Demografía de la araña social Theridion nigroannulatum Keyserling, Reserva de Producción Faunística Cuyabeno, Amazonía Ecuatoriana

El presente estudio describe por primera vez aspectos de la demografía y del ciclo de vida de Theridion nigroannulatum Keyserling, en la Reserva de Producción Faunística Cuyabeno (RPFC), a partir de un conjunto de 131 telas censadas y evaluadas periódicamente y de 283 individuos colectados. Se propone un modelo del ciclo de vida de la especie a partir de la descripción de diez categorías consecutivas de tamaño o estadíos, las cuales describen el proceso de desarrollo post-embrionario desde saco de huevos hasta machos y hembras. Se calculan las tasas de supervivencia para esos estadíos y se discute su relación con la proporción de sexos. Se utiliza el volumen ocupado por la tela, para analizarla como herramienta de una cohorte para sobrevivir, como un componente fundamental del cuidado parental que la hembra brinda a sus crías y como descriptor de la abundancia de individuos en una cohorte. Las telas censadas estudiadas estuvieron habitadas por una hembra sola y sus crías (98% de casos) o por dos o más hembras y sus cohortes (2% de los casos). Se documenta además en estas cohortes observaciones de los procesos de apareamiento y dispersión de los que participan los individuos adultos

Quantum key distribution session with 16-dimensional photonic states

The secure transfer of information is an important problem in modern telecommunications. Quantum key distribution (QKD) provides a solution to this problem by using individual quantum systems to generate correlated bits between remote parties, that can be used to extract a secret key. QKD with D-dimensional quantum channels provides security advantages that grow with increasing D. However, the vast majority of QKD implementations has been restricted to two dimensions. Here we demonstrate the feasibility of using higher dimensions for real-world quantum cryptography by performing, for the first time, a fully automated QKD session based on the BB84 protocol with 16-dimensional quantum states. Information is encoded in the single-photon transverse momentum and the required states are dynamically generated with programmable spatial light modulators. Our setup paves the way for future developments in the field of experimental high-dimensional QKD.Comment: 8 pages, 3 figure

Certifying an irreducible 1024-dimensional photonic state using refined dimension witnesses

We report on a new class of dimension witnesses, based on quantum random access codes, which are a function of the recorded statistics and that have different bounds for all possible decompositions of a high-dimensional physical system. Thus, it certifies the dimension of the system and has the new distinct feature of identifying whether the high-dimensional system is decomposable in terms of lower dimensional subsystems. To demonstrate the practicability of this technique we used it to experimentally certify the generation of an irreducible 1024-dimensional photonic quantum state. Therefore, certifying that the state is not multipartite or encoded using non-coupled different degrees of freedom of a single photon. Our protocol should find applications in a broad class of modern quantum information experiments addressing the generation of high-dimensional quantum systems, where quantum tomography may become intractable.Comment: Journal version (except for small editorial modifications), 4+12 pages, 7 figure

High-dimensional decoy-state quantum key distribution over 0.3 km of multicore telecommunication optical fibers

Multiplexing is a strategy to augment the transmission capacity of a communication system. It consists of combining multiple signals over the same data channel and it has been very successful in classical communications. However, the use of enhanced channels has only reached limited practicality in quantum communications (QC) as it requires the complex manipulation of quantum systems of higher dimensions. Considerable effort is being made towards QC using high-dimensional quantum systems encoded into the transverse momentum of single photons but, so far, no approach has been proven to be fully compatible with the existing telecommunication infrastructure. Here, we overcome such a technological challenge and demonstrate a stable and secure high-dimensional decoy-state quantum key distribution session over a 0.3 km long multicore optical fiber. The high-dimensional quantum states are defined in terms of the multiple core modes available for the photon transmission over the fiber, and the decoy-state analysis demonstrates that our technique enables a positive secret key generation rate up to 25 km of fiber propagation. Finally, we show how our results build up towards a high-dimensional quantum network composed of free-space and fiber based linksComment: Please see the complementary work arXiv:1610.01812 (2016

All-in-fiber dynamic orbital angular momentum mode sorting

The orbital angular momentum (OAM) spatial degree of freedom of light has been widely explored in many applications, including telecommunications, quantum information and light-based micro-manipulation. The ability to separate and distinguish between the different transverse spatial modes is called mode sorting or mode demultiplexing, and it is essential to recover the encoded information in such applications. An ideal $d$ mode sorter should be able to faithfully distinguish between the different $d$ spatial modes, with minimal losses, have $d$ outputs, and have fast response times. All previous mode sorters rely on bulk optical elements such as spatial light modulators, which cannot be quickly tuned and have additional losses if they are to be integrated with optical fiber systems. Here we propose and experimentally demonstrate, to the best of our knowledge, the first all-in-fiber method for OAM mode sorting with ultra-fast dynamic reconfigurability. Our scheme first decomposes the OAM mode in fiber-optical linearly polarized (LP) modes, and then interferometrically recombines them to determine the topological charge, thus correctly sorting the OAM mode. In addition, our setup can also be used to perform ultra-fast routing of the OAM modes. These results show a novel and fiber integrated form of optical spatial mode sorting that can be readily used for many new applications in classical and quantum information processing.Comment: 9 pages, 6 figure