Quantum chaos of the Bose-Fermi Kondo model at intermediate temperature

Han, X.; Yu, Zuodong

doi:10.1103/physrevb.104.085139

Cited by 7 publications

(2 citation statements)

References 40 publications

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“…Eq. (25) shows the singularity at z = z of the G B (z, z ) explicitly. By using G φ (z, z ) instead of the G B (z, z ), we can avoid the singularity issue and Eq.…”

Section: Kadanoff-baym Equationsmentioning

confidence: 99%

“…Studying the non-equilibrium properties of MCKIs can provide insight into extracting universal properties of generic many-body systems far from equilibrium. Especially, the fact that the non-Fermi liquid phase appears in the MCKI models makes it more interesting to study due to its relevance to the quantum chaos [24,25]. Additionally, the existence of fractionalized excitations in the MCKI model [26] serves as a significant motivation for recent researches on its non-equilibrium properties, specifically in relation to the manipulation of qubit states in quantum computing physics.…”

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confidence: 99%

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Thermalization and transient dynamics in Multi-Channel Kondo systems under the quantum quench: Large-$N$ Schwinger-Keldysh approach

Jang¹,

Chang²

2023

Preprint

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Understanding properties in out-of-equilibrium many-body quantum systems is an essential task in modern physics. While cutting-edge numerical methods have been developed, extracting the universal dynamics of generic many-body quantum systems remains a big challenge. The multi-channel Kondo impurity (MCKI) model, one of the exotic phases of matter that hosts an over-screened Kondo state with non-Fermi liquid properties, provides a platform for theoretically studying the universal properties of quantum dynamics in many-body systems. By using the large-N Schwinger-Keldysh approach, we systematically investigate transient dynamics and long-time thermalization properties in MCKI under a sudden change of the Kondo coupling. First, we observe oscillations of physical observables such as spin-spin correlations, the Kondo order parameter, and the Kondo energy density for the initial state being an over-screened Kondo state. These oscillations can be interpreted as the quantum revival of the entangled state that describes the over-screened Kondo state. On the other hand, for the initial state that is the high-temperature Fermi liquid, there are no oscillations due to the de-phasing mechanism. Second, we find thermalization properties such as the thermalization time and the final effective temperature strongly depend on the initial state and the quench protocol. The equilibration happens when the Kondo coupling is suddenly increasing under certain conditions. When the Kondo coupling constant is reduced, we observe incoherent thermalization between the impurity and the conduction electrons from the non-vanishing difference between the final effective temperatures between the Abrikosov fermion representing the impurity and the composite boson composed by the Abrikosov fermion and conduction electrons. Additionally, the quantum cooling effect, the consideration of the 1/N correction to the conduction electrons, and quantum Boltzmann equations are discussed. Our approach sets the groundwork for investigations of more complex many-body systems, and our results reveal several universal properties of quantum dynamics and offer deeper insight into quantum thermalization.

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“…Eq. (25) shows the singularity at z = z of the G B (z, z ) explicitly. By using G φ (z, z ) instead of the G B (z, z ), we can avoid the singularity issue and Eq.…”

Section: Kadanoff-baym Equationsmentioning

confidence: 99%

mentioning

confidence: 99%