In this talk I want to give a brief introduction into matrix product states, which allow the numerical simulation of quantum spin systems in low dimensions at almost machine-precision at arbitrary temperature and in the momentum-frequency domain. I will illustrate their performance by addressing the thermal control of spin excitations in the coupled Ising-chain material RbCoCl3, which presents two low-temperature magnetic phase transitions. In an interplay of high-flux neutron spectroscopy (in the Rüegg group) and numerical simulations, an almost perfect control and understanding of the material can be achieved. The numerical method is - apart from low dimensionality - largely independent of details of the Hamiltonian, which opens the way for numerous further applications.
Dr. Christian Franz
Dr. Christian Lang