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:2304.12962 · Physical review. B./Physical review. B

Nonequilibrium phononic first-order phase transition in a driven fermion chain

Mohsen Yarmohammadi, Marin Bukov, Michael Kolodrubetz

Published Oct 26, 2023• 10 citations
arXivHTMLPDF

Abstract

We study the direct laser drive of infrared-active phonons that are quadratically coupled to a spinless fermion chain. Feedback is incorporated by phonon dressing of the electronic dispersion, which enables effective nonlinearities in the phonon dynamics. We uncover a first-order phase transition in the phononic steady state in which hysteretic effects allow either large or small phonon occupation depending on the drive protocol. We discuss the implications of these findings for probing phase transitions in real driven materials.

DOI
10.1103/physrevb.108.l140305

Related papers

Dynamical phase transition in a strongly hybridized phonon-triplon chain

Mohsen Yarmohammadi

We study a dimerized spin-1/2 chain, such as ${\mathrm{CuGeO}}_{3}$, hosting triplon excitations coupled to optical phonons under weak terahertz laser driving. Both phonons and triplons weakly lose energy into the surrounding baths, forming a nonequilibrium steady state. In the strong phonon-triplon coupling regime, phonons near the two-triplon continuum hybridize strongly with triplons. Using mean-field Lindblad dynamics, we show that strong hybridization induces sharp first-order phase transitions---either single or simultaneous double---in the emission spectrum, mainly due to nonlinearities in the chain and the instantaneous breaking of spatial inversion symmetry, as captured by the phonon displacement. Using mean-field Floquet analysis of harmonic modes in both sectors, we analytically confirm the existence of these phase transitions. Furthermore, we map the complete steady-state phase diagram by varying key control parameters and provide experimentally relevant parameters for observing these transitions in laser-driven ${\mathrm{CuGeO}}_{3}$.

arXiv:2507.20692•Physical review. B./Physical review. B•Oct 6, 2025•5 citations

Spin high harmonic generation through terahertz laser-driven phonons

Negin Moharrami Allafi, Michael Kolodrubetz, Marin Bukov +2 more

In the realm of open quantum systems, steady states and high-harmonic generation (HHG) existing far from equilibrium have become core pillars of ultrafast science. Most solid-state research explores charge HHG with limited investigations into spin degrees of freedom. In this study, we theoretically address spin HHG in the steady state resulting from the terahertz laser-driven spin-phonon coupling in a dissipative dimerized spin-1/2 chain. Instead of directly driving spins using time-dependent magnetic fields, we employ the magnetophononic mechanism, where the laser first drives the lattice, and then the excited lattice subsequently drives the spins. We investigate the role of various model parameters for optimizing HHG. Increasing the laser amplitude amplifies spin HHG beyond the perturbative regime, enhancing both harmonic amplitudes and orders. We find that configuring the drive frequency far below the spin band yields the highest harmonic order. Additionally, we provide a theory matching the numerical results under weak spin-phonon coupling and propose an experimental procedure to probe the emission spectrum of spin HHG.

arXiv:2404.05830•Physical review. B./Physical review. B•Aug 19, 2024•16 citations

Light-enhanced electron-phonon coupling from nonlinear electron-phonon coupling

Michael A. Sentef

We investigate an exact nonequilibrium solution of a two-site electron-phonon model, where an infrared-active phonon that is nonlinearly coupled to the electrons is driven by a laser field. The time-resolved electronic spectrum shows coherence-incoherence spectral weight transfer, a clear signature of light-enhanced electron-phonon coupling. The present study is motivated by recent evidence for enhanced electron-phonon coupling in pump-probe terahertz and angle-resolved photoemission spectroscopy in bilayer graphene when driven near resonance with an infrared-active phonon mode [E. Pomarico et al., Phys. Rev. B 95, 024304 (2017)], and by a theoretical study suggesting that transient electronic attraction arises from nonlinear electron-phonon coupling [D. M. Kennes et al., Nat. Phys. 13, 479 (2017)]. We show that a linear scaling of light-enhanced electron-phonon coupling with the pump field intensity emerges, in accordance with a time-nonlocal self-energy based on a mean-field decoupling using quasiclassical phonon coherent states. Finally, we demonstrate that this leads to enhanced double occupancies in accordance with an effective electron-electron attraction. Our results suggest that materials with strong phonon nonlinearities provide an ideal playground to achieve light-enhanced electron-phonon coupling and possibly light-induced superconductivity.

arXiv:1702.00952•Physical review. B./Physical review. B•May 8, 2017•105 citations

Nonequilibrium phase transition in transport through a driven quantum point contact

Oleksandr Gamayun, A. O. Slobodeniuk, Jean-Sébastien Caux +1 more

We study the transport of noninteracting fermions through a periodically driven quantum point contact (QPC) connecting two tight-binding chains. Initially, each chain is prepared in its own equilibrium state, generally with a bias in chemical potentials and temperatures. We examine the heating rate (or, alternatively, energy increase per cycle) in the nonequilibrium time-periodic steady state established after initial transient dynamics. We find that the heating rate vanishes identically when the driving frequency exceeds the bandwidth of the chain. We first establish this fact for a particular type of QPCs where the heating rate can be calculated analytically. Then we verify numerically that this nonequilibrium phase transition is present for a generic QPC. Finally, we derive this effect perturbatively in leading order for cases when the QPC Hamiltonian can be considered a small perturbation. Strikingly, we discover that for certain QPCs the current averaged over the driving cycle also vanishes above the critical frequency, despite a persistent bias. This shows that a driven QPC can act as a frequency-controlled quantum switch.

arXiv:2006.02400•Physical review. B./Physical review. B•Jan 22, 2021•24 citations

Nonequilibrium steady states and transient dynamics of conventional superconductors under phonon driving

Yuta Murakami, Naoto Tsuji, Martin Eckstein +1 more

The optical manipulation of phonon degrees of freedom can change the effective interactions in solids and potentially enhance superconductivity. However, heating and nonthermal energy distributions need to be considered to understand the ultimate effects of such a driving on ordered states. Using nonequilibrium dynamical mean field theory in the Kadanoff-Baym and Floquet implementation, the authors systematically discuss the effects of parametric phonon driving on conventional superconductivity. Both the transient dynamics of isolated systems and the nonequilibrium steady states in driven-dissipative systems are considered. While the phonon-mediated attractive interaction can be enhanced in certain driving regimes because of Floquet phonon sidebands, the heating and nonthermal distribution effects dominate and generically result in a suppression of superconductivity.

arXiv:1702.02942•Physical review. B./Physical review. B•Jul 19, 2017•154 citations

Nonequilibrium steady states and transient dynamics of superconductors under phonon driving

Yuta Murakami, Naoto Tsuji, Martin Eckstein +1 more

We perform a systematic analysis of the influence of phonon driving on the superconducting Hol- stein model coupled to heat baths by studying both the transient dynamics and the nonequilibrium steady state (NESS) in the weak and strong electron-phonon coupling regimes. Our study is based on the nonequilibrium dynamical mean-field theory, and for the NESS we present a Floquet formu- lation adapted to electron-phonon systems. The analysis of the phonon propagator suggests that the effective attractive interaction can be strongly enhanced in the parametric resonant regime because of the Floquet side bands. While this may be expected to enhance the superconductivity (SC), our fully self-consistent calculations, which include the effects of heating and nonthermal distributions, show that the parametric phonon driving generically results in a suppression or complete melting of the SC order. In the strong coupling regime, the NESS always shows a suppression of the SC gap, the SC order parameter and the superfluid density as a result of the driving, and this tendency is most prominent at the parametric resonance. Using the real-time nonequilibrium DMFT formalism, we also study the dynamics towards the NESS, which shows that the heating effect dominates the transient dynamics, and SC is weakened by the external modulations, in particular at the parametric resonance. In the weak coupling regime, we find that the SC fluctuations above the transition tem- perature are generally weakened under the driving. The strongest suppression occurs again around the parametric resonance because of the efficient energy absorption.

•Feb 9, 2017•3 citations
We study the direct laser drive of infrared-active phonons that are quadratically coupled to a spinless fermion chain. Feedback is incorporated by phonon dressing of the electronic dispersion, which enables effective nonlinearities in the phonon dynamics. We uncover a first-order phase transition in the phononic steady state in which hysteretic effects allow either large or small phonon occupation depending on the drive protocol. We discuss the implications of these findings for probing phase transitions in real driven materials.
We study a dimerized spin-1/2 chain, such as CuGeO3{\mathrm{CuGeO}}_{3}CuGeO3​, hosting triplon excitations coupled to optical phonons under weak terahertz laser driving. Both phonons and triplons weakly lose energy into the surrounding baths, forming a nonequilibrium steady state. In the strong phonon-triplon coupling regime, phonons near the two-triplon continuum hybridize strongly with triplons. Using mean-field Lindblad dynamics, we show that strong hybridization induces sharp first-order phase transitions---either single or simultaneous double---in the emission spectrum, mainly due to nonlinearities in the chain and the instantaneous breaking of spatial inversion symmetry, as captured by the phonon displacement. Using mean-field Floquet analysis of harmonic modes in both sectors, we analytically confirm the existence of these phase transitions. Furthermore, we map the complete steady-state phase diagram by varying key control parameters and provide experimentally relevant parameters for observing these transitions in laser-driven CuGeO3{\mathrm{CuGeO}}_{3}CuGeO3​.
In the realm of open quantum systems, steady states and high-harmonic generation (HHG) existing far from equilibrium have become core pillars of ultrafast science. Most solid-state research explores charge HHG with limited investigations into spin degrees of freedom. In this study, we theoretically address spin HHG in the steady state resulting from the terahertz laser-driven spin-phonon coupling in a dissipative dimerized spin-1/2 chain. Instead of directly driving spins using time-dependent magnetic fields, we employ the magnetophononic mechanism, where the laser first drives the lattice, and then the excited lattice subsequently drives the spins. We investigate the role of various model parameters for optimizing HHG. Increasing the laser amplitude amplifies spin HHG beyond the perturbative regime, enhancing both harmonic amplitudes and orders. We find that configuring the drive frequency far below the spin band yields the highest harmonic order. Additionally, we provide a theory matching the numerical results under weak spin-phonon coupling and propose an experimental procedure to probe the emission spectrum of spin HHG.
We investigate an exact nonequilibrium solution of a two-site electron-phonon model, where an infrared-active phonon that is nonlinearly coupled to the electrons is driven by a laser field. The time-resolved electronic spectrum shows coherence-incoherence spectral weight transfer, a clear signature of light-enhanced electron-phonon coupling. The present study is motivated by recent evidence for enhanced electron-phonon coupling in pump-probe terahertz and angle-resolved photoemission spectroscopy in bilayer graphene when driven near resonance with an infrared-active phonon mode [E. Pomarico et al., Phys. Rev. B 95, 024304 (2017)], and by a theoretical study suggesting that transient electronic attraction arises from nonlinear electron-phonon coupling [D. M. Kennes et al., Nat. Phys. 13, 479 (2017)]. We show that a linear scaling of light-enhanced electron-phonon coupling with the pump field intensity emerges, in accordance with a time-nonlocal self-energy based on a mean-field decoupling using quasiclassical phonon coherent states. Finally, we demonstrate that this leads to enhanced double occupancies in accordance with an effective electron-electron attraction. Our results suggest that materials with strong phonon nonlinearities provide an ideal playground to achieve light-enhanced electron-phonon coupling and possibly light-induced superconductivity.
We study the transport of noninteracting fermions through a periodically driven quantum point contact (QPC) connecting two tight-binding chains. Initially, each chain is prepared in its own equilibrium state, generally with a bias in chemical potentials and temperatures. We examine the heating rate (or, alternatively, energy increase per cycle) in the nonequilibrium time-periodic steady state established after initial transient dynamics. We find that the heating rate vanishes identically when the driving frequency exceeds the bandwidth of the chain. We first establish this fact for a particular type of QPCs where the heating rate can be calculated analytically. Then we verify numerically that this nonequilibrium phase transition is present for a generic QPC. Finally, we derive this effect perturbatively in leading order for cases when the QPC Hamiltonian can be considered a small perturbation. Strikingly, we discover that for certain QPCs the current averaged over the driving cycle also vanishes above the critical frequency, despite a persistent bias. This shows that a driven QPC can act as a frequency-controlled quantum switch.
The optical manipulation of phonon degrees of freedom can change the effective interactions in solids and potentially enhance superconductivity. However, heating and nonthermal energy distributions need to be considered to understand the ultimate effects of such a driving on ordered states. Using nonequilibrium dynamical mean field theory in the Kadanoff-Baym and Floquet implementation, the authors systematically discuss the effects of parametric phonon driving on conventional superconductivity. Both the transient dynamics of isolated systems and the nonequilibrium steady states in driven-dissipative systems are considered. While the phonon-mediated attractive interaction can be enhanced in certain driving regimes because of Floquet phonon sidebands, the heating and nonthermal distribution effects dominate and generically result in a suppression of superconductivity.
We perform a systematic analysis of the influence of phonon driving on the superconducting Hol- stein model coupled to heat baths by studying both the transient dynamics and the nonequilibrium steady state (NESS) in the weak and strong electron-phonon coupling regimes. Our study is based on the nonequilibrium dynamical mean-field theory, and for the NESS we present a Floquet formu- lation adapted to electron-phonon systems. The analysis of the phonon propagator suggests that the effective attractive interaction can be strongly enhanced in the parametric resonant regime because of the Floquet side bands. While this may be expected to enhance the superconductivity (SC), our fully self-consistent calculations, which include the effects of heating and nonthermal distributions, show that the parametric phonon driving generically results in a suppression or complete melting of the SC order. In the strong coupling regime, the NESS always shows a suppression of the SC gap, the SC order parameter and the superfluid density as a result of the driving, and this tendency is most prominent at the parametric resonance. Using the real-time nonequilibrium DMFT formalism, we also study the dynamics towards the NESS, which shows that the heating effect dominates the transient dynamics, and SC is weakened by the external modulations, in particular at the parametric resonance. In the weak coupling regime, we find that the SC fluctuations above the transition tem- perature are generally weakened under the driving. The strongest suppression occurs again around the parametric resonance because of the efficient energy absorption.