题 目：A Model of Quantum Gravity within Riemann-Cartan Geometry

报告人：DMITRIY G. PAK Professor，Senior Research Scientist， Lab. of Few Nucleon Systems, Institute of Nuclear Physics, Uzbekistan

时 间：2013年3月15日(星期五)上午10:00

地 点：中心教学楼610

ABSCTRACT：
The notion of We consider foundations of possible theory of quantum gravity which inherits geometrical structure from the classical Einstein general relativity. We start with basic concepts of space and with the fundamental principle of equivalence and explore the idea of Lorentz gauge gravity. Our main result is that we propose a class of Lorentz gauge gravities with torsion which admits a topological phase in the gravitational sector. It turns out that there is a unique Lagrangian that implies dynamic spin one mode in correspondence with gauge theories of other fundamental interactions. Remarkably, despite a non-compact structure of the Lorentz gauge group, the model possesses rather a positive-definite Hamiltonian. This implies further consistent quantization and leads to a renormalizable quantum theory. It is assumed that the proposed model describes possible mechanism of emergent Einstein gravity. Possible relationship with origin of dark matter and dark energy is discussed.

简历：
Education

1989 PhD in Physics and Mathematics (Candidate of Physical and Mathematical Sciences), Uzbekistan National University

Fellowships and awards

2011-2012 Special Professorship Award for Foreign Senior Scientists from Chinese Academy of Sciences.

2003-2006, Research Professor Fellowships under Brain Pool Program, SNU, Korea

2008-2009

1999-2001 Research Fellowship in APCTP (Asia Pacific Center for Theoretical Physics) Seoul, KOREA

Employment, visits

2012.09 - present Senior Research Scientist, Lab. of few nucleon systems, Inst. of Nuclear Physics (permanent affiliation), Ulugbek, Uzbekistan.

2011.07 - 2012.07 Visiting Professor, Institute of Modern Physics, CAS, Lanzhou, China

2010 - 2012 Visiting Professor, APCTP, Pohang, Korea, short visits

2010.09 - 2010.11 Visiting Senior Research Scientist, JINR, BLTP, Dubna, Russia

2008.02 - 2009.06 Research Professor, Center of Theoretical Physics, Seoul National University, Seoul, Korea

2007.01 - 03 Invited Professor, Chern Institute of Mathematics, Tianjin University, China.

2004 – 2006 Research-Professor, Center for Theoretical Physics, Seoul National University, Korea

2003 – 2004 PostDoctoral Fellow, School of Physics, Seoul National University, Korea

1998 – 2001 Fellowship, APCTP (Asia Pacific Center for Theoretical Physics), Seoul, Korea

Academic activity

Advising PhD, MsD students at Uzbekistan Nat. Univ. (Uzbekistan),

Seoul National Univ. (Korea, 2004-2006, 2008-2009);

Lecture courses and Labs for undergraduate and graduate students

Uzbekistan National University

"Theory of elementary particles and gauge fields",

"Functional methods in quantum field theory",

"Electrodynamics", "Quantum Chromodynamics",

"Supersymmetry and supergravity".

STATEMENT OF RESEARCH INTERESTS

I. Gravity and Cosmology

1. Quantum gravity models in Riemann-Cartan-Weyl geometry, origin of space-time.

2. Vacuum effects in gravity: vacuum tunneling, gravitational (torsion) condensates.

3. Dark matter and dark energy problems. Origin and properties of dark matter and dark energy.

II. Quantum field theory

1. Quantum chromodynamics (QCD): quark and color confinement problems. Topological and quantum structure of QCD vacuum, origin of color confinement. Quantum effective action in quantum electrodynamics and standard model.

2. Generation of mass gap and consistent non-perturbative quantization scheme for Yang-Mills theory (7th Millennium problem). 

3. Hadron physics at high and low energies. Confinement-deconfinement phase transitions. Nucleon spin structure, proton spin crisis.

III. Mathematical physics

1. Classical solutions in non-Abelian Yang-Mills-Higgs theory in Minkowski and Euclidean space-time: monopoles, instantons. 

2. Exact classical solutions in Einstein-Maxwell-Higgs theory and in Riemann-Cartan gravity: black strings, knots, vortices, monopoles. 

3. Supersymmetry and supergravity, differential geometry of supermanifolds, non-commutative geometry and their possible physical implications.

Selected papers

1. D.G. Pak, Y.M. Kim and T. Tsukioka, A Lorentz gauge theory as a model of energent gravity, Phys. Rev. D85 (2012) 084006.

2. Y.M. Cho, D.G. Pak, P.M. Zhang, L.P. Zhou, Weyl symmetric structure of QCD, Phys. Rev. D86 (2012) 045025; arxiv: 1204.5970.

3. Y.M. Cho, D.G. Pak, Vacuum tunneling in gravity, Class.Quant. Grav. 28 (2011) 155008.

4. Y. M. Cho, D. G. Pak, A Convergent Series for the QED effective action, Phys.Rev.Lett. 86 (2001) 1947.

List of Journal Publications:

1. P.M. Zhang and D.G. Pak, On gauge invariant nucleon spin decomposition, Eur. Phys. J. A (2012) 48: 91; arxiv: 1110.6516;

2. Y.M. Cho, D.G. Pak, P.M. Zhang, L.P. Zhou, Weyl symmetric structure of QCD, Phys. Rev. D86 (2012) 045025; arxiv: 1204.5970.

3. D.G. Pak, Y.M. Kim and T. Tsukioka, A Lorentz gauge theory as a model of emergent gravity, Phys. Rev. D85 (2012) 084006; arxiv: 1112.5952.

4. Y.M. Cho, D.G. Pak, Vacuum tunneling in gravity, Class.Quant. Grav. 28 (2011) 155008.

5. D. G. Pak, Confinement, vacuum structure: from QCD to Quantum Gravity, Nucl.Phys.A844:115-119 (2010).

6. Y.M. Cho, D.G. Pak, B.S. Park, A minimal model of Lorentz gauge gravity with dynamical torsion, Int. J. Mod. Phys. A25 (2010) 2867; arXiv:0911.3688.

7. S.W. Kim, D. G. Pak, Torsion as a dynamic degree of quantum gravity, Class.Quant.Grav.25:065011, 2008.

8. D.G. Pak, On P_T-distribution of gluon production rate in constant chromoelectric field, Mod.Phys.Lett.A22:2885-2891,2007; hep-th/0702095.

9. Y.M. Cho, J.H. Kim, D.G. Pak, QCD effective action with a most general homogeneous field background, Mod. Phys. Lett. A21, 2789-2797, 2006.

10. Y.M. Cho, D.G. Pak, M.L. Walker, Light propagation effects in QED: Effective action approach, Phys.Rev.D73:065014, 2006.

11. Y. M. Cho, D. G. Pak, Stable Monopole-Antimonopole String Background in SU(2) QCD, Phys. Lett. B632, p. 745, 2006.

12. B. A. Fayzullaev, M. M. Musakhanov, D. G. Pak, M. Siddikov, Knot soliton in Weinberg-Salam model, Phys.Lett. B609 (2005) 442-448, hep-th/0412282.

13. Y. M. Cho, M. L. Walker, D. G. Pak, Monopole Condensation and Dimensional Transmutation in SU(2) QCD, JHEP 05 (2004) 073, hep-th/0209208 .

14. Y.M. Cho, D. G. Pak, Monopole Condensation in SU(2) QCD, Phys.Rev. D65 (2002) 074027, hep-th/0201179.

15. M. Cho, H. W. Lee, D. G. Pak, Faddeev-Niemi conjecture and effective action of QCD, Phys.Lett. B525 (2002) 347-354, hep-th/0105198.

16. W. S. Bae, Y. M. Cho, D. G. Pak, Electric-Magnetic Duality in QED Effective Action, Phys.Rev. D64 (2001) 017303.

17. Y. M. Cho, D. G. Pak, A Convergent Series for the QED effective action, Phys.Rev.Lett. 86 (2001) 1947.

18. Y. M. Cho, D. G. Pak, Magnetic Confinement in QCD, J. Korean Phys.Soc. 38 (2001) 151-154.

19. D.G. Pak, Differential calculus on the quantum group SUq(2) consistent with gauge transformations, Theor.Math.Phys., 1998, V.116:(2), 947-955.

20. B.M. Zupnik, D.G. Pak, Differential and integral forms in supergauge theories and supergravities, Classical and Quantum Gravity, 1989, Vol.6, 723-729.

21. B.M. Zupnik, D.G. Pak, Superfield formulation of simple three-dimensional gauge theories and conformal supergravities, J. of Theor. and Math. Phys. 1988, v.77, 97-106.

22. B.M. Zupnik, D.G. Pak, Topologically massive gauge theories in superspace, Izvestiya VUZov SSSR. Ser.Fizika (Soviet journal), 1988, No.12, 13-17.

23. B.M. Zupnik, D.G. Pak, Superfield methods of quantization in supergravity, Yadernaya Fizika, 1985, vol.42, 710-719.

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