Two-mode squeezed vacuum and squeezed light in correlated interferometry

We study in detail a system of two interferometers aimed to the detection of extremely faint phase-fluctuations. This system can represent a breakthrough for detecting a faint correlated signal that would remain otherwise undetectable even using the most sensitive individual interferometric devices, that are limited by the shot noise. If the two interferometers experience identical phase-fluctuations, like the ones introduced by the so called "holographic noise", this signal should emerge if their output signals are correlated, while the fluctuations due to shot noise and other independent contributions will vanish. We show how the injecting quantum light in the free ports of the interferometers can reduce the photon noise of the system beyond the shot-noise, enhancing the resolution in the phase-correlation estimation. We analyze both the use of two-mode squeezed vacuum or twin-beam state (TWB) and of two independent squeezing states. Our results basically confirms the benefit of using squeezed beams together with strong coherent beams in interferometry, even in this correlated case. However, mainly we concentrate on the possible use of TWB, discovering interesting and probably unexplored areas of application of bipartite entanglement and in particular the possibility of reaching in principle surprising uncertainty reduction

Coastal landscape management in mexican tourist regions: Punta de Mita case in Bahía de Banderas, Nayarit

This article analyzes the process of coastal landscape management in the Mexican tourist region from the transformation of the landscape of Punta de Mita. This peninsula is part of the interstate metropolitan zone of Puerto Vallarta - Bahía de Banderas, located between the State of Jalisco and State of Nayarit. It is one of three coastal metropolitan zones of Mexico. This research has a qualitative approach and adopts the concept of the landscape defined by the European Landscape Convention as “any part of the territory, as perceived by people, whose character is the result of the action and interaction of natural and/or human factors” (Council of Europe, 2000). The units of analysis were the peninsular zone of Punta de Mita and the actors who participated in their transformation. The information was collected through semi-structured interviews with key informants selected using the snowball technique, qualitative observation, review of official documentary sources (plans, projects, reports) as well as historiographical and aerial photographs. The identification of the participation of each type of actor is highlighted in the transformation of the landscape: the State provides the land and enables for tourism investment; economic actors take ownership and monetize their aesthetic values; social actors are deprived of the use and enjoyment of the landscape. The symbols printed on the territory are mainly touristic and, in the second instance, natural whose conservation represents a point of agreement between the state and the residents

Testing Quantum Gravity by Quantum Light

In the last years quantum correlations received large attention as key ingredient in advanced quantum metrology protocols, in this letter we show that they provide even larger advantages when considering multiple-interferometer setups. In particular we demonstrate that the use of quantum correlated light beams in coupled interferometers leads to substantial advantages with respect to classical light, up to a noise-free scenario for the ideal lossless case. On the one hand, our results prompt the possibility of testing quantum gravity in experimental configurations affordable in current quantum optics laboratories and strongly improve the precision in "larger size experiments" such as the Fermilab holometer; on the other hand, they pave the way for future applications to high precision measurements and quantum metrology.Comment: PRL in pres