150 years of Margarita and Vladimir Man'ko

This special issue celebrates jubilees of two outstanding physicists and science organizers: Margarita Alexandrovna Man'ko and Vladimir Ivanovich Man'ko. Margarita Barysheva (Man'ko) was born in Moscow on 4 December 1939. A few months later, on 2 April 1940 Vladimir Man'ko was born, also in Moscow. In 1957, they graduated with Golden and Silver Medals from different high schools in Moscow and became students of the Physics Department of the Lomonosov Moscow State University. They met each other two years later when they were third-year students, and they have now been married for almost 55 years.

Vladimir was a student of the Chair of Theoretical Physics (headed by Professor N N Bogolyubov). In 1961, he successfully passed all exams of the prestigious Landau theoretical minimum. His name appears as number 41 in the famous 'list of 43' persons who were examined and approved personally by Landau. After that he was accepted as a diploma student at the Landau theoretical group under the supervision of Professor Igor Dzyaloshinskiy. In 1963, Vladimir graduated from the Lomonosov Moscow State University. His diploma work was entitled 'Hidden antiferromagnetism in cubic crystals'. While writing this work, Vladimir was impressed by the beauty and power of group theory, such that applications of this theory to various fields of quantum physics became one of the main directions of his research for the coming decades.

Margarita studied under the Chair of Physics and Theory of Oscillations. From 1961 she worked on her diploma project in the group of Professor Nikolay G Basov (1964 Nobel Prize Winner) in the Laboratory of Oscillations (headed by another 1964 Nobel Prize Winner, Professor Alexander M Prokhorov) of the Lebedev Physical Institute of the Academy of Sciences of the USSR. The title of her diploma work (defended in 1963) was 'Maser with sequential resonators'. As Margarita sometimes recounts, this was, perhaps, one of the last diploma theses devoted to masers, since soon after 1961 the main attention of the majority of researchers in that field was directed to the physics of lasers. Experimental laser physics, with an emphasis on semiconductor lasers, was the subject of Margarita's studies from 1963 until the beginning of the new millenium.

Since 1963, the scientific careers of Margarita and Vladimir have been connected with the Lebedev Physical Institute, where Margarita started work as a researcher and Vladimir as a PhD student. In 1966, Vladimir defended his thesis 'Some aspects of applying group-theoretical methods in physics' (under the supervision of Professor Moisey A Markov), and in 1972 he defended his habilitation thesis 'Dynamical symmetries and coherent states of quantum systems'. Margarita's PhD thesis 'Spectral characteristics of diode lasers and methods of mode selection' was defended in 1970.

In that period Vladimir published several brilliant papers with his classmate and close childhood friend, Dr Ilya A Malkin, that attracted the attention of many specialists from all over the world. In one of them, entitled 'Symmetry of hydrogen atom' and published in JETP Letters in 1965, the existence of dynamical symmetry in the hydrogen atom connected with $O(4,2)$ symmetry group was discovered; thus generalizing famous results obtained by V A Fock in the 1930s concerning the O(4)-symmetry of the hydrogen atom. The concept of dynamical symmetries became very popular from the middle of the 1960s, and working together with I A Malkin, V I Man'ko was among the founders and propagandists of this concept and its applications in different areas of quantum physics. Another important concept born in the first half of 1960 was that of coherent states. It is connected with the names of R J Glauber, J R Klauder and E C G Sudarshan (although we know that its roots can be traced to the very first years of quantum mechanics), but, in 1968, V I Man'ko and I A Malkin were first to construct coherent states of a charged particle (or oscillator) in a uniform magnetic field. A few years later, together with their students, they developed a general theory of dynamical invariants and coherent states for nonstationary quantum systems. In fact, the time-dependent coherent states considered in their papers in the early 1970s are nothing but coherent squeezed states, although this name was invented a decade later.

During the decades that followed, Vladimir Ivanovich Man'ko and his students and collaborators published many papers on different kinds of nonclassical states in quantum physics (for example, the so-called 'even/odd coherent states', which became very popular in the current literature as models of the Schrödinger cats, were introduced in one of their papers at the beginning of the 1970s). In the early 1990s, he promoted the idea of the possibility of experimental verification of the so-called nonstationary (dynamical) Casimir effect in the laboratory using, in particular, superconducting quantum circuits. A quarter of a century later, this idea seems to be close to realization. Since the beginning of the 1990s, working with numerous colleagues and students, Vladimir Man'ko has developed a new tomographic approach to quantum mechanics.

Besides the above-mentioned intensive scientific research work, since 1968, Vladimir Ivanovich Man'ko has taught quantum mechanics to the students of Moscow Institute of Physics and Technology (MIPT), where he is full professor of the Chair of Theoretical Physics, a post he has held since 1989. Several generations of 'fiztechs' learned and loved quantum mechanics under his guidance as lecturer, 'seminarist' or supervisor. I met V I in 1969, when he performed seminars on quantum mechanics in our group. I saw a live example of 'perpetuum mobile', because V I gave individual problems to each student and continued to move around the classroom for a period of two hours, checking solutions, giving advice and posing new problems. This is a great talent that I have not seen in anybody else. I tried to follow his style when I started to work as a teacher, but I did not succeed in maintaining such an exhausting rhythm for more than a few weeks. Preparing this text I looked for comments about professors of MIPT on the institute websites and found a lot of enthusiastic comments about Professor Man'ko. The most surprising feature of these comments was that the 'perpetuum mobile' continues to work after a period of more than 40 years! In addition, V I Man'ko supervised many diploma (masters degree) works; about 20 students obtained their PhD degrees under his guidance, including me, and some received their habilitation in mathematical and theoretical physics under his supervision.

In addition to experimental work in the laboratory, Margarita Man'ko dedicated a significant part of her time over more than three decades to the publication activities of the Lebedev Institute. She was Deputy-Editor-in-Chief of the Lebedev Proceedings when Professors Basov and Keldysh were the Lebedev directors and Professor Basov was the Editor-in-Chief of the Lebedev Proceedings and other journals. She is the head of the IOP publishing division at the Lebedev Institute, Scientific Editor of the Journal of Russian Laser Research (published by Springer) and Associate Editor of Physica Scripta.

Vladimir and Margarita have participated in hundreds of international conferences and visited a great number of research groups in Europe, Asia and both Americas, establishing very fruitful collaborations every time. They have published several hundred scientific papers in international journals, but a great number of researchers all over the world know Margarita and Vladimir as the organizers of many important scientific conferences. Many of us like to participate in different scientific meetings, appreciating their importance for the development of science. A much smaller number of us are engaged in organizing such events, and the main thought of the majority of the organizers at the end of any event is: 'this is a job that I shall never do again!'. But Margarita and Vladimir have organized or helped to organize dozens of events! Several very successful series of conferences have been maintained for decades thanks to the considerable efforts of Margarita Man'ko, especially in relation to the publication of conference proceedings or related papers. As examples, I can mention the annual Central European Workshops on Quantum Optics and the bi-annual International Conferences on Squeezed States and Uncertainty Relations.

This brief description of the achievements and the diverse activities of Margarita and Vladimir can explain why so many colleagues from many countries accepted the invitation to submit their papers to this special issue. It contains contributions from three generations of researchers: from friends and collaborators who have known Margarita and Vladimir since the beginning of their careers to (using Vladimir's terminology) their 'scientific children and grandchildren' (including biological ones, too). The reader can see that the subjects of the papers cover rather wide areas of theoretical, mathematical and experimental physics, reflecting the ample scientific interests of Margarita and Vladimir.

I am extremely grateful to Dr Suzy Lidström, Editor-in-Chief of Physica Scripta for her strong support for the idea to organize this special issue. Great work has been done on the preparation of more than 60 contributions for publication by Yasmin McGlashan, Physica Scripta's publisher, and by the staff of Physica Scripta. I thank the authors for making excellent contributions and more than 100 referees (whose names will remain anonymous) for careful reading of the initial manuscripts and numerous useful remarks and suggestions. In addition, I have to apologize to many friends and colleagues who wished to submit their papers but were unable to do this owing to very squeezed time available for the preparation. Perhaps, we should have thought about this special issue a little earlier, but clever thoughts frequently come to mind with some delay!

Finally, sharing the common wishes of all authors, I say on their behalf: we cordially congratulate Margarita and Vladimir on this magnificent jubilee and wish them many more happy years in science and life!