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A. Buchleitner

Publications and source records attributed to A. Buchleitner.

8 recordsLinked to original sources
arXiv2014

Nonlinear Spectroscopy of Controllable Many-Body Quantum Systems

We establish a novel approach to probing spatially resolved multi-time correlation functions of interacting many-body systems, with scalable experimental overhead. Specifically, designing nonlinear measurement protocols for multidimensional spectra in a chain of trapped ions with single-site addressability enables us, e.g., to distinguish coherent from incoherent transport processes, to quantify potential anharmonicities, and to identify decoherence-free subspaces.

quant-ph↗
arXiv2014

Local Detection of Quantum Correlations with a Single Trapped Ion

As one of the most striking features of quantum mechanics, quantum correlations are at the heart of quantum information science. Detection of correlations usually requires access to all the correlated subsystems. However, in many realistic scenarios this is not feasible since only some of the subsystems can be controlled and measured. Such cases can be treated as open quantum systems interacting with an inaccessible environment. Initial system-environment correlations play a fundamental role for the dynamics of open quantum systems. Following a recent proposal, we exploit the impact of the correlations on the open-system dynamics to detect system-environment quantum correlations without accessing the environment. We use two degrees of freedom of a trapped ion to model an open system and its environment. The present method does not require any assumptions about the environment, the interaction or the initial state and therefore provides a versatile tool for the study of quantum systems.

quant-ph↗
arXiv2014

Coherent backscattering of intense light by cold atoms with degenerate energy levels: Diagrammatic treatment

We present a generalization of the diagrammatic pump-probe approach to coherent backscattering (CBS) of intense laser light for atoms with degenerate energy levels. We employ this approach for a characterization of the double scattering signal from optically pumped atoms with the transition $J_g\rightarrow J_e=J_g+1$ in the helicity preserving polarization channel. We show that, in the saturation regime, the internal degeneracy becomes manifest for atoms with $J_g\geq 1$, leading to a faster decrease of the CBS enhancement factor with increasing saturation parameter than in the non-degenerate case.

quant-ph↗
arXiv2006

Quantum Accelerator Modes from the Farey Tree

We show that mode-locking finds a purely quantum non-dissipative counterpart in atom-optical quantum accelerator modes. These modes are formed by exposing cold atoms to periodic kicks in the direction of the gravitational field. They are anchored to generalized Arnol'd tongues, parameter regions where driven nonlinear classical systems exhibit mode-locking. A hierarchy for the rational numbers known as the Farey Tree provides an ordering of the Arnol'd tongues and hence of experimentally observed accelerator modes.

physics.atom-ph↗
arXiv2005

Equilibrium entanglement vanishes at finite temperature

We show that the equilibrium entanglement of a bipartite system having a finite number of quantum states vanishes at finite temperature, for arbitrary interactions between its constituents and with the environment.

cond-mat.stat-mech↗
arXiv2003

Interaction-induced decoherence of atomic Bloch oscillations

We show that the energy spectrum of the Bose-Hubbard model amended by a static field exhibits Wigner-Dyson level statistics. In itself a characteristic signature of quantum chaos, this induces the irreversible decay of Bloch oscillations of cold, interacting atoms loaded into an optical lattice, and provides a Hamiltonian model for interaction induced decoherence.

cond-mat.soft↗