Mihai Gavrilă
Encyclopedia
Mihai Gavrilă is a Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

n quantum physicist, member of the Romanian Academy
Romanian Academy
The Romanian Academy is a cultural forum founded in Bucharest, Romania, in 1866. It covers the scientific, artistic and literary domains. The academy has 181 acting members who are elected for life....

 since 1974. He made fundamental contributions to quantum theories of electromagnetic interactions with atoms. His parents were Ion and Florica Gavrilă (née Vișoiu). His father taught medicine and his mother taught English at the University of Cluj.

Education

He began his higher education at the Gheorghe Lazăr High School in Sibiu
Sibiu
Sibiu is a city in Transylvania, Romania with a population of 154,548. Located some 282 km north-west of Bucharest, the city straddles the Cibin River, a tributary of the river Olt...

, and completed his studies at the Seminarul Pedagogic Universitar of the University of Cluj. Then, in 1948, he enrolled in the School of Mathematics and Physics of the University of Bucharest
University of Bucharest
The University of Bucharest , in Romania, is a university founded in 1864 by decree of Prince Alexander John Cuza to convert the former Saint Sava Academy into the current University of Bucharest.-Presentation:...

 from which he graduated with a major in physics, and a minor in radiotechnology, in 1953. While still a student, between 1951 and 1953, he became a teaching assistant to Professor Eugen Bădărău in the Optics Laboratory of the School of Physics.

Doctoral studies

In 1953, he was accepted for doctoral studies in theoretical physics by Acad. Professor Dr. Șerban Țițeica in the School of Physics at the University of Bucharest, and completed successfully his doctoral studies with the Ph.D. thesis entitled ``The Relativistic Theory of the Photoelectric Effect", apparently following in Albert Einstein's and Alexandru Proca's footsteps. He published in 1959 the main results of his Ph.D. thesis in a peer-reviewed paper in Physical Review
Physical Review
Physical Review is an American scientific journal founded in 1893 by Edward Nichols. It publishes original research and scientific and literature reviews on all aspects of physics. It is published by the American Physical Society. The journal is in its third series, and is split in several...

.

Academic career

In 1956, Gavrilă was appointed Assistant Professor in the Department of Thermodynamics, Statistical Physics and Quantum Mechanics of the School of Physics of the University of Bucharest, where he was subsequently promoted to a lecturesip, an Associate Professorship in 1962, and to full Professorship in 1968. He studied also a visiting scholar at several major physics centers around the world: Joint Institute for Nuclear Research
Joint Institute for Nuclear Research
The Joint Institute for Nuclear Research, JINR , in Dubna, Moscow Oblast , Russia, is an international research centre for nuclear sciences, with 5500 staff members, 1200 researchers including 1000 Ph.D.s from eighteen member states The Joint Institute for Nuclear Research, JINR , in Dubna, Moscow...

, JINR (at Dubna in Russia
Dubna
Dubna is a town in Moscow Oblast, Russia. It has a status of naukograd , being home to the Joint Institute for Nuclear Research, an international nuclear physics research centre and one of the largest scientific foundations in the country. It is also home to MKB Raduga, a defence aerospace company...

), Joint Institute for Laboratory Astrophysics
Joint Institute for Laboratory Astrophysics
JILA, formerly known as the Joint Institute for Laboratory Astrophysics, is one of the leading physical science research institutes in the United States. Its faculty, graduate students, and postdoctoral research associates explore some of today's most challenging and fundamental scientific questions...

, JILA (Boulder, Colorado
Boulder, Colorado
Boulder is the county seat and most populous city of Boulder County and the 11th most populous city in the U.S. state of Colorado. Boulder is located at the base of the foothills of the Rocky Mountains at an elevation of...

, USA), International Centre for Theoretical Physics
International Centre for Theoretical Physics
The Abdus Salam International Centre for Theoretical Physics was founded in 1964 by Pakistani scientist and Nobel Laureate Abdus Salam after consulting with Munir Ahmad Khan. It operates under a tripartite agreement among the Italian Government, UNESCO, and International Atomic Energy Agency...

, ICTP (Trieste
Trieste
Trieste is a city and seaport in northeastern Italy. It is situated towards the end of a narrow strip of land lying between the Adriatic Sea and Italy's border with Slovenia, which lies almost immediately south and east of the city...

 in Italy), and the University of Pittsburgh
University of Pittsburgh
The University of Pittsburgh, commonly referred to as Pitt, is a state-related research university located in Pittsburgh, Pennsylvania, United States. Founded as Pittsburgh Academy in 1787 on what was then the American frontier, Pitt is one of the oldest continuously chartered institutions of...

, (Pittsburgh, Pennsylvania
Pittsburgh, Pennsylvania
Pittsburgh is the second-largest city in the US Commonwealth of Pennsylvania and the county seat of Allegheny County. Regionally, it anchors the largest urban area of Appalachia and the Ohio River Valley, and nationally, it is the 22nd-largest urban area in the United States...

, USA). He taught courses on Quantum Mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...

, Group theory representations
Group theory
In mathematics and abstract algebra, group theory studies the algebraic structures known as groups.The concept of a group is central to abstract algebra: other well-known algebraic structures, such as rings, fields, and vector spaces can all be seen as groups endowed with additional operations and...

 and Lorentz group
Lorentz group
In physics , the Lorentz group is the group of all Lorentz transformations of Minkowski spacetime, the classical setting for all physical phenomena...

 transformations.

He was elected a corresponding Member of the Romanian Academy
Romanian Academy
The Romanian Academy is a cultural forum founded in Bucharest, Romania, in 1866. It covers the scientific, artistic and literary domains. The academy has 181 acting members who are elected for life....

 in 1974. However, in spite of his election to
the Academy, he refused to become entangled in any political affairs under the increasingly dictatorial communist regime, and finally he had to leave his country for Norway in the autumn of 1974. At first, he worked
at the Norwegian University of Science and Technology
Norwegian University of Science and Technology
The Norwegian University of Science and Technology , commonly known as NTNU, is located in Trondheim. NTNU is the second largest of the eight universities in Norway, and, as its name suggests, has the main national responsibility for higher education in engineering and technology...

, NTNU
NTNU
NTNU can refer to several universities.*Norwegian University of Science and Technology *National Taiwan Normal University*Nigerian Turkish Nile University...

 (in Trondheim
Trondheim
Trondheim , historically, Nidaros and Trondhjem, is a city and municipality in Sør-Trøndelag county, Norway. With a population of 173,486, it is the third most populous municipality and city in the country, although the fourth largest metropolitan area. It is the administrative centre of...

) and at the Royal Institute of Technology
Royal Institute of Technology
The Royal Institute of Technology is a university in Stockholm, Sweden. KTH was founded in 1827 as Sweden's first polytechnic and is one of Scandinavia's largest institutions of higher education in technology. KTH accounts for one-third of Sweden’s technical research and engineering education...

, KTH, in Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...

. In 1975 he settled in Amsterdam
Amsterdam
Amsterdam is the largest city and the capital of the Netherlands. The current position of Amsterdam as capital city of the Kingdom of the Netherlands is governed by the constitution of August 24, 1815 and its successors. Amsterdam has a population of 783,364 within city limits, an urban population...

 at the FOM Institute for Atomic and Molecular Physics, AMOLF
AMOLF
AMOLF, also known by its full name as FOM Institute AMOLF is one of the three research institutes operated by the Dutch Foundation for Fundamental Research on Matter, also known as FOM. The institute is one of the leading research institute in Europe in the field of physics and biological physics...

, where he became the theoretical physics group leader. Since 1992 he works as a Senior Scientist at the Institute of Theoretical, Atomic, Molecular and Optical Physics (ITAMP) of the Harvard–Smithsonian Center for Astrophysics, in Cambridge
Cambridge
The city of Cambridge is a university town and the administrative centre of the county of Cambridgeshire, England. It lies in East Anglia about north of London. Cambridge is at the heart of the high-technology centre known as Silicon Fen – a play on Silicon Valley and the fens surrounding the...

, Massachusetts.

After 1990 he was able to visit Romania several times and continued to contribute also to the development of theoretical physics research in Romania.

Scientific achievements

Radiative transitions between the inner atomic shells

Mihai Gavrilă completed in 1977 his previous work on the relativistic theory of the photoelectric effect in the
inner atomic orbitals that he had begun in his PhD thesis in 1958; thus, he applied radiative corrections to his previous calculations
He also investigated two-photon excitations and the elastic photon scattering amplitude in the hydrogen ground state,. He completed also the non-relativistic Compton scattering calculation for an electron in the K-shell
These calculations were then extended in the dipolar approximation to the study of Compton scattering in the L- shell. The results of his investigations confirmed the presence of the infrared divergence
Infrared divergence
In physics, an infrared divergence or infrared catastrophe is a situation in which an integral, for example a Feynman diagram, diverges because of contributions of objects with very small energy approaching zero, or, equivalently, because of physical phenomena at very long distances.The infrared ...

—as predicted in quantum electrodynamics, and also predicted the presence of a resonance in the spectrum of the scattered photons.

Interactions of laser beams with atoms

He began these studies in 1976 in connection with experimental studies carried out at AMOLF by group of Marnix van der Wiel. Initially, his interest was focused on multi-photon transitions treated by non-perturbation quantum theory. However, he switched to perturbation methods in quantum theory when it became possible experimentally to attain ultra-high laser intensities at very high frequencies based on the High-Intensity High-Frequency Floquet Theory (HI-HFFT). His investigations lead to very surprising results—the phenomenon of ``atomic dichotomy" in which the hydrogen atom when it is placed in a linearly polarized field exhibits a splitting of its spherical charge distribution into two lobes that oscillate in the laser field. On the other hand, in a circularly polarized laser field, the
hydrogen atom's charge distribution takes on a toroidal shape with its symmetry axis oriented along the propagation vector of the field and passing through the center of the atom. His theory also predicts for two-electron atoms the appearance of a new bound state which is induced by the ultra-intense laser field; these are 'light-induced excited states'. Apparently paradoxical events do occur in the presence of the extremely intense laser field: a proton can bind more than two electrons thus leading to the formation of hydrogen negative ions with multiple negative charges that are relatively stable. Other novel and unexpected properties of molecules were also predicted in the presence of such ultra-intense laser fields.

Publications at the Library of Congress


Scientific leadership

Professor Gavrilă organized several international physics conferences, such as International Conference on Atomic Physics, International Conference on Photonic, Electronic, and Atomic Collisions, and International Conference on Multiphoton Processes. He was also a peer-reviewer for Physical Review A (1991–1993), Journal of Physics B and several other international physics journals.

He also managed several projects financed by EU and Stichting FOM
AMOLF
AMOLF, also known by its full name as FOM Institute AMOLF is one of the three research institutes operated by the Dutch Foundation for Fundamental Research on Matter, also known as FOM. The institute is one of the leading research institute in Europe in the field of physics and biological physics...

. He coordinated successfully the project Atoms in Super-intense, Femtosecond Pulses involving four experimental laboratories and theoretical groups from France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

, Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 and the Netherlands
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

, to build an ultra high-power laser at the Laboratoire d'Optique Appliquée (Palaiseau
Palaiseau
Palaiseau is a commune in the southern suburbs of Paris, France. It is located from the center of Paris. Palaiseau is a sub-prefecture of the Essonne department and the seat of the Arrondissement of Palaiseau....

 in France).

External links

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