Alejandro Muramatsu

Alejandro Muramatsu, professor at the University of Stuttgart and chair of the Institute for Theoretical Physics III, died on November 16, 2015 after a serious illness. Alejandro was born in Buenos Aires, Argentina on December 12, 1951 and obtained his undergraduate degree in physics from the University of Buenos Aires. Within a year of the 1976 Argentine coup, whose inhumane actions he experienced personally, he moved to Stuttgart, Germany to start graduate work at the Max Planck Institute for Solid State Physics. After obtaining his doctorate on the subject of electronic instabilities and the influence of the electron-phonon interaction on semiconductor surfaces, Alejandro at first stayed on for almost two years as a postdoc at the Max Plank Institute and subsequently moved to the Institute for Theoretical Physics (ITP) at the University of California at Santa Barbara, where he was awarded a postdoctoral fellowship. Over the years, he would come back repeatedly for stays at the ITP (later the KITP).

In 1986, the year high-temperature (HTC) superconductivity was discovered, Alejandro took on an assistant position at the University of Wuerzburg, where he obtained the habilitation in 1989. In his time in Wuerzburg, HTC superconductivity became one of his major interests and remained so for the rest of his career. In the early years of HTC superconductivity, Alejandro was quick to realize the value of unbiased computational techniques and, in particular, of quantum Monte Carlo methods in the investigation of strongly correlated lattice models, such as the Hubbard and t-J models, which were and still are leading candidates for a microscopic description. Among the approaches developed by him is an efficient hybrid algorithm to study the t-J model. In 1996, after two years as an associate professor in Augsburg, Alejandro moved to Stuttgart as a full professor. In Stuttgart, he continued to expand his research on strongly correlated electrons, in particular, by developing and applying quantum field theory approaches. In his time in Stuttgart, Alejandro served as Associate Dean in the Faculty of Mathematics and Physics and as a consultant for the supercomputing center at Jülich as well as for the Beijing Computational Science Research Center.

In the early 2000s, Alejandro’s research moved in a significant new direction. He was among the first condensed matter physicists that recognized the potential of ultracold gases to act as a testbed for complex quantum many-body phenomena. In the subsequent decade, he made important contributions to this field, in particular, in understanding the importance of quantum fluctuations and quantum criticality. At about the same time, Alejandro developed an interest in the physics of strongly interacting quantum systems far from equilibrium. He contributed to the development of unbiased computational techniques, such as the time-dependent density matrix renormalization group, to study such phenomena. His early work included important contributions to debates on the presence or absence of quantum thermalization and the emergence of light-cone-like phenomena after quantum quenches. In recent years, Alejandro developed a keen interest in the anti-de Sitter space-conformal field theory duality and its application to condensed matter physics. Unfortunately, his untimely death put a premature end to his nascent work in this area.

Outside of physics, Alejandro had a lively interest in social problems, which he particularly enjoyed discussing with friends and colleagues. His integrity, openness to new ideas, and sense of humor left a distinct mark on those discussions. Alejandro was an excellent host, a fact which, together with his culinary talents, made visiting Stuttgart a pleasant and memorable experience. Helping and mentoring junior collaborators was an obligation that was very important to him; he was a dedicated advisor as well as a friend to those of us that were lucky enough to work under his supervision. We will miss him sorely as a mentor and as a critical, intellectual spirit who always turned his gaze to the future, full of hope and commitment to his ideals.