Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2411.00313 · Physical review. B./Physical review. B

Optical absorption activated by an ultrashort half-cycle pulse in metallic and superconducting states of the Hubbard model

Kazuya Shinjo, Shigetoshi Sota, Seiji Yunoki, Takami Tohyama

Published May 29, 2025• 3 citations
arXivHTMLPDF

Abstract

The development of high-intensity ultrashort laser pulses unlocks the potential of pump-probe spectroscopy in sub-femtosecond timescale. Notably, subcycle pump pulses can generate electronic states unreachable by conventional multicycle pulses, leading to a phenomenon that we refer to as subcycle-pulse engineering. In this study, we employ the time-dependent density-matrix renormalization group method to unveil the transient absorption spectra of superconducting and metallic states in nearly half-filled one-dimensional and two-dimensional Hubbard models excited by an ultrashort half-cycle pulse, which can induce a current with inversion-symmetry breaking. In a superconducting state realized in attractive on-site interactions, we find the transient activation of absorptions at energies corresponding to the amplitude modes of superconducting and charge-density-wave states. On the other hand, in a metallic state realized in the two-dimensional model with repulsive on-site interactions, we obtain another type of absorption enhancements, which are distributed broadly in spin excitation energies. These findings indicate that superconducting and metallic states are sensitive to an ultrashort half-cycle pulse, leading to the transient activations of optical absorptions with their respective mechanisms.

DOI
10.1103/q1fw-tdk1

Related papers

Controlling inversion and time-reversal symmetries by subcycle pulses in the one-dimensional extended Hubbard model

Kazuya Shinjo, Shigetoshi Sota, Seiji Yunoki +1 more

Owning to their high controllability, laser pulses have contributed greatly to our understanding of strongly correlated electron systems. However, typical multicycle pulses do not control the symmetry of systems, which plays an important role in the emergence of novel quantum phases. Here, we demonstrate that subcycle pulses whose oscillation is less than one period within a pulse envelope can control inversion and time-reversal symmetries in the electronic states of the one-dimensional extended Hubbard model. Using an ultrashort subcycle pulse, one can generate a steady electric current (SEC) in a photoexcited state due to an Aharonov-Bohm flux instantaneously introduced through the phase of an electric field. Consequently, time-reversal symmetry is broken. In contrast, a broad subcycle pulse does not induce SEC but instead generates electric polarization, thus breaking inversion symmetry. Both symmetry breakings in a photoexcited state can be monitored by second-harmonic generation. These findings provide a new methodology for designing the symmetries of electronic states and open up a new field of subcycle-pulse engineering.

arXiv:2211.08694•Physical review. B./Physical review. B•May 2, 2023•3 citations

Sub-cycle multidimensional spectroscopy of strongly correlated materials

V. N. Valmispild, Evgeny Gorelov, Martin Eckstein +5 more

Abstract Strongly correlated solids are complex and fascinating quantum systems, where new electronic states continue to emerge, especially when interaction with light triggers interplay between them. In this interplay, a sub-laser-cycle electronic response is particularly attractive as a tool for the ultrafast manipulation of matter at the petahertz scale. Here we introduce a new type of nonlinear multidimensional spectroscopy, which allows us to unravel charge and energy flows in strongly correlated systems interacting with few-cycle infrared pulses and the complex interplay between different correlated states evolving on the sub-femtosecond timescale. We demonstrate that the sub-cycle spectroscopy of a single-particle electronic response is extremely sensitive to correlated many-body dynamics and provides direct access to many-body response functions. For the two-dimensional Hubbard model under the influence of ultrashort, intense electric-field transients, we resolve the sub-femtosecond pathways of charge and energy flows between localized and delocalized many-body states and the creation of a highly correlated state surviving after the end of the laser pulse. Our findings open the way towards a regime of imaging and manipulating strongly correlated materials at optical rates, beyond the multicycle approach employed in Floquet engineering, with the sub-cycle response being a key tool for accessing many-body phenomena.

Nature Photonics•Jan 24, 2024•31 citations

Pump-probe spectroscopy of the one-dimensional extended Hubbard model at half filling

K. Sugimoto, Satoshi Ejima

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 lies on nonequilibrium optical conductivity and single-particle excitation spectra. In the spin-density-wave (SDW) phase, we identify an in-gap state in the nonequilibrium optical conductivity due to the formation of excitons (or doublon-holon pairs), generated by the pulse through nonlocal interactions. In the strong-coupling regime, we discern additional multiple in-gap and out-of-gap states. In the charge-density-wave (CDW) phase, we detect not only an in-gap state but also a finite Drude weight, which results from the dissolution of charge order by photoexcitation. Analyzing time-dependent single-particle excitation spectra directly in the thermodynamic limit confirms the origin of these new states in the SDW and CDW phases as the excitation of newly emerged dispersions. We illustrate that the pump-probe spectroscopy simulations in the thermodynamic limit furnish unambiguous spectral structures that allow for direct comparison with experimental results, and the integration of nonequilibrium optical conductivity and time- and angle-resolved photoemission spectroscopy provides comprehensive insights into nonequilibrium states.

arXiv:2305.09909•Physical review. B./Physical review. B•Nov 14, 2023•7 citations

Photoinduced Hubbard band mixing due to ultrafast laser irradiation of a one-dimensional Mott insulator

J. D. Lee, Jun‐ichi Inoue

Based on the nonperturbative many-body time-dependent approach, photoinduced Hubbard band mixing by ultrashort laser pulse is found in a one-dimensional half-filled Hubbard model through the optical conductivity. The nonlinear development of Drude-like (metallic) weight in the resonant optical pumping (${\ensuremath{\omega}}_{\mathrm{pu}}\ensuremath{\approx}{E}_{g}$; ${\ensuremath{\omega}}_{\mathrm{pu}}$ is the pumping laser energy and ${E}_{g}$ is the gap energy) indicates reconstruction and mixing of the upper and lower Hubbard bands, in contrast to the case of linear development in off-resonant pumping $({\ensuremath{\omega}}_{\mathrm{pu}}⪢{E}_{g})$ where the rigid band picture is valid. The photoemission response after the ultrashort pulse confirms our finding.

Physical Review B•Nov 28, 2007•16 citations

Glassy dynamics of the one-dimensional Mott insulator excited by a strong terahertz pulse

Kazuya Shinjo, Shigetoshi Sota, Takami Tohyama

The elucidation of nonequilibrium states in strongly correlated systems holds the key to emergence of novel quantum phases.The nonequilibrium-induced insulator-to-metal transition is particularly interesting since it reflects the fundamental nature of competition between itinerancy and localization of the charge degrees of freedom.We investigate pulse-excited insulator-to-metal transition of the half-filled one-dimensional extended Hubbard model.Calculating the time-dependent optical conductivity with the time-dependent density-matrix renormalization group, we find that strong mono-and half-cycle pulses inducing quantum tunneling strongly suppress spectral weights contributing to the Drude weight σ D , even if we introduce a large number of carriers n d .This is in contrast to a metallic behavior of σ D ∝ n d induced by photon absorption and chemical doping.The strong suppression of σ D in quantum tunneling is a result of the emergence of the Hilbert-space fragmentation, which makes pulse-excited states glassy.

arXiv:2202.04322•Physical Review Research•Aug 3, 2022•8 citations

Ultrafast transient interference in pump-probe spectroscopy of band and Mott insulators

Kazuya Shinjo, Takami Tohyama

Ultrafast pump-probe spectroscopy with high temporal and spectral resolutions provides new insight into ultrafast nonequilibrium phenomena. We propose that transient interference between pump and probe pulses is realized in pump-probe spectroscopy of band and Mott insulators, which can be observed only after recent developments of ultrafast spectroscopic techniques. A continuum structure in the excitation spectrum of band insulators is found to act as a medium for storing the spectral information of the pump pulse, and the spectrum detected by the probe pulse is interfered with by the medium, generating the transient interference in the energy domain. We also demonstrate the transient interference in the presence of electron correlations in a one-dimensional half-filled Hubbard model. Furthermore, bosons coupled to electrons additively contribute to the interference. Our finding will provide an interpretation of probe-energy-dependent oscillations recently observed in the pump-probe spectrum for a two-dimensional Mott insulator.

arXiv:1805.09486•Physical review. B./Physical review. B•Oct 2, 2018•14 citations
The development of high-intensity ultrashort laser pulses unlocks the potential of pump-probe spectroscopy in sub-femtosecond timescale. Notably, subcycle pump pulses can generate electronic states unreachable by conventional multicycle pulses, leading to a phenomenon that we refer to as subcycle-pulse engineering. In this study, we employ the time-dependent density-matrix renormalization group method to unveil the transient absorption spectra of superconducting and metallic states in nearly half-filled one-dimensional and two-dimensional Hubbard models excited by an ultrashort half-cycle pulse, which can induce a current with inversion-symmetry breaking. In a superconducting state realized in attractive on-site interactions, we find the transient activation of absorptions at energies corresponding to the amplitude modes of superconducting and charge-density-wave states. On the other hand, in a metallic state realized in the two-dimensional model with repulsive on-site interactions, we obtain another type of absorption enhancements, which are distributed broadly in spin excitation energies. These findings indicate that superconducting and metallic states are sensitive to an ultrashort half-cycle pulse, leading to the transient activations of optical absorptions with their respective mechanisms.
Owning to their high controllability, laser pulses have contributed greatly to our understanding of strongly correlated electron systems. However, typical multicycle pulses do not control the symmetry of systems, which plays an important role in the emergence of novel quantum phases. Here, we demonstrate that subcycle pulses whose oscillation is less than one period within a pulse envelope can control inversion and time-reversal symmetries in the electronic states of the one-dimensional extended Hubbard model. Using an ultrashort subcycle pulse, one can generate a steady electric current (SEC) in a photoexcited state due to an Aharonov-Bohm flux instantaneously introduced through the phase of an electric field. Consequently, time-reversal symmetry is broken. In contrast, a broad subcycle pulse does not induce SEC but instead generates electric polarization, thus breaking inversion symmetry. Both symmetry breakings in a photoexcited state can be monitored by second-harmonic generation. These findings provide a new methodology for designing the symmetries of electronic states and open up a new field of subcycle-pulse engineering.
Abstract Strongly correlated solids are complex and fascinating quantum systems, where new electronic states continue to emerge, especially when interaction with light triggers interplay between them. In this interplay, a sub-laser-cycle electronic response is particularly attractive as a tool for the ultrafast manipulation of matter at the petahertz scale. Here we introduce a new type of nonlinear multidimensional spectroscopy, which allows us to unravel charge and energy flows in strongly correlated systems interacting with few-cycle infrared pulses and the complex interplay between different correlated states evolving on the sub-femtosecond timescale. We demonstrate that the sub-cycle spectroscopy of a single-particle electronic response is extremely sensitive to correlated many-body dynamics and provides direct access to many-body response functions. For the two-dimensional Hubbard model under the influence of ultrashort, intense electric-field transients, we resolve the sub-femtosecond pathways of charge and energy flows between localized and delocalized many-body states and the creation of a highly correlated state surviving after the end of the laser pulse. Our findings open the way towards a regime of imaging and manipulating strongly correlated materials at optical rates, beyond the multicycle approach employed in Floquet engineering, with the sub-cycle response being a key tool for accessing many-body phenomena.
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 lies on nonequilibrium optical conductivity and single-particle excitation spectra. In the spin-density-wave (SDW) phase, we identify an in-gap state in the nonequilibrium optical conductivity due to the formation of excitons (or doublon-holon pairs), generated by the pulse through nonlocal interactions. In the strong-coupling regime, we discern additional multiple in-gap and out-of-gap states. In the charge-density-wave (CDW) phase, we detect not only an in-gap state but also a finite Drude weight, which results from the dissolution of charge order by photoexcitation. Analyzing time-dependent single-particle excitation spectra directly in the thermodynamic limit confirms the origin of these new states in the SDW and CDW phases as the excitation of newly emerged dispersions. We illustrate that the pump-probe spectroscopy simulations in the thermodynamic limit furnish unambiguous spectral structures that allow for direct comparison with experimental results, and the integration of nonequilibrium optical conductivity and time- and angle-resolved photoemission spectroscopy provides comprehensive insights into nonequilibrium states.
Based on the nonperturbative many-body time-dependent approach, photoinduced Hubbard band mixing by ultrashort laser pulse is found in a one-dimensional half-filled Hubbard model through the optical conductivity. The nonlinear development of Drude-like (metallic) weight in the resonant optical pumping (${\ensuremath{\omega}}_{\mathrm{pu}}\ensuremath{\approx}{E}_{g}$; ${\ensuremath{\omega}}_{\mathrm{pu}}$ is the pumping laser energy and Eg{E}_{g}Eg​ is the gap energy) indicates reconstruction and mixing of the upper and lower Hubbard bands, in contrast to the case of linear development in off-resonant pumping $({\ensuremath{\omega}}_{\mathrm{pu}}⪢{E}_{g})$ where the rigid band picture is valid. The photoemission response after the ultrashort pulse confirms our finding.
The elucidation of nonequilibrium states in strongly correlated systems holds the key to emergence of novel quantum phases.The nonequilibrium-induced insulator-to-metal transition is particularly interesting since it reflects the fundamental nature of competition between itinerancy and localization of the charge degrees of freedom.We investigate pulse-excited insulator-to-metal transition of the half-filled one-dimensional extended Hubbard model.Calculating the time-dependent optical conductivity with the time-dependent density-matrix renormalization group, we find that strong mono-and half-cycle pulses inducing quantum tunneling strongly suppress spectral weights contributing to the Drude weight σ D , even if we introduce a large number of carriers n d .This is in contrast to a metallic behavior of σ D ∝ n d induced by photon absorption and chemical doping.The strong suppression of σ D in quantum tunneling is a result of the emergence of the Hilbert-space fragmentation, which makes pulse-excited states glassy.
Ultrafast pump-probe spectroscopy with high temporal and spectral resolutions provides new insight into ultrafast nonequilibrium phenomena. We propose that transient interference between pump and probe pulses is realized in pump-probe spectroscopy of band and Mott insulators, which can be observed only after recent developments of ultrafast spectroscopic techniques. A continuum structure in the excitation spectrum of band insulators is found to act as a medium for storing the spectral information of the pump pulse, and the spectrum detected by the probe pulse is interfered with by the medium, generating the transient interference in the energy domain. We also demonstrate the transient interference in the presence of electron correlations in a one-dimensional half-filled Hubbard model. Furthermore, bosons coupled to electrons additively contribute to the interference. Our finding will provide an interpretation of probe-energy-dependent oscillations recently observed in the pump-probe spectrum for a two-dimensional Mott insulator.