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.

 

 

He thus studied physics at the Friedrich-Wilhelm University in Bonn, graduated with honors, and then, with a Siemens scholarship, received his PhD on compound materials for superconducting wires and cables.He started his professional career working as an analyst for Deutsche Bank evaluating projects and portfolio companies for IPOs.  Eventually, he profited from the know-how in financing when founding the start-up company Trithor.  It was the time when the first wave of superconductivity hype already subsided and many big companies were withdrawing from the field. Jens recognized that a dedicated superconductor company would be necessary to keep things moving on. With the double strategy to produce superconducting wire as well as HTS components and devices, Trithor teamed up with the machine maker Bültmann to develop the first HTS-based induction heater of billets. After the insolvency of Trithor he managed to attract new investors to continue this development under the label Zenergy Power. From 2006 on, Jens led and expanded the Zenergy group with new subsidiaries in the US and Australia.

 

The first commercial breakthrough came in 2008 when the billet heater was successfully commissioned as the world’s first industrial scale HTS installation in a German aluminum extrusion plant.  The convincing concept and large energy savings of this product were immediately recognized and awarded a number of prestigious prizes – among them the Hermes Award (2008, see HE15), German Environmental Award (2009), the Innovation Award for Climate and Environment (2009), and the European Business Award for the Environment (2010).

 

At the same time, Jens initiated within the Zenergy group the development of large HTS generators and fault current limiters for electric power supply. The first hydro-generator has been successfully tested and will be soon installed in a German hydro-power plant.  Another premiere was the first live-grid HTS fault current limiter installation that protected Southern California in 2010 from a power outage due to a sudden current surge. Jens also pushed the development of lower- cost HTS coated conductors. Zenergy started developing a 2G manufacturing process based on ink-jet printing and an all-chemical solution approach.

 

In 2011, the board of directors decided to abandon the superconductivity activities at Zenergy. Jens was released from his position at the Zenergy Power group and could not prevent the insolvency of the German Zenergy Power branch. To continue the work on HTS components, he founded,  together with former fellow partners, the engineering consulting company ECO5 with focus on the development of HTS wind power generators.

 

Jens Müller was a visionary – always one step ahead, and a tireless promoter of the HTS cause. He initiated significant developments and increased public awareness of superconductor technology. His inventions are documented in numerous patents.

 

Jens was a friendly and cheerful person, who gave hold, strength, and confidence to his colleagues and fellow men. His successes were due to expertise, tireless efforts deep commitment, and the unique skill to convince and to inspire others with his ideas.

 

Jens lost his life at the age of only 42. With him we have lost a protagonist of superconductor technology, an excellent businessman, partner, and friend. He has left marks, and the gap caused by his death will be hard to close. Our grief and deep compassion is with his wife and three kids. 

 

By Werner Prusseit  (ivSupra) and Ursula Kollenbach (formerly Zenergy Power)