### Research

**Spin observables in medium energy electromagnetic strong (hadron) reactions**

Many experiments at Jefferson National Laboratory (JLAB), which provides an intense beam of 6 GeV electrons, involve polarized photons, polarized protons, and polarized targets. Precision studies of the electromagnetic production of (spin 0, 1 and 2) mesons are underway. By studying the spin characteristics of these reactions, we probe the underlying strong interaction dynamics and its relationship to basic QCD ideas. Predictions are made and subject to experimental tests. The excited states of nucleons (neutrons and protons) are examined, which is the subject called hadron spectroscopy.**Quantum Computing**

As a "spin–off" of the above studies of spin observables using density matrix methods, I have initiated a research program on quantum computing (QC) and information. " QDENSITY, " a Mathematica simulation of the basic QC teleportation, Grover's search, and Shor's factorization algorithims has been published. A large scale parallel supercomputer QC simulation (called QCMPI) based on various density matrix evolution models was published and is available on the web. In 2010, an updated version of " QDENSITY, " called QCWAVE, was completed. QCWAVE includes a multiverse approach to the affect of noise on quantum algorithms and includes simulation of quantum error correction, using parallel computing features of Mathematica 7.0/8.0. It is available at http://www.pitt.edu/~tabakin/QW. In 2016, QDENSITY/QCWAVE was extended to qutrit and hybrid qubit/qutrit systems. A paper "Model Dynamics for Quantum Computing" will be submitted soon.**Numerical methods for solving nonlinear physics problems**

In this collaboration with Victor Mandelzweig (Hebrew University, Israel), methods for solving nonlinear problems in Physics have been developed and applied to several fields of Physics. The methods we have developed combine a quasilinearization technique combined with using a wavelet basis for solving particularly difficult equations.

In addition to electromagnetic interactions, over the years I have studied strong interactions, the nuclear many–body problem, proton–antiproton reactions, and a variety of other mesonic and nucleon interactions. Numerous PhD thesis have been written on these subjects under my supervision.

### Selected Publications

"Dynamical coupled-channel approach to hadronic and electromagnetic production of kaon-hyperon on the proton," B. Julia-Diaz, B. Saghai (DAPNIA, Saclay), T.-S.H. Lee (Argonne, PHY) , F. Tabakin (Pittsburgh U.), Phys.Rev.C73: 055204, 2006

*and references therein*."Qdensity: a Mathematica Quantum Computer Simulation," B. Julia-Diaz, J. M. Burdis, F. Tabakin, Computer Physics Comm., 174 (2006) 914; quant-ph/0508101; Mathematica Repository; QDENSITY webpage.

QCWAVE: "A Mathematica quantum computer simulation update ," F. Tabakin and B. Julia-Diaz

*Computer Physics Communications 182 (2011) 1693*.*Computer Physics Communications*,*Volume 201*,*April 2016*,*Pages 171-172 QDENSITY/QCWAVE: A Mathematica quantum computer simulation update. The description is in the paper:*Update14.pdf"Mixing of the f(0) and a(0) scalar mesons in threshold photoproduction," B. Kerbikov (Moscow, ITEP) , F. Tabakin (Pittsburgh U.), Phys.Rev.C62: 064601, 2000.

"Analytic calculation of energies and wave functions of the quartic and pure quartic oscillators," E. Z. Liverts, V. B. Mandelzweig, F. Tabakin, J. Math. Phys. 47, 062109 (2006)

*and references therein*."Quasilinearization approach to nonlinear problems in physics with application to nonlinear ODEs," V. B. Mandelzweig, F. Tabakin, Computer Physics Comm., Volume 141, Issue 2, 30 Nov. 2001, Pages 268-281.

"Constraints on vector meson photoproduction spin observables," W.M. Kloet (Rutgers U.), F. Tabakin (Pittsburgh U.), Phys.Rev.C61: 015501, 2000.

"Quark - anti-quark bound states within a Dyson-Schwinger Bethe-Salpeter formalism," C. Savkli (William-Mary Coll.), F. Tabakin (Pittsburgh U.), Nucl.Phys. A628: 645-668, 1998.