__Kashyap V. Vasavada__

__Research Interests__

My research interests are in theoretical calculations and computer simulations of various physical phenomena. Over the years, I have studied systems relevant to high energy physics, atomic physics, nuclear magnetic resonance, electron paramagnetic resonance, optical physics and electromagnetic scattering from complex objects such as aircraft. Very often such simulations reveal properties of systems which are not at all obvious from just looking at the experimental data. In many cases these simulations require inversions of large matrices and solutions of several coupled partial differential equations. Sometimes it is necessary to develop special mathematical techniques before computer simulations become feasible.One such example was development of conjugate gradient technique to invert very large sparce matrices. I have also applied simulation techniques such as finite difference and finite element methods. In optical physics, my research is concerned with simulations on noise spectroscopy, lasing without inversion, pulse propagation in coherently prepared media , laser instability, chaos and laser synchronization.

__Publications__

1. K. V. Vasavada, Partial Wave Dispersion Relations for Pionic Disintegration of Deuteron, Ann. of Physics, 34, 191-237 (1965).

2. K. V. Vasavada, Dynamics of T = 2, S- ¹ System - I, Nuovo Cimento 40, 1045- 1054 (1965).

3. J. C. Pati and K. V. Vasavada, Dynamics of J = 3/2+ -KX and KN Systems in the 27- Fold Representation. Some Remarks on a Typical Feature of the Balazs-Type Procedure, Phys. Rev. 144, 1270-1275 (1966).

4. K. V. Vasavada, Coupling Constants of Spin-2 Mesons with Two Pseudo-Scalar Mesons, Phys. Rev. 144, 1351-1355 (1966).

5. Y. S. Kim and K. V. Vasavada, Perturbed Bound-State Poles in Potential Scattering, II, Phys. Rev. 150, 1236-1240 (1966).

6. P. Nath and K. V. Vasavada, Is the Nucleon a ¹-N Bound State?, Phys. Rev. 152, 1254-1258.

7. K. V. Vasavada and Y. S. Kim, Radius of Nucleon in a Bound State Model, Phys. Rev. 152, 1259-1262.

8. K. V. Vasavada, Incompatibility of a Superconvergence Relation with Conservation of A-Parity, Nuovo Cimento 49, 499-503 (1967).

9. K. V. Vasavada, P. Nath and Y. N. Srivastava, Reggeized Bootstrap of the K* Meson, Phys. Rev. 163, 1815-1819 (1967).

10. A. Temkin and K. V. Vasavada, The Scattering of Electrons from H2+: The Method of Polarized Single-Center Orbitals, Phys. Rev. 160, 109-117 (1967).

11. K. V. Vasavada and P. Nath, Generalized Potential for the Pion-Nucleon System, Phys. Rev. 166, 1532-1538 (1968).

12. K. V. Vasavada, The Solutions of Bethe-Salpeter and N/D Equations, Phys. Rev. 165, 1830-1834 (1968).

13. K. V. Vasavada and K. Raman, Generalized Dispersion Sum Rules and the A2 Trajectory in Pion Photoproduction, Phys. Rev. Letters 21, 577-580 (1968).

14. K. Raman and K. V. Vasavada, Continuous Moment Sum Rules and Pion Conspiracy in Photoproduction, Phys. Rev. 175, 2191-2194 (1968).

15. K. V. Vasavada, Generalized Superconvergence Relations for KN and KN Scattering, Can. J. Phys. 46, 2471-2472 (1968).

16. M. M. Islam and K. V. Vasavada, Hadronic and Electromagnetic Structure of the Proton, Phys. Rev. 178, 2140-2143 (1969).

17. K. V. Vasavada, High Energy Contributions to Current Algebra Sum Rules I, Phys. Rev. 178, 2350-2355 (1969).

18. K. V. Vasavada, High Energy Contributions to Current Algebra Sum Rules II, Phys. Rev. 184, 1594-1601 (1969).

19. A. Temkin, K. V. Vasavada, E. S. Chang and A. Silver, Scattering of Electrons from H2+ II, Phys. Rev. 186, 57-66 (1969).

20. K. V. Vasavada, Veneziano Model with Secondary Terms for Pion-Pion Scattering, Phys. Rev. D1, 88-94 (1970).

21. K. V. Vasavada, Veneziano Model and Finite Energy Sum Rules, Can. J. Phys. 48, 1879 (1970).

22. K. V. Vasavada, Continuous-Moment Sum Rules and Pion Photoproduction Data, Phys. Rev. D2, 2098-2100 (1970).

23. K. V. Vasavada, Role of Non-Pomeranchuk Regge Cuts in High Energy Scattering, Physics Letters, 34B, 214-218 (1971).

24. K. V. Vasavada, Dispersion of the Veneziano Representation in Trajectory Parameters,Regge Cuts, and Unitarity Corrections, Phys. Rev. D3, 2442-2447 (1971).

25. K. V. Vasavada, Regge Pole-Cut Effective Trajectories and the Dual Absorptive Model,Nuovo Cimento Letters 2, 1339-1345 (1971).

26. K. V. Vasavada, J. H. Scharenguivel, et al, Study of ë++ Production in the Reaction ¹+p " ¹+¹¼p at 13.1 GeV/c, Nuclear Physics B36, 363-372 (1972).

27. Y. S. Kim and K. V. Vasavada, Normalizable Wave Functions for Bound States and Resonances in S-Matrix Theory, Phys. Rev. D5, 1002-1011 (1972).

28. K. V. Vasavada, Effective Regge Trajectory in the Entire Complex-Angular Momentum Plane, Nuovo Cimento Letters 6, 453-458 (1973).

29. K. V. Vasavada, F. T. Meiere, L. J. Gutay and R. L. McIlwain, Zeros of the Vector-Meson Production Amplitude and their Implications, Phys. Rev. Letters 30, 465- 468 (1973).

30. L. J. Gutay and K. V. Vasavada, Phase Coherence of P-Wave Single Pion Production Amplitudes, Physics Letters B46, 88-90 (1973).

31. L. J. Gutay and K. V. Vasavada, Relative Phases of Single Pion Production Amplitudes, Proceedings of Tallahassee Conference on ¹ - ¹ Scattering, 255-259 (1973).

32. A. F. Garfinkel and K. V. Vasavada, Pion Nucleon Charge Exchange Scattering in a Regge-Regge-Cut Model, Phys. Rev. D8, 2880-2886 (1973).

33. L. R. Ram Mohan and K. V. Vasavada, Role of Pomeron in Tensor Meson Dominance, Phys. Rev. D9, 2627-2630 (1974).

v34. K. V. Vasavada and L. J. Gutay, Relations Between the Ball Amplitudes and the Zeros of p¼ Decay Density Matrix Elements, Phys. Rev. D9, 2563-2566 (1974).

35. K. V. Vasavada, Mass Formulas, Strong Gravity and Scalar-Tensor Universality, Phys. Rev. D12, 2918-2921 (1975).

36. K. V. Vasavada, -K¥¼ (890) - Decay Density Matrix Elements and Partial Conservation of Strangeness Changing Vector Current, Phys. Rev. D14, 3111-3114 (1976).

37. K. V. Vasavada, Couplings of Vector Mesons to Tensor Mesons and the Pomeron, Phys. Rev. D15, 1984-1990 (1977).

38. K. V. Vasavada, Theoretical Models for Angular Distribution of Massive Muon Pair Produced in Hadronic Collisions, Phys. Rev. D16, 146-151(1977).

39. M. Duong-Van, K. V. Vasavada and R. Blankenbecler, Model for Massive-Lipton- Pair Production, Phys. Rev. D16, 1389-1396 (1977).

40. K. V. Vasavada, Constituent Interchange Model for Inclusive Vector-Meson Production, Phys. Rev. D20, 2304-2313 (1979).

41. K. V. Vasavada, Meson Contribution to §L/§T in Deep Inelastic Liptoproduction, Physics Letters 92B, 183-185 (1980).

42. K. V. Vasavada and L. J. Gutay, Pion Exchange in Proton-Nucleus Charge Exchange Reactions at Intermediate Energy, Nuovo Cimento Letters 27, 475-480 (1980).

43. K. V. Vasavada, J. I. Kaplan and B. D. Nageswara Rao, Density Matrix Theory of ABC À A'B' + C' Chemical Exchange: Application to 31P NMR Spectra of Interconverting Enzyme-Bound Reactants and Products of Phosphoryl Transfer Enzymes, Journal of Magnetic Resonance 41, 467-482 (1980).

44. K. V. Vasavada, J. I. Kaplan and B. D. Nageswara Rao, Spin-Spin Coupling Effects Arising from Fast Exchange between Weakly Coupled Spin Systems, Journal of Magnetic Resonance 44, 270-276 (1981).

45. J. I. Kaplan and K. V. Vasavada, A Numerical Calculation of the NMR Lineshape Using the Finite Difference Method, Journal of Magnetic Resonance 52, 475-479 (1983).

46. K. V. Vasavada, J. I. Kaplan and B.D. Nageswara Rao, Analysis of 31P NMR Spectra of Enzyme-Bound Reactants and Products of Adenylate Kinase Using Density Matrix Theory of Chemical Exchange, Biochemistry 23, 961-968 (1984).

47. K. V. Vasavada, B. D. Ray and B. D. Nageswara Rao, 31P NMR Lineshapes of º- P (ATP) in the Presence of Mg2+and Ca2+: Estimate of Exchange Rates, Journal of Inorganic Biochemistry 21, 232-335 (1984).

48. K. V. Vasavada and J. I. Kaplan, Distinction Between Linewidths of Identical and Non-Identical Dipolar Coupled Systems with and without Exchange, Journal of Magnetic Resonance 62, 37-41 (1985).

49. K. V. Vasavada and J. I. Kaplan, NMR Lineshape Under the Conditions Where the Exchange Time Approaches Correlation Time, Journal of Magnetic Resonance 64, 32- 37 (1985).

50. K. V. Vasavada, D. J. Schneider and J. H. Freed, Calculation of ESR Spectra and Related Fokker-Planck Forms by the Use of the Lanczos Algorithm II. Criteria for Truncation of Basis Sets and Recursive Steps Utilizing Conjugate Gradients, J. Chem. Phys. 86 (2) 647-661 (1987).

51. K. V. Vasavada and B. D. Nageswara Rao, Nuclear Spin Relaxation in Liquids Due to Interaction with Paramagnetic Ions Having Anisotropic g-Tensors, Journal of Magnetic Resonance 81, 275-283 (1989).

52. K. V. Vasavada and J. H. Freed, Application of Lanczos and Conjugate Gradient Methods to a Class of Computational Problems in Physics, Computers in Physics 3, 81- 84 (1989).

53. I. Bertini, C. Luchinat and K. V. Vasavada, The Effect of Magnetic Anisotropy on the Longitudinal Nuclear Relaxation Time in Paramagnetic Systems, Journal of Magnetic Resonance 89, 243-254 (1990).

54. G.Vemuri, K.V.Vasavada and G.S. Agarwal, Electromagnetic Field Induced Quenching of the Effects of Noisy Lasers, Phys. Rev. A 50, 2599-2607 (1994).

55. G.Vemuri K.V. Vasavada, and G.S. Agarwal, Lasing without inversion in the absence of a coherent coupling field Phys. Rev. A 52, 3228-3230 (1995)

56. J.I. Alexander, K.V. Vasavada and G. Vemuri, Observation of delayed bifurcations at the threshold of a TI: Sapphire laser, Quantum and Semiclassical Optics B7, 467- 478 (1995)

57. K. V. Vasavada, G. Vemuri and G. S. Agarwal , Diode-Laser-Noise-Based Spec- troscopy of Allowed and Crossover Resonances, Phys. Rev. A 52, 4159-4166 (1995).

58. G. Vemuri,K.V. Vasavada, G.S. Agarwal and Q.Zhang , Coherence-induced effects in pulse-pair propagation through absorbing media, Physical Review A , 54, 3394-

3399 (1996)

59. G. Vemuri and K.V. Vasavada, Pulse propagation in coherently prepared media, Optics Communications 129, 379-386 (1996)

60 G. Vemuri, G.S. Agarwal, and K.V. Vasavada, Cloning, dragging, and parametric amplification of solitons in a coherently driven, non-absorbing system,Phys. Rev. Lett. 79, 3889-3892.

61 S.H.Choi,E. White,D.M.Wood,T.Dodson, K.V.Vasavada and G.Vemuri; Delayed bifurcations and negative hysteresis in semiconductor lasers:the role of initial conditions, Optics Communications,160,261-267 (1998)

**Presentations**

1. K. V. Vasavada and J. H. Freed, Finite Element Method for Simulation of ESR Spectra, 13th International Conference on Magnetic Resonance in Biological Systems, Madison, WI, Aug. 8-19, 1988.

2. K. V. Vasavada and B. D. Nageswara Rao, Nuclear Spin Relaxation in Liquids Due to Interaction with Paramagnetic Ions Having Anisotropic g-Tensors, 4th Chianti Workshop on Magnetic Resonance, San Miniato, Italy, May 28-June 2, 1990.

3. K. V. Vasavada, Calculation of Nuclear Magnetic Relaxation Rates Due to Bound Paramagnetic Ions, Indianapolis Meeting of the American Physical Society, March 16- 20, 1992.

4. N. P. Benetis, K. V. Vasavada and B. D. Nageswara Rao, Interpretation of the P- 31 NMR Longitudinal Relaxivity Dip in Aqueous Solutions of the Kinase-CO(II)-ATP Complex, 26th Congress Ampere on Magnetic Resonance, Athens, Greece, September 1992.

5. K.V. Vasavada, G. Vemuri and G.S. Agarwal, Electromagnetic Field Induce Quenching of the Effects of Noisy Lasers, the joint meeting of the Optical Society of America and Interdisciplinary Laser Science Conference, Dallas, Texas, Oct. 2-7, 1994.

6. K.V. Vasavada, G. Vemuri, G.S. Agarwal " Pulse-Pair Propagation in Coherently Prepared Media", American Physical Society Annual meeting, Indianapolis, 2- 5 May, 1996.

7. K.V.Vasavada, M.Carter, N.Gustafson, G.Vemuri "On the Control of Chaos in Semiconductor Lasers by Filtered Optical Feedback", American Physical Society March Meeting, Indianapolis, 18-22 March,2002.