A5016282235- Cold Atom Physics and Bose-Einstein Condensates
- Quantum Information and Cryptography
- Quantum optics and atomic interactions
- Quantum Mechanics and Applications
- Quantum Computing Algorithms and Architecture
- Quantum many-body systems
- Quantum, superfluid, helium dynamics
- Laser-Matter Interactions and Applications
- Quantum and electron transport phenomena
- Atomic and Subatomic Physics Research
- Mechanical and Optical Resonators
- Spectroscopy and Quantum Chemical Studies
- Strong Light-Matter Interactions
- Topological Materials and Phenomena
- Physics of Superconductivity and Magnetism
- Spectroscopy and Laser Applications
- Atomic and Molecular Physics
- Neural Networks and Reservoir Computing
- Photonic and Optical Devices
- Advanced Thermodynamics and Statistical Mechanics
- Advanced Frequency and Time Standards
- Advanced Fiber Laser Technologies
- Advanced Chemical Physics Studies
- Force Microscopy Techniques and Applications
- Advanced Condensed Matter Physics
Austrian Academy of Sciences
2016-2025
Universität Innsbruck
2016-2025
Institute for Quantum Optics and Quantum Information Innsbruck
2010-2023
Max Planck Institute of Quantum Optics
2004-2019
Université Libre de Bruxelles
2017
International Solvay Institutes
2017
Helios Dr. Horst Schmidt Kliniken Wiesbaden
2013-2014
National Institute of Standards and Technology
1986-2012
Harvard University
2002-2012
University of Maryland, College Park
2012
A quantum computer can be implemented with cold ions confined in a linear trap and interacting laser beams. Quantum gates involving any pair, triplet, or subset of realized by coupling the through collective quantized motion. In this system decoherence is negligible, measurement (readout register) carried out high efficiency.
The dynamics of an ultracold dilute gas bosonic atoms in optical lattice can be described by a Bose-Hubbard model where the system parameters are controlled laser light. We study continuous (zero temperature) quantum phase transition from superfluid to Mott insulator induced varying depth potential, corresponds commensurate filling (``optical crystal''). Examples for formation structures lattices with superimposed harmonic trap, and superlattices presented.
In quantum communication via noisy channels, the error probability scales exponentially with length of channel. We present a scheme repeater that overcomes this limitation. The central idea is to connect string (imperfect) entangled pairs particles by using novel nested purification protocol, thereby creating single distant pair high fidelity. Our tolerates general errors on percent level, it works polynomial overhead in time and logarithmic number need be controlled locally.
We propose a scheme to utilize photons for ideal quantum transmission between atoms located at spatially separated nodes of network. The protocol employs special laser pulses that excite an atom inside optical cavity the sending node so its state is mapped into time-symmetric photon wave packet will enter receiving and be absorbed by there with unit probability. Implementation our would enable reliable transfer or sharing entanglement among distant atoms.
An inseparability criterion based on the total variance of a pair Einstein-Podolsky-Rosen type operators is proposed for continuous variable systems. The provides sufficient condition entanglement any two-party states. Furthermore, all Gaussian states, this turns out to be necessary and inseparability.
We describe a technique for manipulating quantum information stored in collective states of mesoscopic ensembles. Quantum processing is accomplished by optical excitation into with strong dipole-dipole interactions. The resulting "dipole blockade" can be used to inhibit transitions all but singly excited states. This employed controlled generation atomic spin as well nonclassical photonic and scalable logic gates. An example involving cold Rydberg gas analyzed.
We propose several schemes for implementing a fast two-qubit quantum gate neutral atoms with the operation time much faster than scales associated external motion of in trapping potential. In our example, large interaction energy required to perform operations is provided by dipole-dipole excited low-lying Rydberg states constant electric fields. A detailed analysis imperfections given.
We show that by using cold controlled collisions between two atoms one can achieve conditional dynamics in moving trap potentials. discuss implementing qubit quantum--gates and efficient creation of highly entangled states many optical lattices.
We use the theory of continuous measurement to analyze effects decoherence on a realistic model quantum computer based cavity QED. show how affects computation, and methods prevent it.
We propose an experimentally feasible scheme to achieve quantum computation based solely on geometric manipulations of a system. The desired operations are obtained by driving the system undergo appropriate adiabatic cyclic evolutions. Our implementation all-geometric is laser manipulation set trapped ions. An approach, apart from its fundamental interest, offers possible method for robust computation.
We investigate the dynamics of neutral atoms in a 2D optical lattice which traps two distinct internal states different columns. Two Raman lasers are used to coherently transfer from one state other, thereby causing hopping between By adjusting laser parameters appropriately we can induce non-vanishing phase particles moving along closed path on lattice. This is proportional enclosed area and thus simulate magnetic flux through set-up described by Hamiltonian identical for electrons subject...
We present two approaches to the dynamics of a quench-induced phase transition in quantum Ising model. One follows standard treatment thermodynamic second order transitions but applies it transitions. The other approach is quantum, and uses Landau-Zener formula for probabilities avoided level crossings. show that predictions how density defects scales with quench rate are compatible, discuss ensuing insights into
We show how to design different couplings between a single ion trapped in harmonic potential and an environment. The coupling is due the absorption of laser photon subsequent spontaneous emission. variation frequencies intensities allows one ``engineer'' select master equation describing motion ion.
We introduce a new approach to create and detect Majorana fermions using optically trapped 1D fermionic atoms. In our proposed setup, two internal states of the atoms couple via an optical Raman transition-simultaneously inducing effective spin-orbit interaction magnetic field-while background molecular BEC cloud generates s-wave pairing for The resulting cold-atom quantum wire supports at phase boundaries between topologically trivial nontrivial regions, as well "Floquet fermions" when...