Werner Weber Remembered

October 10, 2014 (PO36). Werner Weber, professor emeritus of theoretical physics at the Technical University of Dortmund (TUD), Germany, died suddenly and unexpectedly at his home on 3rd of July 2014.

Werner was born on 6th of August, 1945, in Bad Urach, Germany, and studied physics at the Munich Technical University, 1964-1970. Two years later (1972) he earned his PhD on “Lattice Dynamics in Hard Materials and Transition Metals”, a broad subject absorbing him for most of his scientific career.  In August 1972 he joined Max Planck Institute of Solid State Physics in Stuttgart, Germany, where he remained until 1977. His  study of that period on "Adiabatic bond charge model for phonons in diamond, Si, Ge, and α-Sn“ (1977) has been one of his most cited publications [i]. It appeared in print during his two-years-long research stint at Bell Laboratories, where he collaborated closely with Chandra Varma on reformulating the problem of lattice dynamics in transition metals and applying to understand the phonon anomalies discovered more than 15 years earlier by neutron scattering. They showed that the traditional views of phonon anomalies as due to nesting, (W. Kohn and A. Overhauser), needed a serious modification. The modification was the momentum-dependence introduced by local field effects. They found an easy way to include them by using moving tight binding orbitals [ii]. When Werner went back to Germany, he extended this method to various transition metal compounds. All this resulted in a firm quantitative understanding of electron-phonon effects in strong-coupling superconductors.

In 1977 Werner assumed a tenured position the Research Center Karlsruhe and subsequently, in 1983, earned his “habilitation” (a DSc equivalent) at the Karlsruhe Technical University. In mid-1980s (probably 1985-1987) he went again to Bell Labs, where, among other projects, he worked with Varma and a graduate student, Lisa Randall, on application of the Gutzwiller methods to multi-band problems, such as heavy-Fermion compounds [iii] and with L. Mattheiss and by himself on high temperature superconductivity, both widely cited studies [iv].  This was immediately after the discovery of high critical temperatures in cuprates, which exceeded theoretical expectations based on the electron-phonon interaction. Soon thereafter, in 1989, Werner was appointed to the “Chair of Theoretical Physics II” at TUD, which he occupied until his retirement in 2010.

The overall goal of Werner’s efforts was in that period to combine the band theory with the Gutzwiller’s many particle method, which satisfactorily describes 3d and 4d electrons in transition metals. Indeed, in 1996, he and his PhD student Joerg Buenemann, succeeded in a generalization for multiband systems. Werner’s last work in correlations physics was to lay formal basis for the Gutzweiler theory of density functional. His fervent hope was its further development and application.

In 2009 Werner became interested in climate change and in 2010 contributed a publication on "Strong signature of the active Sun in 100 years of terrestrial insolation data", proposing that formation of aerosols due to cosmic radiation contributes to solar energy delivery to Earth’s surface thus decisively affecting the climate [v].  This work, representing a minority point of view, was seriously debated in the climatologist community.

At TUD, Werner was an engaged faculty member, twice a Dean, and in his last years there also interim Director of the TUD Center of Synchrotron Radiation (DELTA), a research and training facility. After his retirement he remained very involved, especially in shaping and promoting a new TUD Bachelor and Master study in medical physics. This was prompted in part by his participation in a successful industrial venture (Cryoelectra) developing and manufacturing critical components for superconducting synchrotron accelerator systems designed for clinical proton therapy of cancer.

His colleagues and collaborators remember him as warm hearted person and a scientist never satisfied by standard answers while striving at uncovering the real correlations. He was a great mentor, wonderful colleague and friend. We’ll all miss him.

Florian Gebhard, Frithjof Anders, Jörg Fink, Ulrich Eckern, Roser Valenti at TUD, Chandra Varma at UC Riverside, USA, and Alex Braginski at Research Center Juelich, Germany

ⁱW. Weber,  Phys. Rev. B , 15, 4789 (1977). 
ⁱⁱC.M. Varma and W. Weber, Phys. Rev. B, 19, 6142 (1979).
ⁱⁱⁱC.M. Varma, W. Weber and L.J. Randall, Phys. Rev. B, 33, 1015 (1986).
^ivW. Weber, Phys. Rev. Lett. 58, 1371 (1987).
^v W. Weber, Ann. Phys. 552,6, 372-381 (2010).