Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · cond-mat/0603321

Controllability of Wavepacket Dynamics in Coherently Driven Double-Well Potential

Akira Igarashi·Hiroaki Yamada
View original source ↗Read source document ↗Export metadata ↓

Abstract

We numerically study the controllability of quantum dynamics in perturbed one-dimensional double-well potential by using an optimal control theory. As the perturbation strength is small the dynamics of the initially localized aussian wavepacket in the right well shows coherent oscillation between the wells like a behavior of instanton. It was found that as the increase of the strength and/or the number of frequency components of the perturbation the coherent motion changes the irregular one with irreversible delocalization of the wavepacket. We investigate the controllability of the system depending on the perturbation parameters and the initial state by focusing mainly on the delocalized state generated in the polychromatically perturbed system. In the relatively long-time control for the Gaussian wavepacket and the delocalized state, we show that it is well-controllable via the first excited state doublet in spite of the perturbation parameters. On the other hand, in the relatively shor-time control we show the difficulty of the control for the delocalized state because of the numerous local minima. Furthermore, it is demonstrated that chaotic phase space structure of the system assists the controllability of the delocalized state.

Explore related subjects

cond-mat.other

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Akira Igarashi, Hiroaki Yamada. 2006-06-01. Controllability of Wavepacket Dynamics in Coherently Driven Double-Well Potential. https://doi.org/10.1016/j.chemphys.2006.05.016

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Geometry-Induced Effective Tight-Binding Hamiltonians for Phononic Systems: Mode Conversion and SSH-Like Physics

We present a framework that maps harmonic vibrational systems onto effective multi-orbital tight-binding Hamiltonians, establishing a direct correspondence between phononic degrees of freedom and graph-based lattice models. Within this mapping, the Cartesian displacement components of each mass become internal orbitals, while elastic interactions generate effective onsite energies and hopping amplitudes determined by the geometry of the system. This representation enables the application of numerical and conceptual tools originally developed for electronic transport to the study of phononic systems. The method is first applied to a monoatomic chain containing an angular bend. For this benchmark system, analytical expressions for the polarization-resolved transmission and reflection probabilities are derived and compared against calculations performed using a recursive scattering-matrix method within the mapped tight-binding representation. Excellent agreement is obtained, validating the mapping and demonstrating its ability to describe geometry-induced mode conversion and the influence of evanescent states. We then investigate zigzag chains, where alternating bond orientations generate effective dimerized Hamiltonians reminiscent of the Su--Schrieffer--Heeger (SSH) model. Although the uniform zigzag chain develops a spectral gap, no localized edge states are observed. We show that modified boundary parameters generated by the phononic mapping suppress the edge-state formation expected from the ideal SSH picture. Introducing a geometric domain wall restores localized domain-wall states inside the gap, which give rise to resonant transmission channels across an otherwise insulating frequency window. The resonance energies remain robust against system-size variations and the corresponding transmission approaches unity.

cond-mat.other↗
arXiv2026

THz-Driven Quantum Ionic Magnetism in a Quantum Paraelectric SrTiO3

Magnetic moments carried by rotating ionic motion in crystals are becoming recognized as an important contribution to magnetism, angular momentum transport, and optical activity. However, efficient approaches to their dynamical control are lacking. Here, we report THz-driven generation and optical detection of quantum ionic magnetism in quantum paraelectric SrTiO3. We observe an oscillatory ionic magnetization without a corresponding oscillatory polarization, contradicting from the classical relation M~PXdP/dt while its suppression above the quantum paraelectric regime points to a quantum ionic origin. Analysis shows that this effect results from the beating between quantum ionic eigenstates whose degeneracy is lifted due to the directional symmetry breaking by the THz pulse. The presented approach provides a pathway for the ultrafast control of ionic magnetization in quantum materials for spintronic and thermotronic applications.

cond-mat.other↗
arXiv2026

Resonantly Enhanced Multiphonon Scattering and Local Orbital-Phonon Coupling in Bulk and Thin Flakes of 2D Single Crystals of Antiferromagnetic (NixFe1-x)2P2S6

Orbital degrees of freedom play a pivotal role in shaping the physical properties of two-dimensional (2D) van der Waals magnetic systems, strongly influencing electron-phonon coupling and intermediate-state dynamics. In this study, we present a comprehensive temperature and thickness-dependent Raman investigation of the single crystals of 2D van der Waals antiferromagnetic series (NixFe1-x)2P2S6. Utilizing Raman spectroscopy, we explore the interplay between local orbital excitations and lattice vibrations, observing higher-order phonon modes extending up to the fourth order. We observe an anomalously high and weakly temperature-dependent intensity ratio of these higher-order modes relative to low-energy first-order phonons. Theoretical cluster calculations and Franck-Condon modelling reveal that these features originate from resonantly enhanced multiphonon scattering mediated by localized intermediate Ni 3d8 multiplet excitations. The local orbital occupancy of these intermediate states couples strongly to lattice coordinates, providing a selective enhancement mechanism for specific phonon channels. Notably, these higher-order features are absent in the end-member Fe2P2S6. This distinction reflects the charge-transfer character of Ni2P2S6, which places optical transitions in resonance with local multiplet states, contrasted with the Mott-Hubbard insulator regime in Fe-rich analogues. Our findings clarify the microscopic origin of high-frequency Raman scattering in transition metal thiophosphates and underscore the central role of local orbital-phonon interactions in 2D correlated magnets.

cond-mat.other↗