Laboratory of Theoretical physics

Location:

Skunu street 4, Riga, Latvia

Institute of Atomic Physics and Spectroscopy

Mailing address:

Institute of Atomic physics and Spectroscopy,

University of Latvia,

Raina blvd. 19,

LV-1586, Riga,

Latvia

Head of laboratory:  Dr. habil. Phys. Erna Karule (Gailite)

Mailing address: Institute of Physics, Salaspils-1, LV-2169, Latvia

E-mail: karule@latnet.lv    

Tel.: +371-67229747

Fax: +371-67901214

Members:

• Dr. habl. Phys. Imants  Bersons,   Tel.: +371-67229747; E-mail: bersons@latnet.lv ; http://www.lza.lv/scientists/bersonsi.htm 

•  Dr. Phys. Rita Veilande,  Tel.: +371-67229747; E-mail: veilande@latnet.lv

Students:

• Jegor Korovin

• Mihail Vdovičenko
  
   

Research field:

    Atoms in strong electromagnetic field. Multiphoton ionization,  free-free transitions, harmonic generation. Deformation of atomic spectra in external fields. Interactions of atoms with half-cycle pulses, nonlinear equations and solitons.

Research methods: Quantum mechanical and semiclassical.

History of the laboratory:

    Laboratory of theoretical physics is a part of former Laboratory of theoretical physics, which  was  founded in 1958 at the Institute of Physics of Latvian Academy of  Sciences by the Deputy Director Dr. V.Veldre (1926-1967). Starting from sixties of 20th century papers of members of laboratory have been published  in J. Phys. B.: Atomic and Molecular Physics and its members became well known by the international community of atomic physicists as the "Riga's group" (the group of Riga physicists-theorists). The well known members of this group are  Dr.Sc. Raimonds Peterkop (1930-1991) and Dr.Sc. Modris Gailitis (1935-1993). Their papers on Wanier law (threshold law) and on the close coupling methods in electron atom collisions were between the first in this field and are well known by international community. In 1967  V.Veldre, R.Damburg, R.Peterkop, M.Gailitis and E.Karule were awarded with the Latvian State prize for the cycle of papers: " Theory of slow electron collisions with atoms". It was the first State prize awarded to the physicists in Latvia. 

    After Dr. V.Veldre passed away there was a strong pressure to push our laboratory to do, which some  of administration thought is more useful, say, to make some simple calculations for one of the solid state laboratories. We  were interested in basic physical phenomena and its precise mathematical description. The arrival to Riga from StPetersburg  Prof. G.F. Drukarev, who strongly defended our laboratory, saved its exsistence as a laboratory of applied mathematics. In return Laboratory of theoretical Physics never made calculations for any of experimental laboratories of Institute of Physics or University of Latvia but it very successfully collaborated with Dr. E.Andersons atomic theorists group at the Computational Center of University of Latvia. Thanks to the semiempirical wave functions for alkali atoms calculated by this group this group we were able to do our close coupling calculations  

From 1968 to 1992 the Head of laboratory was Dr. R.Damburg (born 1930, since 1996 Professor emeritus).
     Laboratory of theoretical physics of the Institute of Physics has organized two international conferences:

• ICAP VI (VI international Conference on Atomic Physics, Riga 17-22 July 1978). Chair of the local organizing committe Dr. R.Damburg
   

• ECAMP IV (IV European Conference on Atomic Physics, Riga 6-10 April 1992). Chair of the local organizing committee: Dr. E.Karule

In organization of these conferences participated  physicists from the Laboratory of Spectroscopy of University of Latvia.

In 1992 Latvia regained  independence.  Dr. E. Karule was elected by her colleagues to be the Head of laboratory in 1993. The reorganization of science started in Latvia.  Most of the Institutes of the Latvian Academy of Sciences were formally integrated in University of Latvia. In January 1994. Laboratory of Theoretical Physics was moved to the University of Latvia and joined the Laboratory of Spectroscopy.  So in 1994  the Institute of Atomic Physics and Spectroscopy in the University of Latvia was founded. 

Since 1993 science in Latvia is funded by the Latvian Science Council grants. There is  no other state financing.

Recent publications of the laboratory members:

• I.Bersons and Y.Korovin,Electron beam from orientedRydberg atoms irradiated by a half-cycle pulse , J.Phys., B:At.Mol.Opt.Phys. 41 (2008) 155002 (6p.).

• R.Veilande and I.Bersons,Wave packet fractional revivals in one-dimensional Rydberg atom,  J.Phys.B:At.Mol.Opt.Phys. 40 (2007) 2111 (9 p.);

• I.Bērsons, “Elektrodinamika un vakuums”, Zvaigšņotā debess, (2007).

• S. Ozolina, N. Zorina, I. Bersons ,Semiclassical analysis of three-dimensional kicked Rydberg atom, Latvian Journ. of  Phys. and Techn. Sciences 2, 57 (2005);

• R.Veilande and I.Bersons,Revival of ionisation probability for a twice kicked 1D Rydberg atom, , J.Phys.B: At. Mol. Opt. Phys. 38 (2005) S203 (5 p.);

• I.Bersons and R.Veilande, One dimensional twice kicked hydrogen atom,  Applied Physics B: Lasers and Optics 78, 2004, 807-808.

• E.Karule and A.Gailitis, AC-Stark shift of the ground state of atomic hydrogen, Applied Physics B: Lasers and Optics 78, 2004, 817-820.

• I.Bersons and R.Veilande, Analytical investigation of one-dimensional Rydberg atoms interacting with half-cycle pulses, Phys. Rev. A 69, 2004,  43408-43414.

• E. Karule, A.Gailitis, The closed form of the second-order energy shift for the discrete spectrum of atomic hydrogen, J. Phys. B.: At. Mol. Opt. Phys. 37, 2004, 829-841.

• E. Karule,  B. Moine, The general expression for transition amplitude of two-photon ionization of atomic hydrogen,  J.Phys.B.: At. Mol. Opt. Phys. 36, 2003,1963-1969.

• E. Karule  "Survey of Physics in Latvia"  in "Women in Physics" The IUPAP International Conference on Women in Physics, Paris, France, 2002. AIP Conference Proceedings, 628, 189-190.

• I. Bersons, A. Kulsh, and R. Veilande, Atomic wave packets created by short electric pulses.- In: Super-Intense Laser-Atom Physics (Eds. B. Piraux and K. Rzazewski), 2001, 387- 394

• I. Bersons, A. Kulsh, and R. Veilande, Classical form factor for nlm-n’l’m transitions in the hydrogen atom. - Phys. Lett., 2000, A 277, 223- 22

• E. Karule “Closed form for two photon free-free transition matrix elements”, 2000,  Radiation   Physics and Chemistry , 59, p.155-157.

• E. Karule “Transition matrix elements in the closed form for free-free   transitions and ATI of atomic hydrogen in Rydberg States”, 2000  In: “Multiphoton Processes" ICOMPVIII,  8^th International Conference on Multiphoton Processes, AIP Conference Proceedings, Melville, New York, (editors L.F. DiMauro, R.R.Freeman , K.C.Kulander)   p. 3-10.

• I. Bersons and A. Kulsh, Large angular momentum changing in short half-cycle pulse interaction with a Rydberg atom. - Phys. Rev., 1999, A 60, 3144- 3147.

• I. Bersons, A. Kulsh. Excitation and ionization of Rydberg atoms by short half-cycle pulses. - Phys. Rev., 1999, A 59, pp.1399 - 1403

• I. Bersons, A. Kulsh. Transition form factor of the hydrogen Rydberg atom. - Phys. Rev., 1997, A 55, pp.1674 - 1682

• M. Gailitis, A. Gailitis, Photoabsorption of Atomic Hydrogen in an External Electric Field, J. Physics B: Atomic Molecular and Optical Physics, 29, No18, 1996, 4081-4091.

• A. Gailitis and E. Karule,  Hydrogen  Atom  Level-Mixing  in Strong Laser Fields. In: "Resonance Ionization  Spectroscopy", 1994, AIP Press, American Institute of Physics, New York, 411-414.

Research Projects: