Dynamics of coupled spins in the white- and quantum-noise regime

Nägele, Peter; Weiß, Ulrich

doi:10.1016/j.physe.2009.06.060

Cited by 8 publications

(4 citation statements)

References 13 publications

(25 reference statements)

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“…One common approach is to account for the interblip correlations up to first order in the spin-bath coupling α. 3,37 This procedure, however, is equivalent to the perturbative Redfield approach that we have discussed in Sec. IV B.…”

Section: Synchronization Of Spin Dynamicsmentioning

confidence: 99%

Dynamics, synchronization, and quantum phase transitions of two dissipative spins

Orth¹,

Roosen²,

Hofstetter³

et al. 2010

Phys. Rev. B

108

137

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We analyze the static and dynamical properties of two Ising-coupled quantum spins embedded in a common bosonic bath as an archetype of dissipative quantum mechanics. First, we elucidate the ground state phase diagram for an ohmic and a subohmic bath using a combination of bosonic numerical renormalization group (NRG), analytical techniques and intuitive arguments. Second, employing the time-dependent NRG we investigate the system's rich dynamical behavior arising from the complex interplay between spin-spin and spin-bath interactions. Interestingly, spin oscillations can synchronize due to the proximity of the common non-Markovian bath and the system displays highly entangled steady states for certain nonequilibrium initial preparations. We complement our non-perturbative numerical results by exact analytical solutions when available and provide quantitative limits on the applicability of the perturbative Bloch-Redfield approach at weak coupling.

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Section: Synchronization Of Spin Dynamicsmentioning

confidence: 99%

Dynamics, synchronization, and quantum phase transitions of two dissipative spins

Orth¹,

Roosen²,

Hofstetter³

et al. 2010

Phys. Rev. B

108

137

View full text Add to dashboard Cite

show abstract

“…An interesting question is: what happens to this transition if one couples several two-level systems, like impurities or q-bits, to a bosonic dissipative bath? The simplest generalization of this kind is a pair of two-level systems, which has been studied the first time in [6] and subsequently by [7][8][9][10][11][12][13][14]. In many studies of the two-spin-boson model an additional ferromagnetic coupling between the two-level systems of spins has been taken into account.…”

Section: Introductionmentioning

confidence: 99%

Quantum phase transition and correlations in the multi-spin-boson model

Winter

Rieger

2014

Phys. Rev. B

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We consider multiple non-interacting quantum mechanical two-level systems coupled to a common bosonic bath and study its quantum phase transition with Monte Carlo simulations using a continuous imaginary time cluster algorithm. The common bath induces an effective ferromagnetic interaction between the otherwise independent two-level systems, which can be quantified by an effective interaction strength. For degenerate energy levels above a critical value of the bath coupling strength α all two-level systems freeze into the same state and the critical value α c decreases asymptotically as 1/N with increasing N. For a finite number, N, of two-level systems the quantum phase transition (at zero temperature) is in the same universality class as the single spin-boson model, in the limit N → ∞ the system shows mean-field critical behavior independent of the power of the spectral function of the bosonic bath. We also study the influence of a spatial separation of the spins in a bath of bosonic modes with linear dispersion relation on the location and characteristics of the phase transition as well as on correlations between the two-level systems.

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“…We point out that the present model profoundly differs from those studied until now [37][38][39][40][41][42][43][44][45][46][47][48][49][50]. The latter can be classified as direct generalizations of the single-spin-boson model.…”

Section: Modelmentioning

confidence: 61%

“…The interest towards decoherence and dissipation, as well as quantum phase transitions (QPTs) in two-impurity spin-boson models (TISBMs) with competing interactions, has remarkably grown in the last two decades [37][38][39][40][41][42][43][44][45][46][47][48][49][50]. The TISBM is currently under attention to determine the existence of critical points and then the presence of quantum and/or classical phase transitions [38,39].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Quantum and Classical Critical Points for an Integrable Two-Qubit Spin–Boson Model

Grimaudo,

Messina,

Nakazato

et al. 2023

Symmetry

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The class of two-interacting-qubit spin–boson models with vanishing transverse fields on the spin-pair is studied. The model can be mapped exactly into two independent standard single-impurity spin–boson models where the role of the tunneling parameter is played by the spin–spin coupling. The dynamics of the magnetization are analyzed for different levels of (an)isotropy. The existence of a decoherence-free subspace, as well as of different classical regimes separated by a critical temperature, and symptoms of quantum (first-order and Kosterlitz–Thouless type) phase transitions in the Ohmic regime are brought to light.

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Dynamics of coupled spins in the white- and quantum-noise regime

Cited by 8 publications

References 13 publications

Dynamics, synchronization, and quantum phase transitions of two dissipative spins

Dynamics, synchronization, and quantum phase transitions of two dissipative spins

Quantum phase transition and correlations in the multi-spin-boson model

Characterization of Quantum and Classical Critical Points for an Integrable Two-Qubit Spin–Boson Model

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