Wednesday, August 15, 2012

What I expect of my PhD students

Every graduate student needs to be aware of expectations.  Each adviser is unique and operates on different principles.  A small number view their students as a pair of hands to do the dirty work.  In the old days, some advisers expected their grad students to mow their lawn and do housework. A friend of mine from grad school had an old-school adviser who had him come to his place on the weekend for services.  However, most faculty members by that time had already moved into the modern era and this kind of despicable practice is no longer tolerated.

It is important the each student have an understanding of what they are getting into when they join a research group. Here I will explain what I expect.

My highest principle is thinking of a graduate student as a junior-colleague-to-be.  Even the best students start out incapable of doing real research.  They are clumsy in the lab and need lots of hard work to sharpen their analytical skills.  As such, my first criteria is that they be good students who like to learn.  That doesn't mean that they need to be straight-A students.  In fact, many A students make poor researchers because they lack creativity.

On the topic of classes, I believe that the more the better.  I encourage students who are in the middle of their research phase to take classes.  Ironically, the students themselves resist because they feel it interferes with research.  Even some of my colleagues prefer that their students not take courses that are not of direct help to the research at hand.  I strongly disagree with this premise. The process of learning new things sows new ideas.  I myself enjoy learning because these new nuggets of knowledge invariably get incorporated into my research, which leads to totally new and wonderful directions.

Principle 1.  Always keep learning from classes, reading the literature, and just thinking about crazy ideas.  If you feel yourself to be leaving your comfort zone, you are on the right track.  I expect my students to never stop learning and to be constantly pushing themselves.

An important part of being a PhD scientist is independence.  Grants, which support research activities, expect results.  Many advisers thus give their students a very short leash.  The end result is bad for the student's independence.  I prefer to give the student a specific assignment, and let her or him to work on it for a year or so without giving them a detailed map of how to get there.  However, I do give lots of course corrections and teach them things they need to know along the way (or send them to the literature) if their struggles are based on missing information.

I once had a PhD student who complained that I seemed to be giving another student lots of attention while neglecting him.  I treat PhD and masters degrees differently.  The individual with a masters degree needs skills to survive in industry, while a PhD scientist is required to come up with new ideas and to find ways to tackle a new problem.  Having said that, some of my best and independent students happened to be masters students who were quite capable of getting a PhD.

Principle 2. Learn to be self reliant early on in your research.  Read the literature and talk to others to gain the skills you need to do your work, but don't wait for someone to tell you what to do with those skills.  Constantly try new things in the lab or with paper and pencil to both sharpen your skills and generate new ideas.  You will make lots of mistakes along the way when not given step-by-step instructions, but making these mistakes and getting through them are the most important part of the experience.

I do not yell at my students, ever.  I may tell them when I am displeased with research performance, but if a student does not perform, (s)he will not get a degree.  Passing the Prelim and being in a research group is no guarantee of success.   I disagree with the idea espoused by the administration that we need to help the students along so that we increase our graduation rate.  Graduating a PhD without the proper skills and talents serves nobody.  A PhD degree is not a ticket to a good job.  It's the skills that the individual has mastered and the ability to think independently that makes them valuable to society.  A huge pool of unemployed physicists is not what we want to be generating.

It takes lots of hard work and perseverance to finish a PhD degree.  People often ask me how many hours they should work.  My answer is all the time.  If you are not excited by your work and don't enjoy thinking about physics beyond your area of expertise, then you're in the wrong field.  Academic jobs are tough to get, and real research jobs in industry are rare.  However, PhD physicists have lots of success in engineering jobs, which are more plentiful.  If you like to tinker, then engineering may be an excellent way to earn a good living while having fun.

A PhD degree should not only be a guarantee of skills, but of work effort and perseverance.

Principle 3.  Approach your research with a passion.  The benefit of enjoying your work, aside form the direct rush of endorphins, is that you will put in the time required to do a good job.

One of the most important attributes is perseverance.  Watching Star Trek, or other sci-fi shows/movies gives one the impression that scientists apply skills to very easily solve problems.  This is not the case unless a student is super lucky.  I have a long list of stories on the same theme;  students who would spend months trying to get an experiment to run, only to have to start from scratch to try a different approach.  Aside from being good problem solvers, the PhD degree is an imprimatur of a person that does not give up.

In my PhD work, I had spent quite some time building an experiment on a 5' x 10' table optical table, which was filled with all sorts of laser sources and optics, resembling a Borg city.  Each step in the process often required a step backwards.  After completing the construction of the experiment, it still didn't work.  I then figured out the reason, tore the experiment apart and rebuilt the whole thing on another optical table with another laser.  Luckily, it ended up working.  Only then could I start taking the data that was the topic of my thesis.

Principle 4. Don't give up.  When something doesn't work, don't shy away from the problem.  Work twice as hard.  This will serve you well in all aspects of your lives.  When I was a new faculty member, aware of the importance of getting grants, I would write two new proposals for every one that did not get funded.  After  two years, I built a healthy portfolio of projects.

Many people do not recognize the creativity behind science.  Creativity is part of choosing a scientific problem to study, helps in problem solving, and leads to interesting new science.

Principle 5.  Be creative.  Always think about neat implications of what you are doing or find new ways of looking at old problems.  This skill is particularity important in the career of young scientists who want to make it to the next level.

Principle 6.  Be meticulously careful in your work. Do not publish sloppy results, which will come back to haunt you, and always apply the highest standards to yourself.  You should be more critical of your own work than I am as your  adviser.  On the flip side, do not let this attitude prevent you from finishing a project.  In the end, we can never be sure if we are right, and there will always be a mistake somewhere.  If a paper is perfect, it is not science.  When working in the unknown, there are always huge dark shadows in the areas not exposed by your searchlight.

Principle 7.  Be honest with others, but especially with yourself.  Many very good scientists have fallen into the trap of fooling themselves into believing in something that is false.  Consider cold fusion, N-rays. etc.  Design experiments that are resistant to experimenter bias.  Also, do not try to make data fit your adviser's expectations.  I need to know when an experiment contradicts my viewpoint.  And it goes without saying that you should never fudge data in any way or plagiarize the work of others.

Principle 8. Impress me.  Wen you graduate, I need to make an honest assessment of your strengths and weaknesses in the letter of recommendation, which will determine your success on the job market.  Follow all of the above principles.  Do not come into my office and ask, what you should do next.  Tell me the issues you are having, your line of reasoning, possible explanations, and engage me in debate about the possibilities.  You should act as a junior colleague.  Don't worry about offending me.  I am more interested in getting at the truth than being right.  However, that does not give you the right to be caustic.

What I have posted above mentions nothing of the content of the work, which is of central importance.  A short post cannot cover the nuances.  To zeroth-order approximation, I expect the student to add a new piece of physics to the body of knowledge.  This could be a theory that helps us understand a phenomena or the discovery of a new phenomena.  Fitting data to a mathematical expression is not enough.  The parameters of the theory must have meaning that is independently testable, be interpretable in terms of fundamental processes, and make predictions well beyond the domain of the original results that generated the theory.  Perhaps I will write more on the topic later.

If you approach everything in life with a passion, it will be a fulfilling one.   When you take a break from physics, make it count.  While I may seem one-dimensional in this post, I do find time for other activities.  Though I am not good at it, I play ice hockey with a passion.  I enjoy playing the piano and writing.  Taking a break from work is, in a sense, work.  During times of alternate activities, things percolate in the brain.  I have had the most profound revelations while driving my car in the middle of nowhere or playing the piano.  So, don't hesitate to take a break with intense activities.

I have to run now.  After I finish packing, I will take a short walk around San Diego, then I have to catch a plane back to Pullman.  Until then, get excited about physics.

Sunday, August 12, 2012

Perhaps this time it may be right - taking a big chance

I wrote a while back how Shiva's measurements gave 0.29eV as the binding energies in our polymer/dye material (with an experimental uncertainty of 0.02 eV) which is responsible for forming domains that are at the heart of our theory of self-hearing .  I tried to figure out what interactions between molecules and polymer would give this energy and came up with a possibility.  But because I read the data tables incorrectly, I wrongly thought I had solved the problem.

When preparing my talk for SPIE a couple days ago, I drew the PMMA polymer chain with a molecule drawing program and added a few DO11 tautomer molecules to see where they would fit.  Miraculously, as a plopped the DO11 molecules on the page, I immediately saw that the NH from the DO11 tautomer cozies up to one oxygen in the PMMA polymer chain while the OH group naturally attaches itself to another oxygen in the chain, as shown above.  And he energy?  You got it; the sum of the two hydrogen bound energies is 0.30eV, a match.  The table below shows the energies of four types of hydrogen bonds.




There are always other possibilities that we have not yet considered, but this smells right.  Perhaps we are onto something.  Future experimentalists will allow us to test this hypothesis and zero in on what is going on when a molecule self heals.

This project has been one huge puzzle, were each new experiment presents to us a new piece.  It reminds me of how the discovers of the structure of DNA (Crick, Watson, and Wilson  ) pieced together cardboard cutouts of molecules to guess its molecular structure, and confirmed their results using x-ray scattering data from  Rosalind Franklin.  Incidentally, the story behind Franklin's contributions to the discovery of DNA and not being recognized  at the time makes for interesting reading.  I also recommend readers to check out Schrodinger's guess as the structure of DNA using simple physics principles.  The title of his very thin but fascinating book is

"What Is Life?: with 'Mind and Matter' and 'Autobiographical Sketches'"


I can imagine the thrill of discovery experienced by Crick, Wason, Wilson, and Farklin.  From little cardboard pieces and an "X" on a piece of film from an x-ray scattering experiment (shown above), they revolutionized our understanding of the workings of DNA.  Ironically, the forces that hold together the double helix reside in the hydrogen bond, the very forces that seem to be at work in our molecule/polymer system.

I am preparing my talks this morning, and plan to go on a limb proposing stating that the interaction between a DO11 molecule and a polymer chain  through hydrogen bonding underpins the phenomena of self healing.  I am not a chemist and have a naive view of the intricacies of how molecules interact.  But, I hope that my bold proposal will result in good feedback form my audience that will help us fine tune our models of the mechanisms of self healing.

I have been very excited in recent months by all of the discoveries that we are making.   Even if they end up being wrong, the process of the search for the truth is exhilarating.  Gotta run.  Too much to do.  And again, sorry for the typos!

Thursday, August 9, 2012

Even teeny weeny discoveries are great fun


This morning, in the process of editing a paper, I made a small discovery. We have developed a new mathematical framework for determining the properties of quantum graphs in terms of the properties of the pieces. This work provides simple identities on the pieces that will allow us to determine general principles form the ground up rather than having to calculate the properties of the full graph.

I have to run because my wife is calling me to lunch.

Here is my email to my collaborators.

Your introduction to edge states was perfect. I liked the physical approach that leads to the formalism. In fact, its clarity was instrumental in allowing me to make a minor discovery (see below).

With regards to the paper, EDGE STATES ARE WONDERFUL! I am taking a break for lunch now, but FYI, I have been working soley on the appendix because I have done what I think is a really neat calculation which uses the power of the edge state. If you recall, in the past, we used the fact that the sum over all of the edges yields the full sum rule. However, it turns out that there are sum rules on each edge! The edge state formalism has allowed me to do this very easily. The result is given by Equation A20 of the geometry. I have pretty much dropped everything to work on this, but I will need to get back to preparing my talks for SPIE since I still have lots to do.


I suggest the following. I still need to reread the appendix because I was making changes while calculating -- never a good thing in terms of introducing typos. I will work on this after lunch. In the meantime, please check the appendix and let me know if I made any errors. The result is so logical that it seams right. I will then alternate between working on my talks and working on the paper.


Most likely, I will not go in to work today so that I can finish the paper in time to be posted on the archives tonight. Even these small discoveries are great fun.