Unified framework for correlations in terms of local quantum observables (2009)
Acin, A., Augusiak, R., Cavalcanti, D., Hadley, C., Korbicz, J. K., Lewenstein, M., ...
We provide a unified framework to non-signalling, quantum and classical correlations, allowing all to be written as certain local, quantum measurements acting on operators via the trace rule. The...
Quantum kinetic Ising models (2009)
Augusiak, R., Cucchietti, F. M., Haake, F., Lewenstein, M.
We introduce a quantum generalization of classical kinetic Ising models, described by a certain class of quantum many body master equations. Similarly to kinetic Ising models with detailed balance...
Multipartite entanglement percolation (2009)
Perseguers, S., Cavalcanti, D., Lapeyre Jr, G. J., Lewenstein, M., Acín, A.
We present percolation strategies based on multipartite measurements to propagate entanglement in quantum networks. We consider networks spanned on regular lattices whose bonds correspond to pure but...
Topological phase transitions in the non-Abelian honeycomb lattice (2009)
Bermudez, A., Goldman, N., Kubasiak, A., Lewenstein, M., Martin-Delgado, M. A.
Ultracold Fermi gases trapped in honeycomb optical lattices provide an intriguing scenario, where relativistic quantum electrodynamics can be tested. Here, we generalize this system to non-Abelian...
Creating p-wave superfluids and topological excitations in optical lattices (2009)
Massignan, P., Sanpera, A., Lewenstein, M.
We propose to realize an unconventional p-wave superfluid using spinless fermions coexisting with bosons in a deep optical lattice. We analyze its excitations in two dimensions in presence of a...
Quantum complex networks (2009)
Perseguers, S., Lewenstein, M., Acín, A., Cirac, J. I.
In recent years, new algorithms and cryptographic protocols based on the laws of quantum physics have been designed to outperform classical communication and computation. We show that the quantum...
Vortex nucleation in mesoscopic Bose superfluid and breaking of the parity symmetry (2009)
Dagnino, D., Barberán, N., Lewenstein, M.
We analyze vortex nucleation in mezoscopic 2D Bose superfluid in a rotating trap. We explicitly include a weakly anisotropic stirring potential, breaking thus explicitly the axial symmetry. As the...
Dark solitons near the Mott-insulator--superfluid phase transition (2009)
Krutitsky, K. V., Larson, J., Lewenstein, M.
Dark solitons of ultracold bosons in the vicinity of the Mott-insulator--superfluid phase transition are studied. Making use of the Gutzwiller ansatz we have found antisymmetric eigenstates...
Frustrated quantum antiferromagnetism with ultracold bosons in a triangular lattice (2009)
Eckardt, A., Hauke, P., Soltan-Panahi, P., Becker, C., Sengstock, K., Lewenstein, M.
We propose to realize the anisotropic triangular-lattice Bose-Hubbard model with positive tunneling matrix elements by using ultracold atoms in an optical lattice dressed by a fast lattice...
Unconventional superfluidity in Bose-Fermi Mixtures (2009)
Pairing between fermions that attract each other, reveal itself to the macroscopic world in the form of superfluidity. Since the discovery of fermionic superfluidity, intense search has been going on...
Quantum Phases of Cold Polar Molecules in 2D Optical Lattices (2009)
Capogrosso-Sansone, B., Trefzger, C., Lewenstein, M., Zoller, P., Pupillo, G.
We discuss the quantum phases of hard-core bosons on a two-dimensional square lattice interacting via repulsive dipole-dipole interactions, as realizable with polar molecules trapped in optical...
The physics of dipolar bosonic quantum gases (2009)
Lahaye, T, Menotti, C, Santos, L, Lewenstein, M, Pfau, T
This article reviews the recent theoretical and experimental advances in the study of ultracold gases made of bosonic particles interacting via the long-range, anisotropic dipole-dipole interaction,...
Symmetry breaking in quantum systems: the case study of vortex nucleation (2009)
Dagnino, D., Barberan, N., Lewenstein, M., Dalibard, J.
Mean field (MF) methods constitute a very powerful tool for investigations of weakly interacting many-body systems in many branches of physics. In articular they describe with an excellent accuracy...
Pair-supersolid phase in a bilayer system of dipolar lattice bosons (2009)
Trefzger, C., Menotti, C., Lewenstein, M.
The competition between tunneling and interactions in bosonic lattice models generates a whole variety of different quantum phases. While, in the presence of a single species interacting via on-site...
Non-Abelian optical lattices: Anomalous quantum Hall effect and Dirac Fermions (2009)
Goldman, N., Kubasiak, A., Bermudez, A., Gaspard, P., Lewenstein, M., Martin-Delgado, M. A.
We study the properties of an ultracold Fermi gas loaded in an optical square lattice and subjected to an external and classical non-Abelian gauge field. We show that this system can be exploited as...
Josephson oscillations in binary mixtures of F=1 spinor BECs (2009)
Julia-Diaz, B., Guilleumas, M., Lewenstein, M., Polls, A., Sanpera, A.
We study Josephson oscillations of a two component Bose-Einstein condensate (BEC) in a double well-potential. We demonstrate that in the strongly polarized case, the less populated component exhibits...
Ultracold atomic gases in non-Abelian gauge potentials: The case of constant Wilson loop (2009)
Goldman, N., Kubasiak, A., Gaspard, P., Lewenstein, M.
Nowadays it is experimentally feasible to create artificial, and in particular, non-Abelian gauge potentials for ultracold atoms trapped in optical lattices. Motivated by this fact, we investigate...
Quantum polarization spectroscopy of correlations in attractive fermionic gases (2009)
Roscilde, T., Rodriguez, M., Eckert, K., Romero-Isart, O., Lewenstein, M., Polzik, E., ...
We show how spin-spin correlations, detected in a non-destructive way via spatially resolved quantum polarization spectroscopy, strongly characterize various phases realized in trapped ultracold...
Structural approximations to positive maps and entanglement breaking channels (2008)
Korbicz, J. K., Almeida, M. L., Bae, J., Lewenstein, M., Acin, A.
Structural approximations to positive, but not completely positive maps are approximate physical realizations of these non-physical maps. They find applications in the design of direct entanglement...
Ultracold dipolar gas in an optical lattice: the fate of metastable states (2008)
Trefzger, C., Menotti, C., Lewenstein, M.
We study the physics of ultracold dipolar bosons in optical lattices. We show that dipole-dipole interactions lead to the appearance of many insulating metastable states. We study the stability and...
Physical replicas and the Bose-glass in cold atomic gases (2008)
Morrison, S., Kantian, A., Daley, A. J., Katzgraber, H. G., Lewenstein, M., Büchler, H. P., ...
We study cold atomic gases in a disorder potential and analyze the correlations between different systems subjected to the same disorder landscape. Such independent copies with the same disorder...
A. V. Sergienko, M. C. Teich, D. Bruß, M. Lewenstein, A. Sanpera, ...
References 1. Web-based versions of this bibliography with direct weblinks to most of its entries are available at the Springer website
Entanglement and Quantum Groups (2008)
Korbicz, J. K., Wehr, J., Lewenstein, M.
We describe quantum mechanical entanglement in terms of compact quantum groups. We prove an analog of positivity of partial transpose (PPT) criterion and formulate a Horodecki-type Theorem.
Entanglement distribution in pure-state quantum networks (2008)
Perseguers, Sébastien, Cirac, J. Ignacio, Acin, A., Lewenstein, M., Wehr, J.
Ultracold atomic gas in non-Abelian "magnetic" fields: the quantum Hall effect supremacy (2007)
Goldman, N., Kubasiak, A., Gaspard, P., Lewenstein, M.
Nowadays it is experimentally feasible to create artificial, and in particular, non-Abelian gauge potentials for ultracold atoms trapped in optical lattices. Motivated by this fact, we investigate...
Dipolar interaction in ultra-cold atomic gases (2007)
Menotti, C., Lewenstein, M., Lahaye, T., Pfau, T.
Ultra-cold atomic systems provide a new setting where to investigate the role of long-range interactions. In this paper we will review the basics features of those physical systems, in particular...
Entanglement Distribution in Pure-State Quantum Networks (2007)
Perseguers, S., Wehr, J., Acin, A., Lewenstein, M., Cirac, J. I.
We investigate entanglement distribution in pure-state quantum networks. We consider the case when non-maximally entangled two-qubit pure states are shared by neighboring nodes of the network. For a...
Dynamics of Bloch Oscillations in Disordered Lattice Potentials (2007)
Schulte, T., Drenkelforth, S., Büning, G. Kleine, Ertmer, W., Arlt, J., Lewenstein, M., ...
We present a detailed analysis of the dynamics of Bloch oscillations of Bose-Einstein condensates in disordered lattice potentials. Due to the disorder and the interparticle interactions these...
Entanglement of positive definite functions on compact groups (2007)
Korbicz, J. K., Wehr, J., Lewenstein, M.
We define and study entanglement of continuous positive definite functions on products of compact groups. We formulate and prove an infinite-dimensional analog of Horodecki Theorem, giving a...
Statistical-mechanical description of quantum entanglement (2007)
Korbicz, J. K., Hulpke, F., Osterloh, A., Lewenstein, M.
We present a description of finite dimensional quantum entanglement, based on a study of the space of all convex decompositions of a given density matrix. On this space we construct a system of real...
Symmetry breaking in small rotating clouds of trapped ultracold Bose atoms (2007)
Dagnino, D., Barberán Falcón, Núria, Osterloh, K., Riera, A., Lewenstein, M.
We study the signatures of rotational and phase symmetry breaking in small rotating clouds of trapped ultracold Bose atoms by looking at rigorously defined condensate wave function. Rotational...
Wigner Crystallization in Rapidly Rotating 2D Dipolar Fermi Gases (2006)
Baranov, M. A., Fehrmann, H., Lewenstein, M.
We study the competition between the Wigner crystal and the Laughlin liquid states in an ultracold quasi two-dimensional rapidly rotating polarized fermionic dipolar gas, and find that the Wigner...
Metastable states of a gas of dipolar bosons in a 2D optical lattice (2006)
Menotti, C., Trefzger, C., Lewenstein, M.
We investigate the physics of dipolar bosons in a two dimensional optical lattice. It is known that due to the long-range character of dipole-dipole interaction, the ground state phase diagram of a...
Predicting spinor condensate dynamics from simple principles (2006)
Moreno-Cardoner, M., Mur-Petit, J., Guilleumas, M., Polls, A., Sanpera, A., Lewenstein, M.
We study the spin dynamics of quasi-one-dimensional F=1 condensates both at zero and finite temperatures for arbitrary initial spin configurations. The rich dynamical evolution exhibited by these...
Symmetry breaking in small rotating cloud of trapped ultracold Bose atoms (2006)
Dagnino, D., Barberán, N., Lewenstein, M., Osterloh, K., Riera, A.
We study the signatures of rotational and phase symmetry breaking in small rotating clouds of trapped ultracold Bose atoms by looking at rigorously defined condensate wave function. Rotational...
Analysis of Localization Phenomena in Weakly Interacting Disordered Lattice Gases (2006)
Schulte, T., Drenkelforth, S., Kruse, J., Tiemeyer, R., Sacha, K., Zakrzewski, J., ...
Disorder plays a crucial role in many systems particularly in solid state physics. However, the disorder in a particular system can usually not be chosen or controlled. We show that the unique...
Travelling to exotic places with ultracold atoms (2006)
Lewenstein, M., Kubasiak, A., Larson, J., Menotti, C., Morigi, G., Osterloh, K., ...
We review and speculate on two recent developments of quantum optics and ultracold atoms. First, we discuss a possible realization of "phonon" physics, or as we call it "refracton" physics with...
Quantum polarization spectroscopy of ultracold spinor gases (2006)
Eckert, K., Zawitkowski, L., Sanpera, A., Lewenstein, M., Polzik, E. S.
We propose a method for the detection of ground state quantum phases of spinor gases through a series of two quantum nondemolition measurements performed by sending off-resonant, polarized light...
Salieres, P., Villain, P., Lewenstein, M.
We perform a detailed analysis of how high-order harmonic generation (HHG) and above-threshold ionization (ATI) can be controlled by a time-delayed attosecond-pulse train superposed to a strong,...
Ultracold atomic Bose and Fermi spinor gases in optical lattices (2006)
Eckert, K., Zawitkowski, L., Leskinen, M. J., Sanpera, A., Lewenstein, M.
We investigate magnetic properties of Mott-insulating phases of ultracold Bose and Fermi spinor gases in optical lattices. We consider in particular the F=2 Bose gas, and the F=3/2 and F=5/2 Fermi...
Korbicz, J. K., Lewenstein, M.
We sketch a group-theoretical framework, based on the Heisenberg-Weyl group, encompassing both quantum and classical statistical descriptions of mechanical systems. We re-define in group-theoretical...
Ordered structures in rotating ultracold Bose gases (2006)
Barberan, N., Lewenstein, M., Osterloh, K., Dagnino, D.
The characterization of small samples of cold bosonic atoms in rotating microtraps has recently attracted increasing interest due to the possibility to deal with a few number of particles per site in...
Disordered ultracold atomic gases in optical lattices: A case study of Fermi-Bose mixtures (2006)
Ahufinger, V., Sanchez-Palencia, L., Kantian, A., Sanpera, A., Lewenstein, M.
We present a review of properties of ultracold atomic Fermi-Bose mixtures in inhomogeneous and random optical lattices. In the strong interacting limit and at very low temperatures, fermions form,...
Group theoretical approach to entanglement (2006)
Korbicz, J. K., Lewenstein, M.
We present a novel, universal description of quantum entanglement using group theory and generalized characteristic functions. It leads to new reformulations of the separability problem, and the...
Generalized spin squeezing inequalities in $N$ qubit systems: theory and experiment (2006)
Korbicz, J. K., Gühne, O., Lewenstein, M., Haeffner, H., Roos, C. F., Blatt, R.
We present detailed derivations, various improvements and application to concrete experimental data of spin squeezing inequalities formulated recently by some of us [Phys. Rev. Lett. {\bf 95}, 120502...
Strongly correlated Fermi-Bose mixtures in disordered optical lattices (2006)
Sanchez-Palencia, L., Ahufinger, V., Kantian, A., Zakrzewski, Jakub, Sanpera, A., Lewenstein, M.
We investigate theoretically the low-temperature physics of a two-component ultracold mixture of bosons and fermions in disordered optical lattices. We focus on the strongly correlated regime. We...
Strongly correlated Fermi-Bose mixtures in disordered optical lattices (2006)
Sanchez-Palencia, L., Ahufinger, V., Kantian, A., Zakrzewski, Jakub, Sanpera, A., Lewenstein, M.
We investigate theoretically the low-temperature physics of a two-component ultracold mixture of bosons and fermions in disordered optical lattices. We focus on the strongly correlated regime. We...
Strongly correlated Fermi-Bose mixtures in disordered optical lattices (2006)
Sanchez-Palencia, L., Ahufinger, V., Kantian, A., Zakrzewski, Jakub, Sanpera, A., Lewenstein, M.
We investigate theoretically the low-temperature physics of a two-component ultracold mixture of bosons and fermions in disordered optical lattices. We focus on the strongly correlated regime. We...
Ordered structures in rotating ultracold Bose gases (2006)
Barberán Falcón, Núria, Lewenstein, M., Osterloh, K., Dagnino, D.
Two-dimentional systems of trapped samples of few cold bosonic atoms submitted to strong rotation around the perpendicular axis may be realized in optical lattices and microtraps. We investigate...
Dynamics of F=1 87Rb condensates at finite temperatures (2006)
Mur Petit, Jordi, Guilleumas, Montserrat, Polls Martí, Artur, Sanpera I Trigueros, Anna, Lewenstein, M., Bongs, K., ...
We investigate the dynamics of a F=1 spinor Bose-Einstein condensate of 87Rb atoms confined in a quasi-one-dimensional trap both at zero and at finite temperature. At zero temperature, we observe...
Infinite qubit rings with maximal nearest neighbor entanglement: the Bethe ansatz solution (2005)
Poulsen, U. V., Meyer, T., Bruss, D., Lewenstein, M.
We search for translationally invariant states of qubits on a ring that maximize the nearest neighbor entanglement. This problem was initially studied by O'Connor and Wootters [Phys. Rev. A {\bf 63},...
Trapped ion chain as a neural network (2005)
Pons, M., Ahufinger, V., Wunderlich, C., Sanpera, A., Lewenstein, M.
We demonstrate the possibility of realizing a neural network in a chain of trapped ions with induced long range interactions. Such models permit to store information distributed over the whole...
Strongly correlated Fermi-Bose mixtures in disordered optical lattices (2005)
Sanchez-Palencia, L., Ahufinger, V., Kantian, A., Zakrzewski, Jakub, Sanpera, A., Lewenstein, M.
We investigate theoretically the low-temperature physics of a two-component ultracold mixture of bosons and fermions in disordered optical lattices. We focus on the strongly correlated regime. We...
Strongly correlated Fermi-Bose mixtures in disordered optical lattices (2005)
Sanchez-Palencia, L., Ahufinger, V., Kantian, A., Zakrzewski, Jakub, Sanpera, A., Lewenstein, M.
We investigate theoretically the low-temperature physics of a two-component ultracold mixture of bosons and fermions in disordered optical lattices. We focus on the strongly correlated regime. We...
Three level atom optics in dipole traps and waveguides (2005)
Eckert, K., Mompart, J., Corbalan, R., Lewenstein, M., Birkl, G.
An analogy is explored between a setup of three atomic traps coupled via tunneling and an internal atomic three-level system interacting with two laser fields. Within this scenario we describe a...
Zoller,Peter, Beth,Th., Binosi,D., Blatt,R., Briegel,H., Bruss,D., ...
Splitting and merging an elongated Bose-Einstein condensate at finite temperature (2005)
Mebrahtu, A., Sanpera, A., Lewenstein, M.
We analyze coherence effects during the splitting of a quasi one-dimensional condensate into two spatially separated ones and their subsequent merging into a single condensate. Our analysis takes...
Disordered ultracold atomic gases in optical lattices: A case study of Fermi-Bose mixtures (2005)
Ahufinger, V., Sanchez-Palencia, L., Kantian, A., Sanpera, A., Lewenstein, M.
We present a review of properties of ultracold atomic Fermi-Bose mixtures in inhomogeneous and random optical lattices. In the strong interacting limit and at very low temperatures, fermions form,...
Fermi-Dirac statistics and the number theory (2005)
Kubasiak, A., Korbicz, J., Zakrzewski, J., Lewenstein, M.
We relate the Fermi-Dirac statistics of an ideal Fermi gas in a harmonic trap to partitions of given integers into distinct parts, studied in number theory. Using methods of quantum statistical...
Schulte, T., Drenkelforth, S., Kruse, J., Ertmer, W., Arlt, J., Sacha, K., ...
We investigate, both experimentally and theoretically, possible routes towards Anderson-like localization of Bose-Einstein condensates in disordered potentials. The dependence of this quantum...
Differential atom interferometry beyond the standard quantum limit (2005)
Eckert, K., Hyllus, P., Bruss, D., Poulsen, U. V., Lewenstein, M., Jentsch, C., ...
We analyze methods to go beyond the standard quantum limit for a class of atomic interferometers, where the quantity of interest is the difference of phase shifts obtained by two independent atomic...
Quantum gases in trimerized kagom\'e lattices (2005)
Damski, B., Fehrmann, H., Baranov, M., Santos, L., Lewenstein, M.
We study low temperature properties of atomic gases in trimerized optical kagom\'{e} lattices. The laser arrangements that can be used to create these lattices are briefly described. We also present...
Relations between Entanglement Witnesses and Bell Inequalities (2005)
Hyllus, P., Guehne, O., Bruss, D., Lewenstein, M.
Bell inequalities, considered within quantum mechanics, can be regarded as non-optimal witness operators. We discuss the relationship between such Bell witnesses and general entanglement witnesses in...
Spin squeezing inequalities and entanglement of $N$ qubit states (2005)
Korbicz, J., Cirac, J. I., Lewenstein, M.
We derive spin squeezing inequalities that generalize the concept of the spin squeezing parameter and provide necessary and sufficient conditions for genuine 2-, or 3- qubit entanglement for...
One- and two-dimensional quantum walks in arrays of optical traps (2005)
Eckert, K., Mompart, J., Birkl, G., Lewenstein, M.
We propose a novel implementation of discrete time quantum walks for a neutral atom in an array of optical microtraps or an optical lattice. We analyze a one-dimensional walk in position space, with...
Osterloh, K., Baig, M., Santos, L., Zoller, P., Lewenstein, M.
We demonstrate how to create artificial external non-Abelian gauge potentials acting on cold atoms in optical lattices. The method employs $n$ internal states of atoms and laser assisted state...
Sympathetic cooling of trapped fermions by bosons in the presence of particle losses (2005)
Idziaszek, Z., Santos, L., Lewenstein, M.
We study the sympathetic cooling of a trapped Fermi gas interacting with an ideal Bose gas below the critical temperature of the Bose-Einstein condensation. We derive the quantum master equation,...
Disordered ultracold atomic gases in optical lattices: A case study of Fermi-Bose mixtures (2005)
Ahufinger, V., Sanchez-Palencia, L., Kantian, A., Sanpera, A., Lewenstein, M.
We present a review of properties of ultracold atomic Fermi-Bose mixtures in inhomogeneous and random optical lattices. In the strong interacting limit and at very low temperatures, fermions form,...
Disordered ultracold atomic gases in optical lattices: A case study of Fermi-Bose mixtures (2005)
Ahufinger, V., Sanchez-Palencia, L., Kantian, A., Sanpera, A., Lewenstein, M.
We present a review of properties of ultracold atomic Fermi-Bose mixtures in inhomogeneous and random optical lattices. In the strong interacting limit and at very low temperatures, fermions form,...
Quantum gases in trimerized kagomé lattices (2005)
Damski, B., Fehrmann, H., Everts, Henk, Baranov, M.A., Santos, L., Lewenstein, M.
Hilbert's 17th Problem and the Quantumness of States (2005)
Korbicz, J. K., Cirac, J. Ignacio, Wehr, Jan, Lewenstein, M.
Atomic Fermi gas in the trimerized Kagom\'e lattice at the filling 2/3 (2004)
Damski, B., Honecker, A., Fehrmann, H., Santos, L., Lewenstein, M.
We study low temperature properties of an atomic spinless interacting Fermi gas in the trimerized Kagom\'e lattice for the case of two fermions per trimer. The system is described by a quantum spin...
Bound-state corrections in laser-induced nonsequential double ionization (2004)
We perform a systematic analysis of how nonsequential double ionization in intense, linearly polarized laser fields is influenced by the initial states in which both electrons are bound, and by the...
BCS pairing in a trapped dipolar Fermi gase (2004)
Baranov, M. A., Dobrek, L., Lewenstein, M.
We present a detailed study of the BCS pairing transition in a trapped polarized dipolar Fermi gas. In the case of a shallow nearly spherical trap, we find the decrease of the transition temperature...
Phase Fluctuations in Bose-Einstein Condensates (2004)
Hellweg, D., Dettmer, S., Ryytty, P., Arlt, J.J, Ertmer, W., Sengstock, K., ...
We demonstrate the existence of phase fluctuations in elongated Bose-Einstein Condensates (BECs) and study the dependence of those fluctuations on the system parameters. A strong dependence on...
Hilbert's 17th problem and the quantumness of states (2004)
Korbicz, J., Cirac, J. I., Wehr, J., Lewenstein, M.
A state of a quantum systems can be regarded as {\it classical} ({\it quantum}) with respect to measurements of a set of canonical observables iff there exists (does not exist) a well defined,...
Atomic quantum gases in Kagomé lattices (2004)
Santos,L., Baranov,M. A., Cirac,J. Ignacio, Everts,H. U., Fehrmann,H., Lewenstein,M.
Entanglement in spin chains and lattices with long-range Ising-type interactions (2004)
D{ü}r, W., Hartmann, L., Hein, M., Lewenstein, M., Briegel, H. J.
We consider N initially disentangled spins, embedded in a ring or d-dimensional lattice of arbitrary geometry, which interact via some long--range Ising--type interaction. We investigate relations...
Entanglement in the Bogoliubov vacuum (2004)
Poulsen, U. V., Meyer, T., Lewenstein, M.
We analyze the entanglement properties of the Bogoliubov vacuum, which is obtained as a second order approximation to the ground state of an interacting Bose--Einstein condensate. We work on one and...
Liu, X., Sanpera, A., Lewenstein, M.
We address nonsequential double ionization induced by strong, linearly polarized laser fields of only a few cycles, considering a physical mechanism in which the second electron is dislodged by the...
Key distillation from Gaussian states by Gaussian operations (2004)
Navascues, M., Bae, J., Cirac, J. I., Lewenstein, M., Sanpera, A., Acin, A.
We study the secrecy properties of Gaussian states under Gaussian operations. Although such operations are useless for quantum distillation, we prove that it is possible to distill a secret key...
Fractional Quantum Hall States in Ultracold Rapidly Rotating Dipolar Fermi Gases (2004)
Baranov, M. A., Osterloh, Klaus, Lewenstein, M.
We demonstrate the experimental feasibility of incompressible fractional quantum Hall-like states in ultra-cold two dimensional rapidly rotating dipolar Fermi gases. In particular, we argue that the...
Four photon polarization entanglement tests and applications (2004)
Bourennane,Mohamed, Eibl,Manfred, Gaertner,Sascha, Kurtsiefer,Christian, Weinfurter,Harald, Cabello,A., ...
Atomic quantum gases in Kagom\'e lattices (2004)
Santos, L., Baranov, M. A., Cirac, J. I., Fehrmann, H., Lewenstein, M.
We demonstrate the possibility of creating and controlling an ideal and \textit{trimerized} optical Kagom\'e lattice, and study the low temperature physics of various atomic gases in such lattices....
Atomic quantum gases in Kagomé lattices (2004)
Santos, L., Baranov, M. A., Cirac, J. Ignacio, Everts, H. U., Fehrmann, H., Lewenstein, M.
Four photon polarization entanglement tests and applications (2004)
Bourennane, Mohamed, Eibl, Manfred, Gaertner, Sascha, Kurtsiefer, Christian, Weinfurter, Harald, Cabello, A., ...
Ahufinger, V., Sanpera, A., Pedri, P., Santos, L., Lewenstein, M.
We analyze the generation and mobility of discrete solitons in Bose-Einstein condensates confined in an optical lattice under realistic experimental conditions. We discuss first the creation of 1D...
Coherence Properties of Guided-Atom Interferometers (2003)
Kreutzmann, H., Poulsen, U. V., Lewenstein, M., Dumke, R., Ertmer, W., Birkl, G., ...
We present a detailed investigation of the coherence properties of beam splitters and Mach-Zehnder interferometers for guided atoms. It is demonstrated that such a setup permits coherent wave packet...
Finite size effects in entangled rings of qubits (2003)
Meyer, T., Poulsen, U. V., Eckert, K., Lewenstein, M., Bruss, D.
We study translationally invariant rings of qubits with a finite number of sites N, and find the maximal nearest-neighbor entanglement for a fixed z component of the total spin. For small numbers of...
Second Order Correlation Function of a Phase Fluctuating Bose-Einstein Condensate (2003)
Cacciapuoti, L., Hellweg, D., Kottke, M., Schulte, T., Sengstock, K., Ertmer, W., ...
The coherence properties of phase fluctuating Bose-Einstein condensates are studied both theoretically and experimentally. We derive a general expression for the N-particle correlation function of a...
Three level atom optics via the tunneling interaction (2003)
Eckert, K., Lewenstein, M., Corbalan, R., Birkl, G., Ertmer, W., Mompart, J.
Three level atom optics (TLAO) is introduced as a simple, efficient and robust method to coherently manipulate and transport neutral atoms. The tunneling interaction among three trapped states allows...
Superfluidity of trapped dipolar Fermi gases (2003)
Baranov, M. A., Dobrek, L., Lewenstein, M.
We derive the phase diagram for ultracold trapped dipolar Fermi gases. Below the critical value of the dipole-dipole interaction energy, the BCS transition into a superfluid phase ceases to exist....
Mean-field theory of Bose-Fermi mixtures in optical lattices (2003)
Fehrmann, H., Baranov, M. A., Damski, B., Lewenstein, M., Santos, L.
We determine the phase diagram of a mixture of ultracold bosons and polarized fermions placed in an optical lattice using mean field theory. In the limit of strong atom-atom interactions, there exist...
Atomic Bose-Fermi mixtures in an optical lattice (2003)
Lewenstein, M., Santos, L., Baranov, M. A., Fehrmann, H.
A mixture of ultracold bosons and fermions placed in an optical lattice constitutes a novel kind of quantum gas, and leads to phenomena, which so far have been discussed neither in atomic physics,...
Continuous optical loading of a Bose-Einstein Condensate in the Thomas-Fermi regime (2003)
Floegel, F., Santos, L., Lewenstein, M.
We discuss the optical loading of a Bose-Einstein condensate in the Thomas-Fermi regime. The condensate is loaded via spontaneous emission from a reservoir of excited-state atoms. By means of a...
Atomic Bose and Anderson glasses in optical lattices (2003)
Damski, B., Zakrzewski, J., Santos, L., Zoller, P., Lewenstein, M.
An ultra cold atomic Bose gas in an optical lattice is shown to provide an ideal system for the controlled analysis of disordered Bose lattice gases. This goal may be easily achieved under the...
Roton-maxon spectrum and stability of trapped dipolar condensates (2003)
Santos, L., Shlyapnikov, G. V., Lewenstein, M.
We find that pancake dipolar condensates can exhibit a roton-maxon character of the excitation spectrum, so far only observed in superfluid helium. We also obtain a condition for the dynamical...
Laser cooling of a trapped two-component Fermi gas (2002)
Idziaszek, Z., Santos, L., Baranov, M., Lewenstein, M.
The collective Raman cooling of a trapped two-component Fermi gas is analyzed. We develop the quantum master equation that describes the collisions and the laser cooling, in the festina lente regime,...
Entangling strings of neutral atoms in 1D atomic pipeline structures (2002)
Dorner, U., Fedichev, P., Jaksch, D., Lewenstein, M., Zoller, P.
We study a string of neutral atoms with nearest neighbor interaction in a 1D beam splitter configuration, where the longitudinal motion is controlled by a moving optical lattice potential. The...
Atom optics with rotating Bose-Einstein condensates (2002)
Josopait, I., Dobrek, L., Santos, L., Sanpera, A., Lewenstein, M.
The atom optics of Bose-Einstein condensates containing a vortex of circulation one is discussed. We first analyze in detail the reflection of such a condensate falling on an atomic mirror. In a...
Laser cooling of trapped Fermi gases (2002)
Idziaszek, Z., Santos, L., Baranov, M., Lewenstein, M.
The collective Raman cooling of trapped one- and two-component Fermi gases is considered. We obtain the quantum master equation that describes the laser cooling in the festina lente regime, for which...
Experimental detection of entanglement via witness operators and local measurements (2002)
Guehne, O., Hyllus, P., Bruss, D., Ekert, A., Lewenstein, M., Macchiavello, C., ...
In this paper we address the problem of detection of entanglement using only few local measurements when some knowledge about the state is given. The idea is based on an optimized decomposition of...
Characterization and control of phase fluctuations in elongated Bose-Einstein condensates (2002)
Kreutzmann, H., Sanpera, A., Santos, L., Lewenstein, M., Hellweg, D., Cacciapuoti, L., ...
Quasi one dimensional Bose-Einstein condensates (BECs) in elongated traps exhibit significant phase fluctuations even at very low temperatures. We present recent experimental results on the dynamic...
Entanglement properties of composite quantum systems (2002)
Eckert, K., Gühne, O., Hulpke, F., Hyllus, P., Korbicz, J., Mompart, J., ...
We present here an overview of our work concerning entanglement properties of composite quantum systems. The characterization of entanglement, i.e. the possibility to assert if a given quantum state...
Quantum computing with spatially delocalized qubits (2002)
Mompart, J., Eckert, K., Ertmer, W., Birkl, G., Lewenstein, M.
We analyze the operation of quantum gates for neutral atoms with qubits that are delocalized in space, i.e., the computational basis states are defined by the presence of a neutral atom in the ground...
Creation of a dipolar superfluid in optical lattices (2002)
Damski, B., Santos, L., Tiemann, E., Lewenstein, M., Kotochigova, S., Julienne, P., ...
We show that by loading a Bose-Einstein condensate (BEC) of two different atomic species into an optical lattice, it is possible to achieve a Mott-insulator phase with exactly one atom of each...
Quantum computing in optical microtraps based on the motional states of neutral atoms (2002)
Eckert, K., Mompart, J., Yi, X. X., Schliemann, J., Bruss, D., Birkl, G., ...
We investigate quantum computation with neutral atoms in optical microtraps where the qubit is implemented in the motional states of the atoms, i.e., in the two lowest vibrational states of each...
Detection of entanglement with few local measurements (2002)
Guehne, O., Hyllus, P., Bruss, D., Ekert, A., Lewenstein, M., Macchiavello, C., ...
We introduce a general method for the experimental detection of entanglement by performing only few local measurements, assuming some prior knowledge of the density matrix. The idea is based on the...
Characterization of distillable and activatable states using entanglement witnesses (2002)
Kraus,B., Lewenstein,M., Cirac,J. I.
We introduce a formalism that connects entanglement witnesses and the distillation and activation properties of a state. We apply this formalism to two cases: First, we rederive the results presented...
Quantum Correlations in Systems of Indistinguishable Particles (2002)
Eckert, K., Schliemann, J., Bruss, D., Lewenstein, M.
We discuss quantum correlations in systems of indistinguishable particles in relation to entanglement in composite quantum systems consisting of well separated subsystems. Our studies are motivated...
Optical generation of quasisolitons in a single-component gas of neutral fermionic atoms (2002)
Karpiuk, T., Brewczyk, M., Dobrek, L., Baranov, M. A., Lewenstein, M., Rzazewski, K.
We analyze, the generation of soliton-like solutions in a single-component Fermi gas of neutral atoms at zero and finite temperatures with the phase imprinting method. By using both the numerical and...
Vortex-vortex interactions in toroidally trapped Bose-Einstein condensates (2002)
Schulte, T., Santos, L., Sanpera, A., Lewenstein, M.
We analyze the vortex dynamics and vortex-vortex interactions in Bose-Einstein condensates confined in toroidal traps. We show that this particular geometry strongly distorts the vortex dynamics. The...
Phase Fluctuations in Bose-Einstein Condensates (2002)
Hellweg, D., Dettmer, S., Ryytty, P., Arlt, J. J., Ertmer, W., Sengstock, K., ...
We demonstrate the existence of phase fluctuations in elongated Bose-Einstein Condensates (BECs) and study the dependence of those fluctuations on the system parameters. A strong dependence on...
Ultracold dipolar gases - a challenge for experiments and theory (2002)
Baranov, M., Dobrek, L., Goral, K., Santos, L., Lewenstein, M.
We present a review of recent results concerning the physics of ultracold trapped dipolar gases. In particular, we discuss the Bose-Einstein condensation for dipolar Bose gases and the BCS transition...
Characterization of distillable and activatable states using entanglement witnesses (2002)
Kraus, B., Lewenstein, M., Cirac, J. I.
We introduce a formalism that connects entanglement witnesses and the distillation and activation properties of a state. We apply this formalism to two cases: First, we rederive the results presented...
Quantum phases of dipolar bosons in optical lattices (2001)
Goral, K., Santos, L., Lewenstein, M.
The ground state of dipolar bosons placed in an optical lattice is analyzed. We show that the modification of experimentally accessible parameters can lead to the realization and control of different...
Dynamics of dark solitons in elongated Bose-Einstein condensates (2001)
Muryshev, A. E., Shlyapnikov, G. V., Ertmer, W., Sengstock, K., Lewenstein, M.
We find two types of moving dark soliton textures in elongated Bose-Einstein condensates: non-stationary kinks and proper dark solitons. The former have a curved notch region and rapidly decay by...
Characterization of Distillable and Activable States using Entanglement Witnesses (2001)
Kraus, B., Lewenstein, M., Cirac, J. I.
We introduce a formalism that connections entanglement witnesses and the distillation and activation properties of a state. We apply this formalism to two cases: First, we rederive the results...
Reflections upon separability and distillability (2001)
Bruss, D., Cirac, J. I., Horodecki, P., Hulpke, F., Kraus, B., Lewenstein, M., ...
We present an abstract formulation of the so-called Innsbruck-Hannover programme that investigates quantum correlations and entanglement in terms of convex sets. We present a unified description of...
Observation of Phase Fluctuations in Bose-Einstein Condensates (2001)
Dettmer, S., Hellweg, D., Ryytty, P., Arlt, J. J., Ertmer, W., Sengstock, K., ...
The occurrence of phase fluctuations due to thermal excitations in Bose-Einstein condensates (BECs) is studied for a variety of temperatures and trap geometries. We observe the statistical nature of...
Separability Criterion for all bipartite Gaussian States (2001)
Giedke, G., Kraus, B., Lewenstein, M., Cirac, J. I.
We provide a necessary and sufficient condition for separability of Gaussian states of bipartite systems of arbitrarily many modes. The condition provides an operational criterion since it can be...
Classification of mixed three-qubit states (2001)
Acin, A., Bruss, D., Lewenstein, M., Sanpera, A.
We introduce a classification of mixed three-qubit states, in which we define the classes of separable, biseparable, W- and GHZ-states. These classes are successively embedded into each other. We...
Separability and entanglement in 2x2xN composite quantum systems (2001)
We investigate separability and entanglement of mixed states in ${\cal C}^2\otimes{\cal C}^2\otimes{\cal C}^N$ three party quantum systems. We show that all states with positive partial transposes...
Phase Fluctuations in Bose-Einstein Condensates (2001)
Hellweg, D., Dettmer, S., Ryytty, P., Arlt, J.J, Ertmer, W., Sengstock, K., ...
We demonstrate the existence of phase fluctuations in elongated Bose-Einstein Condensates (BECs) and study the dependence of those fluctuations on the system parameters. A strong dependence on...
Phase Fluctuations in Bose-Einstein Condensates (2001)
Hellweg, D., Dettmer, S., Ryytty, P., Arlt, J.J, Ertmer, W., Sengstock, K., ...
We demonstrate the existence of phase fluctuations in elongated Bose-Einstein Condensates (BECs) and study the dependence of those fluctuations on the system parameters. A strong dependence on...
Entanglement capability of two-qubit operations (2001)
Kraus, B., Dur, W., Vidal, G., Cirac, J. I., Lewenstein, M., Linden, N., ...
We study the optimal way of creating bi-partite entanglement using a general two-qubit interaction. On the one hand, we analyze the entanglement capability of an arbitrary non-local Hamiltonian...
Entanglement capability of two-qubit operations (2001)
Kraus, B., Dur, W., Vidal, G., Cirac, J. I., Lewenstein, M., Linden, N., ...
We study the optimal way of creating bi-partite entanglement using a general two-qubit interaction. On the one hand, we analyze the entanglement capability of an arbitrary non-local Hamiltonian...
Loading of a Bose-Einstein condensate in the boson-accumulation regime (2000)
Floegel, F., Santos, L., Lewenstein, M.
We study the optical loading of a trapped Bose-Einstein condensate by spontaneous emission of atoms in excited electronic state in the Boson-Accumulation Regime. We generalize the previous simplified...
Separable approximations of density matrices of composite quantum systems (2000)
We investigate optimal separable approximations (decompositions) of states rho of bipartite quantum systems A and B of arbitrary dimensions MxN following the lines of Ref. [M. Lewenstein and A....
Realistic teleportation with linear optical elements (2000)
Trump, C., Bruss, D., Lewenstein, M.
We calculate the highest possible information gain in a measurement of entangled states when employing a beamsplitter. The result is used to evaluate the fidelity, averaged over all unknown inputs,...
Laser Cooling of Trapped Fermi Gases deeply below the Fermi Temperature (2000)
Idziaszek, Z., Santos, L., Lewenstein, M.
We study the collective Raman cooling of a polarized trapped Fermi gas in the Festina Lente regime, when the heating effects associated with photon reabsorptions are suppressed. We predict that by...
Entangling operations and their implementation using a small amount of entanglement (2000)
Cirac, J. I., Dür, W., Kraus, B., Lewenstein, M.
We study when a physical operation can produce entanglement between two systems initially disentangled. The formalism we develop allows to show that one can perform certain non-local operations with...
Continuous optical loading of a Bose-Einstein Condensate (2000)
Santos, L., Floegel, F., Pfau, T., Lewenstein, M.
The continuous pumping of atoms into a Bose-Einstein condensate via spontaneous emission from a thermal reservoir is analyzed. We consider the case of atoms with a three-level $\Lambda$ scheme, in...
Separability and distillability in composite quantum systems -a primer- (2000)
Lewenstein, M., Bruss, D., Cirac, J. I., Kraus, B., Kus, M., Samsonowicz, J., ...
Quantum mechanics is already 100 years old, but remains alive and full of challenging open problems. On one hand, the problems encountered at the frontiers of modern theoretical physics like Quantum...
Characterization of separable states and entanglement witnesses (2000)
Lewenstein, M., Kraus, B., Horodecki, P., Cirac, J. I.
We provide a canonical form of mixed states in bipartite quantum systems in terms of a convex combination of a separable state and a, so-called, edge state. We construct entanglement witnesses for...
Laser Induced Condensation of Bosonic Gases in Traps (2000)
Santos, L., Idziaszek, Z., Cirac, J. I., Lewenstein, M.
We consider collective laser cooling of atomic gas in the Festina lente regime, when the heating effects associated with photon reabsorptions are suppressed. We demonstrate that an appropriate...
Four-wave mixing in degenerate atomic gases (2000)
Villain, P., Ohberg, P., Santos, L., Sanpera, A., Lewenstein, M.
We study the process of four-wave mixing (4WM) in ultracold degenerate atomic gases. In particular we address the problem of 4WM in boson-fermion mixtures. We develop an approximate description of...
Cooling of a small sample of Bose atoms with accidental degeneracy (2000)
Lewenstein, M., Cirac, J. I., Santos, L.
A system of bosons in a harmonic trap is cooled via their interactions with a thermal reservoir. We derive the master equation that governs the evolution of the system and may describe diverse...
Optimization of entanglement witnesses (2000)
Lewenstein, M., Kraus, B., Cirac, J. I., Horodecki, P.
An entanglement witness (EW) is an operator that allows to detect entangled states. We give necessary and sufficient conditions for such operators to be optimal, i.e. to detect entangled states in an...
Bose-Einstein condensation in trapped dipolar gases (2000)
Santos, L., Shlyapnikov, G. V., Zoller, P., Lewenstein, M.
We discuss Bose-Einstein condensation in a trapped gas of bosonic particles interacting dominantly via dipole-dipole forces. We find that in this case the mean-field interparticle interaction and,...
Time correlations of a laser-induced Bose-Einstein condensate (2000)
Felbinger, T., Santos, L., Wilkens, M., Lewenstein, M.
We analyze the multi-time correlations of a laser-induced Bose-Einstein condensate. We use quantum stochastic methods to obtain under certain circumstances a Fokker-Planck equation which describes...
Probing the statistical properties of Bose-Einstein condensates with light (1999)
Idziaszek, Z., Rzazewski, K., Lewenstein, M.
A scattering of short, weak, nonresonant laser pulses on a Bose-Einstein condensate is proposed as a tool for studying its statistical properties. We show in particular that the variance of the...
Separability in 2xN composite quantum systems (1999)
Kraus, B., Cirac, J. I., Karnas, S., Lewenstein, M.
We analyze the separability properties of density operators supported on $\C^2\otimes \C^N$ whose partial transposes are positive operators. We show that if the rank of $\rho$ equals N then it is...
Coherent Evolution of Bouncing Bose-Einstein Condensates (1999)
Bongs, K., Burger, S., Birkl, G., Sengstock, K., Ertmer, W., Rzazewski, K., ...
We investigate the evolution of Bose-Einstein condensates falling under gravity and bouncing off a mirror formed by a far-detuned sheet of light. After reflection, the atomic density profile develops...
Dark Solitons in Bose-Einstein Condensates (1999)
Burger, S., Bongs, K., Dettmer, S., Ertmer, W., Sengstock, K., Sanpera, A., ...
Dark solitons in cigar shaped Bose-Einstein condensates of Rubidium-87 are created by a phase imprinting method. Coherent and dissipative dynamics of the solitons has been observed.
Scattering of short laser pulses from trapped fermions (1999)
Wong, T., Mustecaplioglu, Ozgur, You, L., Lewenstein, M.
We investigate the scattering of intense short laser pulses off trapped cold fermionic atoms. We discuss the sensitivity of the scattered light to the quantum statistics of the atoms. The temperature...
Distillability and partial transposition in bipartite systems (1999)
Dür, W., Cirac, J. I., Lewenstein, M., Bruss, D.
We study the distillability of a certain class of bipartite density operators which can be obtained via depolarization starting from an arbitrary one. Our results suggest that non-positivity of the...
Optical Generation of Vortices in trapped Bose-Einstein Condensates (1999)
Dobrek, L., Gajda, M., Lewenstein, M., Sengstock, K., Birkl, G., Ertmer, W.
We demonstrate numerically the efficient generation of vortices in Bose-Einstein condensates (BEC) by using a ``phase imprinting'' method. The method consist of passing a far off resonant laser pulse...
Separability and entanglement in 2xN composite quantum systems (1999)
Lewenstein, M., Cirac, J. I., Karnas, S.
We show that all density operators of 2$\times N$--dimensional quantum systems that remain invariant after partial transposition with respect to the first system are separable. Based on this...
Laser Induced Condensation of Trapped Bosonic Gases (1998)
Santos, L., Lewenstein, M., Cirac, J. I., Castin, Y.
We demonstrate that an appropriate sequence of laser pulses allows to condense a gas of trapped bosonic atoms into an arbitrary trap level. Such condensation is robust, can be achieved in...
Quantum Games and Quantum Strategies (1998)
Eisert, J., Wilkens, M., Lewenstein, M.
We investigate the quantization of non-zero sum games. For the particular case of the Prisoners' Dilemma we show that this game ceases to pose a dilemma if quantum strategies are allowed for. We also...
Creation of Dark Solitons and Vortices in Bose-Einstein Condensates (1997)
Dum, R., Cirac, J. I., Lewenstein, M., Zoller, P.
We propose and analyze a scheme to create dark solitons and vortices in Bose-Einstein condensates. This is achieved starting from a condensate in the internal state $|a>$ and transferring the atoms...
Wave packet dynamics with Bose-Einstein condensates (1997)
Dum, R., Sanpera, A., Brewczyk, M., Kus, M., Rzcazewski, K., ...
We study wave packet dynamics of a Bose condensate in a periodically shaken trap. Dichotomy, that is, dynamic splitting of the condensate, and dynamic stabilization are analyzed in analogy with...
Quantum Superposition States of Bose-Einstein Condensates (1997)
Cirac, J. I., Lewenstein, M., Moelmer, K., Zoller, P.
We propose a scheme to create a macroscopic ``Sch\"odinger cat'' state formed by two interacting Bose condensates. In analogy with quantum optics, where the control and engineering of quantum states...
Ground State Laser Cooling Beyond the Lamb-Dicke Limit (1997)
Morigi, G., Cirac, J. I., Lewenstein, M., Zoller, P.
We propose a laser cooling scheme that allows to cool a single atom confined in a harmonic potential to the trap ground state $|0>$. The scheme assumes strong confinement, where the oscillation...