Willem Dickhoff, Professor of Physics
Research
Prof. Dickhoff’s research is focused on solving the nuclear many-body problem. A prominent role in his current research is played by the description and analysis of all experimental data that are directly linked to the single-particle propagator of the corresponding nucleus. Such data include all proton and neutron elastic scattering observables such as the differential cross section, polarization data, total and reaction cross sections. In addition, the removal part of the propagator determines the nuclear charge density, single-particle level structure and its fragmentation that have been explored by one-nucleon knock-out reactions at electron scattering facilities like NIKHEF in Amsterdam, Mainz, and Jefferson Lab in Virginia. Focus of the research in the group aims to provide a solid theoretical background for studying nuclei with extreme ratios of neutrons to protons (or vice versa) that are being probed at rare isotope beam facilities. Together with the radiochemistry group of Profs. Sobotka and Charity he employs the Dispersive Optical Model to provide a road map to these exotic nuclei that are important for nuclear astrophysics. Particular attention is paid to the predicted properties of neutrons in the nuclear ground state including the neutron distribution.
The properties of nucleons as they propagate through the nucleus and nuclear matter have been the focus of detailed calculations in his group that employ Green’s function techniques borrowed from Quantum Field Theory. Wide ranging phenomena are studied in his group: superfluid properties of nuclear matter, giant resonances in finite systems, properties of pions and isobars in matter, saturation properties of nuclear matter, spectroscopic factors for nucleon removal, scattering of particles in a strongly interacting medium, and the properties of strange particles in matter to name a few. Techniques like the Faddeev-RPA method developed in the group with Carlo Barbieri, have also been applied to other many-body systems like atoms and molecules.
Teaching
Does teaching play a significant role at a Research University? Washington University is of course a Research University. This doesn’t mean that teaching takes a back seat. Quite the contrary: by paying careful attention to all issues related to teaching in this department we have been able to almost double the number of physics majors during the last four years. This trend was completely opposite to the national trend that continues to show asubstantial decline in the total number of bachelors degrees in physics. Students who come to Washington University to study science today require a different approach than students in the past. This is mostly related to technology but also to changes in culture. A standard physics lecture from 20 years ago may well fail to keep most of today’s audience awake unless the instructor is extremely gifted. Research has also shown that conceptual understanding by means of standard physics instruction is not as good as it should be. For these reasons we engage students in our year-long introductory course intellectually in the classroom by using Eric Mazur’s “Peer Instruction” method. The more spectacular consequence of this method is that part of the lecture time students are talking in class with each other about conceptual understanding of physics questions. Focused Physics I and II (Physics 193/194) is a special introductory sequence intended for students with a strong interest in physics. The special atmosphere and common interest in physics makes teaching this section a special delight.
Does recruiting for a physics major make sense in today’s world? You bet! I know of no better way for a student to learn how to solve NEW problems. A physics education provides both a technical and theoretical background to acquire these essential skills. A flexible student will therefore be able to apply these skills in completely different settings. While most of our graduates go on to graduate school in physics, there are just as many who either successfully apply to Law, Business, and Medical Schools or succeed in securing a job right after graduation.
Professional History
Professor Dickhoff received his “Kandidaats” (B.Sc.) in 1974, “Doctoraal” (M.Sc.) in 1977, and Ph.D. in 1981 from the Free University in Amsterdam. His advisors were Amand Faessler (then University of Tübingen) and Egbert Boeker (Free University). The title of his thesis was “The particle-hole interaction and pion condensation.” During his doctoral studies he spent the first year at the Institut für Kernphysik in Jülich, Germany collaborating with Amand Faessler, Jürgen Meyer-ter-Vehn, and Herbert Müther. After his thesis defense he moved to Tübingen, Germany, for four years of postdoctoral research and some teaching in German. During this time, a long-standing collaboration with Klaas Allaart from the Free University was started involving quite a few graduate students over the years. After one year at TRIUMF on the campus of UBC in Vancouver, he moved to St. Louis and became assistant professor in the Washington University physics department in 1986. Since 1997 he is a “volle” professor. He has supervised numerous graduate students.
After receiving tenure, Prof. Dickhoff initiated a new course called Physics and Society (Phys 171) which has been team-taught together with Profs. Bender, Friedlander (until his retirement), and Ogilvie every year. Prof. Dickhoff is also a member of the faculty in the Environmental Studies program at Washington University. In 1994 Prof. Dickhoff received a Kemper award for the development of the course Phys 110: Awesome Ideas in Physics. After teaching this course in 1994 and 1996, this course has since been taken over by Prof. Will. The course uses books like Stephen Hawking’s “A Brief History of Time” to discuss some of the most amazing (awesome) ideas that have been developed in the study of physics. Prof. Dickhoff has a strong commitment to teaching and advocates the “Peer Instruction Method” for Introductory Physics courses as developed by Eric Mazur from Harvard University.