Watch a physics lecture exploring how non-linear spectroscopy serves as a powerful tool for investigating quantum many-body systems, particularly in frustrated magnets. Delve into the limitations of traditional linear response techniques and discover how non-linear response methods can reveal previously hidden physics in these complex systems. Learn from speaker Ciarán Hickey of University College Dublin as he examines the exciting developments in non-linear spectroscopy and its applications in studying quantum magnetic systems. Gain insights into why certain physical phenomena remain invisible to linear response frameworks and understand how moving beyond these conventional approaches enables deeper understanding of frustrated quantum magnets.