1,055 research outputs found
Game Engines and MAS: BDI & Artifacts in Unity
In questa tesi vedremo un breve sunto riguardo lo stato dei Sistemi Multi-Agente e andremo ad analizzare le limitazioni che attualmente ne impediscono l'utilizzo ai programmatori di videogiochi. Dopodiché, andremo a proporre un nuovo linguaggio BDI, basato su Prolog e inspirato a Jason, che, grazie all'interprete Prolog sviluppato da I. Horswill, darà la possibilità al programmatore di videogiochi di esprimere comportamenti dichiarativi di alto livello per agenti autonomi all'interno del game engine Unity. Andremo anche a proporre una versione di Artefatto per la modellazione dell'ambiente in una scena Unity e un layer di comunicazione che agenti e artefatti possano utilizzare per interagire tra loro. Infine presenteremo un caso di studio per sottolineare i benefici che questo sistema fornisce
Squeezing on momentum states for atom interferometry
We propose and analyse a method that allows for the production of squeezed
states of the atomic center-of-mass motion that can be injected into an atom
interferometer. Our scheme employs dispersive probing in a ring resonator on a
narrow transition of strontium atoms in order to provide a collective
measurement of the relative population of two momentum states. We show that
this method is applicable to a Bragg diffraction-based atom interferometer with
large diffraction orders. The applicability of this technique can be extended
also to small diffraction orders and large atom numbers by inducing atomic
transparency at the frequency of the probe field, reaching an interferometer
phase resolution scaling , where is the atom
number. We show that for realistic parameters it is possible to obtain a 20 dB
gain in interferometer phase estimation compared to the Standard Quantum Limit.Comment: 5 pages, 4 figure
Coherent control of quantum transport: modulation-enhanced phase detection and band spectroscopy
Amplitude modulation of a tilted optical lattice can be used to steer the
quantum transport of matter wave packets in a very flexible way. This allows
the experimental study of the phase sensitivity in a multimode interferometer
based on delocalization-enhanced Bloch oscillations and to probe the band
structure modified by a constant force.Comment: 8 pages, 3 figures, Submitted to EPJ Special Topics for the special
issue on "Novel Quantum Phases and Mesoscopic Physics in Quantum Gases
Distributed Raman optical amplification in phase coherent transfer of optical frequencies
We describe the application of Raman Optical-fiber Amplification (ROA) for
the phase coherent transfer of optical frequencies in an optical fiber link.
ROA uses the transmission fiber itself as a gain medium for bi-directional
coherent amplification. In a test setup we evaluated the ROA in terms of on-off
gain, signal-to-noise ratio, and phase noise added to the carrier. We
transferred a laser frequency in a 200 km optical fiber link with an additional
16 dB fixed attenuator (equivalent to 275 km of fiber on a single span), and
evaluated both co-propagating and counter-propagating amplification pump
schemes, demonstrating nonlinear effects limiting the co-propagating pump
configuration. The frequency at the remote end has a fractional frequency
instability of 3e-19 over 1000 s with the optical fiber link noise
compensation
Bragg gravity-gradiometer using the S-P intercombination transition of Sr
We present a gradiometer based on matter-wave interference of
alkaline-earth-metal atoms, namely Sr. The coherent manipulation of the
atomic external degrees of freedom is obtained by large-momentum-transfer Bragg
diffraction, driven by laser fields detuned away from the narrow
S-P intercombination transition. We use a well-controlled
artificial gradient, realized by changing the relative frequencies of the Bragg
pulses during the interferometer sequence, in order to characterize the
sensitivity of the gradiometer. The sensitivity reaches
s for an interferometer time of 20 ms, limited only by geometrical
constraints. We observed extremely low sensitivity of the gradiometric phase to
magnetic field gradients, approaching a value 10 times lower than the
sensitivity of alkali-atom based gradiometers. An efficient double-launch
technique employing accelerated red vertical lattices from a single
magneto-optical trap cloud is also demonstrated. These results highlight
strontium as an ideal candidate for precision measurements of gravity
gradients, with potential application in future precision tests of fundamental
physics.Comment: 10 pages, 7 figure
Renal papillary carcinoma developed in a kidney transplant recipient with late IgA-nephropathy
With improvements in immunosuppressive therapy, patient and graft survival in renal transplant recipients have been prolonged. Increasing donor age and patient survival rates have been related to an increase in the number of de novo tumors. Posttransplant malignancy in these patients is an important cause of graft loss and death in these patients. Among cancers occurring after a kidney transplant, renal cell carcinoma is the fifth most common malignancy after lymphoproliferative disorders, and skin, gastrointestinal, and lung cancers. When nonmelanoma skin cancers and in situ carcinoma of the cervix are excluded from malignancies, renal cell carcinoma accounts for 2% of all cancers in the general population, which increases to 5% in solid-organ recipients. The majority of renal cell carcinomas found in transplant recipients develop in the recipient 's native kidneys, but only 9% of tumors develop in the allograft itself. Tumors transmitted by donors represent only 0.02% to 0.2% of cases. Most de novo allograft renal cell carcinomas are single tumors. The mechanisms of development of renal cell carcinoma in renal grafts are not completely understood
Cooling Atoms in an Optical Trap by Selective Parametric Excitation
We demonstrate the possibility of energy-selective removal of cold atoms from a tight optical trap by means of parametric excitation of the trap vibrational modes. Taking advantage of the anharmonicity of the trap potential, we either selectively remove the most energetic trapped atoms or excite those at the bottom of the trap by tuning the parametric modulation frequency. This process, which had been previously identified as a possible source of heating, also appears to be a robust way for forcing evaporative cooling in anharmonic traps
Design and simulation of a source of cold cadmium for atom interferometry
We present a novel optimised design for a source of cold atomic cadmium,
compatible with continuous operation and potentially quantum degenerate gas
production. The design is based on spatially segmenting the first and
second-stages of cooling with the the strong dipole-allowed S-P
transition at 229 nm and the 326 nm S-P intercombination
transition, respectively. Cooling at 229 nm operates on an effusive atomic beam
and takes the form of a compact Zeeman slower (5 cm) and two-dimensional
magneto-optical trap (MOT), both based on permanent magnets. This design allows
for reduced interaction time with the photoionising 229 nm photons and produces
a slow beam of atoms that can be directly loaded into a three-dimensional MOT
using the intercombination transition. The efficiency of the above process is
estimated across a broad range of experimentally feasible parameters via use of
a Monte Carlo simulation, with loading rates up to 10 atoms/s into the 326
nm MOT possible with the oven at only 100 C. The prospects for further
cooling in a far-off-resonance optical-dipole trap and atomic launching in a
moving optical lattice are also analysed, especially with reference to the
deployment in a proposed dual-species cadmium-strontium atom interferometer.Comment: 16 pages, 12 figures, 3 table
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