Oleksiy Kolezhuk




Oleksiy Kolezhuk

POSITION
Professor

WORK EXPERIENCE
1988–1995
Research Fellow
Institute for Metal Physics, Academy of Sciences of Ukraine, Kyiv (Ukraine)

1991
PhD in Solid State Physics
Institute of Magnetism, National Academy of Sciences and Ministry of Education of Ukraine, Kyiv (Ukraine)

1995–2011
Senior Research Fellow
Institute for Metal Physics, Academy of Sciences of Ukraine, Kyiv (Ukraine)

1997–2005, 2006-2007
Research Fellow, from 2002 Lecturer (Privat-Dozent)
Institute for Theoretical Physics, University of Hannover , Hannover (Germany)

2001
Dr. habil. in Physics
University of Hannover , Hannover (Germany)

2004
D.Sc. in Physics
Institute of magnetism, Kyiv (Ukraine)

2005–2006
Visiting Scholar
Department of Physics, Harvard University

2007–2009
Lecturer (Privat-Dozent)
Institute for Theoretical Physics C, RWTH Aachen University (Germany)

2010–2011
Professor (part-time)
Taras Shevchenko national University of Kyiv, Kyiv (Ukraine)

2012–Present
Leading Research Fellow (part-time)
Institute of Magnetism, National Academy of Sciences and Ministry of Education of Ukraine, Kyiv (Ukraine)

2012–Present
Professor, Institute of High Technologies
Taras Shevchenko National University of Kyiv, Kyiv (Ukraine)

AWARDS, GRANTS


2000-2003
PI in the joint project "Low-dimensional magnets in strong magnetic fields", Volkswagen Foundation (Volkswagen-Stiftung)

2004-2009
Heisenberg Fellowship from German Research Foundation (DFG)

2014
State Prize of Ukraine in Science and Technology

Quantum Magnetism

Research Fields:
Physics

Previous and Current Research

Current Research:

  • low-dimensional quantum magnets:
    • quantum phase transitions caused by competing interactions (frustration, anisotropy, 3D coupling, ring exchange, etc.)
    • exotic states in quantum magnets (effects of deconfined criticality, broken chiral or time reversal symmetry, spin nematics, topological order)
    • quantum magnets in high magnetic fields: excitation spectra, effective field-theoretical description, role of impurities
  • cold atoms in optical lattices:
    • multicomponent Bose gases, spinor Bose condensates, polar fermions in optical lattices

Past research:

  • matrix product (MP) states in one-dimensional spin systems
    • general construction of MP states with controlled quantum numbers
    • MP-solvable models of spin chains and ladders
  • quantum tunneling in mesoscopic magnetic systems:
    • tunneling in topological textures
    • influence of external field and of the Dzyaloshinskii-Moriya interaction
  • solitons in one- and two-dimensional spin and lattice systems:
    • soliton diffusion;
    • soliton contribution into thermodynamic quantities and response functions;
    • solitons with internal degrees of freedom;
  • models of polytypism

Methodological and Technical Expertise

Field-theoretical methods in condensed matter.

Selected Publications


B.A.Ivanov and A.K.Kolezhuk.
Quantum tunneling of magnetization in a small-area domain wall.
JETP Letters, 60(11), 805-808 (1994)

Kolezhuk A.K., Mikeska H.-J.
Non-Haldane spin liquid models with exact ground states
Phys. Rev. Lett. vol.80(12), p.2709-2712 (1998)

Kolezhuk A.K., Vekua T.
Field-induced chiral phase in isotropic frustrated spin chains
Phys. Rev. B vol.72, 094424 (2005)

Kolezhuk A.K.,Sachdev S, Biswas R.R., Chen P.
Theory of quantum impurities in spin liquids
Phys. Rev. B, vol.74, 165114 (2006)

Mikeska H.-J, Kolezhuk A.K.
One-dimensional magnetism
Lecture Notes in Physics vol.645, pp.1-83 (2004).

more than 80 refereed publications; h-index (2016) = 26 (Web of Science) 

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Contacts

Homepage: http://iht.univ.kiev.ua/Kolezhuk/


kolezhuk@knu.ua