12:00, Room 426/8
The amplitude mode, the analogue of the Higgs particle, is a ubiquitous collective excitation in condensed matter systems with broken continuous symmetry. It is expected to appear in antiferromagnets, short coherence length superconductors, charge density waves, and superfluids near the Mott transition. Detection of the amplitude mode is a valuable test of the underlying field theory, and its mass gap is a measure of proximity to a quantum critical point. However, since the amplitude mode can decay into low energy Goldstone modes, its experimental visibility has been questioned. Here we show that the visibility depends on the symmetry of the measured susceptibility. In particular, scalar (rotationally invariant) measurements allow for the observation of a sharp amplitude peak throughout the ordered phase. I will propose experimental setups to measure the amplitude peak across many physical systems.