Real-space structure of the impurity screening cloud in the resonant level model

Ghosh, Shreyoshi; Ribeiro, Pedro; Haque, Masudul

doi:10.1088/1742-5468/2014/04/p04011

Cited by 20 publications

(45 citation statements)

References 41 publications

(85 reference statements)

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“…The result is the enhancement of the electron localization. Finally, the rotation of the magnetic field h ef f along the NW also explains why, despite the quench potential (14) directly acts on the charge channel, a response indirectly appears also in the spin channel and, in particular, also in polarization components that are orthogonal to the actual external applied magnetic field.…”

Section: Interpretation Of the Resultsmentioning

confidence: 99%

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Coherent charge and spin oscillations induced by local quenches in nanowires with spin-orbit coupling

et al. 2019

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When a local and attractive potential is quenched in a nanowire, the spectrum changes its topology from a purely continuum to a continuum and discrete portion. We show that, under appropriate conditions, this quench leads to stable coherent oscillations in the observables time evolution. In particular, we demonstrate that ballistic nanowires with spin-orbit coupling (SOC) exposed to a uniform magnetic field are especially suitable to observe this effect. Indeed, while in ordinary nanowires the effect occurs only if the strength U0 of the attractive potential is sufficiently strong, even a weak value of U0 is sufficient in SOC nanowires. Furthermore, in these systems coherent oscillations in the spin sector can be generated and controlled electrically by quenching the gate voltage acting on the charge sector. We interpret the origin of this phenomenon, analyze the effect of variation of the chemical potential and the switching time of the quenched attractive potential, and address possible implementation schemes. arXiv:1909.01574v1 [cond-mat.mes-hall]

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Section: Interpretation Of the Resultsmentioning

confidence: 99%

“…Finally, as a model for the spatial profile for the quench potential in Eq. (14) we adopt the Gaussian profile…”

Section: Density Matrix Approachmentioning

confidence: 99%

Coherent charge and spin oscillations induced by local quenches in nanowires with spin-orbit coupling

et al. 2019

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“…Here, we follow the discussion of Ref. 64. We consider a fermionic impurity with a corresponding creation operator d † coupled to a bath of fermions, which here is represented by a periodic chain of L fermions with associated creation operators c † i .…”

Section: A the Resonant Level Modelmentioning

confidence: 99%

Matrix product state algorithms for Gaussian fermionic states

Schuch

Bauer

2019

Phys. Rev. B

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While general quantum many-body systems require exponential resources to be simulated on a classical computer, systems of non-interacting fermions can be simulated exactly using polynomially scaling resources. Such systems may be of interest in their own right, but also occur as effective models in numerical methods for interacting systems, such as Hartree-Fock, density functional theory, and many others. Often it is desirable to solve systems of many thousand constituent particles, rendering these simulations computationally costly despite their polynomial scaling. We demonstrate how this scaling can be improved by adapting methods based on matrix product states, which have been enormously successful for low-dimensional interacting quantum systems, to the case of free fermions. Compared to the case of interacting systems, our methods achieve an exponential speedup in the entanglement entropy of the state. We demonstrate their use to solve systems of up to one million sites with an effective MPS bond dimension of 10 15 . CONTENTS

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“…In Ref. [44], the equilibrium screening cloud was also characterized through a study of the entanglement entropy, motivated by similar characterizations in Refs. [39,40,45].…”

Section: Model Tight-binding Realization and Equilibrium Propertiesmentioning

confidence: 99%

“…Here ρ A is the reduced density matrix of the subsystem A obtained by tracing out the degrees of freedom lying outside the subsystem, starting from the wavefunction (in this case the ground state wavefunction) of the full system. The so-called impurity entropy, defined as was shown to have, as a function of the subsystem size , a crossover to a an algebraic ∝ −1 decay at large around the same characteristic length scale ξ [44].…”

Section: Model Tight-binding Realization and Equilibrium Propertiesmentioning

confidence: 99%

Dynamics of the impurity screening cloud following quantum quenches of the resonant level model

Ghosh¹,

Ribeiro²,

Haque³

2015

J. Stat. Mech.

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We present a detailed analysis of the evolution of impurity screening cloud in the Resonant Level Model (RLM) followed by quenches of system parameters. The considered quenches are either local or found to be effectively local. The screening cloud is characterized by impurity-bath correlators and by the entanglement of a block centered around the impurity with the rest of the system. We consider several local quench protocols, such as, quenches from initially decoupled to coupled impurity, quenches between different finite couplings of the impurity, and 'detuning quenches' involving changing the onsite impurity potential away from or to the chemical potential of the bath. The relevant correlators and the entanglement display versions of the 'light-cone' effect, since the information about the quench travels through the bath at finite speed. At long times ('inside' the light cone), the impurity screening cloud relaxes exponentially to the final equilibrium structure, with the relaxation rate given by the emergent energy scale of impurity screening. Also, snaphots of the time-evolving spatial profile of impurity-bath correlators show exponential dependences on space, with the length scale given by the screening length. arXiv:1503.06836v1 [cond-mat.str-el] Dynamics of the impurity screening cloud following quantum quenches of the Resonant Level Model 10 � � � �� t xt x J i = 0.35 J i = 0.4 J i = 0.55 J f = 0.3 J f = 0.2 J f = 0.25 J i = 0.3 � � � �� Dynamics of the impurity screening cloud following quantum quenches of the Resonant Level Model 11 0.01 0.1 0.01 0.1 J i = 0 J i = 0.5 0.01 0.1 S(t) − S f 0 200 400 Time t 0.01 0.1 100 1000Time tt −3/4 t −1/2 J f = 0.4 −C Eq f (x) J = 0.25 J = 0.35 J = 0.45 J = 0.25 J i NN = 0.1 J i NN = 0.2 J i NN = 0.3 J f NN = 0.0 J i NN = 0.1 J f NN = 0.0

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Real-space structure of the impurity screening cloud in the resonant level model

Cited by 20 publications

References 41 publications

Coherent charge and spin oscillations induced by local quenches in nanowires with spin-orbit coupling

Coherent charge and spin oscillations induced by local quenches in nanowires with spin-orbit coupling

Matrix product state algorithms for Gaussian fermionic states

Dynamics of the impurity screening cloud following quantum quenches of the resonant level model

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