Ground-state properties of sub-Ohmic spin-boson model with simultaneous diagonal and off-diagonal coupling

Zhou, N. J.; Chen, Lipeng; Zhao, Yue; Mozyrsky, Dmitry; Chernyak, Vladimir

doi:10.1103/physrevb.90.155135

Cited by 35 publications

(75 citation statements)

References 58 publications

(85 reference statements)

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“…Very recently, a multitude of Davydov D 1 Ansatz (the multi-D 1 Ansatz ) has been successfully constructed to study the ground-state properties of the sub-Ohmic SBM with simultaneous diagonal and off-diagonal coupling. Much more accurate results near the quantum phase transition point, in agreement with those from the methods of density matrix renormalization group and exact diagonalization, have been obtained by the multi-D 1 Ansatz [32,33] than those by the single D 1 Ansatz. However, how the multi-D 1 Ansatz fares with the dynamics of the SBM with an arbitrary initial state remains an issue to be addressed.…”

supporting

confidence: 68%

Variational dynamics of the sub-Ohmic spin-boson model on the basis of multiple Davydov D1 states

Wang

Chen

Zhou

et al. 2016

The Journal of Chemical Physics

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Dynamics of the sub-Ohmic spin-boson model is investigated by employing a multitude of the Davydov D1 trial states, also known as the multi-D1 Ansatz. Accuracy in dynamics simulations is improved significantly over the single D1 Ansatz, especially in the weak system-bath coupling regime. The reliability of the multi-D1 Ansatz for various coupling strengths and initial conditions are also systematically examined, with results compared closely with those of the hierarchy equations of motion and the path integral Monte Carlo approaches. In addition, a coherent-incoherent phase crossover in the nonequilibrium dynamics is studied through the multi-D1 Ansatz. The phase diagram is obtained with a critical point sc = 0.4. For sc < s < 1, the coherent-to-incoherent crossover occurs at a certain coupling strength, while the coherent state recurs at a much larger coupling strength. For s < sc, only the coherent phase exists.

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supporting

confidence: 68%

Variational dynamics of the sub-Ohmic spin-boson model on the basis of multiple Davydov D1 states

Wang

Chen

Zhou

et al. 2016

The Journal of Chemical Physics

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“…Very recently, a systematic coherent-state expansion of the ground state wave function that is based on the Davydov D 1 Ansatz, which we shall call the "multi-D 1 Ansatz," is developed for a number of models [59][60][61]. It is a generalization of a variational wave function originally proposed by Silbey and Harris [62], and also an extension of the hierarchy of translationlly-invariant Ansätze proposed by Zhao et al [48,49] A jnq…”

Section: Discussionmentioning

confidence: 99%

Polaron dynamics with a multitude of Davydov D2 trial states

Zhou

Huang

Zhu

et al. 2015

The Journal of Chemical Physics

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We propose an extension to the Davydov D2 Ansatz in the dynamics study of the Holstein molecular crystal model with diagonal and off-diagonal exciton-phonon coupling using the Dirac-Frenkel time-dependent variational principle. The new trial state by the name of the "multi-D2 Ansatz" is a linear combination of Davydov D2 trial states, and its validity is carefully examined by quantifying how faithfully it follows the Schrödinger equation. Considerable improvements in accuracy have been demonstrated in comparison with the usual Davydov trial states, i.e., the single D1 and D2 Ansätze. With an increase in the number of the Davydov D2 trial states in the multi-D2 Ansatz, deviation from the exact Schrödinger dynamics is gradually diminished, leading to a numerically exact solution to the Schrödinger equation.

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“…by applying the time-dependent variational principle [56], δ dtL = 0, upon arbitrary variations of the state vector (7) with respect to its set of variational parameters. for the set of variables v = {p m , q m , f k,m , h k,m }, which can be solved by numerical integration [34,39,[57][58][59].…”

Section: B Many-body Quantum Dynamics With Multi-mode Coherent Statesmentioning

confidence: 99%

Particle production in ultrastrong-coupling waveguide QED

et al. 2018

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Understanding large-scale interacting quantum matter requires dealing with the huge number of quanta that are produced by scattering even a few particles against a complex quantum object. Prominent examples are found from high energy cosmic ray showers, to the optical or electrical driving of degenerate Fermi gases. We tackle this challenge in the context of many-body quantum optics, as motivated by the recent developments of circuit quantum electrodynamics at ultrastrong coupling. The issue of particle production is addressed quantitatively with a simple yet powerful concept rooted in the quantum superposition principle of multimode coherent states. This key idea is illustrated by the study of multi-photon emission from a single two-level artificial atom coupled to a high impedance waveguide, driven by a nearly-monochromatic coherent tone. We find surprisingly that the off-resonant inelastic emission lineshape is dominated by broadband particle production, due to the large phase space associated with contributions that do not conserve the number of excitations. Such frequency conversion processes produce striking signatures in time correlation measurements, which can be tested experimentally in quantum waveguides. These ideas open new directions for the simulation of a variety of physical systems, from polaron dynamics in solids to complex superconducting quantum architectures. arXiv:1802.01665v3 [cond-mat.mes-hall]

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Ground-state properties of sub-Ohmic spin-boson model with simultaneous diagonal and off-diagonal coupling

Cited by 35 publications

References 58 publications

Variational dynamics of the sub-Ohmic spin-boson model on the basis of multiple Davydov D1 states

Variational dynamics of the sub-Ohmic spin-boson model on the basis of multiple Davydov D1 states

Polaron dynamics with a multitude of Davydov D2 trial states

Particle production in ultrastrong-coupling waveguide QED

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