相关论文: Amplitude mode oscillations in pump-probe photoemi…
Motivated by recent development in time-resolved angle-resolved photoemission spectroscopy (trARPES) for d-wave superconductors, we analyze the non-equilibrium relaxation dynamics of the laser pulse excited sample within the scenario of…
We calculate the spectrum of the amplitude mode, the analog of the Higgs mode in high energy physics, for the $d$-density wave (DDW) state proposed to describe the pseudogap phase of the high $T_c$ cuprates. Even though the state breaks…
The role of collective modes in various experiments on the cuprates is investigated. We calculate the neutron scattering, photoemission (ARPES), and Raman scattering intensities below $T_c$ within the fluctuation-exchange (FLEX)…
We study how time- and angle-resolved photoemission (tr-ARPES) reveals the dynamics of BCS-type, s-wave superconducting systems with time-varying order parameters. Approximate methods are discussed, based on previous approaches to either…
Oscillatory signals from coherently excited phonons are regularly observed in ultrafast pump-probe experiments on condensed matter samples. Electron-phonon coupling implies that coherent phonons also modulate the electronic band structure.…
Time- and angle-resolved photoelectron spectroscopy (trARPES) employing a 500 kHz extreme-ultravioled (XUV) light source operating at 21.7 eV probe photon energy is reported. Based on a high-power ytterbium laser, optical parametric chirped…
Non-equilibrium states generated by ultrafast laser pulses are characterized by specific phenomena that are not accessible in static measurements. Previous time- and angle-resolved photoemission spectroscopy (TARPES) studies on rare-earth…
Unconventional superconductors have been long sought for their potential applications in quantum technologies and devices. A key challenge impeding this effort is the difficulty associated with probing and characterizing candidate materials…
We study the dynamics of the longitudinal collective mode in an unconventional superconductor. For concreteness, we assume that the superconductor is described by a $d$-wave order parameter with $d_{x^2-y^2}$ symmetry. After the…
We use time- and angle-resolved photoemission spectroscopy (tr-ARPES) in the Extreme Ultraviolet (EUV) to measure the time- and momentum-dependent electronic structure of photo-excited K0.3MoO3. Prompt depletion of the Charge Density Wave…
Motivated by recent experimental progress we revisit the theory of pump-probe time- and angle-resolved photoemission spectroscopy (trARPES), which is one of the most powerful techniques to trace transient pump-driven modifications of the…
By utilizing time-dependent tensor-network algorithms in the infinite matrix-product-state representation, we theoretically investigate the pump-probe spectroscopy of the one-dimensional extended Hubbard model at half filling. Our focus…
The equations of motion of pair-like excitations in the superconducting state are studied for various types of pairing using the random phase approximation. The collective modes are computed of a layered electron gas described by a $t-t'$…
We propose a pump probe experiment for detecting the d-wave superfluid and d-density wave phases of ultracold Fermions on an optical lattice. The pump consists of periodic modulations of the optical lattice intensity which creates…
Ultrafast responses of BCS superconductor Nb1-xTixN films in a nonadiabatic excitation regime were investigated by using terahertz (THz) pump-THz probe spectroscopy. After an instantaneous excitation with the monocycle THz pump pulse, a…
We use density-matrix theory to calculate the ultrafast dynamics of unconventional superconductors from a microscopic viewpoint. We calculate the time evolution of the optical conductivity as well as pump-probe spectra for a d-wave order…
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…
Time- and angle-resolved photoelectron spectroscopy (trARPES) is a powerful method to track the ultrafast dynamics of quasiparticles and electronic bands in energy and momentum space. We present a setup for trARPES with 22.3 eV…
The collective mode spectrum of a symmetry-breaking state, such as a superconductor, provides crucial insight into the nature of the order parameter. In this context, we present a microscopic weak-coupling theory for the collective modes of…
We investigate the nonequilibrium pair density wave order parameter in a simple microscopic model with the ground state $d-$ wave spatially uniform superconductivity. After pushing the system out of equilibrium by a short-time induced order…