相关论文: Collective modes in a quantum solid
Using a functional integral formulation, we analyze the collective modes in the $d$-density wave state. Since only discrete symmetries are broken, no massless phase mode is present. The only relevant fluctuation is the amplitude fluctuation…
Polarized inelastic neutron scattering experiments recently identified the amplitude (Higgs) mode in C$_9$H$_{18}$N$_2$CuBr$_4$, a two-dimensional near-quantum-critical spin-1/2 two-leg ladder compound, which exhibits a weak easy-axis…
We report neutron scattering measurements of the phonons in bcc solid 4He. In general, only 3 accoustic phonon branches should exist in a monoatomic cubic crystal. In addition to these phonon branches, we found a new ''optic-like'' mode…
We use time-dependent Hartree Fock approximation to study the collective mode spectra of nu=2 quantum Hall bilayers in tilted magnetic field allowing for charge imbalance as well as tunneling between the two layers. In a previous companion…
Fractonic phases of matter, a class of states in which collective excitations with constrained mobility exist, were originally discovered in the study of quantum error-correcting codes in solvable lattice spin models such as Haah's code and…
We discuss the nature of symmetry breaking and the associated collective excitations for a system of bosons coupled to the electromagnetic field of two optical cavities. For the specific configuration realized in a recent experiment at ETH,…
When a continuous symmetry of a physical system is spontaneously broken, two types of collective modes typically emerge: the amplitude and phase modes of the order-parameter fluctuation. For superconductors, the amplitude mode is recently…
Spontaneous symmetry-breaking quantum phase transitions play an essential role in condensed matter physics. The collective excitations in the broken-symmetry phase near the quantum critical point can be characterized by fluctuations of…
Collective excitation modes are a characteristic feature of symmetry-broken phases of matter. For example, superconductors exhibit an amplitude Higgs mode and a phase mode, which are the radial and angular excitations in the Mexican-hat…
The structure of the normal modes of vibration of rotationally invariant $n$-vortices in the Ginzburg-Landau/Abelian Higgs model is completely unveiled for any value of the coupling constant.
The phenomenological Ginzburg-Landau theory and the charge conservation directly lead to the finite Higgs-mode generation and vanishing charge-density fluctuation in the second-order optical response of superconductors at clean limit.…
We study the low-energy excitations of the Bose-Hubbard model in the strongly-interacting superfluid phase using a Gutzwiller approach and extract the single-particle and single-hole excitation amplitudes for each mode. We report emergent…
With increasing emphasis on the study of active solids, the features of these classes of nonequilibrium systems and materials beyond their mere existence shift into focus. One concept of active solids addresses them as active,…
We study collective amplitude modes of the superconducting order parameter in strongly-coupled electron-phonon systems described by the Holstein model using the nonequilibrium dynamical mean-field theory with the self-consistent Migdal…
Spontaneous symmetry breaking plays a key role in our understanding of nature. In a relativistic field theory, a broken continuous symmetry leads to the emergence of two types of fundamental excitations: massless Nambu-Goldstone modes and a…
The complete spectrum of collective modes of the triplet order parameter in the superfluid neutron matter is examined in the BCS approximation below the pair-breaking threshold. The dispersion equations both for the unitary and nonunitary…
We study the observability of the Higgs mode in BEC-BCS crossover. The observability of Higgs mode is investigated by calculating the spectral weight functions of the amplitude fluctuation below the critical transition temperature. At zero…
Higgs modes in condensed matter physics have drawn attention because of analogies to the Higgs bosons of particle physics. Here we use a microscopic time-dependent mean-field theory to study the collective mode spectra of two-dimensional…
We consider head-on collisions at critical coupling of vortices modelled by the Abelian-Higgs model. We investigate the 2-vortex scattering, whereby the vortices are excited by the shape mode causing fluctuations in the gauge-invariant…
We study the Higgs amplitude mode in the s-wave superfluid state on the honeycomb lattice inspired by recent cold atom experiments. We consider the attractive Hubbard model and focus on the vicinity of a quantum phase transition between…