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Personal Data

Karen Z. Hatsagortsyan

Citizenship and NationalityArmenian
addressMax-Planck-Institut für Kernphysik (MPIK)
Max Planck Institute for Nuclear Physics
Saupfercheckweg 1
69117 Heidelberg
Germany
emailkaren.hatsagortsyan@mpi-hd.mpg.de
fax+ 49 (0)6221 516-152
phone+ 49 (0)6221 516-160
officeBO351
languages

Armenian - mother tongue,
Russian - fluent,
English - good,
German - fair.

external databasesGoogle Scholar
ORCID
Publons
Researchgate

Education History

2001

Habilitation in Yerevan State University (Yerevan, Armenia), Doctor of Sciences, Physics
Thesis: "On the theory of free-free transitions and free-electron laser"

1989

Kandidate Phys. Math. Sciences in Theoretical Physics, Yerevan State University (Yerevan, Armenia).
Thesis: "On coherent radiation processes of free charged particles", advisor: Professor Dr. H. K. Avetissian

1980-1983

Post-graduate study, Department of Theoretical Physics, Yerevan State University (Yerevan, Armenia)
Topic: "Combined mechanisms of free electron laser, classical bunching and quantum modulation of electron beam"
Advisor: Professor Dr. H. K. Avetissian

1973-1978

Graduated in Physics, Yerevan State University (Yerevan, Armenia). Specialization in theoretical physics.
Diploma thesis: "Formfactors of nucleons in the quark-gluon model"
Advisors: Dr. S. V. Esaybegyan and Professor Dr. S. G. Matinyan (Yerevan Institute of Physics)

Employment History

since 2004

Group Leader, Max Planck Institute for Nuclear Physics, Heidelberg, Germany

1991-2004

Senior Research Associate, Associate Professor, Department of Theoretical Physics, Yerevan State University (Yerevan, Armenia)
Since 1994 - Leading Research Associate in the Plasma Physics Laboratory

1987-1991

Research Associate, Plasma Physics Laboratory, Institute for Applied Problems of Physics, Academy of Science (Yerevan, Armenia)

1985-1987

Research Assistant, Department of General Physics, Yerevan State University (Yerevan, Armenia)

1984-1985

Research Assistant, Institute for Applied Problems of Physics, Academy of Science (Yerevan, Armenia)

1978-1980

Research Assistant, Yerevan State University (Yerevan, Armenia)

Lecturing Experience

2006

A graduate course at Heidelberg University (shared with Dr. D. Bauer):
"Theory of intense laser-matter interaction"

1991-2001

Graduate courses at Yerevan State University: "Electrodynamics of Continuous Media", "Oscillations and Waves", "Nonlinear Physics", "Radiative Processes", "Plasma Physics", "Plasma Electronics"

Awards and Fellowships

2016

American Physical Society, Outstanding Referee

2015

Elsevier Outstanding Reviewer

2004

Max Planck Fellowship, Max Planck Institute for Nuclear Physics, Heidelberg, Germany, from July 2004 to June 2007

2003

Return Fellowship of the Alexander von Humboldt Foundation, Germany, from September 2003 to June 2004

2002

Georg Forster Fellowship of the Alexander von Humboldt Foundation, Germany, at Theoretische Quantendynamik, Freiburg University (Freiburg, Germany) from February 2, 2002 to May 31, 2003

1999

DAAD (German Foundation for Academic Exchange) grant for a Study Visit at the division Theoretische Quantendynamik, Freiburg University (Freiburg, Germany) from September 25 to November 25, 1998

1998

Travel Grant of the Open Society Institute for initiation of collaboration, spent at Theoretische Quantendynamik, Freiburg University (Freiburg, Germany) from October 10 to November 10, 1998

1993

Individual Grant of the International Science Foundation (Soros)

Community Service

Referee for many physics journals [APS, IOP, OSA, Elsevier, Nature, Science, etc] and funding agencies  [U.S. Department of Energy (DOE); The Fund for Scientific Research, Belgium;  National Science Center, Poland; ETH Zurich Research Commission]

In 2016-2024  Editorial Board Member for the journal "Scientific Reports", Nature Publishing Group.

Research Interests

Strong field physics: relativistic and nondipole regimes, Coulomb effects, tunneling time delay.
Nonlinear QED, polarization, and radiation reaction effects in strong laser fields.
In Institute for Applied  Problems of Physics: Low-temperature acousto-plasma physics.
In Yerevan State University: Stimulated radiative processes with free electrons: free electron lasers and free-free transitions.

Submitted papers

Highly polarized energetic electrons via intense laser-irradiated tailored targets, Xiaofei Shen, Zheng Gong, K. Z. Hatsagortsyan, and C. H. Keitel, arXiv:2406.05493 [physics.plasm-ph]

Fermionic signal of vacuum polarization in strong laser fields, Nan Dai, K. Z. Hatsagortsyan, C. H. Keitel, and Yue-Yue Chen, arXiv:2401.11168 [hep-th]

Unveiling sub-barrier electron dynamics in strong field tunneling,T. Khurelbaatar, M. Klaiber, S. Sukiasyan, K. Z. Hatsagortsyan, C. H. Keitel, and Dong Eon Kim

Photoelectron Polarization Vortexes in Strong-Field Ionization, Pei-Lun He, Zhao-Han Zhang,  K. Z. Hatsagortsyan, and C. H. Keitel, arXiv:2402.11825 [physics.atom-ph, quant-ph]

Atomic polarization and Stark-shift in relativistic strong field ionization, M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel, arXiv: 2403.11285 [physics.atom-ph]

 

Publications in MPIK

Google Scholar
 
124 Nonspreading relativistic electron wavepacket in a strong laser field

A. G. Campos, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Research 6, 023040 (2024)

123 Electron Slingshot Acceleration in Relativistic Preturbulent Shocks Explored via Emitted Photon Polarization

Z. Gong, X. Shen, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 131, 225101 (2023)
 MPIK press release: A slingshot for electrons in astrophysical plasma shocks
 MPIK-Pressemitteilung: Eine Schleuder für Elektronen in astrophysikalischen Plasma-Stoßwellen

122 Laser-driven lepton polarization in the quantum radiation-dominated reflection regime

K. Zhuang, Y. Chen, Y. Li, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review D 108, 033001 (2023)

121 Double-Slit Interference in the Ion Dynamics of Dissociative Photoionization

P. He, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 131, 013201 (2023)

120 Strong signature of one-loop self-energy in polarization resolved nonlinear Compton scattering

Y. Li, Y. Chen, K. Z. Hatsagortsyan, A. Di Piazza, M. Tamburini, and C. H. Keitel
Physical Review D 107, 116020 (2023)

119 Sub-barrier recollisions and the three classes of tunneling time delays in strong-field ionization

M. Klaiber, D. Bakucz Canário, and K. Z. Hatsagortsyan
Physical Review A 107, 053103 (2023)

118 All-optical ultrafast spin rotation for relativistic charged particle beams

W. Wei, F. Wan, Y. I. Salamin, J. Ren, K. Z. Hatsagortsyan, C. H. Keitel, J. Li, and Y. Zhao
Physical Review Research 5, 023030 (2023)

117 Relativistic analytical R-matrix theory for strong-field ionization

M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 107, 023107 (2023)

116 Electron Polarization in Ultrarelativistic Plasma Current Filamentation Instabilities

Z. Gong, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 130, 015101 (2023)
 MPIK press release: Electron polarization for probing plasma current filamentation instability
 MPIK-Pressemitteilung: Elektronenpolarisation zur Sondierung von Instabilitäten in Plasmastrom-Filamentierung

115 Reconciling Conflicting Approaches for the Tunneling Time Delay in Strong Field Ionization

M. Klaiber, Q. Z. Lv, S. Sukiasyan, D. Bakucz Canário, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 129, 203201 (2022)

114 Generation of arbitrarily polarized GeV lepton beams via nonlinear Breit-Wheeler process

K. Xue, R. Guo, F. Wan, R. Shaisultanov, Y. Chen, Z. Xu, X. Ren, K. Z. Hatsagortsyan, C. H. Keitel, and J. Li
Fundamental Research 2, 539-545 (2022)

113 Tunneling ionization in ultrashort laser pulses: Edge effect and remedy

M. Klaiber, Q. Z. Lv, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 105, 063109 (2022)

112 Electron spin- and photon polarization-resolved probabilities of strong-field QED processes

Y. Chen, K. Z. Hatsagortsyan, C. H. Keitel, and R. Shaisultanov
Physical Review D 105, 116013 (2022)

111 Subcycle time-resolved nondipole dynamics in tunneling ionization

M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 105, 053107 (2022)

110 Nondipole Time Delay and Double-Slit Interference in Tunneling Ionization

P. He, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 128, 183201 (2022)
 MPIK press release: Molecular double-slit and quantum tunnelling in intense laser light
 MPIK-Pressemitteilung: Doppelspalt und Tunneleffekt bei Molekülen im intensiven Laserlicht

109 Deciphering in situ electron dynamics of ultrarelativistic plasma via polarization pattern of emitted γ-photons

Z. Gong, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Research 4, L022024 (2022)

108 Helicity Transfer in Strong Laser Fields via the Electron Anomalous Magnetic Moment

Y. Li, Y. Chen, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 128, 174801 (2022)

107 Nondipole Coulomb sub-barrier ionization dynamics and photon momentum sharing

P. He, M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 105, L031102 (2022)

106 Quasimonoenergetic Proton Acceleration via Quantum Radiative Compression

F. Wan, W. Wang, Q. Zhao, H. Zhang, T. Yu, W. Wang, W. Yan, Y. Zhao, K. Z. Hatsagortsyan, C. H. Keitel, S. V. Bulanov, and J. Li
Physical Review Applied 17, 024049 (2022)

105 High-Brilliance Ultranarrow-Band X Rays via Electron Radiation in Colliding Laser Pulses

Q. Z. Lv, E. Raicher, C. H. Keitel, and K. Z. Hatsagortsyan
Physical Review Letters 128, 024801 (2022)

104 Photon polarization effects in polarized electron–positron pair production in a strong laser field

Y. Dai, B. Shen, J. Li, R. Shaisultanov, K. Z. Hatsagortsyan, C. H. Keitel, and Y. Chen
Matter and Radiation at Extremes 7, 014401 (2021)

103 Retrieving Transient Magnetic Fields of Ultrarelativistic Laser Plasma via Ejected Electron Polarization

Z. Gong, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 127, 165002 (2021)

102 Role of reflections in the generation of a time delay in strong-field ionization

D. Bakucz Canário, M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 104, 033103 (2021)

101 Ultrarelativistic electrons in counterpropagating laser beams

Q. Z. Lv, E. Raicher, C. H. Keitel, and K. Z. Hatsagortsyan
New Journal of Physics 23, 065005 (2021)

100 Construction of Dirac spinors for electron vortex beams in background electromagnetic fields

A. G. Campos, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Research 3, 013245 (2021)

99 Anomalous violation of the local constant field approximation in colliding laser beams

Q. Z. Lv, E. Raicher, C. H. Keitel, and K. Z. Hatsagortsyan
Physical Review Research 3, 013214 (2021)

98 Sub-barrier pathways to Freeman resonances

M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 102, 053105 (2020)

97 Stochasticity in radiative polarization of ultrarelativistic electrons in an ultrastrong laser pulse

R. Guo, Y. Wang, R. Shaisultanov, F. Wan, Z. Xu, Y. Chen, K. Z. Hatsagortsyan, and J. Li
Physical Review Research 2, 033483 (2020)

96 High-energy γ-photon polarization in nonlinear Breit-Wheeler pair production and γ polarimetry

F. Wan, Y. Wang, R. Guo, Y. Chen, R. Shaisultanov, Z. Xu, K. Z. Hatsagortsyan, C. H. Keitel, and J. Li
Physical Review Research 2, 032049(R) (2020)

95 Many-body effects for excitonic high-order wave mixing in monolayer transition metal dichalcogenides

H. K. Avetissian, G. F. Mkrtchian, and K. Z. Hatsagortsyan
Physical Review Research 2, 023072 (2020)

94 Nonlinear QED in an ultrastrong rotating electric field: Signatures of the momentum-dependent effective mass

E. Raicher and K. Z. Hatsagortsyan
Physical Review Research 2, 013240 (2020)

93 Polarized Ultrashort Brilliant Multi-GeV γ Rays via Single-Shot Laser-Electron Interaction

Y. Li, R. Shaisultanov, Y. Chen, F. Wan, K. Z. Hatsagortsyan, C. H. Keitel, and J. Li
Physical Review Letters 124, 014801 (2020)

92 Ultrarelativistic polarized positron jets via collision of electron and ultraintense laser beams

F. Wan, R. Shaisultanov, Y. Li, K. Z. Hatsagortsyan, C. H. Keitel, and J. Li
Physics Letters B 800, 135120 (2019)

91 Polarized Positron Beams via Intense Two-Color Laser Pulses

Y. Chen, P. He, R. Shaisultanov, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 123, 174801 (2019)
 MPIK-Pressemitteilung: Laserblitze für polarisierte Elektronen- und Positronenstrahlen
 pro-physik.de: Polarisationstransfer via Laserpuls
 physik.cosmos-indirekt.de: Laserblitze für polarisierte Elektronen- und Positronenstrahlen
 chemie.de: Laserblitze für polarisierte Elektronen- und Positronenstrahlen

90 Holographic interferences in strong-field ionization beyond the dipole approximation: The influence of the peak and focal-volume-averaged laser intensities

B. Willenberg, J. Maurer, U. Keller, J. Daněk, M. Klaiber, N. Teeny, K.Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 100, 033417 (2019)

89 Electron Polarimetry with Nonlinear Compton Scattering

Y. Li, R. Guo, R. Shaisultanov, K. Z. Hatsagortsyan, and J. Li
Physical Review Applied 12, 014047 (2019)

88 Imprint of the stochastic nature of photon emission by electrons on the proton energy spectra in the laser-plasma interaction

F. Wan, K. Xue, Z. Dou, K. Z. Hatsagortsyan, W. Yan, D. Khikhlukha, S. V Bulanov, G. Korn, Y. Zhao, Z. Xu, and J. Li
Plasma Physics and Controlled Fusion 61, 084010 (2019)

87 Semiclassical limitations for photon emission in strong external fields

E. Raicher, S. Eliezer, C. H. Keitel, and K. Z. Hatsagortsyan
Physical Review A 99, 052513 (2019)

86 Ultrarelativistic Electron-Beam Polarization in Single-Shot Interaction with an Ultraintense Laser Pulse

Y. Li, R. Shaisultanov, K. Z. Hatsagortsyan, F. Wan, C. H. Keitel, and J. Li
Physical Review Letters 122, 154801 (2019)
 MPIK-Pressemitteilung: Laserblitze für polarisierte Elektronen- und Positronenstrahlen
 pro-physik.de: Polarisationstransfer via Laserpuls
 physik.cosmos-indirekt.de: Laserblitze für polarisierte Elektronen- und Positronenstrahlen
 chemie.de: Laserblitze für polarisierte Elektronen- und Positronenstrahlen

85 Generation of twisted γ-ray radiation by nonlinear Thomson scattering of twisted light

Y. Chen, K. Z. Hatsagortsyan, and C. H. Keitel
Matter and Radiation at Extremes 4, 024401 (2019)

84 Role of high ponderomotive energy in laser-induced nonsequential double ionization

T. Shaaran, N. Camus, J. Dura, L. Fechner, A. Thai, A. Britz, M. Baudisch, T. Steinle, A. Senftleben, C. D. Schröter, J. Ullrich, T. Pfeifer, C. H. Keitel, J. Biegert, K. Z. Hatsagortsyan, and R. Moshammer
Physical Review A 99, 023421 (2019)

83 Determining the carrier-envelope phase of relativistic laser pulses via electron-momentum distribution

Y. Li, J. Li, K. Z. Hatsagortsyan, Y. Zhao, B. Zhang, Y. Li, Y. Liu, Z. Zhang, Z. Xu, and C. H. Keitel
Physical Review A 99, 013850 (2019)

82 High-energy direct photoelectron spectroscopy in strong-field ionization

P. He, M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 98, 053428 (2018)

81 Electron-angular-distribution reshaping in the quantum radiation-dominated regime

Y. Li, Y. Zhao, K. Z. Hatsagortsyan, C. H. Keitel, and J. Li
Physical Review A 98, 052120 (2018)

80 γ-Ray Beams with Large Orbital Angular Momentum via Nonlinear Compton Scattering with Radiation Reaction

Y. Chen, J. Li, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 121, 074801 (2018)

79 Coulomb effect in laser-induced recollision excitation

T. Shaaran, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 98, 023410 (2018)

78 Analytical approach to Coulomb focusing in strong-field ionization. II. Multiple recollisions

J. Daněk, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 97, 063410 (2018)

77 Analytical approach to Coulomb focusing in strong-field ionization. I. Nondipole effects

J. Daněk, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 97, 063409 (2018)

76 Interplay between Coulomb-focusing and non-dipole effects in strong-field ionization with elliptical polarization

J. Daněk, M. Klaiber, K. Z. Hatsagortsyan, C. H. Keitel, B. Willenberg, J. Mauer, B. W. Mayer, C. R. Phillips, L. Gallmann, and U. Keller
Journal of Physics B: Atomic, Molecular and Optical Physics 51, 114001 (2018)

75 Single-Shot Carrier-Envelope Phase Determination of Long Superintense Laser Pulses

J. Li, Y. Chen, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 120, 124803 (2018)

74 Probing the ionization wave packet and recollision dynamics with an elliptically polarized strong laser field in the nondipole regime

J. Mauer, B. Willenberg, J. Daněk, B. W. Mayer, C. R. Phillips, L. Gallmann, M. Klaiber, K. Z. Hatsagortsyan, C. H. Keitel, and U. Keller
Physical Review A 97, 013404 (2018)

73 Under-the-Tunneling-Barrier Recollisions in Strong-Field Ionization

M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 120, 013201 (2018)

72 Experimental Evidence for Quantum Tunneling Time

N. Camus, E. Yakaboylu, L. Fechner, M. Klaiber, M. Laux, Y. Mi, K. Z. Hatsagortsyan, T. Pfeifer, C. H. Keitel, and R. Moshammer
Physical Review Letters 119, 023201 (2017)
 MPG-Pressemitteilung: Zeitmessung im Quantentunnel
 MPIK-Pressemitteilung: Quantenmechanisches Tunneln braucht Zeit
 Spektrum.de: Wie lange dauert der Tunneleffekt?

71 Limits of Strong Field Rescattering in the Relativistic Regime

M. Klaiber, K. Z. Hatsagortsyan, J. Wu, S. S. Luo, P. Grugan, and B. C. Walker
Physical Review Letters 118, 093001 (2017)

70 Strong-field ionization via a high-order Coulomb-corrected strong-field approximation

M. Klaiber, J. Daněk, E. Yakaboylu, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 95, 023403 (2017)

69 Angle-resolved stochastic photon emission in the quantum radiation-dominated regime

J. Li, Y. Chen, K. Z. Hatsagortsyan, and C. H. Keitel
Scientific Reports 7, 11556 (2017)

68 Fields of an ultrashort tightly focused laser pulse

J. Li, Y. Salamin, K. Z. Hatsagortsyan, and C. H. Keitel
Journal of the Optical Society of America B-Optical Physics 33, 405-411 (2016)

67 Attosecond Gamma-Ray Pulses via Nonlinear Compton Scattering in the Radiation-Dominated Regime

J. Li, K. Z. Hatsagortsyan, B. J. Galow, and C. H. Keitel
Physical Review Letters 115, 204801 (2015)

66 Momentum partition between constituents of exotic atoms during laser-induced tunneling ionization

D. Cricchio, E. Fiordilino, and K. Z. Hatsagortsyan
Physical Review A 92, 023408 (2015)

65 Above-threshold ionization with highly charged ions in super-strong laser fields: III. Spin effects and its dependence on laser polarization

E. Yakaboylu, M. Klaiber, and K. Z. Hatsagortsyan
Physical Review A 91, 063407 (2015)

64 High-Energy Recollision Processes of Laser-Generated Electron-Positron Pairs

S. Meuren, K. Z. Hatsagortsyan, C. H. Keitel, and A. Di Piazza
Physical Review Letters 114, 143201 (2015)

63 Tunneling Dynamics in Multiphoton Ionization and Attoclock Calibration

M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 114, 083001 (2015)

62 Polarization-operator approach to pair creation in short laser pulses

S. Meuren, K. Z. Hatsagortsyan, C. H. Keitel, and A. Di Piazza
Physical Review D 91, 013009 (2015)

61 Spin-asymmetric laser-driven relativistic tunneling from ρ states

M. Klaiber and K. Z. Hatsagortsyan
Physical Review A: Atomic, Molecular, and Optical Physics 90, 063416 (2014)

60 The Wigner time delay for laser induced tunnel-ionization via the electron propagator

E. Yakaboylu, M. Klaiber, and K. Z. Hatsagortsyan
Physical Review A 90, 012116 (2014)

59 Robust Signatures of Quantum Radiation Reaction in Focused Ultrashort Laser Pulses

J. Li, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 113, 044801 (2014)

58 Spin dynamics in relativistic ionization with highly charged ions in super-strong laser fields

M. Klaiber, E. Yakaboylu, C. Müller, H. Bauke, G. G. Paulus, and K. Z. Hatsagortsyan
Journal of Physics B 47, 065603 (2014)
 Europhysics News: Spin flip in ionization of highly charged ions (Vol. 45 No.3)

57 Quasiclassical propagator of a relativistic particle via the path-dependent gauge potential

E. Yakaboylu, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 89, 032115 (2014)

56 Relativistic features and time delay of laser-induced tunnel-ionization

E. Yakaboylu, M. Klaiber, H. Bauke, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 88, 063421 (2013)

55 Attosecond pulses at kiloelectronvolt photon energies from high-order-harmonic generation with core electrons

C. Buth, F. He, J. H. Ullrich, C. H. Keitel, and K. Z. Hatsagortsyan
Physical Review A 88, 033848 (2013)

54 Radiation-Reaction-Force-Induced Nonlinear Mixing of Raman Sidebands of an Ultraintense Laser Pulse in a Plasma

N. Kumar, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 111, 105001 (2013)

53 Under-the-barrier dynamics in laser-induced relativistic tunneling

M. Klaiber, E. Yakaboylu, H. Bauke, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 110, 153004, 1-5 (2013)
 MPIK-Pressemitteilung: Tunneleffekt relativistisch betrachtet
 MPG-Pressemitteilung: Tunneln nahe der Lichtgeschwindigkeit
 idw press release: Relativistic tunnelling

52 Above-threshold ionization with highly charged ions in superstrong laser fields. II. Relativistic Coulomb-corrected strong-field approximation

M. Klaiber, E. Yakaboylu, and K. Z. Hatsagortsyan
Physical Review A 87, 023418, 1-11 (2013)

51 Above-threshold ionization with highly charged ions in superstrong laser fields. I. Coulomb-corrected strong-field approximation

M. Klaiber, E. Yakaboylu, and K. Z. Hatsagortsyan
Physical Review A 87, 023417, 1-8 (2013)

50 Enhancing the high-order harmonic generation yield within a specified spectral window via electron wave-packet engineering

M. C. Kohler and K. Z. Hatsagortsyan
Journal of the Optical Society of America B-Optical Physics 30, 57-61 (2012)

49 Extremely high-intensity laser interactions with fundamental quantum systems

A. Di Piazza, C. Müller, K. Z. Hatsagortsyan, and C. H. Keitel
Reviews of Modern Physics 84, 1177-1228 (2012)

48 Optimization of the recollision step in high-order harmonic generation

M. Klaiber, M. C. Kohler, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 85, 063829, 1-8 (2012)

47 Manipulating the Annihilation Dynamics of Positronium via Collective Radiation

N. Cui, M. Macovei, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 108, 243401, 1-5 (2012)

46 Coulomb focusing in above-threshold ionization in elliptically polarized midinfrared strong laser fields

C. Liu and K. Z. Hatsagortsyan
Physical Review A 85, 023413, 1-10 (2012)

45 Macroscopic aspects of relativistic x-ray-assisted high-order-harmonic generation

M. Kohler and K. Z. Hatsagortsyan
Physical Review A 85, 023819, 1-11 (2012)

44 Coherent x-ray generation from below-threshold harmonics

J. Liu, M. C. Kohler, C. H. Keitel, and K. Z. Hatsagortsyan
Physical Review A 84, 063817 (2011)

43 Scattering of intense laser radiation by a single-electron wave packet

J. P. Corson, J. Peatross, C. Müller, and K. Z. Hatsagortsyan
Physical Review A 84, 053831 (2011)

42 Bragg Scattering of Light in Vacuum Structured by Strong Periodic Fields

G. Y. Kryuchkyan and K. Z. Hatsagortsyan
Physical Review Letters 104, 053604 (2011)

41 Time analysis of above-threshold ionization in extreme-ultraviolet laser pulses

H. Ebadi, C. H. Keitel, and K. Z. Hatsagortsyan
Physical Review A 83, 063418 (2011)

40 Streaking at high energies with electrons and positrons

A. Ipp, J. Evers, C. H. Keitel, and K. Z. Hatsagortsyan
Physics Letters B 702, 383-387 (2011)

39 Wavelength and intensity dependence of multiple forward scattering of electrons at above-threshold ionization in mid-infrared strong laser fields

C. Liu and K. Z. Hatsagortsyan
Journal of Physics B: Atomic, Molecular and Optical Physics 44, 095402 (2011)

38 Phase-matched coherent hard X-rays from relativistic high-order harmonic generation

M. Kohler, M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Europhysics letters 94, 14002 (2011)

37 Attochirp-free High-order Harmonic Generation

M. C. Kohler, C. H. Keitel, and K. Z. Hatsagortsyan
Optics Express 19, 4411-4420 (2011)
 Nature Photonics Research Highlights: Our choice from the recent literature

36 Quantum Radiation Reaction Effects in Multiphoton Compton Scattering

A. Di Piazza, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 105, 220403, 1-4 (2010)

35 Origin of Unexpected Low Energy Structure in Photoelectron Spectra Induced by Midinfrared Strong Laser Fields

C. P. Liu and K. Z. Hatsagortsyan
Physical Review Letters 105, 113003 (2010)

34 Laser-guided relativistic quantum dynamics

C. Liu, M. C. Kohler, K. Z. Hatsagortsyan, C. Müller, and C. H. Keitel
New Journal of Physics 11, 105045 (2009)

33 Exotic atoms in superintense laser fields : applications in atomic, nuclear, and particle physics

C. Müller, A. Shahbaz, T. J. Bürvenich, K. Z. Hatsagortsyan, and C. H. Keitel
European Physical Journal - Special Topics 175, 187-190 (2009)

32 QED vacuum effects in intense laser fields

A. Di Piazza and K. Z. Hatsagortsyan
European Physical Journal - Special Topics 175, 181-185 (2009)

31 Relativistic nonperturbative above-threshold phenomena in strong laser fields

C. Müller, K. Z. Hatsagortsyan, M. Ruf, S. J. Müller, H. G. Hetzheim, M. C. Kohler, and C. H. Keitel
Laser Physics 19, 1743-1752 (2009)

30 Strong Signatures of Radiation Reaction below the Radiation-Dominated Regime

A. Di Piazza, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 102, 254802 (2009)

29 Lepton pair production in high-frequency laser fields

C. Müller, C. Deneke, M. Ruf, G. R. Mocken, K. Z. Hatsagortsyan, and C. H. Keitel
Laser Physics 19, 791-796 (2009)

28 Pair Production in Laser Fields Oscillating in Space and Time

M. Ruf, G. R. Mocken, C. Müller, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 102, 080402 (2009)

27 Laser photon merging in proton laser collisions

A. Di Piazza, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 78, 062109 (2008)

26 Quantum vacuum effects in strong laser beams

A. Di Piazza and K. Z. Hatsagortsyan
Plasma Physics and Controlled Fusion 50, 124035 (2008)

25 Muon pair creation from positronium in a linearly polarized laser field

C. Müller, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 78, 033408, 1-19 (2008)

24 Quantum interaction among intense laser beams in vacuum

A. Di Piazza and K. Z. Hatsagortsyan
European Physical Journal-Special Topics 160, 147-155 (2008)

23 Laser-driven relativistic recollisions

K. Z. Hatsagortsyan, M. Klaiber, C. Müller, M. C. Kohler, and C. H. Keitel
Journal of the Optical Society of America B-Optical Physics 25, B92-B103 (2008)

22 Photoemission of a single-electron wave packet in a strong laser field

J. Peatross, C. Müller, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 100, 153601, 1-4 (2008)

21 High-energy, nuclear and QED processes in strong laser fields

C. Müller, A. Di Piazza, A. Shahbaz, T. J. Bürvenich, J. Evers, K. Z. Hatsagortsyan, and C. H. Keitel
Laser Physics 18, 175-184 (2008)

20 Coherent hard x rays from attosecond pulse train-assisted harmonic generation

M. Klaiber, K. Z. Hatsagortsyan, C. Müller, and C. H. Keitel
Optics Letters 33, 411-413 (2008)

19 Particle physics with a laser-driven positronium atom

C. Müller, K. Z. Hatsagortsyan, and C. H. Keitel
Physics Letters B 659, 209-213 (2008)

18 Nonperturbative vacuum-polarization effects in proton-laser collisions

A. Di Piazza, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 100, 010403 (2008)

17 Fully relativistic laser-induced ionization and recollision processes

M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 75, 063413 (2007)

16 Nonlinear interaction of strong laser fields in vacuum

A. Di Piazza, K. Z. Hatsagortsyan, and C. H. Keitel
Laser Physics 17, 345-349 (2007)

15 Enhancement of vacuum polarization effects in a plasma

A. Di Piazza, K. Z. Hatsagortsyan, and C. H. Keitel
Physics of Plasma 14, 032102 (2007)

14 Relativistic ionization rescattering with tailored laser pulses

M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 74, 051803, 1-4 (2006)

13 Muon pair creation from positronium in a circularly polarized laser field

C. Müller, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review D 74, 074017, 1-16 (2006)

12 Microscopic laser-driven high-energy colliders

K. Z. Hatsagortsyan, C. Müller, and C. H. Keitel
Europhysics Letters 76, 29-35 (2006)

11 Light Diffraction by a Strong Standing Electromagnetic Wave

A. Di Piazza, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 97, 083603, 1-4 (2006)

10 Polarization-operator approach to electron-positron pair production in combined laser and Coulomb fields

A. I. Milstein, C. Müller, K. Z. Hatsagortsyan, U. D. Jentschura, and C. H. Keitel
Physical Review A 73, 062106 (2006)

9 Gauge-invariant relativistic strong-field approximation

M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 73, 053411 (2006)

8 Relativistic high-power laser–matter interactions

Y. I. Salamin, S. X. Hu, K. Z. Hatsagortsyan, and C. H. Keitel
Physics Reports 427, 41-155 (2006)

7 Harmonic generation from laser-driven vacuum

A. Di Piazza, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review D 72, 085005 (2005)

6 Thin crystal layers in superstrong laser fields: Dynamics and coherent x-ray generation

K. Z. Hatsagortsyan and C. H. Keitel
Physical Review A 72, 023812 (2005)

5 Above-threshold ionization beyond the dipole approximation

M. Klaiber, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review A 71, 033408, 1-7 (2005)

4 Positronium in Intense Laser Fields

B. Henrich, K. Z. Hatsagortsyan, and C. H. Keitel
Physical Review Letters 93, 013601 (2004)

3 Phase-matched high-harmonic generation from laser-driven crystals

K. Z. Hatsagortsyan and C. H. Keitel
Journal of Physics B: Atomic, Molecular and Optical Physics 35, L175-L180 (2002)

2 Spin and radiation in intense laser fields

M. Walser, D. J. Urbach, K. Z. Hatsagortsyan, S. Hu, and C. H. Keitel
Physical Review A 65, 043410 (2002)

1 X-Ray Amplification by Laser Controlled Coherent Bremsstrahlung

K. Z. Hatsagortsyan and C. H. Keitel
Physical Review Letters 86, 2277-2280 (2001)

Earlier Publications

20. A. K. Avetissian, K. Z. Hatsagortsian, G. F. Mkrtchian and Kh. V. Sedrakian,
Nonlinear Compton scattering of strong laser radiation on channeled particles in a crystal
Phys. Lett. A 299, 331, (2002)

19. H. K. Avetissian, K. Z. Hatsagortsian, A. G. Markossian and S. V. Movsissian,
Generalized eikonal wave function of a Dirac particle interacting with an arbitrary potential and radiation fields
Phys. Rev. A 59, 549 (1999)

18. H.K. Avetissian, , A.Kh. Bagdasarian, , K.Z. Hatsagortsian and , G.F. Mkrtchian,
Quantum theory of the nonlinear stimulated Cherenkov process
Phys.Lett. A 246, 16 (1998)

17. H. K. Avetissian, A. Kh. Bagdasarian, K. Z. Hatsagortsian and G. F. Mkrtchian,
Quantum theory of induced Cherenkov process at exact resonance
Phys.Lett. A 244, 25 (1998)

16. K. Z. Hatsagortsian and , A. L. Khachatryan,
The effect of the energy and angular spread of electron beam on the stimulated coherent bremsstrahlung gain in a crystal
Opt. Comm. 146, 114 (1998)

15. H. K. Avetissian, K. Z. Hatsagortsian, G. F. Mkrtchian and Kh. V. Sedrakian,
Nonlinear amplification of X-ray channeling radiation"
Phys. Rev. A 56, 4121 (1997)

14. H. K. Avetissian, K. Z. Hatsagortsian and G. F. Mkrtchian,
Stimulated phenomena in the surface Cherenkov process by unmagnetized electron beam
IEEE J.Quant.El. 33, 897 (1997)

13. K. Z. Hatsagortsian and T. R. Hovhannissian,
Stimulated resonant bremsstrahlung in the high-frequency electromagnetic pump field
Phys.Lett. A 221, 5 (1996)

12. H. K. Avetissian, A. K. Avetissian, K. Z. Hatsagortsian and Kh. V. Sedrakian,
Quantum modulation of beams of channeled electrons and positrons by a transverse electromagnetic wave
Zh.Exp. Teor. Fiz. (Sov. JETP) 109, 1159 (1996) [Sov. Phys. JETP 82, 622 (1996)]

11. H. K. Avetissian, K. Z. Hatsagortsian, G. F. Mkrtchian and Kh. V. Sedrakian,
Multiphoton transitions for a channeled particle interacting with a strong electromagnetic wave
Phys.Lett. A 206, 141 (1995)

10. K. Z. Hatsagortsian and G. A. Galechyan,
Acoustic discontraction of gas discharge
Laser Physics 4, 502 (1994)

9. H. K. Avetissian, A. K. Avetissian, K. Z. Hatsagortsian and S. V. Movsissian,
The exact theory of single photon stimulated bremsstrahlung in the Coulomb potential
J. Phys. B 23, 4207 (1990)

8. A. R. Mkrtchyan, K. Z. Hatsagortsian, G. A. Galechyan and E. G. Divanian,
Influence of acoustic waves on plasma column properties
Acustica 69, 124 (1989)

7. H. K. Avetissian, A. K. Avetissian and K. Z. Hatsagortsian,
Superluminal Compton-laser
Phys.Lett. A 137, 463 (1989)

6. H. K. Avetissian, A. K. Avetissian, K. Z. Hatsagortsian and Kh. V. Sedrakian,
Stimulated energy exchange of channeled particle with a transverse electromagnetic wave
Dokl. AN Arm. SSR [Proc. Arm. Acad. Sci.] 85, 164 (1987)

5. H. K. Avetissian and K. Z. Hatsagortsian,
The reduction of the energy or angular spread of charged particles beam by laser pulse
Izv. AN Arm. SSR  [J. Contemp. Phys.]  232, 94 (1987)

4. H.K. Avetissian, A.K. Avetissian, K.Z. Hatsagortsian and S. V. Movsissian,
Classical dynamics of stimulated bremsstrahlung in the Coulomb potential
Phys.Lett. A 117, 111 (1986)

3. H. K. Avetissian and K. Z. Hatsagortsian,
Amplification of electromagnetic wave by the cyclotron resonance process in medium
Zh.Tekh.Fiz. 54, 2347 (1984) [Soviet Physics - Technical Physics 29, 1381 (1984)]

2. K. Z. Hatsagortsian,
Modulation of electron beam by the stimulated bremsstrahlung process on atoms
Zh.Tekh.Fiz. 54 , 1057 (1984) [Soviet Physics - Technical Physics 29, 601 (1984)]

1. I. G. Aznauryan, S. V. Esaybegyan, K. Z. Hatsagortsian and N. L. Ter-Isaakyan,
On the asymptotic of baryon form-factors in quark-gluons model [Diploma Thesis]
Preprint of the Yerevan Institute of Physics (67)-78, 18 p. (1978)