ETD

• background magnetic field
• confinement
• deconfinement
• Monte Carlo
• phase transition
• qcd
• su(3)
• temperature dependence
• topological charge
• topological susceptibility

This thesis analyses the data produced by a Monte Carlo simulation of the topological charge, using stout improved staggered quarks in 2+1 flavour SU(3) lattice QCD, between the temperatures 0-430 MeV and for a background magnetic field strength between 0-9 GeV^2. A novel method is applied for identifying the peaks of the topological charge distribution, which is compared to the usual method, concluding that both are equivalent. The topological susceptibility is studied across the confinement/deconfinement phase transition, observing the following results. At low temperature, below the transition, the susceptibility is enhanced for increasing magnetic field strength, with a peak at 4 GeV^2, before this enhancement reduces at 9 GeV^2. Instead, across the transition, the susceptibility drops sharply, before becoming a slowly decreasing function of temperature. For increasing magnetic field strength, the susceptibility's drop at the transition is steepens, and its suppression above the transition is strongest at 4 GeV^2. Isolating the magnetic dependence above the transition, the stronger the magnetic field, the more the susceptibility is suppressed; and when the temperature is larger than ~3 times the critical temperature, the suppression weakens.