5.9k citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Ludwig-Maximilians-Universität MünchenDE568 papers
- Munich Center for Quantum Science and TechnologyDE404 papers
- Max Planck SocietyDE381 papers
- Centre National de la Recherche ScientifiqueFR143 papers
- Institute of Photonic SciencesES131 papers
- Technical University of MunichDE114 papers
- Universität InnsbruckAT107 papers
- ETH ZurichCH105 papers
- Harvard UniversityUS101 papers
- Austrian Academy of SciencesAT87 papers
- University of ViennaAT83 papers
- Institució Catalana de Recerca i Estudis AvançatsES75 papers
26 papers · 2 filters
Optimal conversion of non--local unitary operations
W. Dür, G. Vidal, J. I. Cirac
We study when a non--local unitary operation acting on two --level systems can probabilistically simulate another one when arbitrary local operations and classical communication…
Entanglement cost of mixed states
G. Vidal, W. Dür, J. I. Cirac
We compute the entanglement cost of several families of bipartite mixed states, including arbitrary mixtures of two Bell states. This is achieved by developing a technique that all…
Intensity-intensity correlations as a probe of interferences - under conditions of none in the intensity
G. S. Agarwal, J. von Zanthier, C. Skornia +1
The different behaviour of first order interferences and second order correlations are investigated for the case of two coherently excited atoms. For intensity measurements this pr…
Secure communication with a publicly known key
Almut Beige, Berthold-Georg Englert, Christian Kurtsiefer +1
We present a scheme for direct and confidential communication between Alice and Bob, where there is no need for establishing a shared secret key first, and where the key used by Al…
Quantum computation with trapped ions in an optical cavity
Jiannis Pachos, Herbert Walther
Two-qubit logical gates are proposed on the basis of two atoms trapped in a cavity setup. Losses in the interaction by spontaneous transitions are efficiently suppressed by employi…
Measuring irreversible dynamics of a quantum harmonic oscillator
Giovanna Morigi, Enrique Solano, Berthold-Georg Englert +1
We show that the unitary evolution of a harmonic oscillator coupled to a two-level system can be undone by a suitable manipulation of the two-level system -- more specifically: by…
Geometric phases of mesoscopic spin in Bose-Einstein condensates
I. Fuentes-Guridi, J. Pachos, S. Bose +2
We propose a possible scheme for generating spin-J geometric phases using a coupled two-mode Bose-Einstein condensate (BEC). First we show how to observe the standard Berry phase u…
Separability of Two-Party Gaussian States
Berthold-Georg Englert, Krzysztof Wodkiewicz
We investigate the separability properties of quantum two-party Gaussian states in the framework of the operator formalism for the density operator. Such states arise as natural ge…
Laser cooling with electromagnetically induced transparency: Application to trapped samples of ions or neutral atoms
F. Schmidt-Kaler, J. Eschner, G. Morigi +4
A novel method of ground state laser cooling of trapped atoms utilizes the absorption profile of a three (or multi-) level system which is tailored by a quantum interference. With…
Trapped-Atom-Interferometer in a Magnetic Microtrap
W. Hänsel, J. Reichel, P. Hommelhoff +1
We propose a configuration of a magnetic microtrap which can be used as an interferometer for three-dimensionally trapped atoms. The interferometer is realized via a dynamic splitt…
Quantum Key Distribution using Multilevel Encoding: Security Analysis
Mohamed Bourennane, Anders Karlsson, Gunnar Bjork +2
We present security proofs for a protocol for Quantum Key Distribution (QKD) based on encoding in finite high-dimensional Hilbert spaces. This protocol is an extension of Bennett's…
Doppler cooling of a Coulomb crystal
Giovanna Morigi, Juergen Eschner
We study theoretically Doppler laser-cooling of a cluster of 2-level atoms confined in a linear ion trap. Using several consecutive steps of averaging we derive, from the full quan…
An optical kaleidoscope using a single atom
P. Horak, H. Ritsch, T. Fischer +4
A new method to track the motion of a single particle in the field of a high-finesse optical resonator is described. It exploits near-degenerate higher-order Gaussian cavity modes,…
An analysis of a two-atom double-slit experiment based on environment-induced measurements
Christian Schoen, Almut Beige
To investigate the effect of a classical environment on a quantum mechanical system we consider two two-level atoms in a free radiation field in the presence of a screen. By assumi…
The breakdown flash of Silicon Avalance Photodiodes - backdoor for eavesdropper attacks?
Christian Kurtsiefer, Patrick Zarda, Sonja Mayer +1
Silicon avalanche photodiodes are the most sensitive photodetectors in the visible to near infrared region. However, when they are used for single photon detection in a Geiger mode…
Four Photon Entanglement from Down Conversion
Harald Weinfurter, Marek Zukowski
Double-pair emission from type-II parametric down conversion results in a highly entangled 4-photon state. Due to interference, which is similar to bunching from thermal emission,…
Monitoring the Dipole-Dipole Interaction via Quantum Jumps of Individual Atoms
C. Skornia, J. von Zanthier, G. S. Agarwal +2
The emission characteristics in the fluorescence of two laser-driven dipole-dipole-interacting three level atoms is investigated. When the light from both atoms is detected separat…
Nonclassical Interference Effects In The Radiation From Coherently Driven Uncorrelated Atoms
C. Skornia, J. von Zanthier, G. S. Agarwal +2
We demonstrate the existence of new nonclassical correlations in the radiation of two atoms, which are coherently driven by a continuous laser source. The photon-photon-correlation…
Verifying Atom Entanglement Schemes by Testing Bell's Inequality
Dimitris G. Angelakis, Almut Beige, Peter L. Knight +2
Recent experiments to test Bell's inequality using entangled photons and ions aimed at tests of basic quantum mechanical principles. Interesting results have been obtained and many…
Quasiprobability and Probability Distributions for Spin 1/2 States
M. O. Terra Cunha, V. I. Man'ko, M. O. Scully
We develop a Radon like transformation, in which quasiprobability distribution for spin 1/2 states is written in terms the tomographic probability distribution .
High efficiency entangled photon pair collection in type II parametric fluorescence
Christian Kurtsiefer, Markus Oberparleiter, Harald Weinfurter
We report on a method for optimizing the collection of entangled photon pairs in type-II parametric fluorescence. With this technique, we detected 360000 polarization-entangled pho…
The mean king's problem: Spin 1
Yakir Aharonov, Berthold-Georg Englert
We show how one can ascertain the values of four mutually complementary observables of a spin-1 degree of freedom.
Universal unitary gate for single-photon 2-qubit states
Berthold-Georg Englert, Christian Kurtsiefer, Harald Weinfurter
Upon entangling a spatial binary alternative of a photon with its polarization, one can use single photons to study arbitrary 2-qubit states. Sending the photon through a Mach-Zehn…
Inhibition of Decoherence due to Decay in a Continuum
G. S. Agarwal, M. O. Scully, H. Walther
We propose a scheme for slowing down decay into a continuum. We make use of a sequence of ultrashort -pulses applied on an auxiliary transition of the system so that there is a…