Daya's Academic Visits Abroad :
1. University of Oregon, Eugene, USA, - attended the IXth International Conference on Few Body Problem, August 17-23, 1980.
2. SLAC Theory Division, Stanford University, California, USA, August 1980.
3. Department of Physics, City College of the City University of New York, September, 1980.
4. ICTP, Trieste, Italy, September 15 - November 1, and November 30 - December 06, 1980.
5. CERN, Theory Division, Geneva, Switzerland, November 22-28, 1980.
6. Division de Physique Theorique, Institute de Physique Nucleair (IPN), Universite de Paris-Sud, Orsay, Cedex, France, November 2-9, 1980.
7. Departmental of Theoretical Physics, Royal Institute of Technology, Stockholm, November 13-14, 1980.
8. DESY Theory Division, Hamburg, Germany, November 1980..
9. Department of Physics, University of Kaiserslautern, Germany, November 20-21, 1980.
10. ICTP Trieste, Attended Summer Workshop in Particle Physics, June 21-July 31, 1982.
11. CERN Theory Division, Geneva, Switzerland, One Week (July-August) 1982.
12. Goethe Institute, Konstanz, Germany, Studied German Language (Mittle Stufe Eines), August-September, 1982.
13. Department of Physics, University of Kaiserslautern, Germany, DAAD Post-Doctoral Fellow, October 1, 1982 - December 31, 1984.
14. University of Karlsruhe, Germany, Attended the Xth International Conference on Few Body Problem in Physics, August 21-27, 1983.
15. MPI for Physics and Astrophysics, Munich, Germany, Attended NATO Advanced Study Institute on Quarks, Leptons and Beyond,
September 5-16, 1983.
16. DESY Theory Division, Hamburg, Germany, Attended DESY Theory Workshop on Hadron and Jet Structure, September 27-29, 1983.
17. LPTHE, Universite de Paris XI, Centre d'Orsay, Cedex, France, November 7-15, 1983.
18. CERN Theory Division, Geneva, Switzerland, December, 11-24, 1983.
19. ICTP Trieste, Attended Summer Workshop in High Energy Physics and Cosmology, June 17- July 31, 1984.
20. Physikalisches Institute University of Bonn, Germany, Attended NATO Advanced Study Institute on Supersymmetry, August 20-31, 1984.
21. DESY Theory Division, Hamburg, Germany, Attended DESY Theory Workshop on Electroweek Interactions and Particle Structure,
September 24-27, 1984.
22. Les Arcs, Savoie, France, Attended XXIII Recontre de Moriond on Current Issues in Hadron Physics, March 06-13, 1988.
23. Institute des Sciences Nucleaire (ISN), Universite de Grenoble, France, March 21-25, 1988.
24. Division de Physique Theorique, Institute de Physique Nucleair (IPN), Universite de Paris-Sud, Orsay, Cedex, France, March 28-April 01, 1988.
25. Department of Physics, University of Kaiserslautern, Germany, April 05-29, 1988.
26. Institute of Theoretical Physics, University of Heidelberg, Germany, April 20, 1988.
27. Institute of Theoretical Physics<, University of Tuebingen, Germany, April 21-22, 1988.
28. Department of Physics, University of Kaiserslautern, Germany Wissenschaftlicher Mitarbeiter (BAT-IIA) and Wissenschaftlichen Assistant (C1) (with Prof. Dr. Harald J. W. Mueller-Kirsten), Januray 1990 - June 1994.
29. Faculty of Mathematics and Physics, Charles Technical University, Prague, Czechoslovakia, October 15-21, 1990.
30. Smolenice, Bratislava, Czechoslovakia, Attended the Conference on Hadron Structure-90 , October 22-26, 1990.
31. DESY Theory Division, Hamburg, Germany, Attended DESY Theory Workshop, October 1991.
32. LPTHE, Universite de Paris Sud, Orsay, Cedex, France, October 1991.
33. Division de Physique Theorique, Institute de Physique Nucleair (IPN), Universite de Paris-Sud, Orsay, Cedex, France, February 15-20, 1992.
34. Montepulciano, Siena, Italy, Attended IInd Workshopon Constraints Theory and Quantization Methods, June 28-July 01, 1993.
35. Institute for Theoretical Physics, University of Washington, Seattle, USA, June 25-28, 1997.
36. SLAC Theory Division, Stanford University, Stanford, California, USA, (visited Prof. Stanley Brodsky), July, 1997.
37. University of California at Berkley, Berkley, California, USA, July 1997.
38. Department of Physics, University of Kaiserslautern, Germany, May 22 - June 20, 1997.
39. Department of Physics, University of Kaiserslautern, Germany, May 25 - July 10, 1998.
40. Department of Physics, University of Mainz, Germany, June 1998.
41. Fakultaet fuer Physik, Universitaet Freiburg, Germany, July 1998.
42. Department of Physics, University of Kaiserslautern, Germany, May 13 - June 29, 2000.
43. Institute for Theoretical Physics, University of Jena, Jena, Germany, June 2000.
44. Institute for Theoretical Physics, RUHR University of Bochum, Bochum, Germany, June 2000.
45. Institute for Theoretical Physics/Thep, University of Mainz, Mainz, Germany, June 2000.
46. Max Planck Institute fuer Kernphysik, Heidelberg, Germany, Attended International Workshop, LC-2000, Heidelberg, June 12-17, 2000.
47. Institute for Theoretical Physics/Thep, University of Mainz, Mainz, Germany, and Department of Physics, Physics, University of Kaiserslautern, Germany, April 15 - July 15, 2001.
48. Department of Physics, Physics, University of Kaiserslautern, Germany, October-December, 2001.
49. Institute for Theoretical Physics, University of Jena, Jena, Germany, February 12-13, 2002.
50. Fermilab Theory Group, Batavia, USA, May 05-13, 2007.
51. OCTS, Ohio State University, Columbus, Ohio, USA, Attended the Light-Cone Conference LC-2007, May 13-19, 2007 (gave an Invited Talk on the Quantization of the String Theories and D-Brane Actions)
52. Department of Physics, Physics, University of Kaiserslautern, Germany, Visit on DAAD-Reinvitation, May 21-July 24, 2007.
53. Division de Physique Theorique, Institute de Physique Nucleair (IPN), Universite de Paris-Sud, Orsay, Cedex, France, May 26-June 10, 2008.
54. Institute of Theoretical Physics, University of Heidelberg, Germany, June 11, 2008.
55. Department of Physics, Physics, University of Kaiserslautern, Germany, June 12 - July 21, 2008.
56. Instiute of Theoretical Physics, Carl von Ossietzky University of Oldenburg, , Germany, June, 2008.
57. EPS, Mulhouse, France, Attended the International Conference on Light-Cone Physics ( LC-2008) on Relativistic Nuclear and Particle Physics , July 07-11, 2008 (gave an Invited Talk).
58. University of Valencia, Valencia, Spain, Attended the International Workshop on Light-Cone Physics (LC-2010) on Relativistic Nuclear and Particle Physics, June 14-18, 2010 (gave an Invited Talk).
59. Instiute of Theoretical Physics, Carl von Ossietzky University of Oldenburg, , Germany, June-July, 2010.
60. Southern Methodist University, Dallas, Texas, USA, Attended the International Light-Cone Conference (LC-2011) on Applications of Light-Front Coordinates to Highly Relativistic Systems, May 22-27, 2011 (gave an Invited Talk on the Light-Front Quantization of D-Brane Actions).
61. Department of Physics and Astronomy, Iowa State University, Ames, Iowa, USA, June-July, 2011.
62. Department of Physics and Astronomy, Iowa State University, Ames, Iowa, USA, April-July, 2012.
63. Department of Physics and Astronomy, Iowa State University, Ames, Iowa, USA, April-July, 2013.
64. North Carolina State University, Raleigh, NC, USA, Attended the International Light-Cone Conference (LC-2014) on Theory and Experiments for Hadrons on the Light-Front, May 26 - 30, 2014 (gave an Invited Talk on the Quantization of the Restricted Gauge Theory of QCD2).
65. Department of Physics and Astronomy, Iowa State University, Ames, Iowa, USA, June-August, 2014.
66. Frascati, LMF, INFN National Laboratories in Frascati (Rome), Italy, September 21-25, 2015, Attended the International Conference on Light-Cone Physics (LC-2015) (gave an Invited Talk on the Light-Front Quantization of the Restricted Gauge Theory of QCD2)
67. Department of Physics and Astronomy, University of Florence, Firenze, Italy, September 28-30, 2015 (gave an Invited Colloquium Talk on the 101 years of General Relativity, Boson Stars, Black Holes, Wormholes and Time Travel)
68. Instiute of Theoretical Physics, Carl von Ossietzky University of Oldenburg, Germany, October 01-25, 2015.
69. Department of Physics, University of Botswana, Gaborone, Botswana, October 14-24, 2016 (Reviewed the Curriculum of Physics of the University of Botswana and gave 2 Invited Talks on (i) Introduction to String Theory and (ii) 101 Years of General Relativity, Boson Stars, Black Holes, Wormholes and Time Travel).
70. Instiute of Theoretical Physics, Carl von Ossietzky University of Oldenburg, Germany, April 19 - July 18, 2017 (gave a series of Lectures on String Theory during the Summer Semester 2017).
71. Institute of Nuclear Physics, Rez, Czech Republic, attended the International Conference on Algebraic and Analytic Methods in Physics, Prague, Czech Republic, September 07-17, 2017 (gave an Invited Talk on the Introduction to String Theory).