This article describes a citizen-science project conducted by the Spanish Virtual Observatory (SVO) to improve the orbits of near-Earth asteroids (NEAs) using data from astronomical archives. The list of NEAs maintained at the Minor Planet Center (MPC) is checked daily to identify new objects or changes in the orbital parameters of already catalogued objects. Using NEODyS we compute the position and magnitude of these objects at the observing epochs of the 938 046 images comprising the Eigth Data Release of the Sloan Digitised Sky Survey (SDSS). If the object lies within the image boundaries and the magnitude is brighter than the limiting magnitude, then the associated image is visually inspected by the projects collaborators (the citizens) to confirm or discard the presence of the NEA. If confirmed, accurate coordinates and, sometimes, magnitudes are submitted to the MPC. Using this methodology, 3,226 registered users have made during the first fifteen months of the project more than 167,000 measurements which have improved the orbital elements of 551 NEAs (6% of the total number of this type of asteroids). Even more remarkable is the fact that these results have been obtained at zero cost to telescope time as NEAs were serendipitously observed while the survey was being carried out. This demonstrates the enormous scientific potential hidden in astronomical archives. The great reception of the project as well as the results obtained makes it a valuable and reliable tool for improving the orbital parameters of near-Earth asteroids.
Superconducting quantum circuits possess the ingredients for quantum information processing and for developing on-chip microwave quantum optics. From the initial manipulation of few-level superconducting systems (qubits) to their strong coupling to microwave resonators, the time has come to consider the generation and characterization of propagating quantum microwaves. In this paper, we design a key ingredient that will prove essential in the general frame: a swtichable coupling between qubit(s) and transmission line(s) that can work in the ultrastrong coupling regime, where the coupling strength approaches the qubit transition frequency. We propose several setups where two or more loops of Josephson junctions are directly connected to a closed (cavity) or open transmission line. We demonstrate that the circuit induces a coupling that can be modulated in strength and type. Given recent studies showing the accessibility to the ultrastrong regime, we expect our ideas to have an immediate impact in ongoing experiments.
We propose a simple circuit quantum electrodynamics (QED) experiment to test the generation of entanglement between two superconducting qubits. Instead of the usual cavity QED picture, we study qubits which are coupled to an open transmission line and get entangled by the exchange of propagating photons. We compute their dynamics using a full quantum field theory beyond the rotating-wave approximation and explore a variety of regimes which go from a weak coupling to the recently introduced ultrastrong coupling regime. Due to the existence of single photons traveling along the line with finite speed, our theory shows a light cone dividing the spacetime in two different regions. In one region, entanglement may only arise due to correlated vacuum fluctuations, while in the other the contribution from exchanged photons shows up.
* Aims. We describe here the main functionalities of the LAEX (Laboratorio de Astrofisica Estelar y Exoplanetas/Laboratory for Stellar Astrophysics and Exoplanets) and NASA portals for CoRoT Public Data. The CoRoT archive at LAEX was opened to the community in January 2009 and is managed in the framework of the Spanish Virtual Observatory. NStED (NASA Star and Exoplanet Database) serves as the CoRoT portal for the US astronomical community. NStED is a general purpose stellar and exoplanet archive with the aim of providing support for NASA planet finding and characterisation goals, and the planning and support of NASA and other space missions. CoRoT data at LAEX and NStED can be accessed at http://sdc.laeff.inta.es/corotfa/ and http://nsted.ipac.caltech.edu,respectively. * Methods. Based on considerable experience with astronomical archives, the aforementioned archives are designed with the aim of delivering science-quality data in a simple and efficient way. * Results. LAEX and NStED not only provide access to CoRoT Public Data but furthermore serve a variety of observed and calculated astrophysical data. In particular, NStED provides scientifically validated information on stellar and planetary data related to the search for and characterization of extrasolar planets, and LAEX makes any information from Virtual Observatory services available to the astronomical community.
Quantum optical photodetection has occupied a central role in understanding radiation-matter interactions. It has also contributed to the development of atomic physics and quantum optics, including applications to metrology, spectroscopy, and quantum information processing. The quantum microwave regime, originally explored using cavities and atoms, is seeing a novel boost with the generation of nonclassical propagating fields in circuit quantum electrodynamics (QED). This promising field, involving potential developments in quantum information with microwave photons, suffers from the absence of photodetectors. Here, we design a metamaterial composed of discrete superconducting elements that implements a high-efficiency microwave photon detector. Our design consists of a microwave guide coupled to an array of metastable quantum circuits, whose internal states are irreversibly changed due to the absorption of photons. This proposal can be widely applied to different physical systems and can be generalized to implement a microwave photon counter.
Incoherent scattering of photons off two remote atoms with a Lambda-level structure is used as a basic Young-type interferometer to herald long-lived entanglement of an arbitrary degree. The degree of entanglement, as measured by the concurrence, is found to be tunable by two easily accessible experimental parameters. Fixing one of them to certain values unveils an analog to the Malus law. An estimate of the variation in the degree of entanglement due to uncertainties in an experimental realization is given.
