Manipulating mesoscopic multipartite entanglement with atom-light interfaces (2009)
Stasińska, Julia, Rodó, Carles, Paganelli, Simone, Birkl, Gerhard, Sanpera, Anna
Entanglement between two macroscopic atomic ensembles induced by measurement on an ancillary light system has proven to be a powerful method for engineering quantum memories and quantum state...
Preparation of Decoherence Free Cluster States with Optical Superlattices (2008)
Jiang, Liang, Rey, Ana Maria, Romero-Isart, Oriol, Garcia-Ripoll, Juan Jose, Sanpera, Anna, Lukin, Mikhail D.
We present a protocol to prepare decoherence free cluster states using ultracold atoms loaded in a two dimensional superlattice. The superlattice geometry leads to an array of 2*2 plaquettes, each of...
Quantum Non-Demolition Detection of Strongly Correlated Systems (2007)
Eckert, Kai, Romero-Isart, Oriol, Rodriguez, Mirta, Lewenstein, Maciej, Polzik, Eugene S., Sanpera, Anna
Preparation, manipulation, and detection of strongly correlated states of quantum many body systems are among the most important goals and challenges of modern physics. Ultracold atoms offer an...
Frustration, Area Law, and Interference in Quantum Spin Models (2007)
De, Aditi Sen, Sen, Ujjwal, Dziarmaga, Jacek, Sanpera, Anna, Lewenstein, Maciej
We study frustrated quantum systems from a quantum information perspective. Within this approach, we find that highly frustrated systems do not follow any general ''area law'' of block entanglement,...
Trapped Ion Chain as a Neural Network: Error Resistant Quantum Computation (2006)
Pons, Marisa, Ahufinger, Veronica, Wunderlich, Christof, Sanpera, Anna, Braungardt, Sibylle, De, Aditi Sen, ...
We demonstrate the possibility of realizing a neural network in a chain of trapped ions with induced long range interactions. Such models permit one to store information distributed over the whole...
Ultracold atomic gases in optical lattices: mimicking condensed matter physics and beyond (2006)
Lewenstein, Maciej, Sanpera, Anna, Ahufinger, Veronica, Damski, Bogdan, De, Aditi Sen, Sen, Ujjwal
We review recent developments in the physics of ultracold atomic and molecular gases in optical lattices. Such systems are nearly perfect realisations of various kinds of Hubbard models, and as such...
The separability versus entanglement problem (2005)
De, Aditi Sen, Sen, Ujjwal, Lewenstein, Maciej, Sanpera, Anna
We review the problem of discriminating entangled states from separable states for bipartite systems. We formally define what entangled states are, present some important criteria to detect...
Disordered complex systems using cold gases and trapped ions (2005)
De, Aditi Sen, Sen, Ujjwal, Lewenstein, Maciej, Ahufinger, Veronica, Pons, Marisa, Sanpera, Anna
We report our research on disordered complex systems using cold gases and trapped ions, and address the possibility of using complex systems for quantum information processing. Two simple...
Continuous Variable Solution for Byzantine Agreement (2005)
Neigovzen, Rodion, Sanpera, Anna
We demonstrate that the Byzantine Agreement Problem (BAP) in its weaker version with detectable broadcast, can be solved using continuous variables Gaussian states with Gaussian operations. The...
Dynamics of F=1 87Rb condensates at finite temperatures (2005)
Mur-Petit, Jordi, Guilleumas, Montserrat, Polls, Artur, Sanpera, Anna, Lewenstein, Maciej, Bongs, Kai, ...
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...
Quantum Information Processing in Disordered and Complex Quantum Systems (2005)
De, Aditi Sen, Sen, Ujjwal, Ahufinger, Veronica, Briegel, Hans J., Sanpera, Anna, Lewenstein, Maciej
We investigate quantum information processing and manipulations in disordered systems of ultracold atoms and trapped ions. First, we demonstrate generation of entanglement and local realization of...
Soliton eigenvalue control with optical lattices (2004)
Kartashov, Yaroslav V., Crasovan, Lucian-Cornel, Zelenina, Anna S., Vysloukh, Victor A., Sanpera, Anna, Lewenstein, Maciej, ...
We address the dynamics of higher-order solitons in optical lattices, and predict their self-splitting into the set of their single-soliton constituents. The splitting is induced by the potential...
Unitarity as preservation of entropy and entanglement in quantum systems (2004)
Hulpke, Florian, Poulsen, Uffe V., Sanpera, Anna, De, Aditi Sen, Sen, Ujjwal, Lewenstein, Maciej
The logical structure of Quantum Mechanics (QM) and its relation to other fundamental principles of Nature has been for decades a subject of intensive research. In particular, the question whether...
Experimental detection of multipartite entanglement using witness operators (2004)
Bourennane,Mohamed, Eibl,Manfred, Kurtsiefer,C., Gaertner,Sascha, Weinfurter,Harald, Gühne,Otfried, ...
Sanpera, Anna, Kantian, Adrian, Sanchez-Palencia, Laurent, Zakrzewski, Jakub, Lewenstein, Maciej
We investigate atomic Fermi-Bose mixtures in inhomogeneous and random optical lattices in the limit of strong atom-atom interactions. We derive the effective Hamiltonian describing the dynamics of...
Simplifying Schmidt number witnesses via higher-dimensional embeddings (2004)
Hulpke, Florian, Bruss, Dagmar, Lewenstein, Maciej, Sanpera, Anna
We apply the generalised concept of witness operators to arbitrary convex sets, and review the criteria for the optimisation of these general witnesses. We then define an embedding of state vectors...
Sanpera, Anna, Kantian, Adrian, Sanchez-Palencia, Laurent, Zakrzewski, Jakub, Lewenstein, Maciej
We investigate atomic Fermi-Bose mixtures in inhomogeneous and random optical lattices in the limit of strong atom-atom interactions. We derive the effective Hamiltonian describing the dynamics of...
Sanpera, Anna, Kantian, Adrian, Sanchez-Palencia, Laurent, Zakrzewski, Jakub, Lewenstein, Maciej
We investigate atomic Fermi-Bose mixtures in inhomogeneous and random optical lattices in the limit of strong atom-atom interactions. We derive the effective Hamiltonian describing the dynamics of...
Sanpera, Anna, Kantian, Adrian, Sanchez-Palencia, Laurent, Zakrzewski, Jakub, Lewenstein, Maciej
We investigate atomic Fermi-Bose mixtures in inhomogeneous and random optical lattices in the limit of strong atom-atom interactions. We derive the effective Hamiltonian describing the dynamics of...
Experimental detection of multipartite entanglement using witness operators (2004)
Bourennane, Mohamed, Eibl, Manfred, Kurtsiefer, C., Gaertner, Sascha, Weinfurter, Harald, Gühne, Otfried, ...
Sanpera, Anna, Kantian, Adrian, Sanchez-Palencia, Laurent, Zakrzewski, Jakub, Lewenstein, Maciej
We investigate atomic Fermi-Bose mixtures in inhomogeneous and random optical lattices in the limit of strong atom-atom interactions. We derive the effective Hamiltonian describing the dynamics of...
Witnessing multipartite entanglement (2003)
Bourennane, Mohamed, Eibl, Manfred, Kurtsiefer, Christian, Gaertner, Sascha, Weinfurter, Harald, Guehne, Otfried, ...
We present the experimental detection of genuine multipartite entanglement using entanglement witness operators. To this aim we introduce a canonical way of constructing and decomposing witness...
Schmidt number witnesses and bound entanglement (2000)
Sanpera, Anna, Bruss, Dagmar, Lewenstein, Maciej
The Schmidt number of a mixed state characterizes the minimum Schmidt rank of the pure states needed to construct it. We investigate the Schmidt number of an arbitrary mixed state by constructing a...
Cormier, Eric, Sanpera, Anna, Lewenstein, Maciej, Agostini, Pierre
We numerically study 2-photon processes using a set of harmonics from a Ti:Sapphire laser and in particular interference effects in the Above Threshold Ionization spectra. We compare the situation...
On the volume of the set of mixed entangled states (1998)
Zyczkowski, Karol, Horodecki, Pawel, Sanpera, Anna, Lewenstein, Maciej
A natural measure in the space of density matrices describing N-dimensional quantum systems is proposed. We study the probability P that a quantum state chosen randomly with respect to the natural...
Quantum inseparability as local pseudomixture (1998)
Sanpera, Anna, Tarrach, Rolf, Vidal, Guifre
We show how to decompose any density matrix of the simplest binary composite systems, whether separable or not, in terms of only product vectors. We determine for all cases the minimal number of...
Separability and entanglement of composite quantum systems (1997)
Lewenstein, Maciej, Sanpera, Anna
We provide a constructive algorithm to find the best separable approximation to an arbitrary density matrix of a composite quantum system of finite dimensions. The method leads to a condition of...
Quantum separability, time reversal and canonical decompositions (1997)
Sanpera, Anna, Tarrach, Rolf, Vidal, Guifre
We propose an interpretation of quantum separability based on a physical principle: local time reversal. It immediately leads to a simple characterization of separable quantum states that reproduces...
Quantum Privacy Amplification and the Security of Quantum Cryptography Over Noisy Channels (1996)
David Deutsch, Artur Ekert, Richard Jozsa, Chiara Macchiavello, Sandu Popescu, Anna Sanpera
Existing quantum cryptographic schemes are not, as they stand, operable in the presence of noise on the quantum communication channel. Although they become operable if they are supplemented by...