Characterizing the nonlocal correlations of particles that never interacted (2009)
Branciard, Cyril, Gisin, Nicolas, Pironio, Stefano
Quantum systems that have never interacted can become nonlocally correlated through a process called entanglement swapping. To characterize nonlocality in this context, we introduce local models...
The local content of bipartite qubit correlations (2009)
Branciard, Cyril, Gisin, Nicolas, Scarani, Valerio
One of the last open problems concerning two qubits in a pure state is to find the exact local content of their correlation, in the sense of Elitzur, Popescu and Rohrlich (EPR2) [Phys. Lett. A 162,...
Waveguide-based OPO source of entangled photon pairs (2009)
Pomarico, Enrico, Sanguinetti, Bruno, Gisin, Nicolas, Thew, Robert, Zbinden, Hugo, Schreiber, Gerhard, ...
In this paper we present a compact source of narrow-band energy-time entangled photon pairs in the telecom regime based on a Ti-indiffused Periodically Poled Lithium Niobate (PPLN) waveguide...
Simulation of equatorial von Neumann measurements on GHZ states using nonlocal resources (2009)
Bancal, Jean-Daniel, Branciard, Cyril, Gisin, Nicolas
Reproducing with elementary resources the correlations that arise when a quantum system is measured (quantum state simulation), allows one to get insight on the operational and computational power of...
Demonstration of atomic frequency comb memory for light with spin-wave storage (2009)
Afzelius, Mikael, Usmani, Imam, Amari, Atia, Lauritzen, Björn, Walther, Andreas, Simon, Christoph, ...
We present a light-storage experiment where the light is mapped onto an inhomogeneously broadened optical transition in a praseodymium-doped crystal, which is shaped into an atomic frequency comb....
Solid state quantum memory for photons at telecommunication wavelengths (2009)
Lauritzen, Björn, Minář, Jiří, De Riedmatten, Hugues, Afzelius, Mikael, Sangouard, Nicolas, Simon, Christoph, ...
We demonstrate experimentally a solid-state quantum memory for photons at telecommunication wavelengths. Weak light fields at the single photon level are stored for a time up to 600 ns in an...
Electric control of collective atomic coherence in an Erbium doped solid (2009)
Minář, Jiří, Lauritzen, Björn, De Riedmatten, Hugues, Afzelius, Mikael, Simon, Christoph, Gisin, Nicolas
We demonstrate fast and accurate control of the evolution of collective atomic coherences in an Erbium doped solid using external electric fields. This is achieved by controlling the inhomogeneous...
Quantum repeaters based on atomic ensembles and linear optics (2009)
Sangouard, Nicolas, Simon, Christoph, De Riedmatten, Hugues, Gisin, Nicolas
The distribution of quantum states over long distances is limited by photon loss. Straightforward amplification as in classical telecommunications is not an option in quantum communication because of...
Device-independent quantum key distribution secure against collective attacks (2009)
Pironio, Stefano, Acin, Antonio, Brunner, Nicolas, Gisin, Nicolas, Massar, Serge, Scarani, Valerio
Device-independent quantum key distribution (DIQKD) represents a relaxation of the security assumptions made in usual quantum key distribution (QKD). As in usual QKD, the security of DIQKD follows...
Ottaviani, Carlo, Simon, Christoph, De Riedmatten, Hugues, Afzelius, Mikael, Lauritzen, Bjoern, Sangouard, Nicolas, ...
The creation of single collective excitations in atomic ensembles via spontaneous Raman emission plays a key role in several quantum communication protocols, starting with the seminal DLCZ protocol...
Quantifying multipartite nonlocality (2009)
Bancal, Jean-Daniel, Branciard, Cyril, Gisin, Nicolas, Pironio, Stefano
The nonlocal correlations of multipartite entangled states can be reproduced by a classical model if sufficiently many parties join together or if sufficiently many parties broadcast their...
Quantum experiments with human eyes as detectors based on cloning via stimulated emission (2009)
Sekatski, Pavel, Brunner, Nicolas, Branciard, Cyril, Gisin, Nicolas, Simon, Christoph
We show theoretically that the multi-photon states obtained by cloning single-photon qubits via stimulated emission can be distinguished with the naked human eye with high efficiency and fidelity....
Non-realism : deep thought or a soft option ? (2009)
The claim that the observation of a violation of a Bell inequality leads to an alleged alternative between nonlocality and non-realism is annoying because of the vagueness of the second term.
Valerio Scarani, Antonio Acín, Grégoire Ribordy, Nicolas Gisin
cryptography protocols robust against photon number
Testing a Bell inequality in multi-pair scenarios (2008)
Bancal, Jean-Daniel, Branciard, Cyril, Brunner, Nicolas, Gisin, Nicolas, Popescu, Sandu, Simon, Christoph
To date, most efforts to demonstrate quantum nonlocality have concentrated on systems of two (or very few) particles. It is however difficult in many experiments to address individual particles,...
Multi-Mode Quantum Memory based on Atomic Frequency Combs (2008)
Afzelius, Mikael, Simon, Christoph, De Riedmatten, Hugues, Gisin, Nicolas
An efficient multi-mode quantum memory is a crucial resource for long-distance quantum communication based on quantum repeaters. We propose a quantum memory based on spectral shaping of an...
Romain Alléaume, Jan Bouda, Cyril Branciard, Thierry Debuisschert, Nicolas Gisin, Mark Godfrey, ...
Version: 5.1 Document history: During the first year of the SECOQC project [1], Philippe Grangier initiated an internal debate regarding the “comparative advantages ” of quantum key distribution...
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...
Jean-daniel Gautier, Jürgen Brendel, Hugo Zbinden, Nicolas Gisin, Bgn Bg
Time-of-flight chromatic dispersion measurement using photon counting.
1. Information-Theoretic Key Agreement from Classical and Quantum Information (2007)
Nicolas Gisin, Renato Renner, Stefan Wolf
Abstract. It was recently pointed out that there is a close connection between information-theoretic key agreement and quantum entanglement purication. This suggests that the concept of bound...
Quantum Information, Computation and Complexity * Programme at the Institut Henri Poincaré, January 4th April 7th, 2006 * Organizers: Ph.Grangier, M.Santha and D.L.Shepelyansky * Lectures have...
Quantum Information, Computation and Complexity * Programme at the Institut Henri Poincaré, January 4th April 7th, 2006 * Organizers: Ph.Grangier, M.Santha and D.L.Shepelyansky * Lectures have...
Energy-time entanglement of quasi-particles in solid-state devices (2003)
Scarani, Valerio, Gisin, Nicolas, Popescu, Sandu
We present a proposal for the experimental observation of energy-time entanglement of quasi-particles in mesoscopic physics. This type of entanglement arises whenever correlated particles are...
Riedmatten, Quantum relays for long distance quantum cryptography (2003)
Daniel Collins, Nicolas Gisin, Hugues De Riedmatten
Quantum cryptography is on the verge of commercial application. One of its greatest limitations is over long distance—secret key rates are low and the longest fibre over which any key has been...
Matthias Fitzi, Nicolas Gisin, Ueli Maurer, Oliver Von Rotz
Abstract. It is well-known that n players, connected only by pairwise secure channels, can achieve unconditional broadcast if and only if the number t of cheaters satisfies t < n/3. In this paper,...
Nicolas Gisin, Grégoire Ribordy, Wolfgang Tittel, Hugo Zbinden
Quantum cryptography could well be the first application of quantum mechanics at the individual quanta level. The very fast progress in both theory and experiments over the recent years are reviewed,...
Matthias Fitzi, Nicolas Gisin, Ueli Maurer, Oliver Von Rotz
It is well-known that n players, connected only by pairwise secure channels, can achieve unconditional broadcast if and only if the number t of cheaters satis es t < n=3. In this paper, we show...
Nicolas Gisin Gre, Nicolas Gisin, Grégoire Ribordy, Wolfgang Tittel, Hugo Zbinden
This paper will show that in compensation for this "quantum noise," quantum mechanics allows us novel forms of coding without analogue in communication channels adequately described by...
Linking classical and quantum key agreement: is there \bound information (2000)
Abstract. After carrying out a protocol for quantum key agreement over a noisy quantum channel, the parties Alice and Bob must process the raw key in order to end up with identical keys about which...
Linking classical and quantum key agreement: is there \bound information (2000)
Abstract. After carrying out a protocol for quantum key agreement over a noisy quantum channel, the parties Alice and Bob must process the raw key in order to end up with identical keys about which...
Linking classical and quantum key agreement: is there \bound information (2000)
Nicolas Gisin, Renato Renner, Stefan Wolf
After carrying out a protocol for quantum key agreement over a noisy quantum channel, the parties Alice and Bob must process the raw key in order to end up with identical keys about which the...
Testing the foundations of quantum mechanics (1999)
Quantum mechanics is certainly one of the most fascinating field of physics. In recent years, the new field of "quantum information processing" based on the most fundamental aspect of quantum...
Optical quantum random number generator (1999)
André Stefanov, Nicolas Gisin, Olivier Guinnard, Laurent Guinnard, Hugo Zbinden
A physical random number generator based on the intrinsic randomness of quantum mechanics is described. The random events are realized by the choice of single photons between the two outputs of a...
Automated plug and play quantum key distribution, Electron (1998)
Grégoire Ribordy, Jean-daniel Gautier, Nicolas Gisin, Olivier Guinnard, Hugo Zbinden
An improved « plug & play » interferometric system for quantum key distribution is presented. Self-alignment and compensation of birefringence remain, while limitations due to reflections are...
Optimal eavesdropping in quantum cryptography (1997)
Christopher A. Fuchs, Nicolas Gisin, Robert B. Griffiths, Chi-sheng Niu, Asher Peres
We consider the Bennett-Brassard cryptographic scheme, which uses two conjugate quantum bases. An eavesdropper who attempts to obtain information on qubits sent in one of the bases causes a...
Birefringence measurements in fibers without polarizer (1989)
Thévenaz, L., Pellaux, Jean-Paul, Gisin, Nicolas, Von Der Weid, Jean-Pierre
A method for measuring the delay between polarization eigenmodes in either high- or low-birefringence fibers is described. The main advantage of this interferometric method is its ability to perform...