Towards a loophole-free test of Bell's inequality with entangled pairs of neutral atoms (2009)
Rosenfeld, Wenjamin, Weber, Markus, Volz, Juergen, Henkel, Florian, Krug, Michael, Cabello, Adan, ...
Experimental tests of Bell's inequality allow to distinguish quantum mechanics from local hidden variable theories. Such tests are performed by measuring correlations of two entangled particles (e.g....
Toth, Geza, Wieczorek, Witlef, Krischek, Roland, Kiesel, Nikolai, Michelberger, Patrick, Weinfurter, Harald
We present general numerical methods to construct witness operators for entanglement detection and estimation of the fidelity. Our methods are applied to detecting entanglement in the vicinity of a...
Experimental entanglement of a six-photon symmetric Dicke state (2009)
Wieczorek, Witlef, Krischek, Roland, Kiesel, Nikolai, Michelberger, Patrick, Toth, Geza, Weinfurter, Harald
We report on the experimental observation and characterization of a six-photon entangled Dicke state. This state has remarkable properties, e.g., it allows to obtain inequivalent entangled states of...
Interference contrast in multi-source few photon optics (2009)
Laskowski, Wieslaw, Wiesniak, Marcin, Zukowski, Marek, Bourennane, Mohamed, Weinfurter, Harald
Many recent experiments employ several parametric down conversion (PDC) sources to get multiphoton interference. Such interference has applications in quantum information. We study here how effects...
Multi-qubit entanglement engineering via projective measurements (2009)
Wieczorek, Witlef, Kiesel, Nikolai, Schmid, Christian, Weinfurter, Harald
So far, various multi-photon entangled states have been observed experimentally by using different experimental set-ups. Here, we present a scheme to realize many SLOCC-inequivalent states of three...
Multiqubit entanglement engineering via projective measurements (2009)
Wieczorek, Witlef, Kiesel, Nikolai, Schmid, Christian, Weinfurter, Harald
Quantum teleportation and entanglement swapping with linear optics logic gates (2009)
Schmid, Christian, Kiesel, Nikolai, Weber, Ulrich K., Ursin, Rupert, Zeilinger, Anton, Weinfurter, Harald
Interference contrast in multisource few-photon optics (2009)
Laskowski, W., Wiesniak, M., Zukowski, M., Bourennane, M., Weinfurter, Harald
Information leakage via side channels in freespace BB84 quantum cryptography (2009)
Nauerth, Sebastian, Fürst, Martin, Schmitt-Manderbach, Tobias, Weier, Henning, Weinfurter, Harald
The SECOQC quantum key distribution network in Vienna (2009)
Peev, M., Pacher, C., Alleaume, R., Barreiro, C., Bouda, J., Boxleitner, W., ...
Experimental Entanglement of a Six-Photon Symmetric Dicke State (2009)
Wieczorek, Witlef, Krischek, Roland, Kiesel, Nikolai, Michelberger, Patrick, Tóth, Géza, Weinfurter, Harald
Tóth, Géza, Wieczorek, Witlef, Krischek, Roland, Kiesel, Nikolai, Michelberger, Patrick, Weinfurter, Harald
Revealing anyonic features in a toric code quantum simulation (2009)
Pachos, J. K., Wieczorek, Witlef, Schmid, Christian, Kiesel, Nikolai, Pohlner, Reinhold, Weinfurter, Harald
Experimental implementation of a four-player quantum game (2008)
Schmid, Christian, Flitney, Adrian P., Wieczorek, Witlef, Kiesel, Nikolai, Weinfurter, Harald, Hollenberg, Lloyd C. L.
Game theory is central to the understanding of competitive interactions arising in many fields, from the social and physical sciences to economics. Recently, as the definition of information is...
Experimental Quantum Cryptography Diplomarbeit von (2008)
Henning Weier, Prof Dr, Harald Weinfurter, Prof Dr, Alfred Laubereau
Gaertner, Sascha, Bourennane, Mohamed, Kurtsiefer, Christian, Cabello, Adan, Weinfurter, Harald
Gao et al. [Phys. Rev. Lett. 101, 208901 (2008)] have described a possible intercept-resend attack for the quantum protocol for detectable Byzantine agreement in Phys. Rev. Lett. 100, 070504 (2008)....
Quantum teleportation and entanglement swapping with linear optics logic gates (2008)
Schmid, Christian, Kiesel, Nikolai, Weber, Ulrich K., Ursin, Rupert, Zeilinger, Anton, Weinfurter, Harald
We report on the usage of a linear optics phase gate for distinguishing all four Bell states simultaneously in a quantum teleportation and entanglement swapping protocol. This is demonstrated by full...
Experimental observation of an entire family of four-photon entangled states (2008)
Wieczorek, Witlef, Schmid, Christian, Kiesel, Nikolai, Pohlner, Reinhold, Gühne, Otfried, Weinfurter, Harald
A single linear optical set-up is used to observe an entire family of four-photon entangled states. This approach breaks with the inflexibility of present linear-optical set-ups usually designed for...
Space-QUEST: Experiments with quantum entanglement in space (2008)
Ursin, Rupert, Jennewein, Thomas, Kofler, Johannes, Perdigues, Josep M., Cacciapuoti, Luigi, De Matos, Clovis J., ...
The European Space Agency (ESA) has supported a range of studies in the field of quantum physics and quantum information science in space for several years, and consequently we have submitted the...
Multi-photon entanglement and interferometry (2008)
Pan, Jian-Wei, Chen, Zeng-Bing, Zukowski, Marek, Weinfurter, Harald, Zeilinger, Anton
Multi-photon interference reveals strictly non-classical phenomena. Thus in quantum information, a significant fraction of key experimental progresses achieved so far comes from multi-photon state...
Collinear source of polarization-entangled photon pairs at non-degenerate wavelengths (2008)
Trojek, Pavel, Weinfurter, Harald
We report on a simple but highly efficient source of polarization-entangled photon pairs at non-degenerate wavelengths. The fully collinear configuration of the source enables very high coupling...
Discriminating multi-partite entangled states (2008)
Schmid, Christian, Kiesel, Nikolai, Laskowski, Wiesław, Wieczorek, Witlef, Zukowski, Marek \., Weinfurter, Harald
The variety of multi-partite entangled states enables numerous applications in novel quantum information tasks. In order to compare the suitability of different states from a theoretical point of...
Deliverable D (report, Christian Kurtsiefer, Harald Weinfurter, Hugues De Riedmatten, Wolfgang Tittel, Hugo Zbinden, ...
This report summarises the ongoing work in QuComm on fiber based entanglement quantum cryptography. Report Version: 1 Report Preparation Date: 2002-01-05 Classification: Internal Project funded by...
Experimental Demonstration of a Quantum Protocol for Byzantine Agreement and Liar Detection (2008)
Gaertner, Sascha, Bourennane, Mohamed, Kurtsiefer, Christian, Cabello, Adán, Weinfurter, Harald
Discriminating Multipartite Entangled States (2008)
Schmid, Christian, Kiesel, Nikolai, Laskowski, Wieslaw, Wieczorek, Witlef, Zukowski, Marek Z., Weinfurter, Harald
Experimental Direct Observation of Mixed State Entanglement (2008)
Schmid, Christian, Kiesel, Nikolai, Wieczorek, Witlef, Weinfurter, Harald, Mintert, Florian, Buchleitner, Andreas
Towards Long-Distance Atom-Photon Entanglement (2008)
Rosenfeld, W., Hocke, F., Henkel, F., Krug, M., Volz, J., Weber, M., ...
Quantum communications at ESA: Towards a space experiment on the ISS (2008)
Perdigues Armengol, Josep Maria, Furch, Bernhard, De Matos, Clovis Jacinto, Minster, Olivier, Cacciapuoti, Luigi, Pfennigbauer, Martin, ...
Experimental demonstration of a quantum protocol for Byzantine agreement and liar detection (2007)
Gaertner, Sascha, Bourennane, Mohamed, Kurtsiefer, Christian, Cabello, Adan, Weinfurter, Harald
We introduce a new quantum protocol for solving detectable Byzantine agreement (also called detectable broadcast) between three parties, and also for solving the detectable liar detection problem....
SECOQC White Paper on Quantum Key Distribution and Cryptography (2007)
Alleaume, Romain, Bouda, Jan, Branciard, Cyril, Debuisschert, Thierry, Dianati, Mehrdad, Gisin, Nicolas, ...
The SECOQC White Paper on Quantum Key Distribution and Cryptography is the outcome on a thorough consultation and discussion among the participants of the European project SECOQC (www.secoqc.net)....
Experimental Demonstration of Free-Space Decoy-State Quantum Key Distribution over 144 km (2007)
Schmitt-Manderbach, Tobias, Weier, Henning, Fürst, Martin, Ursin, Rupert, Tiefenbacher, Felix, Scheidel, Thomas, ...
Reply to Comment on 'Experimental single Qubit Quantum Secret Sharing' (2007)
Schmid, Christian, Trojek, Pavel, Bourennane, Mohamed, Kurtsiefer, Christian, Zukowski, Marek, Weinfurter, Harald
Experimental Demonstration of Four-Party Quantum Secret Sharing (2007)
Gaertner, Sascha, Kurtsiefer, Christian, Bourennane, Mohamed, Weinfurter, Harald
Experimental Observation of Four-Photon Entangled Dicke State with High Fidelity (2007)
Kiesel, Nikolai, Schmid, Christian, Tóth, Géza, Solano, Enrique, Weinfurter, Harald
Remote Preparation of an Atomic Quantum Memory (2007)
Rosenfeld, Wenjamin, Berner, Stefan, Volz, Jürgen, Weber, Markus, Weinfurter, Harald
Experimental analysis of a simple linear optics phase gate (2007)
Schmid, Christian, Kiesel, Nikolai-Thomas, Weber, U., Ursin, R., Weinfurter, Harald
Multiphoton entanglement engineering via projective measurements (2007)
Schmid, Christian, Kiesel, Nikolai, Wieczorek, Witlef, Pohlner, Reinhold, Weinfurter, Harald
Remote preparation of an atomic quantum memory (2006)
Rosenfeld, Wenjamin, Berner, Stefan, Volz, Juergen, Weber, Markus, Weinfurter, Harald
Storage and distribution of quantum information are key elements of quantum information processing and quantum communication. Here, using atom-photon entanglement as the main physical resource, we...
Experimental Observation of Four-Photon Entangled Dicke State with High Fidelity (2006)
Kiesel, Nikolai, Schmid, Christian, Toth, Geza, Solano, Enrique, Weinfurter, Harald
We present the experimental observation of the symmetric four-photon entangled Dicke state with two excitations $|D_{4}^{(2)}>$. A simple experimental set-up allowed quantum state tomography yielding...
Entanglement Persistency of Multiphoton Entangled States (2006)
Bourennane,Mohamed, Eibl,Manfred, Gaertner,Sascha, Kiesel,Nikolai, Kurtsiefer,Christian, Weinfurter,Harald
Observation of Entanglement of a Single Photon with a Trapped Atom (2006)
Volz,Jürgen, Weber,Markus, Schlenk,Daniel, Rosenfeld,Wenjamin, Saucke,Karen, Kurtsiefer,Christian, ...
Single photon emission from SiV centres in diamond produced by ion implantation (2006)
Wang,Chunlang, Kurtsiefer,Christian, Weinfurter,Harald, Burchard,Bernd
Single photon emission from SiV centres in diamond produced by ion implantation (2006)
Wang, Chunlang, Kurtsiefer, Christian, Weinfurter, Harald, Burchard, Bernd
Observation of Entanglement of a Single Photon with a Trapped Atom (2006)
Volz, Jürgen, Weber, Markus, Schlenk, Daniel, Rosenfeld, Wenjamin, Saucke, Karen, Kurtsiefer, Christian, ...
Entanglement Persistency of Multiphoton Entangled States (2006)
Bourennane, Mohamed, Eibl, Manfred, Gaertner, Sascha, Kiesel, Nikolai, Kurtsiefer, Christian, Weinfurter, Harald
Analysis of a single-atom dipole trap (2006)
Weber, Markus, Volz, Jürgen, Saucke, Karen, Kurtsiefer, Christian, Weinfurter, Harald
Complete Deterministic Linear Optics Bell State Analysis (2006)
Schuck, Carsten, Huber, Gerhard, Kurtsiefer, Christian, Weinfurter, Harald
Experimental quantum secret sharing (2006)
Schmid, Christian, Trojek, Pavel, Gaertner, Sascha, Bourennane, M., Kurtsiefer, Christian, Zukowski, M., ...
Free space quantum key distribution: Towards a real life application (2006)
Weier, Henning, Schmitt-Manderbach, Tobias, Regner, Nadja, Kurtsiefer, Christian, Weinfurter, Harald
Experimental Single Qubit Quantum Secret Sharing (2005)
Schmid,Christian, Trojek,Pavel, Bourennane,Mohamed, Kurtsiefer,Christian, Żukowski,Marek, Weinfurter,Harald
Analysis of a single-atom dipole trap (2005)
Weber, Markus, Volz, Juergen, Saucke, Karen, Kurtsiefer, Christian, Weinfurter, Harald
We describe a simple experimental technique which allows to store a single Rubidium 87 atom in an optical dipole trap. Due to light-induced two-body collisions during the loading stage of the trap...
Linear Optics Controlled-Phase Gate Made Simple (2005)
Kiesel,Nikolai, Schmid,Christian, Weber,Ulrich, Ursin,Rupert, Weinfurter,Harald
Experimental Analysis of a Four-Qubit Photon Cluster State (2005)
Kiesel,Nikolai, Schmid,Christian, Weber,Ulrich, Tóth,Géza, Gühne,Otfried, Ursin,Rupert, ...
Atom-Photon Entanglement (2005)
Volz, Juergen, Weber, Markus, Schlenk, Daniel, Rosenfeld, Wenjamin, Vrana, Johannes, Saucke, Karen, ...
We report the observation of entanglement between a single trapped atom and a single photon at a wavelength suitable for low-loss communication over large distances, thereby achieving a crucial step...
Experimental quantum communication complexity (2005)
Trojek,Pavel, Schmid,Christian, Bourennane,Mohamed, Brukner,Časlav, Żukowski,Marek, Weinfurter,Harald
Experimental Analysis of a 4-Qubit Cluster State (2005)
Kiesel, Nikolai, Schmid, Christian, Weber, Ulrich, Guehne, Otfried, Toth, Geza, Ursin, Rupert, ...
Linear optics quantum logic operations enabled the observation of a four-photon cluster state. We prove genuine four-partite entanglement and study its persistency, demonstrating remarkable...
Linear Optics C-Phase gate made simple (2005)
Kiesel, Nikolai, Schmid, Christian, Weber, Ulrich, Ursin, Rupert, Weinfurter, Harald
Linear optics quantum logic gates are the best tool to generate multi-photon entanglement. Simplifying a recent approach [Phys. Rev. A 65, 062324; Phys. Rev. A 66, 024308] we were able to implement...
Experimental one-way quantum computing (2005)
Walther,P., Resch,K. J., Rudolph,T., Schenck,E., Weinfurter,Harald, Vedral,V., ...
Single Qubit Quantum Secret Sharing (2005)
Schmid, Christian, Trojek, Pavel, Weinfurter, Harald, Bourennane, Mohamed, Zukowski, Marek, Kurtsiefer, Christian
We present a simple and practical protocol for the solution of a secure multiparty communication task, the secret sharing, and its experimental realization. In this protocol, a secret message is...
Experimental quantum communication complexity (2005)
Trojek, Pavel, Schmid, Christian, Bourennane, Mohamed, Brukner, Caslav, Zukowski, Marek, Weinfurter, Harald
We prove that the fidelity of two exemplary communication complexity protocols, allowing for an N-1 bit communication, can be exponentially improved by N-1 (unentangled) qubit communication. Taking...
Experimental one-way quantum computing (2005)
Walther, P., Resch, K. J., Rudolph, T., Schenck, E., Weinfurter, Harald, Vedral, V., ...
Linear Optics Controlled-Phase Gate Made Simple (2005)
Kiesel, Nikolai, Schmid, Christian, Weber, Ulrich, Ursin, Rupert, Weinfurter, Harald
Experimental Analysis of a Four-Qubit Photon Cluster State (2005)
Kiesel, Nikolai, Schmid, Christian, Weber, Ulrich, Tóth, Géza, Gühne, Otfried, Ursin, Rupert, ...
Experimental quantum communication complexity (2005)
Trojek, Pavel, Schmid, Christian, Bourennane, Mohamed, Brukner, Časlav, Żukowski, Marek, Weinfurter, Harald
Experimental Single Qubit Quantum Secret Sharing (2005)
Schmid, Christian, Trojek, Pavel, Bourennane, Mohamed, Kurtsiefer, Christian, Żukowski, Marek, Weinfurter, Harald
Decoherence-free quantum information processing with four-photon entangled states (2004)
Bourennane,Mohamed, Eibl,Manfred, Gaertner,Sascha, Kurtsiefer,Christian, Cabello,Adán, Weinfurter,Harald
Four photon polarization entanglement tests and applications (2004)
Bourennane,Mohamed, Eibl,Manfred, Gaertner,Sascha, Kurtsiefer,Christian, Weinfurter,Harald, Cabello,A., ...
Experimental detection of multipartite entanglement using witness operators (2004)
Bourennane,Mohamed, Eibl,Manfred, Kurtsiefer,C., Gaertner,Sascha, Weinfurter,Harald, Gühne,Otfried, ...
Experimental realization of a three-qubit entangled W state (2004)
Eibl,Manfred, Kiesel,Nikolai, Bourennane,Mohamed, Kurtsiefer,Christian, Weinfurter,Harald
Compact source of polarization-entangled photon pairs (2004)
Trojek,Pavel, Schmid,Christian, Bourennane,Mohamed, Weinfurter,Harald, Kurtsiefer,C.
Compact source of polarization-entangled photon pairs (2004)
Trojek, Pavel, Schmid, Christian, Bourennane, Mohamed, Weinfurter, Harald, Kurtsiefer, C.
Decoherence-free quantum information processing with four-photon entangled states (2004)
Bourennane, Mohamed, Eibl, Manfred, Gaertner, Sascha, Kurtsiefer, Christian, Cabello, Adán, Weinfurter, Harald
Experimental detection of multipartite entanglement using witness operators (2004)
Bourennane, Mohamed, Eibl, Manfred, Kurtsiefer, C., Gaertner, Sascha, Weinfurter, Harald, Gühne, Otfried, ...
Experimental realization of a three-qubit entangled W state (2004)
Eibl, Manfred, Kiesel, Nikolai, Bourennane, Mohamed, Kurtsiefer, Christian, Weinfurter, Harald
Four photon polarization entanglement tests and applications (2004)
Bourennane, Mohamed, Eibl, Manfred, Gaertner, Sascha, Kurtsiefer, Christian, Weinfurter, Harald, Cabello, A., ...
High-fidelity source of four-photon entanglement (2003)
Gaertner,Sascha, Bourennane,Mohamed, Eibl,Manfred, Kurtsiefer,C., Weinfurter,Harald
Decoherence-Free Quantum Information Processing with Four-Photon Entangled States (2003)
Bourennane, Mohamed, Eibl, Manfred, Gaertner, Sascha, Kurtsiefer, Christian, Cabello, Adan, Weinfurter, Harald
Decoherence-free states protect quantum information from collective noise, the predominant cause of decoherence in current implementations of quantum communication and computation. Here we...
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...
Experimental Observation of Four-Photon Entanglement from Parametric Down-Conversion (2003)
Eibl,Manfred, Gaertner,Sascha, Bourennane,Mohamed, Kurtsiefer,C., Zukowski,M., Weinfurter,Harald
Ascertaining the Values of σx, σy, and σz of a Polarization Qubit (2003)
Schulz,O., Steinhubl,R., Weber,M., Englert,Berthold-Georg, Kurtsiefer,C., Weinfurter,Harald
Mulitphoton Entanglement (2003)
Bourennane,Mohamed, Eibl,Manfred, Gaertner,Sascha, Kiesel,Nikolai, Kurtsiefer,Christian, Zukowski,Marek, ...
Multiphoton entanglement and interferometry (2003)
Bourennane,Mohamed, Eibl,Manfred, Gaertner,Sascha, Kiesel,Nikolai, Kurtsiefer,Christian, Zukowski,M., ...
Mulitphoton Entanglement (2003)
Bourennane, Mohamed, Eibl, Manfred, Gaertner, Sascha, Kiesel, Nikolai, Kurtsiefer, Christian, Zukowski, Marek, ...
Ascertaining the Values of σx, σy, and σz of a Polarization Qubit (2003)
Schulz, O., Steinhubl, R., Weber, M., Englert, Berthold-Georg, Kurtsiefer, C., Weinfurter, Harald
Experimental Observation of Four-Photon Entanglement from Parametric Down-Conversion (2003)
Eibl, Manfred, Gaertner, Sascha, Bourennane, Mohamed, Kurtsiefer, C., Zukowski, M., Weinfurter, Harald
High-fidelity source of four-photon entanglement (2003)
Gaertner, Sascha, Bourennane, Mohamed, Eibl, Manfred, Kurtsiefer, C., Weinfurter, Harald
Multiphoton entanglement and interferometry (2003)
Bourennane, Mohamed, Eibl, Manfred, Gaertner, Sascha, Kiesel, Nikolai, Kurtsiefer, Christian, Zukowski, M., ...
Kiesel, N., Bourennane, Mohamed, Kurtsiefer, C., Weinfurter, Harald, Kaszlikowski, D., Laskowski, W., ...
Eibl, Manfred, Kiesel, Nikolai, Bourennane, Mohamed, Gaertner, Sascha, Kurtsiefer, Christian, Weinfurter, Harald
Ascertaining the Values of $\sigma_x$, $\sigma_y$, and $\sigma_z$ of a Polarization Qubit (2002)
Schulz, Oliver, Steinhübl, Ruprecht, Weber, Markus, Englert, Berthold-Georg, Kurtsiefer, Christian, Weinfurter, Harald
In the 1987 spin retrodiction puzzle of Vaidman, Aharonov, and Albert one is challenged to ascertain the values of $\sigma_x$, $\sigma_y$, and $\sigma_z$ of a spin-1/2 particle by utilizing...
Secure communication with single-photon two-qubit states (2002)
Beige,Almut, Englert,Berthold-Georg, Kurtsiefer,Christian, Weinfurter,Harald
We propose a cryptographic scheme that is deterministic: Alice sends single photons to Bob, and each and every photon detected supplies one key bit-no photon is wasted. This is in marked contrast to...
Secure communication with a publicly known key (2002)
Beige,Almut, Englert,Berthold-Georg, Kurtsiefer,Christian, Weinfurter,Harald
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 Alice even will...
Communicating with Qubit Pairs (2002)
Beige,Almut, Englert,Berthold-Georg, Kurtsiefer,Christian, Weinfurter,Harald
Long-distance free-space quantum cryptography (2002)
Kurtsiefer,Christian, Zarda,P., Halder,M., Gorman,Ph. M., Tapster,Paul R., Rarity,J. G., ...
Multiphoton Entanglement (2002)
Bourennane,Mohamed, Eibl,Manfred, Gaertner,Sascha, Kiesel,Nikolai, Kurtsiefer,Christian, Weinfurter,Harald
Secure communication with a publicly known key (2002)
Beige, Almut, Englert, Berthold-Georg, Kurtsiefer, Christian, Weinfurter, Harald
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 Alice even will...
Secure communication with single-photon two-qubit states (2002)
Beige, Almut, Englert, Berthold-Georg, Kurtsiefer, Christian, Weinfurter, Harald
We propose a cryptographic scheme that is deterministic: Alice sends single photons to Bob, and each and every photon detected supplies one key bit-no photon is wasted. This is in marked contrast to...
Communicating with Qubit Pairs (2002)
Beige, Almut, Englert, Berthold-Georg, Kurtsiefer, Christian, Weinfurter, Harald
Long-distance free-space quantum cryptography (2002)
Kurtsiefer, Christian, Zarda, P., Halder, M., Gorman, Ph. M., Tapster, Paul R., Rarity, J. G., ...
Multiphoton Entanglement (2002)
Bourennane, Mohamed, Eibl, Manfred, Gaertner, Sascha, Kiesel, Nikolai, Kurtsiefer, Christian, Weinfurter, Harald
Secure communication with a publicly known key (2001)
Beige, Almut, Englert, Berthold-Georg, Kurtsiefer, Christian, Weinfurter, Harald
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 Alice even will...
The breakdown flash of Silicon Avalance Photodiodes - backdoor for eavesdropper attacks? (2001)
Kurtsiefer, Christian, Zarda, Patrick, Mayer, Sonja, Weinfurter, Harald
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, they are known to...
Four Photon Entanglement from Down Conversion (2001)
Weinfurter, Harald, Zukowski, Marek
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, this state is not...
Universal unitary gate for single-photon 2-qubit states (2001)
Englert, Berthold-Georg, Kurtsiefer, Christian, Weinfurter, Harald
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-Zehnder interferometer,...
Secure communication with single-photon two-qubit states (2001)
Beige, Almut, Englert, Berthold-Georg, Kurtsiefer, Christian, Weinfurter, Harald
We propose a cryptographic scheme that is deterministic: Alice sends single photons to Bob, and each and every photon detected supplies one key bit -- no photon is wasted. This is in marked contrast...
High efficiency entangled photon pair collection in type II parametric fluorescence (2001)
Kurtsiefer, Christian, Oberparleiter, Markus, Weinfurter, Harald
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 photon pairs per...
A feasible "Kochen-Specker" experiment with single particles (2000)
Simon, Christoph, Zukowski, Marek, Weinfurter, Harald, Zeilinger, Anton
We present a simple experimental scheme which can be used to demonstrate an all-or-nothing type contradiction between non-contextual hidden variables and quantum mechanics. The scheme, which is...
Experiments towards Falsification of Noncontextual Hidden Variable Theories (2000)
Michler, Markus, Weinfurter, Harald, Zukowski, Marek
We present two experiments testing the hypothesis of noncontextual hidden variables (NCHV's). The first one is based on observation of two-photon pseudo-Greenberger-Horne-Zeilinger correlations, with...
A Fast and Compact Quantum Random Number Generator (1999)
Jennewein, Thomas, Achleitner, Ulrich, Weihs, Gregor, Weinfurter, Harald, Zeilinger, Anton
We present the realization of a physical quantum random number generator based on the process of splitting a beam of photons on a beam splitter, a quantum mechanical source of true randomness. By...
High-Fidelity Teleportation of Independent Qubits (1999)
Bouwmeester, Dik, Pan, Jian-Wei, Weinfurter, Harald, Zeilinger, Anton
Quantum teleportation is one of the essential primitives of quantum communication. We suggest that any quantum teleportation scheme can be characterized by its efficiency, i.e. how often it succeeds...
Violation of Bell's inequality under strict Einstein locality conditions (1998)
Weihs, Gregor, Jennewein, Thomas, Simon, Christoph, Weinfurter, Harald, Zeilinger, Anton
We observe strong violation of Bell's inequality in an Einstein, Podolsky and Rosen type experiment with independent observers. Our experiment definitely implements the ideas behind the well known...
Observation of three-photon Greenberger-Horne-Zeilinger entanglement (1998)
Bouwmeester, Dik, Pan, Jian-Wei, Daniell, Matthew, Weinfurter, Harald, Zeilinger, Anton
We present the experimental observation of polarization entanglement for three spatially separated photons. Such states of more than two entangled particles, known as GHZ states, play a crucial role...
A posteriori teleportation ? (1998)
Bouwmeester, Dik, Pan, Jian-Wei, Daniell, Matthew, Weinfurter, Harald, Zukowski, Marek, Zeilinger, Anton
Braunstein and Kimble observe correctly that, in the Innsbruck experiment, Nature 390, 575 (1997), one does not always observe a teleported photon conditioned on a coincidence recording at the...
Adriano Barenco, David P. Divincenzo, Tycho Sleator, Charles H. Bennett, Norman Margolus, John Smolin, ...
We show that a set of gates that consists of all one-bit quantum gates (U(2)) and the two-bit exclusive-or gate (that maps Boolean values (x, y)to(x, x⊕y)) is universal in the sense that all...
Elementary Gates for Quantum Computation (1995)
Adriano Barenco, Charles H. Bennett, Richard Cleve, David P. DiVincenzo, Norman Margolus, Peter Shor, ...
We show that a set of gates that consists of all one-bit quantum gates (U(2)) and the two-bit exclusive-or gate (that maps Boolean values (x; y) to (x; x \Phi y)) is universal in the sense that all...
Elementary Gates for Quantum Computation (1995)
Adriano Barenco, Charles H. Bennett, Richard Cleve, David P. DiVincenzo, Norman Margolus, Peter Shor, ...
We show that a set of gates that consists of all one-bit quantum gates (U(2)) and the two-bit exclusive-or gate (that maps Boolean values (x; y) to (x; x \Phi y)) is universal in the sense that all...
Elementary Gates for Quantum Computation (1995)
Adriano Barenco, Charles H. Bennett, Richard Cleve, David P. Divincenzo, Norman Margolus, ...
We show that a set of gates that consists of all one-bit quantum gates (U(2)) and the two-bit exclusive-or gate (that maps Boolean values (x; y) to (x; x \Phi y)) is universal in the sense that all...
Elementary Gates for Quantum Computation (1995)
Adriano Barenco, Charles H. Bennett, Richard Cleve, David P. Divincenzo, Norman Margolus, ...
We show that a set of gates that consists of all one-bit quantum gates (U(2)) and the two-bit exclusive-or gate (that maps Boolean values (x; y) to (x; x \Phi y)) is universal in the sense that all...
Elementary Gates for Quantum Computation (1995)
Adriano Barenco, Charles H. Bennett, Richard Cleve, David P. Divincenzo, Norman Margolus, Peter Shor, ...
We show that a set of gates that consists of all one-bit quantum gates (U(2)) and the two-bit exclusive-or gate (that maps Boolean values (x; y) to (x; x \Phi y)) is universal in the sense that all...