Michael Wulf Belatedly Remembered

July 7, 2014 (PO33). Michael Wulf was born on May 9, 1978 in Hamburg and died unexpectedly at 34, presumably on November 16, 2012.

He studied physics at the Hamburg University, Germany (1997-2000), the Georgia Institute of Technology, Atlanta, GA, USA, (2000-2001) and University of Rochester, NY, USA, where in 2002 he earned his M.A. Subsequently, he worked there until 2006 towards a Ph.D.in the field of qubits and quantum computing control circuitry (RSFQ) utilizing superconducting devices. In particular, together with colleagues from Rochester, he published a very interesting paper about possible application of underdamped Josephson junctions in RSFQ comparators for the Josephson qubit readout (IEEE Trans. Appl. Supercond. 13, 974, 2003). His Ph.D. dissertation was planned that time to be on the subject of Steps Towards Superconducting Quantum Computing utilizing superconducting electronics.

In 2006 he moved to PTB Braunschweig, Germany (the German National Metrology Institute), to work in the Quantum Electronics Department on adaptation of cryo-electronic devices for qubit manipulation. He was involved in several EU research projects on superconducting quantum computation. Parallel to this research, he was very much engaged in the study of single electron circuits for application to electrical standards, especially the error statistics in networks of such devices. Eventually, he conceived the brilliant error accounting concept for practical realization of the quantum standard of electric current based on single electron tunneling (Phys. Rev. B 87, 035312, 2013 – the paper appeared after his death). Practical realization of this idea became the main and quite ambitious goal of his scientific life and, suddenly, the new theme of his PhD work. His first attempts to make such experiment using all-metallic circuits (Al electron pumps integrated with Al single electron transistors operated as electrometers) were not as successful as expected. Consequently, to implement this idea, Michael moved in 2012 within PTB to the Semiconductors and Magnetism Department to work on GaAs single-electron pumps for the future quantum current standard. The experimental work within that group, supported by his colleagues from Quantum Electronics Department (they complemented the semiconductor circuits with Al single electron electrometers) relatively soon resulted in a successful practical implementation of the concept, with Michael as a posthumous co-author (Phys. Rev. Lett. 112, 226803, 2014). That work was in 2014 awarded the prestigious Helmholtz Prize. Unfortunately he hadn't lived long enough to share this prize with the other awardees.

Not much is known about Michael’s private life and hobbies, probably because science itself was his main hobby. Still, we remember that he was an avid cyclist and had multiple interests, ranging from classical music and literature to economics and politics. His friends and co-workers remember having with him many discussions on such subjects during the ongoing measurements. At the same time he disliked unavoidable bureaucracy and boring paperwork, today an inseparable supplement of every active scientist’s research. He was interested in people, treated others with interest, respect and in a friendly manner, sometime with fine humor, while not hesitating to express his convictions and put right questions at the right time, thus moving things forward.

Michael Wulf (or Mike, as he liked to be called by colleagues) will always be in our memory as a brilliant minded and technically very gifted person. It is tragic that sudden death extinguished justified hopes for his many significant accomplishments yet to come.

His PTB colleagues