Universal quantum computation with the Orbital Angular Momentum of a single photon

We prove that a single photon with quantum data encoded in its orbital angular momentum can be manipulated with simple optical elements to provide any desired quantum computation. We will show how to build any quantum unitary operator using beamsplitters, phase shifters, holograms and an extraction gate based on quantum interrogation. The advantages and challenges of these approach are then discussed, in particular the problem of the readout of the results.Comment: First version. Comments welcom

Delayed commutation in quantum computer networks

In the same way that classical computer networks connect and enhance the capabilities of classical computers, quantum networks can combine the advantages of quantum information and communications. We propose a non-classical network element, a delayed commutation switch, that can solve the problem of switching time in packet switching networks. With the help of some local ancillary qubits and superdense codes we can route the information after part of it has left the network node.Comment: 4 pages. 4 figures. Preliminar versio

Quantum Multiplexing with the Orbital Angular Momentum of light

The orbital angular momentum, OAM, of photons offers a suitable support to carry the quantum data of multiple users. We present two novel optical setups that send the information of n quantum communication parties through the same free-space optical link. Those qubits can be sent simultaneously and share path, wavelength and polarization without interference, increasing the communication capacity of the system. The first solution, a qubit combiner, merges n channels into the same link, which transmits n independent photons. The second solution, the OAM multiplexer, uses CNOT gates to transfer the information of n optical channels to a single photon. Additional applications of the multiplexer circuits, such as quantum arithmetic, as well as connections to OAM sorting are discussed

Rethinking local cultural policies.

En mayo de 2019 se celebraba en Valladolid el Seminario “Repensar políticas culturales locales. Las políticas locales como creadoras de capital cultural”. En él se presentaron y debatieron asuntos de las agendas culturales locales del presente y el futuro, con motivo del cuarenta aniversario de las primeras elecciones municipales democráticas en España en la segunda mitad del siglo XX. Reforzar el capital cultural local, recuperar para la cultura liderazgo político, luchar contra la brecha cultural y de género en la cultura y hacer convivir los derechos culturales con las industrias culturales y creativas fueron algunos de los temas tratados en la sesión.In May 2019, the Seminar “Rethinking local cultural policies- Local policies as creators of cultural capital,” was held in Valladolid (Spain). Issues regarding actual and future local cultural agendas were presented and discussed, on the occasion of the fortieth anniversary of the first democratic municipal elections in Spain in the second half of the twentieth century. Strengthening local cultural capital, recovering political leadership for culture, fighting the cultural and gender gap in culture and bringing cultural rights together with cultural and creative industries were some of the topics discussed in the session

A counterfactual Rydberg gate for photons

Quantum computation with photons requires efficient two photon gates. We put forward a two photon entangling gate which uses an intermediate atomic system. The system includes a single Rydberg atom which can switch on and off photon absorption in an ensemble using the dipole blockade. The gate is based in a counterfactual protocol. The mere possibility of an absorption that can only occur with a vanishing probability steers the photons to the desired final state.Comment: 4 Figures. 6 pages of tex

The ecology of peace : preparing Colombia for new political and planetary climates

ABSTRACT: Colombia, one of the world’s most species-rich nations, is currently undergoing a profound social transition: the end of a decadeslong conflict with the Revolutionary Armed Forces of Colombia, known as FARC. The peace agreement process will likely transform the country’s physical and socioeconomic landscapes at a time when humans are altering Earth’s atmosphere and climate in unprecedented ways. We discuss ways in which these transformative events will act in combination to shape the ecological and environmental future of Colombia. We also highlight the risks of creating perverse development incentives in these critical times, along with the potential benefits – for the country and the world – if Colombia can navigate through the peace process in a way that protects its own environment and ecosystems