Paper on “Non-Kochen-Specker Contexuality” has been selected as the cover paper of Entropy

Invited paper “Non-Kochen–Specker Contextuality” by Mladen Pavičić, Entropy, 25(8), 1117 (2023), DOI: 10.3390/e25081117, has been selected as the cover paper of issue 8 of Entropy Volume 25 (2023) and the publication charges were waived.

The cover story reads as follows.

Let us consider a triangular hypergraph with three vertices and three hyperedges, each pairwise connecting two of the vertices. If we tried to assign 0 and 1 to vertices, so that just one vertex within each of the three hyperedges is assigned 1 (condition X), we would realize that this is not possible. The hypergraph exhibits a non-Kochen–Specker (KS) contextuality. Why “non-“? Because a KS hypergraph violates the same condition X, however in a space of dimension n ≥ 3 in which all of its hyperedges must contain n vertices. In an n-dim non-KS hypergraph at least one hyperedge has less than n vertices.

If we represented vertices by vectors in a hypergraph, n mutually orthogonal vectors in each hyperedge would be indispensable for an experimental implementation of the hypergraph, KS or not. But although all of them are needed for an implementation, we can choose some smaller set of the vertices when considering contextuality for an application, say, for quantum computation or quantum communication. If the hypergraph with chosen reduced number of vertices violated the aforementioned condition X, it would be a non-KS hypergraph.

How to generate non-KS hypergraphs? A previous method of obtaining them was of exponential complexity and their generation in dimensions higher than eight faced a computational barrier. Therefore, in this paper, we make use of dimensional upscaling which does not scale with dimension. This enables us to generate non-KS hypergraphs in well over 32-dimensional Hilbert spaces. In the paper we give explicit examples for all spaces up to 16-dim ones and show that the minimal number of hyperedges fluctuates between eight (odd dimensions) and nine (even dimensions) under the requirement that at least one the hyperedges contains n vertices, all of which share at least two hyperedges.

CEMS colloquium in joint organization of IF, IRB, and PD-PMF


Prvi tranzistor baziran na jednom sloju MoS2.

First transistor based on a single layer MoS2, which was fabricated in prof. Kis’ group at EPFL.

Next Tuesday, December 22, prof. Andras Kis will present a colloquium titled “2D dichalcogenide electronic materials and devices” at the Institute of Physics. This colloquium of Center of Excellence for Advanced Materials and Sensing Devices is prepared in a joined organization of Institute of Physics, Ruđer Bošković Institute and Department of Physics of Faculty of Science.

Prof. Andras Kis published a pioneering papers on the properties of transistors based on single layer molybdenum disulfide (MoS2) and a research in his group Nanoscale Electronics and Structures regularly brings leading contributions in the field of nanoelectronics on layered 2D materials, which is tightly related to a number of potential applications in electronics, spintronics, optoelectronics, valleytronics, etc.

The colloquium will start at 11 a.m. in lecture hall Mladen Paić at Institute of Physics, Bijenička cesta 46. The abstract is available at this link.