Numerical investigation of bound states in quantum magnets

Bound-states of particles are an interesting problem in quantum mechanics dating back to 1931 Bethe's solution of spin-1/2 Heisenberg chain. These exotic composite states are realized in quantum magnets and are detectable in inelastic neutron scattering (INS) experiments. In this thesis, with the help of recent advances in matrix-product-states based algorithms, we numerically determine the Dynamical Structure Factor (DSF) to study the dynamics and spectrum of underlying spin models. We demonstrate the bound-states in three scenarios of quantum magnetism - (a) one dimensional Heisenberg ferromagnet where by studying temperature dependence of DSF we show that the bound-states appear as a well-defined excitation in temperature ranges J/12