5,863 research outputs found
The Maunakea Spectroscopic Explorer Book 2018
(Abridged) This is the Maunakea Spectroscopic Explorer 2018 book. It is
intended as a concise reference guide to all aspects of the scientific and
technical design of MSE, for the international astronomy and engineering
communities, and related agencies. The current version is a status report of
MSE's science goals and their practical implementation, following the System
Conceptual Design Review, held in January 2018. MSE is a planned 10-m class,
wide-field, optical and near-infrared facility, designed to enable
transformative science, while filling a critical missing gap in the emerging
international network of large-scale astronomical facilities. MSE is completely
dedicated to multi-object spectroscopy of samples of between thousands and
millions of astrophysical objects. It will lead the world in this arena, due to
its unique design capabilities: it will boast a large (11.25 m) aperture and
wide (1.52 sq. degree) field of view; it will have the capabilities to observe
at a wide range of spectral resolutions, from R2500 to R40,000, with massive
multiplexing (4332 spectra per exposure, with all spectral resolutions
available at all times), and an on-target observing efficiency of more than
80%. MSE will unveil the composition and dynamics of the faint Universe and is
designed to excel at precision studies of faint astrophysical phenomena. It
will also provide critical follow-up for multi-wavelength imaging surveys, such
as those of the Large Synoptic Survey Telescope, Gaia, Euclid, the Wide Field
Infrared Survey Telescope, the Square Kilometre Array, and the Next Generation
Very Large Array.Comment: 5 chapters, 160 pages, 107 figure
Quantum Technology: The Second Quantum Revolution
We are currently in the midst of a second quantum revolution. The first
quantum revolution gave us new rules that govern physical reality. The second
quantum revolution will take these rules and use them to develop new
technologies. In this review we discuss the principles upon which quantum
technology is based and the tools required to develop it. We discuss a number
of examples of research programs that could deliver quantum technologies in
coming decades including; quantum information technology, quantum
electromechanical systems, coherent quantum electronics, quantum optics and
coherent matter technology.Comment: 24 pages and 6 figure
On Kottler's path: origin and evolution of the premetric program in gravity and in electrodynamics
In 1922, Kottler put forward the program to remove the gravitational
potential, the metric of spacetime, from the fundamental equations in physics
as far as possible. He successfully applied this idea to Newton's
gravitostatics and to Maxwell's electrodynamics, where Kottler recast the field
equations in premetric form and specified a metric-dependent constitutive law.
We will discuss the basics of the premetric approach and some of its beautiful
consequences, like the division of universal constants into two classes. We
show that classical electrodynamics can be developed without a metric quite
straightforwardly: the Maxwell equations, together with a local and linear
response law for electromagnetic media, admit a consistent premetric
formulation. Kottler's program succeeds here without provisos. In Kottler's
approach to gravity, making the theory relativistic, two premetric
quasi-Maxwellian field equations arise, but their field variables, if
interpreted in terms of general relativity, do depend on the metric. However,
one can hope to bring the Kottler idea to work by using the teleparallelism
equivalent of general relativity, where the gravitational potential, the
coframe, can be chosen in a premetric way.Comment: 72 pages latex with 6 figures; based on an invited talk given at the
Annual Meeting of the German Physical Society (DPG) in Berlin on 20 March
2015, Working Group on Philosophy of Physics (AGPhil); a short version will
be submitted to IJMP
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