Memory truncated Kadanoff-Baym equations

Stahl, Christopher; Dasari, Nagamalleswararao; Li, Jiajun; Picano, Antonio; Werner, Philipp; Eckstein, Martin

doi:10.1103/physrevb.105.115146

Cited by 10 publications

(5 citation statements)

References 78 publications

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“…Because this solution involves Dyson-type equations in which the self-energy plays the role of a memory kernel, a calculation which retains the memory back to the initial state is very costly in terms of memory [O(N 2 )] and computational complexity [O(N 3 ) in the NCA case]. To improve the scaling and propagate the solution to longer times a memory-truncation scheme has been proposed [29,30], in which the self-energy is stored only within a time window defined by a sufficiently large cutoff t cut = N cut h. This allows us to reduce the memory and computational costs to O(N 2 cut ) and O(N • N 2 cut ), respectively.…”

Section: Memory Truncationmentioning

confidence: 99%

Photoinduced charge dynamics in 1T−TaS2

Petocchi

Chen

et al. 2023

Phys. Rev. B

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Recent theoretical studies showed that the electronic structure of 1T -TaS 2 in the low-temperature commensurate charge density wave phase exhibits a nontrivial interplay between band-insulating and Mott-insulating behavior. This has important implications for the interpretation of photodoping experiments. Here we use nonequilibrium dynamical mean-field theory simulations of a realistic multilayer structure to clarify the charge carrier dynamics induced by a laser pulse. The solution is propagated up to the picosecond timescale by employing a memory-truncation scheme. While long-lived doublons and holons only exist in the surface state of a specific structure, the disturbance of bonding states in the bilayers which make up the bulk of the system explain the almost instantaneous appearance of in-gap states. Our simulations consistently explain the coexistence of a doublon feature with a prominent "background" signal in previous time-resolved photoemission experiments, and they suggest strategies for the selective population of the in-gap and doublon states by exploiting the sensitivity to the pump polarization and pump frequency.

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Section: Memory Truncationmentioning

confidence: 99%

Photoinduced charge dynamics in 1T−TaS2

Petocchi

Chen

et al. 2023

Phys. Rev. B

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“…While the effective temperatures extracted from the charge and spin susceptibilities and single-particle Green's function are relatively well defined in frequency space, they differ substantially from each other and depend on the momentum, which shows that a unique nonequilibrium temperature of a strongly perturbed weakly interacting system cannot be defined within a few hopping times after a ramp. How exactly the different effective temperatures approach the thermal value in the weak-and intermediate-correlation regime is an interesting subject for further studies, which however requires the implementation of memory-truncation techniques [45] to access the long-time dynamics.…”

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confidence: 99%

Nonequilibrium Two-Particle Self-Consistent Approach

Simard¹,

Werner²

2022

Preprint

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We present the nonequilibrium implementation of the two-particle self-consistent (TPSC) approach, which has been shown to provide a reliable equilibrium description of interacting lattice systems in the weak-and intermediate-correlation regime. This method captures the effects of local and nonlocal correlations in two-and higher-dimensional systems and satisfies the Mermin-Wagner theorem. We demonstrate the versatility of nonequilibrium TPSC with calculations of the timedependent spin and charge response functions and the evolution of effective temperatures extracted from different correlation functions, after interaction ramps in the two-dimensional Hubbard model.

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“…While dynamical mean-field theory (DMFT) [37] is in principle ideally suited to study the Mott phase, previous simulations simply could not reach sufficiently long times to systematically examine the cold photo-doped states [24,35,36]. Here we use a systematic and convergent truncation of the Kadanoff-Baym equations within DMFT to reach about 50 times longer simulation times [38,39]. This allows us to study the properties of the photo-doped MI up to thousands of hopping times, corresponding to a picosecond timescale if the bandwidth is in the eV range.…”

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A photo-induced strange metal with electron and hole quasi-particles

Dasari,

Li,

Werner

et al. 2020

Preprint

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Photo-doping of Mott insulators or correlated metals can create an unusual metallic state which simultaneously hosts hole-like and electron-like particles. We study the dynamics of this state up to long times, as it passes its kinetic energy to the environment. When the system cools down, it crosses over from a bad metal into a resilient quasiparticle regime, in which quasiparticle bands are formed with separate Fermi levels for electrons and holes, but quasiparticles do not yet satisfy the Fermi liquid paradigm. Subsequently, the transfer of energy to the environment slows down significantly, and the system does not reach the Fermi liquid state even on the timescale of picoseconds. The transient photo-doped strange metal exhibits unusual properties of relevance for ultrafast charge and heat transport: In particular, there can be an asymmetry in the properties of electrons and holes, and strong correlations between electrons and holes, as seen in the spectral properties.

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Memory truncated Kadanoff-Baym equations

Cited by 10 publications

References 78 publications

Photoinduced charge dynamics in 1T−TaS2

Photoinduced charge dynamics in 1T−TaS2

Nonequilibrium Two-Particle Self-Consistent Approach

A photo-induced strange metal with electron and hole quasi-particles

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