Multiconfiguration time-dependent Hartree impurity solver for nonequilibrium dynamical mean-field theory

We study the quench dynamics of an Anderson impurity model using the configuration interaction (CI) method. In particular, we focus on the relaxation behavior of the impurity occupation. The system is found to behave very differently in the weak-coupling and strong-coupling regimes. In the weak-coupling regime, the impurity occupation relaxes to a time-independent constant quickly after only a few oscillations. In the strong-coupling regime, the impurity occupation develops a fast oscillation, with a much slower relaxation. We show that it is the multi-peak structure in the manybody energy spectrum that separates these two regimes. The characteristic behavior, including the power-law decay and the period of oscillation, can also be related to certain features in the manybody energy spectrum. The respective advantages of several impurity solvers are discussed, and the convergence of different CI truncation schemes is provided.

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“…These general features are clearly seen in Figs. 6 and 7, and are observed using other impurity solvers [26,31,49].…”

Section: Analysis Based On Many-body Spectrummentioning

confidence: 54%

“…Recently, pioneered by Zgid and Chan [40,41], the configuration interaction (CI) method, a standard method in quantum chemistry [42][43][44][45], was successfully applied to the impurity model [46][47][48][49]. In Ref.…”

Section: Introductionmentioning

confidence: 99%

Quench dynamics of Anderson impurity model using configuration interaction method

Lin

Demkov

2015

Phys. Rev. B

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“…As will be discussed, this is indeed sufficient in many respects to cover the essentials of the dynamical Mott transition as compared to previous work [23,24]. We also discuss the significance of the method in view of recently proposed Hamiltonian-based impurity solvers [35][36][37].…”

Section: Introductionmentioning

confidence: 84%

“…This limits simulations to short times. Different implementations have been put forward to solve the finite impurity model, using exact-diagonalization techniques [35], the multiconfiguration time-dependent Hartree method [36], as well as an approach based on the matrix-product state representation [37]. With exact-diagonalization methods [35] propagation up to t max ≈ 3 inverse hoppings has been possible by providing L b = 8 bath sites at weak interactions, whereas using matrix-product states [37], t max ≈ 7 (t max ≈ 5.5) could be reached with L b = 24 (L b = 18) sites at strong (weak) interactions, i.e., the Hamiltonian based solvers are currently aiming at a numerical exact solution at short times.…”

Section: Discussion Of the Methodsmentioning

confidence: 99%

Nonequilibrium self-energy functional approach to the dynamical Mott transition

2016

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The real-time dynamics of the Fermi-Hubbard model, driven out of equilibrium by quenching or ramping the interaction parameter, is studied within the framework of the nonequilibrium self-energy functional theory. A dynamical impurity approximation with a single auxiliary bath site is considered as a reference system, and the time-dependent hybridization is optimized as prescribed by the variational principle. The dynamical two-site approximation turns out to be useful to study the real-time dynamics on short and intermediate time scales. Depending on the strength of the interaction in the final state, two qualitatively different response regimes are observed. For both weak and strong couplings, qualitative agreement with previous results of nonequilibrium dynamical mean-field theory is found. The two regimes are sharply separated by a critical point at which the low-energy bath degree of freedom decouples in the course of time. We trace the dependence of the critical interaction of the dynamical Mott transition on the duration of the interaction ramp from sudden quenches to adiabatic dynamics and therewith link the dynamical to the equilibrium Mott transition.

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“…To aid this the use of state-ofthe-art experimental quantum technologies has recently been proposed based on quantum simulating the dynamics of the SIAM with trapped ions [31] and superconducting qubits [32]. Otherwise popular approaches on a classical computer include exact diagonalization [30], multi-configurational time-dependent Hartree Fock [33] and matrix product state (MPS) calculations [17,34]. In this work we exploit a slightly different version of the latter as we now describe.…”

Section: Hamiltonian Formulationmentioning

confidence: 99%

Ultra‐Fast Control of Magnetic Relaxation in a Periodically Driven Hubbard Model

et al. 2017

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Motivated by cold atom and ultra-fast pumpprobe experiments we study the melting of longrange antiferromagnetic order of a perfect Néel state in a periodically driven repulsive Hubbard model. The dynamics is calculated for a Bethe lattice in infinite dimensions with non-equilibrium dynamical mean-field theory. In the absence of driving melting proceeds differently depending on the quench of the interactions to hopping ratio U /ν 0 from the atomic limit. For U ≫ ν 0 decay occurs due to mobile charge-excitations transferring energy to the spin sector, while for ν 0 U it is governed by the dynamics of residual quasi-particles. Here we explore the rich effects that strong periodic driving has on this relaxation process spanning three frequency ω regimes: (i) high-frequency ω ≫ U , ν 0 , (ii) resonant l ω = U > ν 0 with integer l , and (iii) ingap U > ω > ν 0 away from resonance. In case (i) we can quickly switch the decay from quasiparticle to charge-excitation mechanism through the suppression of ν 0 . For (ii) the interaction can be engineered, even allowing an effective U = 0 regime to be reached, giving the reverse switch from a charge-excitation to quasi-particle decay mechanism. For (iii) the exchange interaction can be controlled with little effect on the decay. By combining these regimes we show how periodic driving could be a potential pathway for controlling magnetism in antiferromagnetic materials.Finally, our numerical results demonstrate the accuracy and applicability of matrix product state techniques to the Hamiltonian DMFT impurity problem subjected to strong periodic driving.

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Multiconfiguration time-dependent Hartree impurity solver for nonequilibrium dynamical mean-field theory

Cited by 36 publications

References 46 publications

Quench dynamics of Anderson impurity model using configuration interaction method

Quench dynamics of Anderson impurity model using configuration interaction method

Nonequilibrium self-energy functional approach to the dynamical Mott transition

Ultra‐Fast Control of Magnetic Relaxation in a Periodically Driven Hubbard Model

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