It is with great sadness that we announce the passing of our esteemed colleague Prof. Emeritus Joshua Zak, one of the founders of the Physics department and recipient of the Israel Prize for Physics and Chemistry Research for the year 2022 and the 2014 Wigner medal.

Prof. Zak led scientific breakthroughs that led to significant applications. He is responsible for many achievements in physics, and two of them are named after him: the Zack Transform, which is presently used in signal processing, and the Zak Phase – a unique 1D crystal phase, which he published in 1989 in the scientific journal Physical Review Letters. He completed a doctorate at the Technion under the supervision of Prof. Nathan Rosen, who was Albert Einstein’s student and assistant, and Prof. Giulio (Yoel) Racah from the Hebrew University. Prof. Zak won the prestigious Wigner Medal in 2014 and was elected an honorary fellow of the Israel Physics Society (IPS) in 2018. In 2022 he was awarded the Israel Prize for Physics and Chemistry Research.

Zak was born in Vilna in 1929. At the age of 12, he and his family were sent to the ghetto, and later, he was deported to forced labor camps and a concentration camp, during which time he lost both parents. As an adolescent, Zak was forced to join the Death March to the west and was released by and immediately recruited to the Red Army – all before he had reached the age of 16. Following his discharge in 1948 he returned to Vilna and began to attend high school, graduating with honors despite having missed many years of schooling due to the war and his military service.

He completed his studies in Physics with distinction at Vilnius University in 1955, while simultaneously earning the title of Lithuanian kayak champion. In the same year, he was accepted to further studies in Leningrad and began studying there. In 1957 immigrated to Israel. Within a short time, he was accepted by the Technion, where he completed his doctoral studies under the supervision of Technion Professor Nathan Rosen. In 1960, Zak received his D.Sc., spent some time at the Massachusetts Institute of Technology (MIT), and then returned to the Technion, where he began studying in the Department of Physics. Ten years later, he founded, and headed, the Solid State Institute at the Technion.

Technion President Professor Uri Sivan said: “Today we are saying goodbye to a great scientist, one of the pillars and influencers of the Physics Department at the Technion. His research paved new ways in the understanding of fundamental phenomena in quantum mechanics and accelerated the development of important engineering applications. Prof. Zak is among the generation of giants who laid the foundations for theoretical physics in Israel. As a faculty member in the Physics department, I had the privilege of getting to know him closely and having fascinating scientific conversations with him. Prof. Zak's achievements earned him worldwide recognition and we were all very happy when in 2022 he received the Israel Prize for Physics and Chemistry Research, a prize that he greatly deserved.”
The Dean of the Physics department Professor Adi Nusser said: “Professor Zak was one of the founders of the Physics Department and of its leader. Beyond the high-quality science that came out under his supervision, he made a great impact on the faculty. Prof. Zak made an important contribution to physics, which earned him the Wigner Prize and the Israel Prize. Even after he retired a few years ago, the Physics department and its academic quality were important to him until his last day, and until recently he came to the faculty regularly and participated in all the activities.”

The Israel Prize was awarded to Prof. Zak on the 74th Independence Day of the State of Israel, in May 2022, for the "development of mathematical tools such as 'Zak Transform' and 'Zak Phase' used to decipher the phenomena of electrical conduction in a magnetic field. These tools allow for the prediction of materials with unique properties to build electronic devices. The Committee further emphasized that “…his scientific contributions serve, and will continue to serve, in gaining an understanding of the chemistry and physics of material.”

Last year, the Physics Department at the Technion held a special four-day international conference, dedicated to Prof. Zak. The conference, focused on the connection between topology and physics, was organized by Professors Eric Akkermans and Ari Turner. “Topology, like group theory, is an elegant field of mathematics that allows one to describe geometrical forms, wherever they occur.” Said prof. Akkermans. “It is surprising how dramatic the implications of some of its concepts can be for physics experiments. The conference, which was attended by about 200 people, most of them young researchers, brought together many of the physicists contributing creatively to the “topological revolution” in condensed matter physics – a field professor Joshua Zak was one of its pioneers.”

In addition to the scientific sessions, a special session was dedicated to Prof. Zak. In this session, his former students talked about his character as a teacher and educator who devoted a lot of effort to educating new generations of engineers and researchers, and his colleagues shared about his groundbreaking path in the field of topology of condensed matter physics. According to Prof. Akkermans, "Throughout his career at the Technion, Prof. Zak emphasized the importance of a warm and active research environment in the faculty, which is essential to attract talented researchers, and at the conference we were able to meet his criteria for excellence and social interaction - both in terms of the invited lecturers, including Nobel and Wolf laureates, and in terms of the participants - and we proved once again that the Technion is a beacon of excellence in physics."

May he rest in peace.

Pictures:
1. Professor Joshua Zak
2. Israel Prize 2022 – Minister of Education at the time Dr. Yifat Shasha-Biton presents the Israel Prize to the late Prof. Joshua Zak.
Photo: Oded Karni/La”m
3.Obituary notice

Video: Professor Joseph (Yosi) Avron of the Technion Physics Department /
interviewing Professor Joshua Zak.
https://www.youtube.com/watch?v=jcvRigYG5_M