6 research outputs found
Dynamical structure factor of the anisotropic Heisenberg chain in a transverse field
We consider the anisotropic Heisenberg spin-1/2 chain in a transverse
magnetic field at zero temperature. We first determine all components of the
dynamical structure factor by combining exact results with a mean-field
approximation recently proposed by Dmitriev {\it et al}., JETP 95, 538 (2002).
We then turn to the small anisotropy limit, in which we use field theory
methods to obtain exact results. We discuss the relevance of our results to
Neutron scattering experiments on the 1D Heisenberg chain compound .Comment: 13 pages, 14 figure
Controllable coupling and quantum correlation dynamics of two double quantum dots coupled via a transmission line resonator
We propose a theoretical scheme to generate a controllable and switchable coupling
between two double-quantum-dot (DQD) spin qubits by using a transmission line resonator
(TLR) as a bus system. We study dynamical behaviors of quantum correlations described by
entanglement correlation (EC) and discord correlation (DC) between two DQD spin qubits
when the two spin qubits and the TLR are initially prepared in X-type
quantum states and a coherent state, respectively. We demonstrate that in the EC death
regions there exist DC stationary states in which the stable DC amplification or
degradation can be generated during the dynamical evolution. It is shown that these DC
stationary states can be controlled by initial-state parameters, the coupling, and
detuning between qubits and the TLR. We reveal the full synchronization and
anti-synchronization phenomena in the EC and DC time evolution, and show that the EC and
DC synchronization and anti-synchronization depends on the initial-state parameters of the
two DQD spin qubits. It is shown that the initial quantum correlation may be suppressed
completely when the evolution time approaches to the infinity in the presence of
dissipation. These results shed new light on dynamics of quantum correlations