When the continuous symmetry of a physical system is spontaneously broken, two types of
collective modes typically emerge: the amplitude and the phase modes of the order …

Abstract Within the Bardeen–Cooper–Schrieffer (BCS) theory, superconductivity is entirely
governed by the pairing energy scale, which gives rise to the superconducting energy gap …

The concept of mass generation by means of the Higgs mechanism was strongly inspired by
earlier works on the Meissner–Ochsenfeld effect in superconductors. In quantum field …

Recent experiments with strong THz fields in both conventional and unconventional
superconductors have clearly evidenced a marked third-harmonic generation below the …

The development of the fundamental superconducting (SC) energy scales—the SC energy
gap Δ and the superfluid stiffness J—of granular aluminum, ie, thin films composed of …

Despite the formal analogy with the Higgs particle, the amplitude fluctuations of the order
parameter in weakly coupled superconductors do not identify a real mode with a Lorentz …

We investigate the behavior of the Higgs (amplitude) mode when superconductivity emerges
on a preexisting charge-density-wave state. We show that the weak overdamped square …

Layered superconductors like high-T c cuprates display out-of-plane plasma oscillations
between layers sustained by the weak Josephson coupling among the superconducting …

Multiband superconductors can host collective excitations with marked differences with
respect to their single-band counterpart. We first study the spectrum of collective amplitude …

Microwave circuit electrodynamics of disordered superconductors is a very active research
topic spawning a wide range of experiments and applications. For compact superconducting …