Optomechanics assisted with a qubit: From dissipative state preparation to many-body physics

We propose and analyze nonlinear optomechanical protocols that can be implemented by adding a single atom to an optomechanical cavity. In particular, we show how to engineer the environment in order to dissipatively prepare the mechanical oscillator in a superposition of Fock states with fidelity close to one. Furthermore, we discuss how a single atom in a cavity with several mechanical oscillators can be exploited to realize nonlinear many-body physics by stroboscopically driving the mechanical oscillators. We show how to prepare non-classical many-body states by either applying coherent protocols or engineering dissipation. The analysis of the protocols is carried out using a perturbation theory for degenerate Liouvillians and numerical tools. Our results apply to other systems where a qubit is coupled to a mechanical oscillator via a bosonic mode, e.g., in cavity quantum electromechanics

Master equation approach to optomechanics with arbitrary dielectrics

We present a master equation describing the interaction of light with dielectric objects of arbitrary sizes and shapes. The quantum motion of the object, the quantum nature of light, as well as scattering processes to all orders in perturbation theory are taken into account. This formalism extends the standard master equation approach to the case where interactions among different modes of the environment are considered. It yields a genuine quantum description, including a renormalization of the couplings and decoherence terms. We apply this approach to analyze cavity cooling of the center-of-mass mode of large spheres. Furthermore, we derive an expression for the steady-state phonon numbers without relying on resolved-sideband or bad-cavity approximations.Comment: 17 pages, 5 figure

Ray transfer matrix for a spiral phase plate

We present a ray transfer matrix for a spiral phase plate. Using this matrix, we determine the stability of an optical resonator made of two spiral phase plates, and trace stable ray orbits in the resonator. Our results should be relevant to laser physics, optical micromanipulation, quantum information and optomechanics.Comment: 5 pages, 3 figure

Clemente de Alejandría y la filosofía griega

Clemente de Alejandría, una de las mentes más amplias del primitivo Cristianismo entiende que la filosofía griega significa la difusión de la nueva religión entre los espíritus cultivados, y al hacerlo, combina en su trabajo, las aspiraciones de los cristianos y los conceptos más elevados que los griegos tenían de divinidad.Clement of Alexandria, one of the broadest minds in the early Christianity, understand that the Greek philosophy is the only means of spreading about the new religion among the cultivated spirits and, by doing so, in his work, he blends the aspirations of the Christian in the loftiest notions the Greeks had of divinity

Muestreo de insectos en el aire: diseño de un prototipo de soporte para trampas

El Proyecto de Investigación AIR3-CT94-1607, titulado «Versatile controlled release dispenser for mating disruption with pheromones», financiado por la Comisión de las Comunidades Europeas, incluye el muestreo de campos cultivados de avellano (Corylus avellana Linnaeus, 1753) para la captura de machos de Zeuzera pyrina Linnaeus, 1761 (Lepidoptera, Cossidae), en la provincia de Tarragona. La colocación de trampas sobre un arbusto como el avellano presenta ciertas dificultades, especialmente para que las trampas se mantengan en buen estado, en el mismo lugar y orientación, a lo largo de todo el período de muestreo, soportando incluso las posibles inclemencias meteorológicas propias de la zona. Ante tales dificultades, hubo que estudiar un sistema de colocación que resultase efectivo sin interferir los resultados del muestreo ni las condiciones propias de desarrollo del agroecosistema. Por tal motivo se diseñó un prototipo que, además de resolver el problema que teníamos planteado, creemos puede tener una aplicación mucho más amplia para el muestreo de insectos con fines científicos (Método LEAAM). El método permite que la trampa permanezca fija en un lugar determinado, pudiendo girar libremente sobre sí misma, y además se pueden simultanear los muestreos a diferentes alturas y con varios tipos de trampas.Design of a Prototype for the Placement of Traps in order to sample insects in the air. The Project AIR3-CT94-1607, entitled «Versatile controlled release dispenser for mating disruption with pheromones» and financed by the Commission of the European Communities, includes to sample on hazel nut fields (Corylus avellana Linnaeus, 1753) for the capture of males of Zeuzera pyrina Linnaeus, 1761 (Lepidoptera, Cossidae), in the province of Tarragona (Spain). The placement of traps should stay in good state, in the same place and orientation, and they are supposed to support the possible meteorological adversities along the sampling period. In front of like difficulties we had to study a system of placement of the traps that result effective without interfering the results of sampling neither the conditions of appropriate cultiva-tion in this agroecosystem. Thereby a prototype was designed that, besides solving the problem that we had, we think could have an application much more wide for the sampling of insects with scientific aims (LEAAM Method). The method allows that the trap is fixed in a select location, but it can gyrate. In addition, we can make a simultaneous sampling at diferents highs and/or with different types of traps

Quantum Spin Stabilized Magnetic Levitation

We theoretically show that, despite Earnshaw's theorem, a non-rotating single magnetic domain nanoparticle can be stably levitated in an external static magnetic field. The stabilization relies on the quantum spin origin of magnetization, namely the gyromagnetic effect. We predict the existence of two stable phases related to the Einstein--de Haas effect and the Larmor precession. At a stable point, we derive a quadratic Hamiltonian that describes the quantum fluctuations of the degrees of freedom of the system. We show that in the absence of thermal fluctuations, the quantum state of the nanomagnet at the equilibrium point contains entanglement and squeezing.Comment: Published version. 5 pages, 2 figure

Probing magnetic order in ultracold lattice gases

A forthcoming challenge in ultracold lattice gases is the simulation of quantum magnetism. That involves both the preparation of the lattice atomic gas in the desired spin state and the probing of the state. Here we demonstrate how a probing scheme based on atom-light interfaces gives access to the order parameters of nontrivial quantum magnetic phases, allowing us to characterize univocally strongly correlated magnetic systems produced in ultracold gases. This method, which is also nondemolishing, yields spatially resolved spin correlations and can be applied to bosons or fermions. As a proof of principle, we apply this method to detect the complete phase diagram displayed by a chain of (rotationally invariant) spin-1 bosons.Comment: published versio