My "old" professor, Michael Cohen, from grad school

I owe a lot to Michael Cohen for teaching me physics. I never had a class from him; but, we used to solve problems together in his office. It is during those regular meetings at his blackboard that I evolved into a physicist. Memories of seeing him in action still bring chills down my spine. (Mike, in the white T-Shirt, is seen at his favorite climbing rock in Philadelphia with a younger climber back in 2008.)

At Penn, we had a problem-solving seminar run by Cohen that helped prepare us for the PhD qualifying exam. The first time I ever spoke to him was when I entered Mike's office to ask him a question. Before answering, he required me to solve a perturbation theory problem on the blackboard. His impish smile as he handed me the chalk will forever be imprinted in my brain. I suffered through the problem as he derided me for my lack of understanding. Though I had taken and passed all the classes, my poor mastery of the material was exposed.

The source of my problem was that perturbation theory did not hold in the regular way in this particular case. There would not have been a problem had I understood the concept. With a simple re-derivation of perturbation theory, the problem became trivial. To maintain his image as a hard-ass (he was feared by the graduate students), Cohen commented that my difficulties originated in the fact that I was an idiot. I was undeterred by his comments and continued to visit with him to learn about the wonderful mysteries of physics. I soon found that beneath the caustic exterior was lots of heart.

As I was walking by his office a year later, I saw a new graduate student literally sweating at the blackboard. I poked my head through the door and saw the infamous perturbation theory problem. Michael Cohen leaned forward from his desk with a somber expression and pointed at me stating "though Kuzyk here is an idiot, he can solve this problem." I was given the chalk and the three of us solved all sorts of problems for the rest of the afternoon.

I look back at those times with great fondness. More than thirty years have passed since first contact with Cohen, and I still rely on some of the intuition that I developed as a result of our relationship. A couple weeks back, I had a dream that Mike had been on our campus for months, and failed to stop by my office for a visit. So, I sent him an email to see how he was doing. I learned from his reply that he is now in his eighties and still rock climbing. For a story about Mike and his passion for rock climbing, check out http://chetroy.com/wordpress/?p=385.

Part of me misses those grad school days when time was filled with intense learning. All of you students out there should appreciate these days and spare no efforts to learn as much as possible. Not only is learning fun, but it shapes you into who you are. Never stop learning!