Heat transport in theXXZspin chain: from ballistic to diffusive regimes and dephasing enhancement

Mendoza‐Arenas, J. J.; Al-Assam, Sarah; Clark, Stephen R. L.; Jaksch, Dieter

doi:10.1088/1742-5468/2013/07/p07007

Cited by 86 publications

(112 citation statements)

References 73 publications

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“…Note that this condition is independent of the integrability of the system. For example, it is consistent with the observation that the XXZ model has normal conducting states in spite of its integrability [2][3][4][5]. We can understand intuitively that Eq.…”

Section: Introductionsupporting

confidence: 88%

Origin of Temperature Gradient in Nonequilibrium Steady States in Weakly Coupled Quantum Spin Systems

Ishida

Sugita

2016

J. Phys. Soc. Jpn.

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We study nonequilibrium steady states (NESSs) in quantum spin-1/2 chains in contact with two heat baths at different temperatures. We consider the weak-coupling limit both for spin-spin coupling in the system and for system-bath coupling. This setting allows us to treat NESSs with a nonzero temperature gradient analytically. We develop a perturbation theory for this weak-coupling situation and show a simple condition for the existence of nonzero temperature gradient. This condition is independent of the integrability of the system. * Electronic address: sugita@a-phys.eng.osaka-cu.ac.jp 1 arXiv:1704.01731v1 [cond-mat.stat-mech]

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Section: Introductionsupporting

confidence: 88%

Origin of Temperature Gradient in Nonequilibrium Steady States in Weakly Coupled Quantum Spin Systems

Ishida

Sugita

2016

J. Phys. Soc. Jpn.

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“…See Fig.1 for the energy rectification versus the driving strength f for different values of ∆. We recall that for large, homogeneous chains, the cases ∆ > 1 and ∆ < 1 (α = 1) describe different situations: in the absence of a magnetic field, the ground state diagram of this model engenders a gapped phase for ∆ > 1, and a gapless one for ∆ < 1, with consequences on the transport properties [22]. In Fig.2 we plot the energy rectification versus the interaction asymmetry δ, for different values of external magnetic field B.…”

Section: Steady State Computation: Solutions and Propertiesmentioning

confidence: 98%

Energy rectification in quantum graded spin chains: Analysis of the XXZ model

2016

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In this work, with focus on the energy transport properties in quantum, low dimensional, graded materials, we address the investigation of the energy (and spin) current in XXZ open chains with graded inner structures and driven out of equilibrium by magnetization pumping applied at the ends. We study several types of graded structures in different situations in order to show a ubiquitous occurrence of energy rectification, even for the system under a homogeneous magnetic field. Due to technical difficulties, we carry out the computation for small chains, but we present arguments which indicate the extension of some results to larger systems. Recalling the generic existence of energy rectification in classical, graded materials, which are described by anharmonic chains of oscillators, and recalling also the anharmonicity of these XXZ models, which involve quartic terms in more transparent representation in terms of fermionic creation and annihilation operators, we may say that our results extend the ubiquity of energy rectification occurrence in classical graded materials to the case of quantum systems.

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“…20,23,[33][34][35][36] Besides the usual formulation in terms of Kubo formulae, many studies have recently considered steady-state transport in open quantum systems coupled to baths where similar questions, namely the conditions for the emergence of ballistic, diffusive or other forms of transport, are under active investigation, 31,[37][38][39][40] including classical models.…”

Section: 32mentioning

confidence: 99%

Real-time and real-space spin and energy dynamics in one-dimensional spin-12systems induced by local quantum quenches at finite temperatures

2014

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We study the spin-and energy dynamics in one-dimensional spin-1/2 systems induced by local quantum quenches at finite temperatures using a time-dependent density matrix renormalization group method. System sizes are chosen large enough to ensure that the time-dependent data for the accessible time scales represent the behavior in the thermodynamic limit. As a main result, we observe a ballistic spreading of perturbations of the energy density in the integrable spin-1/2 XXZ chain for all temperatures and exchange anisotropies, related to the divergent thermal conductivity in this model and the exact conservation of the energy current. In contrast, the spin dynamics is ballistic in the massless phase, but shows a diffusive behavior at high temperatures in the easy-axis phase in the case of a vanishing background spin density. We extract a quantitative estimate for the spin diffusion constant from the time dependence of the spatial variance of the spin density, which agrees well with values obtained from current-current correlation functions using an Einstein relation. Interestingly, the diffusion constant approaches a constant value deep in the easy-axis regime. As an example for non-integrable models, we consider two-leg ladders, for which we observe indications of diffusive energy and spin dynamics. The relevance of our results for recent experiments with quantum magnets and bosons in optical lattices is discussed.

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Heat transport in theXXZspin chain: from ballistic to diffusive regimes and dephasing enhancement

Cited by 86 publications

References 73 publications

Origin of Temperature Gradient in Nonequilibrium Steady States in Weakly Coupled Quantum Spin Systems

Origin of Temperature Gradient in Nonequilibrium Steady States in Weakly Coupled Quantum Spin Systems

Energy rectification in quantum graded spin chains: Analysis of the XXZ model

Real-time and real-space spin and energy dynamics in one-dimensional spin-12systems induced by local quantum quenches at finite temperatures

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