Category Archives: Perspective

Do you ever get the feeling that…

…when you look at science today that things seem blown way out of proportion?

I get the feeling that many press releases make a big deal out of experiments/theoretical work that are not groundbreaking, are not going to cause an upheaval in anyone’s way of thinking and frankly, are humdrum science (not to diminish the importance of humdrum science!).

In all honesty, really great scientific works are rare and sometimes it takes a long time to recognize the importance of a great leap in understanding. There are many examples of this, but here’s one: Gregor Mendel, who I would refer to as the discoverer of the gene, died before his work was recognized as truly path-breaking, which took about 50 years.

A lot of good science happens all the time, but let’s not kid ourselves — the science is not as revolutionary as a lot of press releases make it seem. Of course, most professional scientists are aware of this, but to the young graduate student and to the public at large, press releases can easily be mistaken for groundbreaking science and often are. How many times have you come across someone from outside of science excited about an article they read online that you know is either extremely speculative or actually pretty mundane? It is hard to respond to reactions like this because you don’t want to dampen someone’s excitement about a subject you care about!

I don’t know what is driving all of this — the media, funding agencies, university rankings or some other metric, but to be perfectly honest, I find much of the coverage on sites like Phys.Org ugly, cynical and detrimental.

While it can be argued that this media coverage does serve some important purpose, it seems to me that this drive to “sell one’s work” may have the adverse effect of exacerbating impostor syndrome (especially among younger colleagues), which is already rampant in physics departments as well as in other academic fields (i.e. you feel like because you need to “sell your work”, and because it gets blown way out of proportion, that you have manipulated people into thinking your work is more important than you really know it to be).

If you just went about your business, trying to do science you think is worthy (without the citation-counting and the excessive media coverage), my guess is science (and more importantly scientists!) would probably be healthier.

I know this viewpoint is pretty one-dimensional and lacks some nuance, so I would like to encourage comments and especially opposing opinions.

Discovery vs. Q&A Experiments

When one looks through the history of condensed matter experiment, it is strange to see how many times discoveries were made in a serendipitous fashion (see here for instance). I would argue that most groundbreaking findings were unanticipated. The discoveries of superconductivity by Onnes, the Meissner effect, superfluidity in He-4, cuprate (and high temperature) superconductivity, the quantum Hall effect and the fractional quantum Hall effect were all unforeseen by the very experimentalists that were conducting the experiments! Theorists also did not anticipate these results. Of course, a whole slew of phases and effects were theoretically predicted and then experimentally observed as well, such as Bose-Einstein condensation, the Kosterlitz-Thouless transition, superfluidity in He-3 and the discovery of topological insulators, not to diminish the role of prediction.

For the condensed matter experimentalist, though, this presents a rather strange paradigm.  Naively (and I would say that the general public by and large shares this view), science is perceived as working within a question and answer framework. You pose a concrete question, and then conduct and experiment to try to answer said question. In condensed matter physics, this often not the case, or at least only loosely the case. There are of course experiments that have been conducted to answer concrete questions — and when they are conducted, they usually end up being beautiful experiments (see here for example). But these kinds of experiments can only be conducted when a field reaches a point where concrete questions can be formulated. For exploratory studies, the questions are often not even clear. I would, therefore, consider these kinds of Q&A experiments to be the exception to the rule rather than the norm.

More often then not, discoveries are made by exploring uncharted territory, entering a space others have not explored before, and tempting fate. Questions are often not concrete but posed in the form, “What if I do this…?”. I know that this makes condensed matter physics sound like it lacks organization, clarity and structure. But this is not totally untrue. Most progress in the history of science did not proceed in a straight line like textbooks make it seem. When weird particles were popping up all over the place in particle physics in the 1930s and 40s, it was hard to see any organizing principles. Experimentalists were discovering new particles at a rate with which theory could not keep up. Only after a large number of particles had been discovered did Gell-Mann come up with his “Eightfold Way”, which ultimately led to the Standard Model.

This is all to say that scientific progress is tortuous, thought processes of scientists are highly nonlinear, and there is a lot of intuition required in deciding what problems to solve or what space is worth exploring. In condensed matter experiment, it is therefore important to keep pushing boundaries of what has been done before, explore, and do something unique in hope of finding something new!

Exposure to a wide variety of observations and methods is required to choose what boundaries to push and where to spend one’s time exploring. This is what makes diversity and avoiding “herd thinking” important to the scientific endeavor. Exploratory science without concrete questions makes some (especially younger graduate students) feel uncomfortable, since there is always the fear of finding nothing! This means that condensed matter physics, despite its tremendous progress over the last few decades, where certain general organizing principles have been identified, is still somewhat of a “wild west” in terms of science. But it is precisely this lack of structure that makes it particularly exciting — there are still plenty of rocks that need overturning, and it’s hard to foresee what is going to be found underneath them.

In experimental science, questions are important to formulate — but the adventure towards the answer usually ends up being more important than the answer itself.

Disorganized Reflections

Recently, this blog has been concentrating on topics that have lacked a personal touch. A couple months ago, I started a postdoc position and it has gotten me thinking about a few questions related to my situation and some that are more general. I thought it would be a good time to share some of my thoughts and experiences. Here is just a list of some miscellaneous questions and introspections.

  1. In a new role, doing new work, people often make mistakes while getting accustomed to their new surroundings. Since starting at my new position, I’ve been lucky enough to have patient colleagues who have forgiven my rather embarrassing blunders and guided me through uncharted territory. It’s sometimes deflating admitting your (usually) daft errors, but it’s a part of the learning process (at least it is for me).
  2. There are a lot of reasons why people are drawn to doing science. One of them is perpetually doing something new, scary and challenging. I hope that, at least for me, science never gets monotonous and there is consistently some “fear” of the unknown at work.
  3. In general, I am wary of working too much. It is important to take time to exercise and take care of one’s mental and emotional health. One of the things I have noticed is that sometimes the most driven and most intelligent graduate students suffered from burnout due to their intense work schedules at the beginning of graduate school.
  4. Along with the previous point, I am also wary of spending too much time in the lab because it is important to have  time to reflect. It is necessary to think about what you’ve done, what can be done tomorrow and conjure up experiments that one can possibly try, even if they may be lofty. It’s not a bad idea to set aside a little time each day or week to think about these kinds of things.
  5. It is necessary to be resilient, not take things personally and know your limits. I know that I am not going to be the greatest physicist of my generation or anything like that, but what keeps me going is the hope that I can make a small contribution to the literature that some physicists and other scientists will appreciate. Maybe they might even say “Huh, that’s pretty cool” with some raised eyebrows.
  6. Is physics my “passion”? I would say that I really like it, but I could have just as easily studied a host of other topics (such as literature, philosophy, economics, etc.), and I’m sure I would have enjoyed them just as much. I’ve always been more of a generalist in contrast to being focused on physics since I was a kid or teenager. There are too many interesting things out there in the world to feel satiated just studying condensed matter physics. This is sometimes a drawback and sometimes an asset (i.e. I am sometimes less technically competent than my lab-mates, but I can probably write with less trouble).
  7. For me, reading widely is valuable, but I need to be careful that it does not impede or become a substitute for active thought.
  8. Overall, science can be intimidating and it can feel unrewarding. This can be particularly true if you measure your success using a publication rate or some so-called “objective” measure. I would venture to say that a much better measure of success is whether you have grown during graduate school or during a postdoc by being able to think more independently, by picking up some valuable skills (both hard and soft) and have brought a  multi-year project into fruition.

Please feel free to share thoughts from your own experiences! I am always eager to learn about people whose experiences and attitudes differ from mine.

A few nuggets on the internet this week:

  1. For football/soccer fans:
    http://www.espnfc.us/blog/the-toe-poke/65/post/3036987/bayern-munichs-thomas-muller-has-ingenious-way-of-dodging-journalists

  2. Barack Obama’s piece in Science Magazine:
    http://tinyurl.com/jmeoyz5

  3. An interesting read on the history of physics education reform (Thanks to Rodrigo Soto-Garrido for sharing this with me):
    http://aapt.scitation.org/doi/full/10.1119/1.4967888

  4. I wonder if an experimentalist can get this to work:
    http://www.bbc.com/news/uk-england-bristol-38573364

Fractional quasiparticles and reality

As a condensed matter physicist, one of the central themes that one must become accustomed to is the idea of a quasiparticle. These quasiparticles are not particles as nature made them per se, but only exist inside matter. (Yes, nature made matter too, and therefore quasiparticles as well, but come on — you know what I mean!)

Probably the first formulation of a quasiparticle was in Einstein’s theory of specific heat in a solid at low temperature. He postulated that the sound vibrations in a solid, much like photons from a blackbody, obeyed the Planck distribution, implying some sort of particulate nature to sound. This introduction was quite indirect, and the first really explicit formulation of quasiparticles was presented by Landau in his theory of He4. Here, he proposed that most physical observables could be described in terms of “phonons” and “rotons“, quantized sound vibrations at low and high momenta respectively.

In solid state physics, one of the most common quasiparticles is the hole; in the study of magnetism it is the magnon, in semiconductor physics, the exciton is ubiquitous and there are many other examples as well. So let me ask a seemingly benign question: are these quasiparticles real (i.e. are they real particles)?

In my experience in the condensed matter community, I suspect that most would answer in the affirmative, and if not, at least claim that the particles observed in condensed matter are just as real as any particle observed in particle physics.

Part of the reason I bring this issue up is because of concerns raised soon following the discovery of the fractional quantum Hall effect (FQHE). When the theory of the FQHE was formulated by Laughlin, it was thought that his formulation of quasiparticles of charge e/3 may have been a mere oddity in the mathematical description of the FQHE. Do these particles carrying e/3 current actually exist or is this just a convenient mathematical description?

In two papers that appeared almost concurrently, linked here and here, it was shown using quantum shot noise experiments that these e/3 particles did indeed exist. Briefly, quantum shot noise arises because of the discrete nature of particles and enables one to measure the charge of a current-carrying particle to a pretty good degree of accuracy. In comparing their results to the models of particles carrying charge e versus particles carrying charge e/3, the data shows no contest. Here is a plot below showing this result quite emphatically:

FracCharge.PNG

One may then pose the question: is there a true distinction between what really “exists out there” versus a theory that conveniently describes and predicts nature? Is the physicist’s job complete once the equations have been written down (i.e should he/she not care about questions like “are these fractional charges real”)?

These are tough questions to answer, and are largely personal, but I lean towards answering ‘yes’ to the former and ‘no’ to the latter. I would contend that the quantum shot noise experiments outlined above wouldn’t have even been conducted if the questions posed above were not serious considerations. While asking if something is real may not always be answerable, when it is, it usually results in a deepened understanding.

This discussion reminds me of an (8-year old!) YouTube video of David who, following oral surgery to remove a tooth, still feels the affects of anesthesia :

Consistency in the Hierarchy

When writing on this blog, I try to share nuggets here and there of phenomena, experiments, sociological observations and other peoples’ opinions I find illuminating. Unfortunately, this format can leave readers wanting when it comes to some sort of coherent message. Precisely because of this, I would like to revisit a few blog posts I’ve written in the past and highlight the common vein running through them.

Condensed matter physicists of the last couple generations have grown up ingrained with the idea that “More is Different”, a concept first coherently put forth by P. W. Anderson and carried further by others. Most discussions of these ideas tend to concentrate on the notion that there is a hierarchy of disciplines where each discipline is not logically dependent on the one beneath it. For instance, in solid state physics, we do not need to start out at the level of quarks and build up from there to obtain many properties of matter. More profoundly, one can observe phenomena which distinctly arise in the context of condensed matter physics, such as superconductivity, the quantum Hall effect and ferromagnetism that one wouldn’t necessarily predict by just studying particle physics.

While I have no objection to these claims (and actually agree with them quite strongly), it seems to me that one rather (almost trivial) fact is infrequently mentioned when these concepts are discussed. That is the role of consistency.

While it is true that one does not necessarily require the lower level theory to describe the theories at the higher level, these theories do need to be consistent with each other. This is why, after the publication of BCS theory, there were a slew of theoretical papers that tried to come to terms with various aspects of the theory (such as the approximation of particle number non-conservation and features associated with gauge invariance (pdf!)).

This requirement of consistency is what makes concepts like the Bohr-van Leeuwen theorem and Gibbs paradox so important. They bridge two levels of the “More is Different” hierarchy, exposing inconsistencies between the higher level theory (classical mechanics) and the lower level (the micro realm).

In the case of the Bohr-van Leeuwen theorem, it shows that classical mechanics, when applied to the microscopic scale, is not consistent with the observation of ferromagnetism. In the Gibbs paradox case, classical mechanics, when not taking into consideration particle indistinguishability (a quantum mechanical concept), is inconsistent with the idea the entropy must remain the same when dividing a gas tank into two equal partitions.

Today, we have the issue that ideas from the micro realm (quantum mechanics) appear to be inconsistent with our ideas on the macroscopic scale. This is why matter interference experiments are still carried out in the present time. It is imperative to know why it is possible for a C60 molecule (or a 10,000 amu molecule) to be described with a single wavefunction in a Schrodinger-like scheme, whereas this seems implausible for, say, a cat. There does again appear to be some inconsistency here, though there are some (but no consensus) frameworks, like decoherence, to get around this. I also can’t help but mention that non-locality, à la Bell, also seems totally at odds with one’s intuition on the macro-scale.

What I want to stress is that the inconsistency theorems (or paradoxes) contained seeds of some of the most important theoretical advances in physics. This is itself not a radical concept, but it often gets neglected when a generation grows up with a deep-rooted “More is Different” scientific outlook. We sometimes forget to look for concepts that bridge disparate levels of the hierarchy and subsequently look for inconsistencies between them.

The Struggle

Haruki Murakami, the world-renowned Japanese novelist, has garnered a large following because one can easily relate to his protagonists. I have been reading his novels for around ten years now, and recently picked up his unique memoir What I Talk About When I Talk About Running. It is a quirky book, at once about his marathon and ultra-marathon running endeavors, his writing struggles, and how the two are interwoven.

To me, the most inspirational part of this book lies in how through mundaneness and mediocrity springs a rather unique exceptionalism. Murakami is an outstanding writer, but his talents have a limit, and he is honest about this. Most of the book is about struggling, with running and with writing. When I reflect on the book, the image I have in my mind is of a  truck wheel, bearing huge weight, going around and around, yet somehow trudging forward.

Here is a passage from the book I particularly enjoyed, which is applicable in many contexts:

…writers who aren’t blessed with much talent — those who barely make the grade — need to build up their strength at their own expense. They have to train themselves to improve their focus, to increase their endurance. To a certain extent, they’re forced to make these qualities stand in for talent. And while they’re getting by on these, they may actually discover real, hidden talent within them. They’re sweating, digging out a hole at their feet with a shovel, when they run across a deep, secret water vein. It’s a lucky thing, but what made this good fortune possible was all the training they did that gave them the strength to keep on digging. I imagine that late-blooming writers have all gone through a similar process.

Naturally, there are people in the world (only a handful, for sure) blessed with enormous talent that, from beginning to end, doesn’t fade, and whose works are always of the highest quality. These fortunate few have a water vein that never dries up, no matter how much they tap into it. For literature, this is something to be thankful for. It’s hard to imagine the history of literature without such figures as Shakespeare, Balzac and Dickens. But the giants are, in the end, giants — exceptional, legendary figures. The remaining majority of writers who can’t reach such heights (including me, of course) have to supplement what’s missing from their store of talent through whatever means they can. Otherwise it’s impossible for them to keep on writing novels of any value. The methods and directions a writer takes in order to supplement himself becomes part of that writer’s individuality, what makes him special.

Most of what I know about writing I’ve learned through running everyday. These are practical, physical lessons. How much can I push myself? How much rest is appropriate — and how much is too much? How far can I take something and still keep it decent and consistent? When does it become narrow-minded and inflexible? How much should I be aware of the world outside, and how much should I  focus on my inner world? To what extent should I be confident in my abilities, and when should I start doubting myself? I know that if I hadn’t become a long-distance runner when I became a novelist, my work would have been vastly different. How different? Hard to say, but something would have definitely been different.

The book ends with what Murakami hopes his tombstone will read:

Haruki Murakami

1949-20**

Writer (and Runner)

At Least He Never Walked

On Science and Meaning

The history of science has provided strong evidence to suggest that the humanity’s place in the universe is not very special. We have not existed for very long in the history of the universe, we are not at the center of the universe and we likely will not exist in the future of the universe. This kind of sentiment can seem depressing to some, as can be seen in the response to the video made by Neil DeGrasse Tyson and MinutePhysics:

It appears that such ideas can make human life and our actions here on earth (and beyond) seem rather meaningless. As I have referenced in a previous post, this can especially be true for graduate students! However, on a more serious note, I would contend the exact opposite.

Because life on earth is so fragile and transient and only exists in some far-flung corner on the universe, the best thing we can hope to do as humans is celebrate our existence through acts of exploration, beauty, creation, truth and acts that enrich the lives of others and our environment.

When working in the lab or on a calculation that requires attention to small details, this larger context is often forgotten. To my mind, it is important not to lose sight of the basic reason why we are there in the first place, which is all too easy to do. The universe can seem meaningless, but not so when she lets us peer into her depths, usually revealing order of spectacular beauty.

I apologize if this post comes off as a little preachy or pretentious– I suspect I am really the one that needed this pep talk.