| 1. |
- Aamodt, K., et al.
(author)
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The ALICE experiment at the CERN LHC
- 2008
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In: Journal of Instrumentation. - 1748-0221. ; 3:S08002
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Research review (peer-reviewed)abstract
- ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries, Its overall dimensions are 16 x 16 x 26 m(3) with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008.
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| 2. |
- Tamburini, F., et al.
(author)
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Tripling the capacity of a point-to-point radio link by using electromagnetic vortices
- 2015
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In: Radio Science. - 0048-6604 .- 1944-799X. ; 50:6, s. 501-508
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Journal article (peer-reviewed)abstract
- In this paper we report the results from outdoor experiments showing that it is possible to increase the data transmission capacity using at least three coherent, orthogonal beams on the same frequency, 17.128GHz, each in a unique orbital angular momentum state. Each beam was encoded with the digital modulations used in present-day telecommunications. We achieved an error-free throughput of 3x11Mbit/s with four-Quadrature Amplitude Modulation over a 7MHz bandwidth over 100m and 150m long links.
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| 3. |
- Thide, Bo, et al.
(author)
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Angular Momentum Radio
- 2014
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In: Complex Light and Optical Forces VIII. - : SPIE. - 9780819499127 ; , s. 89990B-
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Conference paper (peer-reviewed)abstract
- Wireless communication amounts to encoding information onto physical observables carried by electromagnetic (EM) fields, radiating them into surrounding space, and detecting them remotely by an appropriate sensor connected to an information-decoding receiver. Each observable is second order in the fields and fulfills a conservation law. In present-day radio only the EM linear momentum observable is fully exploited. A fundamental physical limitation of this observable, which represents the translational degrees of freedom of the charges (typically an oscillating current along a linear antenna) and the fields, is that it is single-mode. This means that a linear-momentum radio communication link comprising one transmitting and one receiving antenna, known as a single-input-single-output (SISO) link, can provide only one transmission channel per frequency (and polarization). In contrast, angular momentum, which represents the rotational degrees of freedom, is multi-mode, allowing an angular-momentum SISO link to accommodate an arbitrary number of independent transmission channels on one and the same frequency (and polarization). We describe the physical properties of EM angular momentum and how they can be exploited, discuss real-world experiments, and outline how the capacity of angular momentum links may be further enhanced by employing multi-port techniques, i.e., the angular momentum counterpart of linear-momentum multiple-input-multiple-output (MIMO).
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| 4. |
- Mari, E., et al.
(author)
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Sub-Rayleigh optical vortex coronagraphy
- 2012
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In: Optics Express. - 1094-4087. ; 20:3, s. 2445-2451
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Journal article (peer-reviewed)abstract
- We introduce a new optical vortex coronagraph(OVC) method to determine the angular distance between two sources when the separation is sub-Rayleigh. We have found a direct relationship between the position of the minima and the source angular separation. A priori knowledge about the location of the two sources is not required. The superresolution capabilities of an OVC, equipped with an l = 2 N-step spiral phase plate in its optical path, were investigated numerically. The results of these investigations show that a fraction of the light, increasing with N, from the secondary source can be detected with a sub-Rayleigh resolution of at least 0.1 lambda/D.
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| 5. |
- Tamburini, F., et al.
(author)
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Reply to Comment on 'Encoding many channels on the same frequency through radio vorticity : first experimental test'
- 2012
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In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 14, s. 118002-
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Journal article (other academic/artistic)abstract
- Our recent paper (Tamburini et al 2012 New J. Phys. 14 033001), which presented results from outdoor experiments that demonstrate that it is physically feasible to simultaneously transmit different states of the newly recognized electromagnetic (EM) quantity orbital angular momentum (OAM) at radio frequencies into the far zone and to identify these states there, has led to a comment (Tamagnone et al 2012 New J. Phys. 14 118001). These authors discuss whether our investigations can be regarded as a particular implementation of the multiple-input-multiple-output (MIMO) technique. Clearly, our experimental confirmation of a theoretical prediction, first made almost a century ago (Abraham 1914 Phys. Z. XV 914-8), that the total EM angular momentum (a pseudovector of dimension length x mass x velocity) can propagate over huge distances, is essentially different from-and conceptually incompatible with-the fact that there exist engineering techniques that can enhance the spectral capacity of EM linear momentum (an ordinary vector of dimension mass x velocity). Our OAM experiments (Tamburini et al 2012 New J. Phys. 14 033001; Tamburini et al 2011 Appl. Phys. Lett. 99 204102-3) confirm the availability of a new physical layer for real-world radio communications based on EM rotational degrees of freedom. The next step is to develop new protocols and techniques for high spectral density on this new physical layer. This includes MIMO-like and other, more efficient, techniques.
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