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Decay of spin helices in XXZ quantum spin chains with single-ion anisotropy
Florian Lange, Frank Göhmann, Gerhard Wellein +1
Long-lived spin-helix states facilitate the study of non-equilibrium dynamics in quantum magnets. We consider the decay of transverse spin-helices in antiferromagnetic spin- XXZ…
Charge-order melting in the one-dimensional Edwards model
Florian Lange, Gerhard Wellein, Holger Fehske
We use infinite matrix-product-state techniques to study the time evolution of the charge-density-wave (CDW) order after a quench or a light pulse in a fundamental fermion-boson mo…
Metal-insulator transition in the Edwards model
H. Fehske, S. Ejima, G. Wellein +1
To understand how charge transport is affected by a background medium and vice versa we study a two-channel transport model which captures this interplay via a novel, effective fer…
Numerical approaches to time evolution of complex quantum systems
Holger Fehske, Jens Schleede, Gerald Schubert +3
We examine several numerical techniques for the calculation of the dynamics of quantum systems. In particular, we single out an iterative method which is based on expanding the tim…
Correlation-induced metal insulator transition in a two-channel fermion-boson model
G. Wellein, H. Fehske, A. Alvermann +1
We investigate charge transport within some background medium by means of an effective lattice model with a novel form of fermion-boson coupling. The bosons describe fluctuations o…
Localized polarons and doorway vibrons in finite quantum structures
H. Fehske, G. Wellein, J. Loos +1
We consider transport through finite quantum systems such as quantum barriers, wells, dots or junctions, coupled to local vibrational modes in the quantal regime. As a generic mode…
Carrier-density effects in many-polaron systems
Martin Hohenadler, Georg Hager, Gerhard Wellein +1
Many-polaron systems with finite charge-carrier density are often encountered experimentally. However, until recently, no satisfactory theoretical description of these systems was…
The spin-Peierls chain revisited
Georg Hager, Alexander Weisse, Gerhard Wellein +2
We extend previous analytical studies of the ground-state phase diagram of a one-dimensional Heisenberg spin chain coupled to optical phonons, which for increasing spin-lattice cou…
Spectral signatures of the Luttinger liquid to charge-density-wave transition
M. Hohenadler, G. Wellein, A. R. Bishop +2
Electron- and phonon spectral functions of the one-dimensional, spinless-fermion Holstein model at half filling are calculated in the four distinct regimes of the phase diagram, co…
Spectral signatures of Holstein polarons
Holger Fehske, Andreas Alvermann, Martin Hohenadler +1
We review numerical results for ground-state and spectral properties of the single-electron Holstein model.
Hole doped Hubbard ladders
H. Fehske, G. Hager, G. Wellein +1
The formation of stripes in six-leg Hubbard ladders with cylindrical boundary conditions is investigated for two different hole dopings, where the amplitude of the hole density mod…
Optical response of many-polaron systems
G. Wellein, A. R. Bishop, M. Hohenadler +2
Exact results for the density of states and the ac conductivity of the spinless Holstein model at finite carrier density are obtained combining Lanczos and kernel polynomial method…
Many-polaron problem by cluster perturbation theory
Martin Hohenadler, Gerhard Wellein, Andreas Alvermann +1
The carrier-density dependence of the photoemission spectrum of the Holstein many-polaron model is studied using cluster perturbation theory combined with an improved cluster diago…
Optical absorption and activated transport in polaronic systems
G. Schubert, G. Wellein, A. Weiße +2
We present exact results for the optical response in the one-dimensional Holstein model. In particular, by means of a refined kernel polynomial method, we calculate the ac and dc e…
Photoemission spectra of many-polaron systems
M. Hohenadler, D. Neuber, W. von der Linden +3
The cross over from low to high carrier densities in a many-polaron system is studied in the framework of the one-dimensional spinless Holstein model, using unbiased numerical meth…
Stripe formation in doped Hubbard ladders
G. Hager, G. Wellein, E. Jeckelmann +1
We investigate the formation of stripes in $7\chunks \times 6$ Hubbard ladders with $4\chunks$ holes doped away from half filling using the density-matrix renormalization group (DM…
Luttinger liquid versus charge density wave behaviour in the one-dimensional spinless fermion Holstein model
H. Fehske, G. Wellein, G. Hager +3
We discuss the nature of the different ground states of the half-filled Holstein model of spinless fermions in 1D. In the metallic regime we determine the renormalised effective co…
Single-particle excitations and phonon softening in the one-dimensional spinless Holstein model
S. Sykora, A. Huebsch, K. W. Becker +2
We investigate the influence of the electron-phonon coupling in the one-dimensional spinless Holstein model at half-filling using both a recently developed projector-based renormal…
Quantum lattice dynamical effects on the single-particle excitations in 1D Mott and Peierls insulators
H. Fehske, G. Wellein, G. Hager +2
As a generic model describing quasi-one-dimensional Mott and Peierls insulators, we investigate the Holstein-Hubbard model for half-filled bands using numerical techniques. Combini…
Parallelization Strategies for Density Matrix Renormalization Group Algorithms on Shared-Memory Systems
G. Hager, E. Jeckelmann, H. Fehske +1
Shared-memory parallelization (SMP) strategies for density matrix renormalization group (DMRG) algorithms enable the treatment of complex systems in solid state physics. We present…
Peierls-insulator Mott-insulator transition in 1D
H. Fehske, G. Wellein, A. Weiße +3
In an attempt to clarify the nature of the crossover from a Peierls band insulator to a Mott Hubbard insulator, we analyze ground-state and spectral properties of the one-dimension…
Density-Matrix Algorithm for Phonon Hilbert Space Reduction in the Numerical Diagonalization of Quantum Many-Body Systems
Alexander Weiße, Gerhard Wellein, Holger Fehske
Combining density-matrix and Lanczos algorithms we propose a new optimized phonon approach for finite-cluster diagonalizations of interacting electron-phonon systems. To illustrate…
Optimized phonon approach for the diagonalization of electron-phonon problems
A. Weisse, H. Fehske, G. Wellein +1
We propose a new optimized phonon approach for the numerical diagonalization of interacting electron-phonon systems combining density-matrix and Lanczos algorithms. We demonstrate…
Lattice polaron formation: Effects of non-screened electron-phonon interaction
H. Fehske, J. Loos, G. Wellein
We explore the quasiparticle properties of lattice polarons on the basis of a quite general electron-phonon Hamiltonian with a long-range displacement-type of interaction. To treat…