Joachim Jänecke: Conferences, Reminiscences

.                                                                                          JJ:  September, 2014

It was in the fall of 1998 shortly after my retirement that I attended the International Conference on Exotic Nuclei and Atomic Masses ENAM1998 at the Shanty Creek Resorts near Bellaire in Northern Michigan. One day I became aware that several of my faculty colleagues from the University of Michigan were present, Fred Becchetti, Larry Jones, Bob Lewis, Ted Hecht, Byron Roe, and a few others. I asked them whether they had come to play golf at the resort. Well, they hadn’t. What I didn’t know was that at the beginning of the banquet in the evening Fred Becchetti announced that I had retired, and he gave me a present and a document. I then had to say a few words which were not very coherent. I very much regret not thinking about this earlier, because I could have made some interesting comments for the attendees of this conference and selected reminiscences about earlier atomic mass conferences.

For example, something like this: “First, I want to thank my colleagues from the University of Michigan to have come here on this occasion. When I saw them earlier I thought they had come to play golf. Also, I thank you for the gift. – Given the opportunity, I want to say a few words mostly about earlier AMCO and ENAM conferences. (Atomic Masses and Fundamental Constants / Exotic Nuclei and Atomic Masses)

The first AMCO Conference which I attended was AMCO3 at Winnipeg, Mannitoba, in 1967. I had received a letter from Professor Burcham in England whether I could give a talk on Coulomb energies. I had just published a paper on “Vector and Tensor Coulomb Energies”.

But let me very briefly back up. The first International Nuclear Physics Conference which I ever attended was as a beginning student in Heidelberg in about 1950. The occasion was the 60s birthday of Professor Bothe. He later became my Ph.D. thesis chairman, also – more importantly – he received the Nobel Prize. This was the very first international conference in Germany after the second world war. It was attended by Bothe, of course, Kopfermann, Mayer-Leibnitz, Heisenberg, Otto Hahn, Schmelzer – who built the Univac at the GSI in Darmstadt – J.H.D.Jensen and Maria Goeppert-Meyer from Chicago – later both recipients of the Nobel prize for the discovery of the nuclear shell model. Then Gentner who became important at CERN and then director of the MPI in Heidelberg, Prof. Clay from Leyden, Nordheim from California, remember the Nordheim rules, Scandinavian participation, Lise Meitner, Wolfgang Pauli, also a recipients of the Nobel prize, and many others. Again, this was my first international nuclear physics conference. – Another interesting conference which I attended was a few years later in 1958 in Geneva on the “Peaceful Uses of Atomic Energy”. I came back and told my colleagues at the Max–Planck-Institute what I had learned, fusion energy will become available in 2-3 years.

A conference which changed my life was the Congrès International de Physique Nucleaire in 1964 in Paris. I had previously spent a couple of years as a Research Associate and Lecturer at the University of Michigan, and I had returned to Germany. At this conference I again met my colleague Bill Parkinson from Ann Arbor. He asked me why I had never responded to their letter. I hadn’t received this letter. It got lost. Well, they had made me an offer for a faculty position. The rest is history.

JaneckeWithParkinsonParis1964Professor William Parkinson with  Joachim and Christa Jänecke

Back to AMCO3 in Winnipeg. I gave my invited presentation, and I still remember that a distinguished participant of the Conference, actually a very distinguished participant, fell asleep in the first row. I am inclined to believe that this was due to jetlag, of course. – But I also distinctly remember walking down a hallway, with sunshine coming in from the side, when three Israeli physicists came the other direction. I had exchanged pre- and re-prints with Nissan Zeldes before, but this was the first time I met him in person. I did not know then that this would become a lifelong friendship with him and later also with his wife Carla. Christa and I met Carla when they spend a long sabbatical in Ann Arbor at the end of the 1980s and again in 1995.

And then came all the other wonderful and interesting AMCO Conferences in Teddington near London, in Paris, East Lansing, Damstadt. Then the joint NFFS/AMCO conference in 1992 in Bernkastel-Kues, beautiful sunshine, and the first ENAM (Exotic Nuclei and Atomic Masses) conference in Arles, France. And finally the present conference in Northern Michigan.

At the Teddington Conference I remember the evening when Nissan and I went to see the play “Fiddler on the Roof”. In Paris I remember the banquet up on the Eiffel Tower, and also the initial reception at the Musèe de Metrology. We were reminded of the 100-year anniversary of the 1875 “Convention du Mètre”. But I still have to memorize that 1 mile has 5280 feet and a gallon of milk contains 128 fluid ounces !

So, let me conclude with AMCO 8, the conference which wasn’t. AMCO 8 was to take place in Jerusalem in 1990 organized by Nissan Zeldes. I had prepared such a nice talk, and then it was cancelled because of events in the Middle East. E-mails went back and forth before the conference, whether one should cancel, or whether the Israeli organizers had worked out plans to evacuate all participants. Well, long before the beginning of the conference I had requested airline tickets from TWA using frequent flyer miles, still worth something in those days. So, I had two free tickets from Detroit Metro to Ben Gurion Airport. Also with a one-week stop in Rome. And, since TWA didn’t fly Rome-Israel, “unfortunately” we had to fly back to Paris for another two days. Well, we arrived in Israel but there was no conference. Therefore, Nissan and Carla had all the time to spend with us. There were no tourists in town. At the hotel we could pick the room with the best view down onto the Old City and the Jaffa Gate. Christa and I together with a woman from New York tried to have a guided tour through the Old City. After much effort the boss of the tourist organization took us around to interesting places. In one place Yeshiva students shouted at us because women were not allowed there, in another place young Palestinian boys wanted to throw stones at us. One day the four of us drove down to the Dead Sea. We swam, and then we sat down in a spa hotel lobby, and I remember that we started talking into the dark as if we had known each other since childhood, even though our childhoods in Germany and Israel, Carla’s in Italy before she had to leave, were indeed very different. – After the week in Jerusalem was over, at the suggestion of a secretary, I was the only one who had his registration fee reimbursed. After all, I had attended the Conference !

International Conferences are important for the exchange of scientific ideas and for establishing collaborations. But these gatherings are equally important for making personal contacts between people from different parts of the world and different cultures. – Let me stop here.”

Added later: Since ENAM1995 in Arles the four of us always spend time together after the conference, then driving through the Provence with Nîmes and Avignon. In 1998 at the conference in Bellaire the two wives explored the Northern Michigan countryside while the husband listened to lectures, and afterward we spend time together at our cottage on Lake Michigan. In 2001 after the conference in Finland we flew to Saint Petersburg to enjoy this beautiful city with its museums. The last of this sequence of conferences we both attended was ENAM2004 at the beautiful Callaway Gardens in Georgia. After this conference we drove back to Ann Arbor and spent a week together. Yes, friendships are important. Since then only email, snail mail, telephone calls.

AnnArbor2004-1&2     (L) Carla and Nissan Zeldes with Joachim and Christa Jänecke
(R) Nissan Zeldes with Homer Neal 

I have, of course attended over the years very many other meetings, symposia, workshops, and conferences, many in the United States, but also in Canada and many places in Europe, and in later years in Russia and Japan. In 1990 I attended the Symposium “Nuclear Physics in the 1990’s” in Santa Fe in Honor of Akito Arima, an important Japanese theorist and administrator and visitor to Ann Arbor in 1973 for a 2-week workshop. In 1991 I helped to organize here in Ann Arbor an International Symposium to Honor our colleague K.T.Hecht, “Group Theory and Special Symmetries in Nuclear Physics”. In 2000, at the last conference I attended in Japan, a special challenge arose when towards the end I had to express thanks to the conference organizer – in Japanese.

Shown in the photographs are Nissan Zeldes (1926 – 2014) and his wife Carla Zeldes (1929 – 2013).  Nissan  was Professor of Theoretical Physics at the Racah Institute of Physics, Hebrew University of Jerusalem. During his career he has been guest scientist at the Niels Bohr Institut in Copenhagen, at the Technische Hochschule in Darmstadt, at the National Autonomous University of Mexico, at CSNSM and IPN in Orsay, at the Gesellschaft für Schwerionenforschung in Darmstadt, at the University of Michigan in Ann Arbor, and at the University of Tennesse in Knoxville. In particular, he spent a sabbatical of 15 months at the University of Michigan in 1989/90 and again for 3–4 months in 1995. He interacted primarily with the Nuclear Group and the Theory Group, also with Professor Homer Neal.
.   Nissan Zeldes’ last publication was a review of the groundbreaking papers of Racah who developed the mathematical methods for the calculation of the spectra of complex atoms. This work was carried out in Jerusalem in complete scientific isolation during the years of World War II. In this work Racah pioneered the use of symmetries and group theory.
Zeldes, N., “Giulio Racah and Theoretical Physics in Jerusalem”, Arch Hist Exact Sci 63, 289 – 323 (2009)

Wayne Hazen interview

Wayne Hazen was a member of the Michigan Physics faculty as one of the leaders in cosmic ray research from 1947 until he retired in 1984; he continued to be a presence in the department until shortly before his death, at age 94, in 2010.

Wayne Hazen, ~19508580B_Jean_WayneHazen2005

Jean Hazen (1918-2014) was trained in landscape architecture and botany and was later well known for her creative pottery. Remarkably, in earlier years Jean had become a private pilot and then earned her commercial pilot certificate with instrument and multi-engine ratings. While in Leeds, England she completed an RAF aerobatic instructor course, then returned to Ann Arbor and worked as an aerobatic flight instructor.
The interview presented here was done in 2007;  The transcription by Sara Stoutland has benefited from edits by her husband Eric Hazen, Larry Jones, Jack van der Velde, Tris Coffin, and Mike Sanders.  Jens Zorn then did an augmented edit.


Peter Franken – on not taking yourself too seriously


Peter, an extraordinarily accomplished,  world-famous physicist took a humorous approach to university/academic affairs. He left Michigan at a time when we were looking for a vice president for research, and it may be that his well-known love of a good joke may have kept our administration from making the offer.

Peter Franken on Research Inhibitions

from International J. Science & Technology, May 1963

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Experiences with Professor Otto Laporte

Marvel John Yoder

September 2, 2014

 I was a new graduate student in 1962 and needed to find a research assistant position to support myself and my wife. I had graded papers and taken office hours for Dr. Dolph in the Engineering Math department, and he suggested that I contact Professor Otto Laporte. Even though I had been at Michigan for 4 years, I had not heard of Professor Laporte. That was because since he had just returned from Japan where he had been a Scientific Advisor to the US Embassy, so he had not been around Randall Laboratory.

 I boldly knocked on his door and asked him if he had any work/research for me. Little did I know his reputation for sometimes being very demanding and gruff if he did not like what you were saying/asking. That afternoon he was most gracious and asked me if I knew anything about computers. My reply was negative, but he said, that’s ok, you can learn about them. He had a project to solve Laplace’s equation on the exterior of a sphere, he and was looking for a numerical solution.   He also had some money to support this work.

 Later, when I talked to my other student colleagues about my conversation they said “you asked him WHAT? And he did not throw you out of the office?” He evidently had quite a reputation for sternness. I told them how nice he was. Little did they know that his strictness was only external (a little like a German professor) and that when you were working with him, he was usually as mild as a “pussy cat”.

 I spent a year learning about computers and programming his problem. Unfortunately in those new days of large IBM computers you could not form a matrix larger than about 400 x 400 or the computer would run out of memory and would crash, so it took a while to get good solutions. Also, you had to submit your pile of IBM punch cards in the computer center one day and had to wait for another day to see if you had made any mistakes (usually formatting, spelling or other small problems). We were programming in MAD (Michigan Algorithmic Decoder) language and if you made a mistake you got a print-out of Alfred E. Newman with a statement “What, me worry?” Later we programmed in Fortran. Otto seemed to be pleased with the calculated results. This all was a great learning experience for me since computers were just becoming popular and useful.

 The second year I took Otto’s two semester Theoretical Physics class and enjoyed it a lot. He prided himself on teaching the class without notes.   I learned however, that for about an hour before the class, he took out his previous notes and went over them thoroughly. He then closed up his notes and went empty-handed to the class.

 I somehow did not think I did well on the final exam and was too embarrassed to ask him about summer work. (In fact, I did quite well in the course but did not know it.) So I got a summer job for the University moving furniture into the new dorms and washing dorm windows. A few weeks into the summer I got a phone call from Laporte asking me what I was doing. He said that he had other work for me if I chose to do something other than washing windows. Of course I agreed to see him about it. As I entered his office he said “aha! The prodigal son returns.” Part of my work was checking his arithmetical calculations and another part involved more programming.   His detailed calculations were very precise and whenever I thought that I found a calculation mistake, it was usually mine, not his. I did better with the programming.

One day during his theoretical physics course Otto asked the class about the origin of sodium D lines. No one answered. He became very angry and threw his chalk against the blackboard and said “class dismissed, come back next week when you know about this basic fact in spectroscopy”. Things like this kept us students on our toes, never knowing when he was going to ask another similar question.

 My wife and I took three semesters of German, and we had saved our money so that we could spend a year studying in Germany in 1964-65 after my master’s degree in 1964. I worked for Laporte during the summer and was prepared to go to Göttingen, Germany starting in September. In August Laporte brought up the subject of what I would do in the fall. Thinking that he would be pleased, I said that I was going to spend the next year studying in Germany. He frowned, was stern and asked why in the world would I want to do that! I replied something about learning about science in Germany and broadening my experiences in the world and learning another language. He seemed OK with that and asked me where I had my scholarship. My answer was that I had no scholarship. He was most annoyed. “That will never do,” he said. “You go over to the German Department right away and see Chairman Otto Graf. He will give you a scholarship.” (Evidently he had been at a cocktail party with Professor Graf and they had discussed how only German-studies students took part in the exchange programs. “Real people” did not usually do it.)

 I then approached Otto Graf with trepidation wondering if this possibility was real, since I had not applied for it, but he was prepared for me. He had all the papers laid out. He said, how about going to the Freie Universität Berlin? I readily agreed. I got 500 marks a month and books and tuition.   Without that assistance we would never have been able to complete the year in Germany. There was no paperwork for application and no competition for this exchange scholarship. I was amazed and very happy.

 When I returned from Germany in the fall of 1965 I asked Laporte for more work, and he had a funded position in the experimental Shock Tube Project. Laporte had a reputation of requiring a lot of work and it taking a long time to complete the thesis research. This was not a problem for me at that time. It took me about 5 years to complete the research and write my Ph.D. thesis. About 4 years into this work he said that I needed to complete my work soon (perhaps he was concerned about his health problems, I don’t know). He wanted me to “test” the validity of the Rankine-Hugoniot equation as my final project. I said that it was ok, but I wanted to add a measurement of the rotational relaxation times for orthohydrogen and parahydrogen to my cryogenic shock tube research. He accepted that, but said that I needed to hurry up and get out into the real world and learn about other science and technologies. I would learn more there than by staying at the University. He was right.

 Otto invited me to lunch several times to discuss technical and other issues. One of the times I offered to pay, to which he answered. “When you return several years after your degree, I will be glad to take you up on that offer.” Unfortunately that never happened.

 Several times I dropped into his office to talk to him just as he was leaving to teach a class. He said that he could not do it then, but he invited me do walk with him to talk. That was most enjoyable. Otto had a particular way of holding his notes/books under his arm. I noticed that I was doing the same thing with my notes/books. It was an interesting but totally unintentional imitation.

One semester Otto was to teach the 500 Advanced Mechanics course (Euler-Lagrange equations, Hamiltonians, etc.), but he had to miss the first three weeks of class because he was in Europe. I had done well in the class a year earlier and offered to teach the class for him. He agreed that it would be ok but I could only teach one class per week. Little did I know how hard it was to teach it well. All I did during those three weeks was to prepare for a single lecture on Friday. The lectures went very well, and I had good feed-back from the students. However, I learned that knowing a subject well and presenting it in an interesting and intelligible way were two different things. Good teachers are not born, people have to work hard to become good teachers.

At Michigan I had several noteworthy classes/lectures that left me in awe of physics. These were delivered by George Uhlenbeck (1961 physics colloquium), Gabi Weinreich, Karl Hecht, David Dennison and others. One of the noteworthy lectures was by Otto in a quantum mechanics class. He derived two solutions of the Schrödinger equation for centro-symmetric atoms. One solution implied that the spectral lines for transitions between the states would consist of a triplet at a higher frequency and an associated singlet at a lower frequency. The other solution implied that the singlet would be at a higher frequency than the triplet. Only one of them occurred in nature. The other did not. From this directly followed the Laporte Rule that transitions occurred between states with a change in parity [even (gerade) parity to odd (ungerade) parity or vice-versa], but not from even to even parity or odd to odd parity. These latter transitions were forbidden. After he reached this conclusion, he left the room with no further discussion. My jaw dropped in amazement at the simplicity of the derivation and the consequences.

Another memorable lecture was given in about 1969 in a Wednesday colloquium in which Otto gave first hand reports of his interactions with Arnold Sommerfeld, Wolfgang Pauli, and his contemporary Munich graduate students Werner Heisenberg, Gregor Wentzel, Karl Herzfeld, and Paul Peter Ewald. One of his stories was that Wilhelm Wien (of the Wien displacement law) did not want to grant a doctorate to Heisenberg. After much urging from Sommerfeld, Wien finally agreed to approve Heisenberg’s doctorate, but only with the lowest possible grade.

 In about 1969 I was aware of Otto’s stomach problems, but did not know that it was cancer. I finished the draft of my thesis in late 1970 and gave it to him. He retuned it with a few small changes and thought it was good. Unfortunately Otto died in March of 1971. It was very sad. He seemed old to me at the time, but now that I am 75, he was not old at all. I finished my final draft and Ph.D. thesis defense with Professor Michael Sanders in late 1971.

Honoring Dick Crane and Peter Franken

To honor the enormous contributions of Dick Crane and Peter Franken to our department, we have installed bronze portrait busts of them in the 4th floor conference rooms (4246 and OPIL) of New Randall Lab. The sculptor is Liz Zorn, the sister of Jens.
1 7294A-86A-Franken-Crane
–Among his many accomplishments, Crane was recognized for the first (1938) quantitative measurement of neutrino momentum, for accelerator development, for his theory that explained the spiral structure of DNA, for the first measurements of the magnetic moment of the free electron, and for his leadership of the American Association of Physics Teachers.

–Peter Franken was a guiding spirit over the years 1956-1972 for Michigan’s large and active group in atomic and molecular physics; among his many accomplishments at Michigan, we particularly recall his his work in level-crossing spectroscopy, his leading the team that opened the field of non-linear optics, and his irrepressible joie de physique that inspired dozens of students and faculty.


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Resonance Group Reunion-1993

Sixty five people attended the October 15-16, 1993  reunion of the Resonance Group, those faculty and students who worked in atomic, molecular, optical, and condensed matter physics in the years following 1950.  This had been originally conceived as a gathering of those who had worked with Peter Franken and Dick Sands back in the days when real scientists built their own circuits and their own vacuum systems, and when they didn’t need computers to do integrals, plot data, and write papers.   However, plans expanded to include alumni of the g-factor group and those doing related theory.

People at the Resonance Group Reunion, Set 1 — click on image for slide show  (JCZ photos)

Among reminiscences of work, classes, practical jokes, Peter Franken’s nickel bets, and other adventures, there were also talks on the development of science in our lab.  For example Bob Lewis described how his early work on angular correlations in nuclear decay led to the theory behind level crossing spectroscopy (link here).  Other speakers included Peter Franken, Dick Sands,  Mike Sanders, Jens Zorn, and Gabi Weinreich.    No matter the topic, all the speakers  recalled the special relationships that flourished in the late 1950’s  and for two decades thereafter.  Weinreich gave the concluding talk of the reunion (link here), saying “Humor and research are actually very similar entities.  Looking for the unexpected twist that clicks, and which everyone else knows clicks too.   Remember the story of the Cheshire Cat in Alice in Wonderland?  The Cheshire Cat sat on a branch, with a smile, and as the situation developed the Cheshire Cat disappeared more and more..  That’s research, it seems to me, to start with a cat and find the smile”

People at the Resonance Group Reunion, Set 2 (JCZ photos)

People at the Resonance Group Reunion, Set 3 (JCZ photos)

People at the Resonance Group Reunion, Set 4 (JCZ photos)

Weinreich: Imitating Stradivarius

Weinreich’s work in Musical Acoustics

Gabriel Weinreich is an Emeritus Professor at the University of Michigan. He received a Ph.D. in Physics from Columbia University in 1953, working under the direction of the Nobel laureate, I. I. Rabi. He subsequently worked at Bell Labs on fundamental properties of semiconductors; he is credited with the theory and observation of the acoustoelectric effect, where an ultrasonic wave in a semiconductor gives rise to a direct electrical current.  In 1960 he accepted a professorship at Michigan where he became renowned for his teaching and for his lecture notes on elementary physics and on musical acoustics.  He published books on the theory of condensed matter (1965), thermodynamics (1968) and extended vector mathematics (1998).    His  contributions to research included  the discovery (with Franken, Hill and Peters) of optical harmonics, his theoretical studies of vortices in liquid helium, and his measurements of electron-atom scattering.

In the mid-1970s Weinreich turned to theoretical and experimental research in musical acoustics with a vigor that convinced the NSF to provide financial support for an extended period . His studies of the piano gave new understandings of the hammer-string interaction and of the coupled motions of piano strings.  His studies of the violin showed how the directional pattern of acoustic radiation from the instrument influences the perceived tone color.  He also invented an electronic violin bowing system and devised a new way to measure mechanical admittance in violins.   This work continued well beyond his formal retirement in 1995.

In recent years, Weinreich has collaborated with the violinmaker Joseph Curtin on the development of an electric violin that can be held and bowed exactly like a traditional violin (let’s call it a Stradivarius) but that outputs an electrical signal which, when fed into a traditional amplifier and speaker, produces the sound of the Stradivarius as it would be picked up by an excellent studio microphone.   This would meet the frequent need for a violin to be played in concert venues that demand amplified sound.


 The Weinreich-Curtin electric violin has a solid body with a normal fingerboard and with strings that are bowed in the usual way. Vibrations are picked up by several sensors, digitized, and combined in real time with the previously measured impulse response of the real Stradivarius. In this way all the bowing gestures of the violinist are combined with the playing characteristics and sound of the Stradivarius, but with an instrument that costs far less than the original.

 Links to some relevant articles
From the April, 2000 issue of The Strad: On Directional Tone Color in the Violin

NPR/American Public Media  August 15, 2013
WUNC North Carolina Public Radio Production, 9 minute audio
The Story: The Elusive Digital Stradivarius

See also the video of Weinreich’s 2012 talk at McGill University:

On the Motion of Piano Strings

Ralph Sawyer accepts a position at Michigan.

Ralph Alanson Sawyer (1895 -1978) was an active member of the Michigan physics faculty for 45 years. He had a distinguished record for pure and applied research along with a talent for administration that brought him to important positions of scientific, military, and academic leadership.   From 1919 to 1939 he rose from instructor to full professor within the physics department.  With the onset of WWII he went on active duty with the Navy and then, back as a civilian, became the scientific director of the 1946 Bikini atomic bomb tests.  The University then recalled him in 1947 to serve as dean of the Rackham Graduate School and, in 1959 added the title of vice president for research.  He was president of the Optical Society of America from 1955–57 and chairman of the board of governors of the American Institute of Physics 1959-1971.

          In 1967, Sawyer was interviewed at length by the distinguished science historian Charles Weiner; the transcript
         of their conversation is available on the AIP website.  (
The following text derives and is adapted from a short portion of that interview.


Ralph Sawyer graduated in 1915 from Dartmouth and by 1919 had finished his Ph.D. under Robert Millikan at the University of Chicago.   In the summer of that year, Randall wrote a letter inviting Sawyer to join the Michigan faculty. The two men had not met, but Randall had been impressed by an article on ultraviolet spectroscopy that Sawyer and Millikan had published in the Physical Review.  Randall, knowing that that Millikan had been busy and often away from Chicago during WWI, conjectured that Sawyer had done most of the work himself and thus was capable of independent research.   The negotiations were entirely by correspondence; Sawyer first saw Ann Arbor when he arrived to join the University of Michigan faculty in September of 1919.  He retained the affiliation with Michigan for his entire career.

Sawyer came to Ann Arbor to establish a research program, but he also knew that his responsibilities included teaching.   He had been appointed as an instructor, and the standard teaching load for instructors was 12 hours per week; moreover, instructors did not have teaching assistants and so had to grade exams, quizzes, and homework themselves.   For several years, then, Sawyer had five recitation sections, about 150 students in all, every semester.

In his 1967 interview with Wiener, Sawyer recalled this load as being nearly murderous.  Nevertheless, he quickly attracted graduate students as he built a laboratory for visible and ultraviolet spectroscopy that complemented the infrared spectroscopy for which Michigan was already famous.

Paul William Zitzewitz, in memoriam

Paul Zitzewitz, 2002

PAUL ZITZEWITZ (1942-2013)

Remarks at the Memorial Gathering of 24 May, 2013
A. by Jens Zorn
B. by David Gidley

Paul Zitzewitz, who contributed so strongly to our research enterprise, had many colleagues on the Ann Arbor campus.  Four of those colleagues are with us today, and each of them could be speaking in my stead: David Gidley,  the leader of the positron group;  Ralph Conti of General Dynamics; Bita Ghaffari of the Ford Motor Company, and Rich Vallery, chair of physics at Grand Valley State University .

I also speak on behalf of dozens of Paul’s colleagues in atomic physics, a group whose members enjoy an unusual sense of community because so many of them can trace their scientific genealogy to a very few primary branches on the “Rabi Tree”.   That tree (which has 20 Nobel laureates on its branches) shows that Paul and I are scientific cousins since our thesis directors (Norman Ramsey at Harvard and Vernon Hughes at Yale) had both been students of I.I. Rabi at Columbia.

Another scientific cousin with us today, who could well be speaking in commemoration of Paul, is Robert Hilborn, a fellow Ramsey graduate student who is now, after a distinguished university career, Executive Officer of the American Association of Physics Teachers.


Paul graduated from Carleton in 1964 and entered the graduate program at Harvard.  He soon joined Norman Ramsey’s group, arguably then the best atomic experimentalists in the world with many of its graduates already in careers of unusual distinction in academia, industry, and government.

I know from personal experience that it is not easy to make the transition from being the top student in a small college, confident in one’s grasp of physics, to being a first year student in a hypercompetitive graduate school.  (I see Bob Hilborn smiling in knowing assent).    You often face the larger reality that a fundamental understanding of some topics may be beyond your talents, mastery not coming no matter how hard you try.   Your discouragement is amplified if there are others in the class who seem to master the topic with ease.   At this point you must stop obsessing over not being able to understand everything and, instead, focus on what you can do well.  You need to find a thesis advisor who will help match a research topic to your theoretical insights and your experimental talents.

Paul was an outstanding example of putting effort into those things that he could do best.

Ramsey, as one of the most influential physicists of the 20th century, was frequently away from Harvard.  He did set the general direction of the laboratory’s research, he aided in choice of thesis topics, and he did engage with critical issues when time permitted.   But the students in Ramsey’s group were largely responsible for working out the day-to-day problems of their own research, often by consulting other students and postdoctoral fellows.

Paul rose to the challenge presented by that research situation.  His doctoral dissertation was on minimizing systematic errors that affected the frequency of the hydrogen maser, this with the intent of developing an atomic clock to be used as a precise standard of time.  Metaphorically, we can regard oscillations within a hydrogen atom as the pendulum for the clock.  But motions of that pendulum were perturbed whenever the hydrogen atom bounced from the walls of its container.  Paul’s achievement was to design those walls so that the pendulum suffered only minimal perturbation as the atom underwent many wall collisions. Paul’s research provided a foundation on which others (e.g. Tom English, a Michigan PhD and a postdoc with Ramsey) built the atomic clocks now used on GPS satellites.

Transition To Dearborn

Paul finished his work at Harvard in1970, a time when the Mansfield amendment had drastically reduced the federal funding of academic research.  Universities had cut back sharply on the hiring of new faculty and   the job market for physics PhD’s shifted more to industry.  In this harsh employment climate, Paul was able to obtain a postdoctoral fellowship at the University of Western Ontario and then move to a research position at the Corning Glass Works.

Yet Paul’s drive for an academic career persisted.  His talent and accomplishments led to an assistant professorship at the Dearborn Campus of the University of Michigan, the 1973 start of the enormously successful academic career which Don Bord has so eloquently described.

Research With Positronium In Ann Arbor

After getting started at UM Dearborn, Paul’s drive to do fundamental research led to his collaboration with Arthur Rich’s large and well-funded group that was doing research on positrons on the Ann Arbor campus.   That collaboration started in the mid-1970s with studies of the interaction of positrons with surfaces and with the making of low energy, focused beams of positrons.    This opened several new areas of inquiry:  for example the availability of spin-polarized positron beams made it possible to search for the origin of the preference for left-handed twists in the molecules associated with life.

Paul also made major contributions to the group’s extensive research on the lifetime of the positronium atom.   Gidley’s early (1976) work had shown that earlier measurements of this critical quantity were probably in error.  Measurements of this lifetime formed a major portion of the group’s research effort until Vallery, Zitzewitz and Gidley published the definitive result in 2003.

Paul’s understandings have contributed immeasurably to other positron-related work, for example the APS award-winning work on chaotic transport in charged particle traps done by Bita Ghaffari, Ralph Conti and Tom Steiger.    Paul also contributed to the Positron Annihilation Lifetime Spectroscopy (PALS) for measuring nanoscale defects and open volumes being done by Dave Gidley and his students.

Paul is a coauthor of more than twenty positron-related papers, a half-dozen of which are in Physical Review Letters.  Not to be overlooked is that he was also the main conduit for news about innovations in physics education to the Ann Arbor department.

Paul was a long-term, valued member of the Ann Arbor positron group who did much for group morale.  Arthur Rich was a gifted physicist who demanded much from his students and we were fortunate that Paul, being a first-class researcher in his own right, was uniquely positioned to make friendly interventions when discussions became too intense.   Moreover, Paul was very helpful when Dave Gidley assumed leadership of the group after Rich’s unexpected, untimely death in 1990.

Concurrent Achievements

It is remarkable that Paul maintained an extended, fruitful collaboration with Ann Arbor, 25 miles away from his home base in Dearborn where he was, concurrently and for extended periods, carrying heavy responsibilities for teaching and administration, contributing to texts and outreach for K-12 teaching, and devoting time as an officer of the American Association of Physics Teachers.    We must also recognize Paul’s and Barbara’s generosity in endowing both local and national fellowships for study in physics.

Paul had an extraordinary gift for bringing out the best in others.
We were fortunate in having had him as a colleague,
as mentor, and as a friend for more than 35 years.
We are deeply grateful to Barbara Zitzewitz for
all that she did to make that possible.


David Gidley, Professor of Physics, University of Michigan, Ann Arbor

In the mid-1970s Paul had started to come out to Ann Arbor to work with Art Rich’s g-factor and positron/positronium group.  He had the idea that new areas for positron research would open up with the advent of low energy, focused beams of positrons (focused as one would do for electron beams in a cathode ray tube) and I believe that he and Art also thought the beam could be spin polarized as well.  Using what looked to us as a surplus, vintage ion pump and working on a shoe-string budget, Paul had made the group’s first “beam” of positrons—the plural here was jokingly optimistic as he struggled to find moderators to convert fast beta decay positrons into focusable low energy positrons.  He detected positrons by focusing them onto the 1 cm cone of a channel electron multiplier. The count rate was initially so low that Paul made an “up-down” counter that added counts when the beam was on and then subtracted background with the beam turned off—he was statistically digging the beam out of the multiplier’s background noise while searching for the right tune of the beam lenses.

I was minding my own business as I began my thesis experiment to measure the decay rate of ortho-Positronium (o-Ps) in some very light fluffy powders of SiO2 and MgO.  The results (1976 PRL) were startling as we deduced an o-Ps  decay rate, extrapolated to a vacuum environment, that was some 2% less than the two 0.1% measurements (at Yale and at University College London) that extrapolated over gas density.  Moreover the existing theoretical calculation agreed with the gas measurements! .  The systematic concern with all of these experiments is that you need some material to supply electrons to form the electron-positron (Positronium) bound state but then the subsequent interaction of the Ps with that same material (gas molecules or powder grains) increases the overlap of molecular electrons with the positron in the Ps, and hence increasing the measured decay rate.  The trick is to correctly extrapolate the measured decay rates to zero density. Ideally, one wants Ps isolated in vacuum.

I’m sure Paul was aware of this clear discrepancy in decay rates as there were always wonderful group discussions in Art’s group but I distinctly remember running down the hall and bursting into Paul’s corner of the lab with the question “Paul, can we put a gamma detector next to your beam to see if you are making Ps in vacuum on the cone of your electron multiplier?”  Together we jumped on this so fast that our first paper with Paul was published with the ultra-rare sans review in PRL (Paul, Art, Ken Marko, and Dave) within that same year of 1976.  The controversy only deepened as this direct measurement in vacuum nominally agreed with our powder results.  At this point we had a tiger by the tail so none of us were letting go—Paul was hooked on decay rate measurements.

We had to understand if there is something fundamentally wrong with either the gas measurements or our powder/vacuum results.  So we enlisted a longtime positron expert, Derek Paul from the University of Toronto, to work with us on our own gas experiment.  In 1978 we published another PRL wherein our extrapolation in gas density is even lower in decay rate than either the powder or vacuum results (not to mention the earlier gas experiments, now almost 3% higher).  At the same time we continued to use Paul’s ever-improving beam to improve our vacuum measurement.  I still have a Polaroid picture of Paul’s positron rate meter with a note pasted to it exclaiming the unparalleled count rate of 80 per second!  With Paul’s help modern positron beams achieve rates of over 108 per second.  This improved vacuum measurement was published in Physics Letters, also in 1978.  It would be 12 more years before we would again publish a new vacuum measurement, Jeff Nico’s thesis work, also in PRL.  In 2003 we published our final PRL on the vacuum measurement as Rich Vallery’s thesis. Paul was intimately involved in these two PhD thesis projects.

After the initial burst of decay rate activity Paul continued to work on his beam and we quickly showed that his beam is spin polarized in a 1979 PRL.  Paul’s spin polarized beam was then the centerpiece of one of Art’s pet projects, that of seeing whether the violation of parity in beta decay might underlie nature’s preference for handedness (chirality) in molecules that occur within living organisms.  (As Art was twisting the arm of our long-term NSF contract monitor Rolf Sinclair for funding of this project, Rolf quipped that we should apply to the Vatican…. and the name “Vatican experiment” stuck from then on in the group…)  Together with Paul we wrote a paper on this that was published in the prestigious journal, Nature, in 1982

In that very intense 6 year period Paul and I collaborated on 3 PRL’s, one Physics Letter, and one Nature article.  Our publication rate slowed down after that but positron beams came to be the centerpiece of my research career and much of this I owe to Paul Zitzewitz.  I became aware what a marvelous and dedicated teacher Paul became and I will let others who knew so well this side of Paul comment on it.  But I knew Paul for some 35 years first as a top notch physicist.

Dave Gidley
May 24, 2013

Paul’s obituary in Physics Today ( April 30, 2013) gives more details of his contributions to teaching.    See also the AAPT’s memoriam notice about Paul on the website of the American Association of Physics Teachers.