The fluctuation around the molecular field of the spin density wave (SDW) state has been examined by calculating the collective modes and the spectral weight as a function of arbitrary strength of the repulsive on-site interaction, U , for a one-dimensional system with the half-filled band. The transverse mode is well described by the spin wave for both the small U and the large U and takes the spectral weight which is dominant compared with that of the longitudinal mode for the large U . The temperature dependence of the static magnetic susceptibility is calculated for both the longitudinal and transverse cases.The fluctuation around the molecular field of the spin density wave (SDW) state has been examined by calculating the collective modes and the spectral weight as a function of arbitrary strength of the repulsive on-site interaction, U , for a one-dimensional system with the half-filled band. The transverse mode is well described by the spin wave for both the small U and the large U and takes the spectral weight which is dominant compared with that of the longitudinal mode for the large U . The temperature dependence of the static magnetic susceptibility is calculated for both the longitudinal and transverse cases.

Journal of the Physical Society of JapanJun 15, 19953 citations

Photoinduced melting dynamics and collective mode in a correlated charge-ordered system

Yasuhiro Tanaka, Hitoshi Seo

We theoretically investigate the transient spectral function during the photoinduced melting of charge order in a correlated electron system, to unravel the dynamical processes triggered by different initial excitations. We employ a one-dimensional interacting spinless fermion model introducing a pulsed laser light, and perform a comparative study by the Hartree-Fock approximation and by the exact diagonalization method to numerically solve the time-dependent Schrödinger equation. We find characteristic behavior in the transient spectral function, whose features strongly depend on the pump light frequency $ω_p$ . When $ω_p$ is resonant with the collective phase mode of frequency $Ω_c\simeq Δ_{\rm CO}/2$ , where $Δ_{\rm CO}$ is the charge gap, the transient spectral function exhibits a photoinduced in-gap weight which triggers large responses. With increasing the laser intensity, the development of in-gap weight directly turns into the collapse of the gap. This charge-order destabilization process is in sharp contrast to the case of $ω_p>Δ_{\rm CO}$ , where the photoirradiation induces interband electron-hole excitations giving rise to a shrinkage of the gap. The impact of quantum fluctuations and spatial inhomogeneity on the photoinduced dynamics is also discussed.We theoretically investigate the transient spectral function during the photoinduced melting of charge order in a correlated electron system, to unravel the dynamical processes triggered by different initial excitations. We employ a one-dimensional interacting spinless fermion model introducing a pulsed laser light, and perform a comparative study by the Hartree-Fock approximation and by the exact diagonalization method to numerically solve the time-dependent Schrödinger equation. We find characteristic behavior in the transient spectral function, whose features strongly depend on the pump light frequency $ω_p$. When $ω_p$ is resonant with the collective phase mode of frequency $Ω_c\simeq Δ_{\rm CO}/2$, where $Δ_{\rm CO}$ is the charge gap, the transient spectral function exhibits a photoinduced in-gap weight which triggers large responses. With increasing the laser intensity, the development of in-gap weight directly turns into the collapse of the gap. This charge-order destabilization process is in sharp contrast to the case of $ω_p>Δ_{\rm CO}$, where the photoirradiation induces interband electron-hole excitations giving rise to a shrinkage of the gap. The impact of quantum fluctuations and spatial inhomogeneity on the photoinduced dynamics is also discussed.

arXiv:2510.16855Physical review. B./Physical review. BFeb 23, 20260 citations

Spectral singularities in one-dimensional electron liquids

Tetsuo Ogawa

Materials Science and Engineering BAug 1, 19971 citation

Elementary electronic excitations in one-dimensional continuum and lattice systems

D. W. Wang, S. Das Sarma

We systematically investigate the mode dispersion and spectral weight of the elementary excitation spectra in one-dimensional continuum and lattice electron systems by using the RPA, the Luttinger liquid model, and the Hubbard model. Both charge and spin excitations are studied in detail and compared among the theoretical models. For the lattice Hubbard model we use both Bethe-ansatz equations and Lanczos-Gagliano method to calculate dispersion and spectral weight separately. We discuss the theoretically calculated elementary excitation spectra in terms of the experimental inelastic light (Raman) scattering spectroscopy of one-dimensional (1D) semiconductor quantum wire systems. Our results show that in the polarized (i.e., non-spin-flip) Raman-scattering spectroscopy, only the 1D charge density excitations should show up with observable spectral weight with the single-particle excitations (in random-phase approximation) or singlet spin excitations (in the Luttinger model and the Hubbard model) having negligible spectral weight. The depolarized (spin-flip) Raman-scattering spectra manifest the spin density or the triplet spin excitations. We also provide a qualitative comparison between the continuum and the lattice 1D elementary excitation spectra.We systematically investigate the mode dispersion and spectral weight of the elementary excitation spectra in one-dimensional continuum and lattice electron systems by using the RPA, the Luttinger liquid model, and the Hubbard model. Both charge and spin excitations are studied in detail and compared among the theoretical models. For the lattice Hubbard model we use both Bethe-ansatz equations and Lanczos-Gagliano method to calculate dispersion and spectral weight separately. We discuss the theoretically calculated elementary excitation spectra in terms of the experimental inelastic light (Raman) scattering spectroscopy of one-dimensional (1D) semiconductor quantum wire systems. Our results show that in the polarized (i.e., non-spin-flip) Raman-scattering spectroscopy, only the 1D charge density excitations should show up with observable spectral weight with the single-particle excitations (in random-phase approximation) or singlet spin excitations (in the Luttinger model and the Hubbard model) having negligible spectral weight. The depolarized (spin-flip) Raman-scattering spectra manifest the spin density or the triplet spin excitations. We also provide a qualitative comparison between the continuum and the lattice 1D elementary excitation spectra.

arXiv:cond-mat/0101061Physical review. B, Condensed matterDec 13, 200112 citations

Single particle spectral weight of a 2-D Hubbard model

Elbio R. Dagotto, F. Ortolani, D. Saclapino

Jan 1, 19920 citations

ω_p

. When

ω_p

is resonant with the collective phase mode of frequency

Ω_c\simeq Δ_{\rm CO}/2

, where

Δ_{\rm CO}

is the charge gap, the transient spectral function exhibits a photoinduced in-gap weight which triggers large responses. With increasing the laser intensity, the development of in-gap weight directly turns into the collapse of the gap. This charge-order destabilization process is in sharp contrast to the case of

ω_p>Δ_{\rm CO}

, where the photoirradiation induces interband electron-hole excitations giving rise to a shrinkage of the gap. The impact of quantum fluctuations and spatial inhomogeneity on the photoinduced dynamics is also discussed.