Pentagrams and paradoxes (2009)
Badziag, Piotr, Bengtsson, Ingemar, Cabello, Adan, Granstrom, Helena, Larsson, Jan-Ake
Klyachko and coworkers consider an orthogonality graph in the form of a pentagram, and in this way derive a Kochen-Specker inequality for spin 1 systems. In some low-dimensional situations Hilbert...
Hidden variable models for quantum mechanics can have local parts (2009)
Larsson, Jan-Ake, Cabello, Adan
We criticize Colbeck and Renner's (CR's) proof that "any hidden variable model can only be compatible with quantum mechanics if its local part is trivial" [Phys. Rev. Lett. 101, 050403 (2008)]. We...
Cabello, Adan, Larsson, Jan-Ake, Rodriguez, David
The chained Bell inequalities of Braunstein and Caves involving N settings per observer have some interesting applications. Here we obtain the minimum detection efficiency required for a...
Seevinck, Michael, Larsson, Jan-Ake
De Raedt et al. (Eur. Phys. J. B 53: 139-142, 2006) have claimed to provide a local realist model for correlations of the singlet state in the familiar Einstein-Podolsky-Rosen-Bohm (EPRB) experiment...
Minimum detection efficiency for a loophole-free atom-photon Bell experiment (2007)
Cabello, Adan, Larsson, Jan-Ake
In Bell experiments, one problem is to achieve high enough photodetection to ensure that there is no possibility of describing the results via a local hidden-variable model. Using the Clauser-Horne...
Security aspects of the Authentication used in Quantum Cryptography (2006)
Cederlof, Jorgen, Larsson, Jan-Ake
Unconditionally secure message authentication is an important part of quantum cryptography (QC). In this correspondence, we analyze security effects of using a key obtained from QC for authentication...
Mubs and Hadamards of Order Six (2006)
Bengtsson, Ingemar, Bruzda, Wojciech, Ericsson, Asa, Larsson, Jan-Ake, Tadej, Wojciech, Zyczkowski, Karol
We report on a search for mutually unbiased bases (MUBs) in 6 dimensions. We find only triplets of MUBs, and thus do not come close to the theoretical upper bound 7. However, we point out that the...
Bell's inequality and the coincidence-time loophole (2003)
Larsson, Jan-Ake, Gill, Richard
This paper analyzes effects of time-dependence in the Bell inequality. A generalized inequality is derived for the case when coincidence and non-coincidence [and hence whether or not a pair...
Bell Inequalities for Position Measurements (2003)
Bell inequalities for position measurements are derived using the bits of the binary expansion of position-measurement results. Violations of these inequalities are obtained from the output state of...
No information flow using statistical fluctuations, and quantum cryptography (2003)
The communication protocol of Home and Whitaker [Phys. Rev. A 67, 022306 (2003)] is examined in some detail, and found to work equally well using a separable state. The protocol is in fact completely...
Qubits from Number States and Bell Inequalities for Number Measurements (2002)
Bell inequalities for number measurements are derived via the observation that the bits of the number indexing a number state are proper qubits. Violations of these inequalities are obtained from the...
A Practical Trojan Horse for Bell-inequality-based Quantum Cryptography (2001)
Quantum Cryptography, or more accurately, Quantum Key Distribution (QKD) is based on using an unconditionally secure ``quantum channel'' to share a secret key among two users. A manufacturer of QKD...
A Kochen-Specker inequality (2000)
By probabilistic means, the concept of contextuality is extended so that it can be used in non-ideal situations. An inequality is presented, which at least in principle enables a test to discard...
Strict detector-efficiency bounds for n-site Clauser-Horne inequalities (2000)
Larsson, Jan-Ake, Semitecolos, Jason
An analysis of detector-efficiency in many-site Clauser-Horne inequalities is presented, for the case of perfect visibility. It is shown that there is a violation of the presented n-site...
Two-photon Franson-type experiments and local realism (1999)
Aerts, Sven, Kwiat, Paul, Larsson, Jan-Ake, Zukowski, Marek
The two-photon interferometric experiment proposed by Franson [Phys. Rev. Lett. 62, 2205 (1989)] is often treated as a "Bell test of local realism". However, it has been suggested that this is...
Strengthening the Bell Theorem: conditions to falsify local realism in an experiment (1999)
Zukowski, Marek, Kaszlikowski, Dagomir, Baturo, Adam, Larsson, Jan-Ake
The two-particle correlation obtained from the quantum state used in the Bell inequality is sinusoidal, but the standard Bell inequality only uses two pairs of settings and not the whole sinusoidal...
Modeling the Singlet State with Local Variables (1999)
A local-variable model yielding the statistics from the singlet state is presented for the case of inefficient detectors and/or lowered visibility. It has independent errors and the highest...
Two-photon Franson-type interference experiments are not tests of local realism (1998)
Larsson, Jan-Ake, Aerts, Sven, Zukowski, Marek
We report a local hidden-variable model which reproduces quantum predictions for the two-photon interferometric experiment proposed by Franson [Phys. Rev. Lett. 62, 2205 (1989)]. The model works for...