move to Illinois after 9 years at MIT. Why?

P.P.: I was forced out. What I was doing had nothing to do with their definition of chemistry. Some supported me and some didn't. But even if I had gotten tenure, I would have had to move to a physics department.

Q: Were you aware at the time that you were risking tenure?

P.P.: Yes, I was very much aware of this. You have to be honest with yourself. There were no problems in chemistry that interested me. I have always just thought that you should do what you think is important regardless of whether it might work out or regardless of whether or not your colleagues think it will work out.

Q: You obtained tenure at the University of Illinois right away. Do you feel as though you've found your place now?

P.P.: Illinois has been absolutely a gold mine for me, yes. Personality-wise, in terms of the research I'm able to pursue here, in terms of a supportive environment, in terms of my research being central to the condensed matter effort of the department.

Credit: Rick Kubetz, University of Illinois

Philip Phillips collaborated with theoretical particle physicist Robert Leigh, also of the University of Illinois, Urbana-Champaign. Not shown in the picture and also contributors to the work are postdoctoral fellow Mohammad Edalati and graduate student Ka Wai Lo.

Q: So what has been your focus at Illinois?

P.P.: The big problem I have been trying to solve since 1995 is the physics of strongly coupled electron systems. I have been attempting to figure out what it is that the electrons are doing as they interact with one another [within cuprate superconductors]. Our work shows that they form composites, and so once you understand what the composites are, then you can begin to describe the macroscopic properties of the system.

[In 1998, Argentinean physicist Juan] Maldacena made a conjecture in which he argued that there is a relationship between a strongly coupled quantum mechanical system and a gravitational system [that] is entirely classical Einsteinian gravity. So in fact, strongly coupled quantum mechanical systems that are charged are equivalent to a curved space-time with a black hole in it. We showed that if you just introduce some probe fermions and these probe fermions are coupled to the space-time in a particular way, that system looks identical to the normal [nonsuperconducting] state of high-temperature superconductors.

Others have used this mapping before. What we did that was new is that we used a particular interaction between the probe fermions and the black hole that is really irrelevant to the physics of the black hole but changes the physics at the boundary of the space-time [which is where the quantum mechanical theory lives]. No one suspected it.

With such a model, you can just forget about trying to figure out what the basic building blocks are, just go and solve this geometry problem and extrapolate it to what's going on at the surface of this geometry, and you'll see what the quantum mechanical system is doing.

Q: And so have all these years of getting closer to your true scientific interests finally paid off?

P.P.: It takes a lot of daring to invest the time to go and learn this machinery [for geometrizing quantum mechanics] because it's fairly nontrivial stuff, and to think that it has answers for a real-life system is another risk.

I certainly thought that, God, if I were more traditionally trained, maybe I could have known some of the pitfalls of some of the things I've tried in the past. But now it's turning out that it was a good thing. The most important thing about my roundabout way is that I don't have any biases. I'm very open to new approaches and new problems and I don't mind just going and rolling up my sleeves and trying something new. This research is the culmination of what I thought I wanted to do when I was a graduate student.

Philip Phillips C.V. Highlights

1979: Receives bachelor's degree in math and chemistry from Walla Walla Community College in Washington state

1979–81: Graduate research assistant in theoretical chemistry at the University of Washington, Seattle

1981–84: Miller Postdoctoral Fellowship, University of California, Berkeley

1984–90: Assistant professor of chemistry, Massachusetts Institute of Technology, Cambridge

1990–93: Associate professor, Department of Chemistry, Massachusetts Institute of Technology, Cambridge

1993–99: Associate professor, Department of Physics, University of Illinois, Urbana-Champaign

2000–Present: Professor of physics, Department of Physics, University of Illinois, Urbana-Champaign

Schrodinger's cat fattened up

The famous Schrodinger cat now gets fattened up to 430 atoms [http://www.nature.com/news/2011/110405/full/news.2011.210.html]!

In the famous thought experiment conceived by Erwin Schrödinger in 1935 to illustrate the apparent paradoxes of quantum theory, a cat would be poisoned or not depending on the state of an atom — the atom's state being governed by quantum rules. Because quantum theory required that these rules allowed superpositions, it seemed that Schrödinger's cat could itself exist in a superposition of 'live' and 'dead' states.

The paradox highlights the question of how and when the rules of the quantum world – in which objects such as atoms can exist in several positions at once – give way to the 'classical' mechanics that governs the macroscopic world of our everyday experience, where things must be one way or the other but not both at the same time. This is called the quantum-to-classical transition.

It is now generally thought that 'quantumness' is lost in a process called decoherence, in which disturbances in the immediate environment make the quantum wavefunction describing many-state superpositions appear to collapse into a well-defined, unique classical state. This decoherence tends to become more pronounced the bigger the object, as the opportunities for interacting with the environment increase.

One manifestation of quantum superposition is the interference that can occur between quantum particles passing through two or more narrow slits. In the classical world the particles pass through with their trajectories unchanged, like footballs rolling through a doorway.

But quantum particles can behave like waves, which interfere with one another as they pass through the slits, either enhancing or cancelling each other out to produce a series of bright and dark bands. This interference of quantum particles, first seen for electrons in 1927, is effectively the result of each particle passing through more than one slit: a quantum superposition.

As the experiment is scaled up in size, at some point quantum behaviour (interference) should give way to classical behaviour (no interference). But how big can the particles be before that happens?

Scaling up

In 1999, a team at the University of Vienna demonstrated interference in a many-slit experiment using beams of 60-atom carbon molecules (C₆₀), which are shaped like hollow spheres². Now Markus Arndt, one of the researchers involved in that experiment, and his colleagues in Austria, Germany, the United States and Switzerland have shown much the same effect for considerably larger molecules tailor-made for the purpose — up to 6 nanometres (millionths of a millimetre) across and composed of up to 430 atoms. These are bigger than some small protein molecules, such as insulin.

In the team's experiment, the beams of molecules are passed through three sets of slits. The first slit, made from a slice of silicon nitride patterned with a grating consisting of slits 90 nanometres wide, forces the molecular beam into a coherent state, in which the matter waves are all in step. The second, a 'virtual grating' made from laser light formed by mirrors into a standing wave of light and dark, causes the interference pattern. The third grating, also of silicon nitride, acts as a mask to admit parts of the interference pattern to a quadrupole mass spectrometer, which counts the number of molecules that pass through.

The researchers report in Nature Communications today that this number rises and falls periodically as the outgoing beam is scanned from left to right, showing that interference, and therefore superposition, is present.

Although this might not sound like a Schrödinger cat experiment, it probes the same quantum effects. It is essentially like firing the cats themselves at the interference grating, rather than making a single cat's fate contingent on an atomic-scale event.

Quantum physicist Martin Plenio of the University of Ulm in Germany calls the study part of an important line of research. "We have perhaps not gained deep new insights into the nature of quantum superposition from this specific experiment," he admits, "but there is hope that with increasing refinement of the experimental technique we will eventually discover something new."

Arndt says that such experiments might eventually allow tests of fundamental aspects of quantum theory, such as how wavefunctions collapse under observation. "Predictions, such as that gravity might induce wavefunction collapse beyond a certain mass limit, should become testable at significantly higher masses in far-future experiments," he says.

Can living organisms – perhaps not cats, but microorganisms such as bacteria – be placed in superpositions? That has been proposed for viruses³, the smallest of which are just a few nanometres across – although there is no consensus about whether viruses should be considered truly alive. "Tailored molecules are much easier than viruses to handle in such experiments," says Arndt. But he adds that if various technical issues can be addressed, "I don't see why it should not work".

This cat has been at the center of quantum community since its first time being proposed by Schrodinger. Arguably, it contains the main piece of every mystery of quantum physics: it is stated that, the cat can be in a superposition state of death and alive. Somebody think there might exist a kind of 'quantum-to-classical' transition, say, due to gravity. Although it is quite fair to claim that quantum mechanics applies to cats of any mass, not only microscopic ones but also macroscopic, it is still a special interest to experimentally confirm it. If quantum mechanics really captures something true, it would be crazy to think that, it is applicable only to small things. The success of this theory in all kinds of practices has only demonstrated its universality.

... Thus consciousness becomes the source of what we call scientific reality. The entire creation of the universe(s) is a product of expanding human mind.

This is not true. Because science, as a creation of minds, cannot replace the objects it reflects on. Not only scientists, but also every human look at things in their own way. Despite various reflections upon it, the reality is one. Reflections, however many and ingenious they are, can by no means be called reality. Science is reflections of this kind that are scrutinized by reasoning.

What is wrong with the world ?

Is it really the trees of knowledge ruining the trees of life ?
The daily world seemingly gets more and more incomprehensible under living pressure.
http://physicsandphysicists.blogspot.com/2010/07/no-higgs-yet.html

Rejection and Ridicule

Rejection and Ridicule

Science Career section has a very nice article on what happens when you (i.e. a scientist) try to challenge a prevalent idea.

Not everyone who thinks they've made a game-changing discovery is right. Many -- perhaps most -- apparent breakthroughs are just wrong. Here, the input of peers brings to light inconsistencies in data or errors of interpretation. The process works best when scientists stand up -- with integrity, perseverance, and a certain degree of open-mindedness -- right up until it becomes clear that they're wrong.

But what if you're not wrong? Thick skin and persistence are keys to making the process play out well. Progress is made when good scientists keep working -- and keep supporting what they believe is true -- despite the criticism. Following are some coping strategies gleaned from our cohort of audacious scientists.

This is an important aspect in how science is done that a lot of the general public does not know. Certainly, when something new is presented that contradicts an current understanding, one EXPECTS a challenge, and one expects that the new idea or conclusion must have strong backing to survive. Even Einstein had to go through this rigorous process.

But when you read the article, keep a couple things in mind that are very clear:

1. These game-changing ideas were published in peer-reviewed journals. So crackpots who can't even get their "theory" into such a medium can't complain that the "system" will only publish papers that only follow the status quo. These are clear evidence to falsify such faulty claims.

2. That time and further refinement of evidence will eventually support you if you are correct. This is a crucial characteristic of a valid idea, whereby further studies will produce more evidence in favor of it, and will refine it even more. This is in contrast with "evidence" from pseudoscience where over time, the validity of its existence is under question.

Perhaps the best advice in the whole article can be summed up in this paragraph:

"At the end of the day, it's an empirical process," says David Botstein, the biologist at Princeton University who figured out how to map human genes, laying the foundation for the Human Genome Project. "If you disagree with conventional wisdom and the data are on your side, then you've got to persist. If on the other hand, you have a crackpot idea and the data are on the other side, you have to not be in love with your own idea."

This article adds another dimension to a similar and excellent article written by the late Dan Koshland in Science a while back.

Zz.

The Standard Model Explained - Briefly

The Telegraph has this "cheat sheet" for the public. It is a very, VERY, brief description (I wouldn't call it an explanation) of the Standard Model.

It isn't a bad description. It is just that, as with other news item for the public, it appeals to the short-attention-span crowd who only likes sound bites. There's A LOT missing here, which are the details. But who cares about the details, right?

Theorists and experimentlists

In my opinion,

A theorist should pay close attention to experimental facts. He should lay greater weight on facts than on the thoughts from his peers. It is the facts that say the last word, and that constitute the objects which he has to be directly faced with. He should not do simply cobbler and tailor type jobs. He must try to figure out what is hidden behind phenomenology. In a sense, the thoughts from his contemporaries are just secondary. So, theorists, please attend meticulously to facts.

Similarly, an experimentalist should listen carefully to speculative views. Because, ignoring these views make him blind to the meanings of his experiments. It is a theory that confers essence upon observations. Without theory, it is futile and pointless to make observations.

Henceforth, a real physicist should intend to be complete.

Taking The Mind Of God Out Of Science

By Marcelo Gleiser

"Beauty is truth, truth beauty," wrote the poet John Keats in 1819. For centuries, this belief has been the life force of science and of physics in particular. No wonder that the emblem of the venerable Institute for Advanced Study in Princeton, Einstein's American academic home after 1933, depicts the goddesses Beauty and Truth holding hands. Here, beauty represents the rational order behind the perceived complexity of the natural world, an expression of mathematical symmetry and perfection.

This rational order is truth in its purest form, the hidden code of Nature, the blueprint of Creation. The implicit assumption is that we, humans, can decipher it through the diligent application of reason and intuition. As we search, we transcend our human boundaries, our frailty, lifting ourselves into a higher plane of existence. This has been the dream of countless philosophers and scientists, from Plato and Ptolemy to Kepler and Einstein. Who can resist the seductive appeal of searching for immortal truth through reason? Who wouldn't want to play god?

Since Thales asked what is the primal substance that makes up all matter around 650 BCE, we have been searching for oneness. This search, as old as philosophy, has served us well. There is a value system behind it, based on a double belief: First, that there is indeed an overarching structure behind all that is; second, that we can figure it out.

I question both. The corollary here is that this unique structure is beautiful and thus true: the aesthetics of physics. Yesterday, my esteemed co-blogger Adam Frank presented some of the thoughts behind this search, as he generously introduced A Tear at the Edge of Creation to our faithful 13.7 readers. Today, I want to take this notion further.

Symmetry principles are extremely useful in the natural sciences. The problem starts when symmetry ceases to be a tool and is made into dogma. Nowadays, the hidden code of Nature is represented by the so-called theory of everything, or final theory. The best candidate is superstring theory, a theoretical construction that shifts the basic atomistic paradigm -- that matter is made of small building blocks -- to a new one whereby vibrating strings in nine spatial dimensions can represent what we measure as particles at lower energies and in 3d.

I spent my Ph.D. years and a few years after working in higher dimensional theories, trying to make sense of how to go from 9 to 3 spatial dimensions. For many years, I was a devoted unifier. Now I see things in very different ways, prompted by a combination of empirical evidence (or better, lack thereof) and an understanding of the historical roots of monistic thinking in science.

People should be free to search for theoretical constructions and follow their tastes and beliefs. However, as a scientist, one should also think critically about what's going on and ponder if, indeed, the pursuit of a certain idea makes sense. After some 26 years, we have no clue how to construct a viable superstring model that reproduces our universe. Right now, there seems to be a near-infinite number of possible formulations, each producing a different cosmos. We may call these solutions parts of a multiverse, but that doesn't really help. We don't know even how to write down the equations for string theory to search for plausible solutions. Add to this very practical and technical limitation the empirical lack of any reason to believe there is a single theory behind the myriad phenomena of Nature, and you start to realize that maybe this is simply the wrong way to think about the world.

The world isn't perfect in a rational, mathematical sense. Yes, we find symmetries out there, and they are useful. But we should have the humility to see Nature for what it is and not for what we want it to be. Fifty years of particle physics have again and again crushed the symmetries that we have hoped for.

(For the experts, just think of the violation of parity and of charge conjugation in the weak nuclear force. Also, remember that even electromagnetism is only perfectly symmetric in vacuo, that is, in the absence of sources: there are no magnetic monopoles. Finally, the electroweak unification is not a true unification since the electromagnetic and weak forces retain their signatures throughout. And Grand Unified Theories, well, no trace of them either.)

Science is a construction, a wonderfully successful but still limited construction. What we have are models that approximate what we measure with more or less efficiency. And speaking of measurement, we see right here an impediment to a final theory: because what we know depends on what we measure, and what we measure is limited by our instruments, we can never be certain of what's hiding in the shadows of our ignorance. No, I'm not speaking of gods, fairies, and spirits. I'm speaking of a possible new layer of "fundamental" particles, a new force, an unexpected effect. We can't know all there is to know. Ergo, we can't ever know if our theory is final or not. We should take the mind of God out of physics. It's very liberating! We don't need to believe in the existence of a sunken treasure to explore the ocean. The treasures are many, starting with each drop of water.

It's time to let go of the old aesthetic of perfection, of equating beauty with truth. Here is a new banner, based on the beauty of imperfection: Nature creates through asymmetry. Perhaps we can use Andy Warhol's print of Marilyn Monroe as our emblem, stressing her very prominent and very beautiful asymmetric beauty mark. Would she be as beautiful without it?

Teaching physics ? A view from Mr.Zz

Teaching Physics To Kids (And Dogs)

For the longest time, I resisted myself from making any comments on this. I respect other physicists who spend time and effort trying to educate the public on various aspects of physics. It isn't easy, not just because of the nature of the subject, but because we have to be very careful on what we say and how we say certain things. This is because we can mean one thing when we say it, but the public may understand things in a very different way because of the different "vocabulary" that we some time use. So trying to explain something, or writing a book, on physics is an endeavor that requires a lot of self-exploration and self-evaluation.

I've read a bit of Chad Orzel's book "How to Teach Physics to Your Dog", and I've read many reviews about it. It's a fun book, and I highly recommend it. However, I am a bit uncomfortable with the title of the book, and I will try to explain it here. I only hope the reasons don't become confusing and I end up sounding as if I'm criticizing the book, which is far from my intention.

What do we mean when we try to teach someone something? If I tell you that Newton's 2nd Law says "F=ma", have I taught you anything? If tell you that the largest planet in the solar system is Jupiter, have I taught you anything? To me, teaching means the imparting of knowledge, not simply the imparting of information. There's a difference there. Information can be a series of disconnected, disjointed items, whereas a knowledge is not just information, but how these items connect to each other. In other words, you know not only that "F=ma", but you know what it means, and how to use it. This isn't automatic. Many people know F=ma. In fact, we write it early in our class in intro physics. Yet, give these students a simply projectile problem to do right after you introduce that equation and see how many can use it to solve such a problem. This clearly shows that just because you have that information, it doesn't mean that you have the knowledge of what it is.

So that brings us back to whether you can teach your dog, or your kids, physics. At some level, you can. You can certainly show simple concepts until the kids see a pattern, and they now understand how something behaves. They might even be able to replicate such a thing with other examples. So yes, that would be teaching. But how do you teach kids (and dogs) quantum mechanics, for example? All the pop-science books meant for the public have done it simply by telling the readers the "weird" properties of QM, how a quantum system behaves, and what possible implication it could mean. But these are nothing more than telling someone a series of information. In fact, when done this way, these series of information, more often than not, appear disjointed and disconnected. People learn about the Schrodinger cat, for example, but do not realize that the same principle (superposition) is what makes quantum entanglement so weird. Without that principle, quantum entanglement is no more strange than the classical case of a simple conservation of (angular) momentum. Or would people realize that the Heisenberg Uncertainty Principle isn't really a "principle", or that it is not separate from the wavefunction itself and how we define what we call "observables"? The HUP is almost always automatically there when we deal with the Schrodinger equation wavefunction.

To me, this is not teaching physics. It is teaching ABOUT physics. There's a difference. There is value in teaching about physics, and many pop-science books do a tremendous service to the field by introducing people to it. But it should not be confused with teaching physics. The latter involves imparting knowledge in such a way that the recipient obtains the ability and skill to use and apply the information. I consider being able to use F=ma and solve kinematical problems as a sign that someone has a knowledge of F=ma. In Mary Boas's "Mathematical Methods in the Physical Science", she stated:

To use mathematics effectively in applications, you need not just knowledge, but skill. Skill can be obtained only through practice. You can obtain a certain superficial knowledge of mathematics by listening to lectures, but you cannot obtain skill this way.

And I would apply that to the difference between information and knowledge, physics and about physics, as used in this context. One needs to clearly differentiate the superficial understanding of something versus learning something. This should be done both by the instructor (or author) and the student (or the reader).

There's plenty of worthiness in a book that teaches physics, and a book that teaches ABOUT physics. One can only hope that a reader does not confuse the two.

Zz.

What interests you most in science ?

Making A Supersonic Jet In Your Home

As always, I'm a sucker for articles like this. While it may not have earth-shattering ramifications, I always love reading curious but common phenomenon like this that produced something that is highly unexpected.

The paper shows that when you drop, say, a marble, into a liquid, what happens next can actually produce a supersonic jet of air! A review of this work can be found here, and you can also get access to the actual paper in the link.

In the kitchen version of the experiment, the marble creates a crown-shaped splash and crater as it falls into the liquid. The crater deepens to the point at which the walls start to contract. This is due to both the weight of the water outside and possibly surface tension, both of which create pressure gradients that force the collapse. Air inside this collapsing neck must escape upward or downward as the neck approaches pinch-off. It is in this escaping air that Gekle et al. found supersonic velocities—the first jet in this simple experiment.

A video of this also accompanies the review article.

I often wonder if the fun and fascinating tidbits of apparently "mundane" things like this is the reason why I got into physics in the first place. I know many people cite trying to understand the universe, or wanting to find the meaning of life, etc... etc. as the reason they study physics. I often find that I don't have such grand ambition. Instead, I find delightful pleasure in figuring out if quantum effects causes a pencil balanced on its tip to fall over, or if warm water freezes faster than cold water! Maybe I have a small mind....

LHC, a grand oddyssy

With its successful test run at the end of 2009, the Large Hadron Collider near Geneva seized the world record for the highest-energy particle collisions created by mankind. We can now reflect on the next questions: What will it discover, and why should we care?

Despite all we have learned in physics -- from properties of faraway galaxies to the deep internal structure of the protons and neutrons that make up an atomic nucleus -- we still face vexing mysteries. The collider is poised to begin to unravel them. By colliding protons at ultra-high energies and allowing scientists to observe the outcome in its mammoth detectors, the LHC could open new frontiers in understanding space and time, the microstructure of matter and the laws of nature.

We know, for example, that all the types of matter we see, that constitute our ordinary existence, are a mere fraction -- 20% -- of the matter in the universe. The remaining 80% apparently is mysterious "dark matter"; though it is all around us, its existence is inferred only via its gravitational pull on visible matter. LHC collisions might produce dark-matter particles so we can study their properties directly and thereby unveil a totally new face of the universe.

The collider might also shed light on the more predominant "dark energy," which is causing the universe's expansion to accelerate. If the acceleration continues, the ultimate fate of the universe may be very, very cold, with all particles flying away from one another to infinite distances.

More widely anticipated is the discovery of the Higgs particle -- sometimes inaptly called the God particle -- whose existence is postulated to explain why some matter has mass. Were it not for the Higgs, or something like it, the electrons in our bodies would behave like light beams, shooting into space, and we would not exist.

If the Higgs is not discovered, its replacement may involve something as profound as another layer of substructure to matter. It might be that the most elementary known particles, like the quarks that make up a proton, are made from tinier things. This would be revolutionary -- like discovering the substructure of the atom, but at a deeper level.

More profound still, the LHC may reveal extra dimensions of space, beyond the three that we see. The existence of a completely new type of dimension -- what is called "supersymmetry" -- means that all known particles have partner particles with related properties.Supersymmetry could be discovered by the LHC producing these "superpartners," which would make characteristic splashes in its detectors.Superpartners may also make up dark matter -- and two great discoveries would be made at once.

Or, the LHC may find evidence for extra dimensions of a more ordinary type, like those that we see -- still a major revolution. If these extra dimensions exist, they must be wound up into a small size, which would explain in part why we can't see or feel them directly. The LHC detectors might find evidence of particles related to the ones we know but shooting off into these dimensions.

Even more intriguing, if these extra dimensions are configured in certain ways, the LHC could produce microscopic black holes. As first realized by Stephen Hawking, basic principles of quantum physics tell us that such black holes evaporate in about a billionth of a billionth of a billionth of a second -- in a spectacular spray of particles that would be visible to LHC detectors.

This would let us directly probe the deep mystery of reconciling two conflicting pillars of 20th century physics: Einstein's theory of general relativity and quantum mechanics. This conflict produces a paradox -- related to the riddle of what happens to stuff that falls into a black hole -- whose resolution may involve ideas more mind-bending than those of quantum mechanics or relativity.

Other possible discoveries include new forces of nature, similar to electric or magnetic forces. Any of these discoveries would represent a revolution in physics, though one that had been already considered. We may also discover something utterly new and unexpected -- perhaps the most exciting possibility of all. Even not discovering anything is important -- it would tell us where phenomena we know must exist are not to be found.

Such talk of new phenomena has worried some -- might ultra-high-energy particle collisions be dangerous? The simple answer is no. Though it will be very novel to produce these conditions in a laboratory, where they can be carefully studied, nature is performing similar experiments all the time, above our heads. Cosmic ray protons with energies over a million times those at the LHC regularly strike the protons in our atmosphere, and in other cosmic bodies, without calamity. Also, there are significant indications that nature performed such experiments early in the universe, near the Big Bang, without untoward consequences. Physicists have carefully investigated these concerns on multiple occasions.

All this may seem like impractical and esoteric knowledge. But modern society would be unrecognizable without discoveries in fundamental physics. Radio and TV, X-rays, CT scans, MRIs, PCs, iPhones, the GPS system, the Web and beyond -- much that we take for granted would not exist without this type of physics research and was not predicted when the first discoveries were made. Likewise, we cannot predict what future discoveries will lead to, whether new energy sources, means of space travel or communication, or amazing things entirely unimagined.

The cost of this research may appear high -- about $10 billion for the LHC -- but it amounts to less than a ten-thousandth of the gross domestic product of the U.S. or Europe over the approximately 10 years it has taken to build the collider. This is a tiny investment when one accounts for the continuing value of such research to society.

But beyond practical considerations, we should ponder what the value of the LHC could be to the human race. If it performs as anticipated, it will be the cutting edge for years to come in a quest that dates to the ancient Greeks and beyond -- to understand what our world is made of, how it came to be and what will become of it. This grand odyssey gives us a chance to rise above the mundane aspects of our lives, and our differences, conflicts and crises, and try to understand where we, as a species, fit in a wondrous universe that seems beyond comprehension, yet is remarkably comprehensible.

Steve Giddings is a physics professor at UC Santa Barbara and an expert in high-energy and gravitational physics. He coauthored the first papers predicting that black hole production could be an important effect at the LHC and describing certain extradimensional scenarios that the LHC might explore.

Is time in a hurry?

By Marcelo Gleiser

Well, 2009 is almost over. To me at least, and I bet to most of you, it went way too fast. On average, it was a year like any other, with some new things to celebrate and others to lament. (I'll abstain from listing them. Each person has her own list.) But it's hard to shake off the feeling that everything happened faster, that time seems to be in a hurry to get somewhere. Sometimes, people ask me if it's possible, from a physics perspective, for time to be passing faster. It can't.

According to the theory of relativity, time can slow down but not speed up. There are a few ways to do this. For example, you may move faster than other people. If you get to speeds close to the speed of light, time will slow down for you relative to the others. Hard to do, as the speed of light is a whopping 186,400 miles per second, in round numbers. Or, you may go live on the surface of the Sun. Time there would tick slower than here as well. But that's really not what people have in mind when they wonder about time. The question is about our psychological perception of time. And I am sure many of you would agree that sometimes it does feel like time is on a roller coaster.

Time is a measure of change. If nothing happens, time is unnecessary. So, at a personal level, we perceive the passage of time in the changes that happen around and within us. What's interesting is that--as anyone who has tried to meditate knows--even if you shut off all your senses, time keeps ticking away. As our thoughts unfold, our brains give us time. To "quiet the chatter" is the big challenge for going deeper into a meditative state, to be in the now.

The passage of time is about the ordering of events, things that happen one after another. Numbers, some say, are devices that were created to help us order time. Maybe, although counting chicks is also very useful if you are a hen. However, if we are to order events, we must remember them. Ergo, the perception of time is deeply related to memory. If our memories were to be erased, we would revert to the wonder of babyhood, where time extends forever. The more we have to learn, the more memories we make, the slower time passes. Routine, sameness, makes time speed up. Since routine is not usually equated with fun, this seems to go contrary to the "time flies when you're having fun" dictum. What's going on here?

The answer may be in the level of mindful engagement, that is, in how tuned-in your brain is to what you are doing. Newness, as in fun newness, works as a flood of information and places the focus on the immediate. There is no ordering between events yet and not sense of the passage of time. I have felt this disengagement when lost in a calculation for hours or trying out a new trout stream with my fly rod. This is the opposite of routine, where new memories are not being made and the now is all there is. But maybe someone will prove me wrong.

In physics, things are simpler. Time is a fundamental quantity, something that cannot be defined in terms of anything else. There are some issues with this, that we will address some other time. (Sorry...) The second is the universal unit, and it's defined as 9,192,631,770 oscillations between two levels of the cesium-133 atom. Very different from the tick-tack of old mechanical clocks, which are not very reliable.

Einstein had a colloquial definition of the relativity of time: by the side of a pretty girl an hour feels like a second; if you burn your hand on the stove, a second feels like an hour. His special theory of relativity showed that the simultaneity of two events depends on how they are observed: what may be simultaneous for one observer will not be for another moving with respect to the first. Be that as it may, even in physics the ordering of time is essential: that's causality, causes preceding effects so that the present vanishes into the past and the future becomes the present.

At the cosmic level, there is a well-defined direction of time: the expansion of the universe, which has been going on for 13.7 billion years, pointing resolutely forward. Link it to our own passage through life, and we have a well-defined asymmetry of time, what's sometimes called time's arrow . There is not much we can do to escape this at the physical level. But at the psychological level, to slow down time we have to engage our minds, create more memories, absorb knowledge. Perhaps I will leave my guitar aside for a while and start playing the piano.

Although we use clocks to count time, it is impossible to know if the clock is in hurry or not. Because, to know if the clock goes differently, you need refer to another clock. Actually, time is defined by uniform periodic motions. But, how do you know if it is uniform or not ? You would need another motion to define uniform. So, this is a cyclic logic: time itself needs be used to define time. Eventually, it seems falling upon our sense to make a decision on 'uniform or not' !

What does understanding mean ?

I'm attempting to make a definition of understanding. Because I think this is as primary as it is useful. We need understanding when we feel baffled, i.e., we feel that our pure logical deductions can not make an immediate connection between what we know (as a part of our experience) and what we just observed (which is the object to be understood). In other words, we feel that, these two ends, our knowledge as one end and the object as the other, seem very distant. Our logical deductions seem helpless in ferrying us from one end to the other. As long as this ferry is not finished satisfactorily, the understanding will be on-going. The process of understanding is to build these logical steps (the causal chain), starting either from existing models or a new one, all the way to reach the object. So, only when (1) the proper model has been found and (2) the causal chain has been forged can the understanding be settled, and can we be released from the baffling. Our baffling, in my opinion, is a gift. The sense of being baffled promotes us to raise questions, and raising questions reverts us into another baffling. We are baffled when we have questions. As long as we have questions, we shall be baffled. This is a joyful voyage. That is why Einstein once remarked, 'the best one can have in life is the experience of mythtery, and I'm content with a life of mythteries'.

An example. If a man fucks a woman, this woman may get pregnant. So, the question is, 'why does she have to get pregnant ?' 'Why cant it be otherwise ?' . 'Why cant it be otherwise ?' is a question that urges one to answer. We know a fucked woman may get pregnant, but we don't know why this simple fucking could lead to a baby ! If one asks himself, he'll be baffled and curious. It is never self-evident that a fucking shall bring about a baby. An understanding may be achieved if he finds, 'fucking ——> ejaculation of semen ——> semen entering the womb ——> semen's synergy with an egg in the womb ——> this compounded object divides and grows ——> a baby forms in the womb'. If this chain is found, his baffling shall be more or less alleviated. However, only after he completely confirms every element of this chain will be fully relaxed.

In the same spirit, I wish to talk about computer simulations, which have become a very important tool in theoretical physics and other fields. It often offers very important insight that may lead to ultimate understanding, albeit it is not an understanding by itself. It helps understanding, just as experiments. Actually, computer simulations play the same role of experiments, I reckon. In experiments, you set experimental knobs and then start experiments and observes what will happen and make record. In computer simulations, you set and input required parameters and then let a computer to execute orders and output results and you record the results. The only difference is that, in the former it is the Nature that composes and executes the orders while in the latter it is you who write the codes to be executed by the computer. After simulations or experiments, you get the outputs. But you don't know why the output looks like this but not like that. The causal chain between the input and the output is not clear and awaits building. Frequently, this chain can seldom be exactly built. Many approximations have to be made. Much the way one builds a bridge. For the bridge to be strong, perfect materials should be used. But perfect materials can hardly be found, so instead one uses the best at hand. 'The best' may not be perfect, but at least a bridge can be laid down. When better materials are found, an improved one can be built.

That is the way science is done, I think.

wave-corpulscle duality: wield or elegant ?

Wave-corpuscle duality is usually (and maybe best) illustrated in the famous double-slit experiment, where one lets a beam of particles pass through a wall with two slits to reach a screen, on which an intensity pattern shall be observed. Now if these particles are what every one understands with his daily experience, such as bullets and sands, one gets a pattern displaying all features one can find with bullets. On the other hand, if these particles are light quanta, i.e., photons, a completely different pattern, which is usually called interference pattern, shows up exhibiting all features one may perceive with water waves bypassing two obstacles (e.g., two big stones). If the first pattern prevails over the latter, then one may say this beam behaves more like a beam of particles. And the opposite case corresponds to wave-like behaviors. Now the 'wield' thing is that, the same beam can display both patterns, depending on whether a slit is open or closed !

Common sense would say, a bullet is always a bullet, regardless of the experimental setup. However, the quantum world goes absolutely against one's common sense, since by operating a slit switch without explicitly affecting the gun, the bullets become something else. Were such quantum effect dominant in daily world, one would be able to alter the moon by playing with something on earth. Wield ! Completely wield !

Yes, it is wield relative to common sense, as wield as curved space-time! Einstein said our universe is curved, which is also counter-intuitive. Nevertheless, in spite of their wields, they are elegant. Why ? Because they seem to be the simplest notions one can have to solve all puzzles in their own fields. One can hardly expel them without encountering awkwardness. They have a unique unifying power. In the eyes of theoretical physicists, the elegance of a concept consists largely of its unifying power. Such concept solves not one phenomenon, not two phenomena, but a dozen of seemingly isolated phenomena. In quantum world, it is hard to dispense with wave-corpuscle duality and at the same time explains everything. It is impossible to explain double-slit experiment using a particle-only picture without invoking some very ugly assumptions. It is impossible to dispense with the notion of relativity of simultaneity while at the same time accounting for all fast phenomena.

So, wield and elegant are likely to go hand in hand. Further, what is wield is constantly changing, because our common sense is constantly changing. It is never a good reason to reject an elegant idea just because it is wield !

P.S.: this blog is intrigued by a research presented in PHYS.FORUM, aiming at eradicating wave-particle duality. The author was motivated by this question, 'what goes through the slits ?'. In my opinion, all exiting answers to this question differ as sheerly an issue of semantics. You may use another name of wave-particle duality, but the content remains the same, because, it is at the heart of quantum mechanics.

Models and explanation

As I have said many times, the following, this time which was said by Sergei Maslov, is my credo in doing science:

Even more important than tools, theoretical physics has taught me about the power of simple models in revealing the essence of complex phenomena. Simple models are indispensable if one wants not to just reproduce the complexity of a system (e.g. by detailed computer simulations) but to truly understand it.

In my opinion, no comprehension can be achieved without simple models, despite how accurate a simulation may be. Because understanding is not simply about accuracy. More, it is about how to establish a clear connection between one's own already existing experience (including his knowledge) and the phenomena under consideration. Only when this connection can be built in light of his experience can he be satisfied in understanding. This process of building connection is actually a process of constructing models based on what he knows and reasoning with his model.

P.S., Maslov is doing research in systems biology and complex networks.

The following is a quotation from a guy I highly respect. I agree with him very much on the relevant matter as said below:

Creationist Refutes Darwin’s Evolutionary Theory - A Rebuttal

I mentioned about this talk about a week ago of a creationist attempting to falsify Darwin's theory of evolution. This morning, I found this response written by a physics major junior that easily threw a lot of doubt in the garbage that was spewed at that talk.

Carter used a wonderful scientific vocabulary and showed some facts that were true.

However, blinded by science jargon, he put up facts and figures with little truth to them, no way to verify them (or if he did, they were not accurate and considered fraudulent in the scientific community), nor accuracy to the science actually used.

This man performed a wonderful show, and is an outstanding example of how the public will believe almost anything that has numbers and graphs in it with no scientific proof.

The writer listed several examples where Carter simply can't produce valid sources for his numbers.

I'm left to wonder how many people in the audience who bought into what they were told. We often talk about the public needed to be scientifically literate. What we mean by that is NOT that the public knows all these "facts", but rather, having the skill to analyze how one goes from A to B to C to D. How, for example, do you draw up the conclusion that, say, "gay marriage" leads to "undermining traditional marriage". People throw out those two phrases all the time, but no one seems to explain the mechanism that show how "gay marriage" CAUSES "undermining of traditional marriage". Not only that, if such mechanism exists, one needs to publish such a thing and be scrutinized for it by others who are experts in the field of study to ensure that such a mechanism is valid, and that leads to the unique conclusion.

The same thing is occurring here. One simply can't throw out all of these numbers and conclusions (something that is commonly done in politics and economics) without any basis to show that they are valid. But the public that isn't familiar with the scientific process are ignorant of that. This is why I'm very proud of this young writer who already has the skill (hopefully something he gained from his education) to analyze and question how such conclusions are made. So well done, Jim Eakins!

Making the public be scientifically literate should mean making them able to make a rational analysis of how one draws up a conclusion. It is why when I proposed a revamping of the undergraduate intro physics labs, I try to steer away from making "textbook tests" of physics principles. Rather, I focused on how one can draw up the conclusion on how A depends on B, and what is the exact relationship between those two. Our world has always been focused on how we can relate things, how are they interconnected, etc. These types of lab exercises precisely present such tests.

It is a nice statement.

The Philosophy of Science

I do science because I want to see how things operate causally. I believe they should operate causally.

Science is about how to comprehend natural phenomena in a logical way. The phenomena, at first glance, seem scattered and unrelated, the unification of which is the goal of science. Science attempts to achieve unification with a conceptual model, based on which logical deductions set in. In science, one tries to relate various phenomena using the possibly smallest number of concepts and axioms, much the way everything about flat space geometry is wholly built on Pythagorean theorem. Doing science is like a play. The player all the time looks for new way of playing with the toy in hand. Frequently, he looks for new toys. He examines a toy from various perspectives and thinks about what will happen if some conditions are given. And he tries to do what he speculates. He entertains himself in doing this. The toy for scientists is any piece of Nature.

We take a piece of Nature and think what we can do with it. We may place it in a heat bath and measure its heat capacity. We may apply an electric field to it and watch its responses. We may consider how a beam of light can be influenced by it. Or, we may bombard it using a beam of electrons or other kinds of particles and observe what will happen to the beam and the target. We want to know more and more of what will happen if this and that ... ...On the other hand, we may also examine it theoretically, namely, we put forth a model and employ math and ideas to make predictions on what may occur given this and that ... ...We also contrast the predictions with observations and see how fit the model is and see how a better understanding may be accomplished with another model.

It is not simply about experiments and models. It is fundamentally about how to know more of and how to better understand nature, rationally. It is about exploring nature. It is a pursuit. It is an Odyssey. Science is a life style. Like arts, science is an endeavor to capture the world.

Incidentally, it is essential to realize that, science is not a part of Nature itself, but rather of human's culture. Thus, though it proves of great values to mankind's development, science does not bear any objective meanings. It is shaped by humans, as clothes. As once remarked by Albert Einstein, 'one knows little of life. Anyway, how much does a fish know of the water it lives in ?'