We discuss the coupling between dark energy and matter by considering a homogeneous tachyonic scalar field as a candidate for dark energy. We obtained the functional form of scale factor by assuming that the coupling strength depends linearly on the Hubble parameter and energy density. We also estimated the cosmic age of the Universe for different values of coupling constant.

Being the "mother distributions" of all types of two-parton correlation functions, generalized transverse momentum dependent parton distributions (GTMDs) have attracted a lot of attention over the last years. We argue that exclusive double production of pseudoscalar quarkonia in nucleon-nucleon collisions gives access to GTMDs of gluons.

We present a calculation of Wigner distributions for gluons in a light-front dressed quark model. We calculate the kinetic and canonical gluon orbital angular momentum and spin-orbit correlation of the gluons in this model.

We calculate the Wigner functions for a quark target dressed with a gluon at one loop in perturbation theory. The Wigner distributions give the combined position and momentum space information of the quark distributions and are related to both generalized parton distributions and transverse momentum dependent parton distributions. We calculate and compare the different definitions of quark orbital angular momentum and the spin-orbit correlations in this perturbative model. We compare our results with other model calculations.

We present a calculation of the generalized parton distributions (GPDs) of the photon when the helicity of the initial photon is different from the final photon. We calculate the GPDs using overlaps of photon light-front wave functions (LFWFs) at leading order in electromagnetic coupling and zeroth order in the strong coupling , when the momentum transfer is purely in the transverse direction. These involve a contribution of orbital angular momentum of two units in the LFWFs. We express these GPDs in the impact parameter space.