| Records |
| Author |
Perez, A.; Romanelli, A. |
| Title |
Spatially Dependent Decoherence and Anomalous Diffussion of Quantum Walks |
Type |
Journal Article |
| Year |
2013 |
Publication |
Journal of Computational and Theoretical Nanoscience |
Abbreviated Journal |
J. Comput. Theor. Nanosci. |
| Volume |
10 |
Issue |
7 |
Pages |
1591-1595 |
| Keywords |
Decoherence; Quantum Walk; Non-Translational Invariance |
| Abstract |
We analyze the long time behavior of a discrete time quantum walk subject to decoherence with a strong spatial dependence, acting on one half of the lattice. We show that, except for limiting cases on the decoherence parameter, the quantum walk at late times behaves sub-ballistically, meaning that the characteristic features of the quantum walk are not completely spoiled. Contrarily to expectations, the asymptotic behavior is non Markovian, and depends on the amount of decoherence. This feature can be clearly shown on the long time value of the Generalized Chiral Distribution (GCD). |
| Address |
[Perez, A.] Univ Valencia, Dept Fis Teor, CSIC, E-46100 Burjassot, Spain |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Scientific Publishers |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1546-1955 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000322605800007 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial  |
1528 |
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| Author |
Hinarejos, M.; Bañuls, M.C.; Perez, A. |
| Title |
A Study of Wigner Functions for Discrete-Time Quantum Walks |
Type |
Journal Article |
| Year |
2013 |
Publication |
Journal of Computational and Theoretical Nanoscience |
Abbreviated Journal |
J. Comput. Theor. Nanosci. |
| Volume |
10 |
Issue |
7 |
Pages |
1626-1633 |
| Keywords |
Quantum Walk; Wigner Function; Negativity |
| Abstract |
We perform a systematic study of the discrete time Quantum Walk on one dimension using Wigner functions, which are generalized to include the chirality (or coin) degree of freedom. In particular, we analyze the evolution of the negative volume in phase space, as a function of time, for different initial states. This negativity can be used to quantify the degree of departure of the system from a classical state. We also relate this quantity to the entanglement between the coin and walker subspaces. |
| Address |
[Hinarejos, M.; Perez, A.] Univ Valencia, Dept Fis Teor, CSIC, E-46100 Burjassot, Spain |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Scientific Publishers |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1546-1955 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000322605800014 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1529 |
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| Author |
Brown, J.M.C.; Gillam, J.E.; Paganin, D.M.; Dimmock, M.R. |
| Title |
Laplacian Erosion: An Image Deblurring Technique for Multi-Plane Gamma-Cameras |
Type |
Journal Article |
| Year |
2013 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
| Volume |
60 |
Issue |
5 |
Pages |
3333-3342 |
| Keywords |
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| Abstract |
Laplacian Erosion, an image deblurring technique for multi-plane Gamma-cameras, has been developed and tested for planar imaging using a GEANT4 Monte Carlo model of the Pixelated Emission Detector for RadioisOtopes (PEDRO) as a test platform. A contrast and Derenzo-like phantom composed of I-125 were both employed to investigate the dependence of detection plane and pinhole geometry on the performance of Laplacian Erosion. Three different pinhole geometries were tested. It was found that, for the test system, the performance of Laplacian Erosion was inversely proportional to the detection plane offset, and directly proportional to the pinhole diameter. All tested pinhole geometries saw a reduction in the level of image blurring associated with the pinhole geometry. However, the reduction in image blurring came at the cost of signal to noise ratio in the image. The application of Laplacian Erosion was shown to reduce the level of image blurring associated with pinhole geometry and improve recovered image quality in multi-plane Gamma-cameras for the targeted radiotracer I-125. |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0018-9499 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000325827200020 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1609 |
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| Author |
Cabello, J.; Torres-Espallardo, I.; Gillam, J.E.; Rafecas, M. |
| Title |
PET Reconstruction From Truncated Projections Using Total-Variation Regularization for Hadron Therapy Monitoring |
Type |
Journal Article |
| Year |
2013 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
| Volume |
60 |
Issue |
5 |
Pages |
3364-3372 |
| Keywords |
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| Abstract |
Hadron therapy exploits the properties of ion beams to treat tumors by maximizing the dose released to the target and sparing healthy tissue. With hadron beams, the dose distribution shows a relatively low entrance dose which rises sharply at the end of the range, providing the characteristic Bragg peak that drops quickly thereafter. It is of critical importance in order not to damage surrounding healthy tissues and/or avoid targeting underdosage to know where the delivered dose profile ends-the location of the Bragg peak. During hadron therapy, short-lived beta(+)-emitters are produced along the beam path, their distribution being correlated with the delivered dose. Following positron annihilation, two photons are emitted, which can be detected using a positron emission tomography (PET) scanner. The low yield of emitters, their short half-life, and the wash out from the target region make the use of PET, even only a few minutes after hadron irradiation, a challenging application. In-beam PET represents a potential candidate to estimate the distribution of beta(+)-emitters during or immediately after irradiation, at the cost of truncation effects and degraded image quality due to the partial rings required of the PET scanner. Time-of-flight (ToF) information can potentially be used to compensate for truncation effects and to enhance image contrast. However, the highly demanding timing performance required in ToF-PET makes this option costly. Alternatively, the use of maximum-a-posteriori-expectation-maximization (MAP-EM), including total variation (TV) in the cost function, produces images with low noise, while preserving spatial resolution. In this paper, we compare data reconstructed with maximum-likelihood-expectation-maximization (ML-EM) and MAP-EM using TV as prior, and the impact of including ToF information, from data acquired with a complete and a partial-ring PET scanner, of simulated hadron beams interacting with a polymethyl methacrylate (PMMA) target. The results show that MAP-EM, in the absence of ToF information, produces lower noise images and more similar data compared to the simulated beta(+) distributions than ML-EM with ToF information in the order of 200-600 ps. The investigation is extended to the combination of MAP-EM and ToF information to study the limit of performance using both approaches. |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0018-9499 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000325827200023 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1610 |
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| Author |
Oliver, J.F.; Fuster-Garcia, E.; Cabello, J.; Tortajada, S.; Rafecas, M. |
| Title |
Application of Artificial Neural Network for Reducing Random Coincidences in PET |
Type |
Journal Article |
| Year |
2013 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
| Volume |
60 |
Issue |
5 |
Pages |
3399-3409 |
| Keywords |
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| Abstract |
Positron Emission Tomography (PET) is based on the detection in coincidence of the two photons created in a positron annihilation. In conventional PET, this coincidence identification is usually carried out through a coincidence electronic unit. An accidental coincidence occurs when two photons arising from different annihilations are classified as a coincidence. Accidental coincidences are one of the main sources of image degradation in PET. Some novel systems allow coincidences to be selected post-acquisition in software, or in real time through a digital coincidence engine in an FPGA. These approaches provide the user with extra flexibility in the sorting process and allow the application of alternative coincidence sorting procedures. In this work a novel sorting procedure based on Artificial Neural Network (ANN) techniques has been developed. It has been compared to a conventional coincidence sorting algorithm based on a time coincidence window. The data have been obtained from Monte-Carlo simulations. A small animal PET scanner has been implemented to this end. The efficiency (the ratio of correct identifications) can be selected for both methods. In one case by changing the actual value of the coincidence window used, and in the other by changing a threshold at the output of the neural network. At matched efficiencies, the ANN-based method always produces a sorted output with a smaller random fraction. In addition, two differential trends are found: the conventional method presents a maximum achievable efficiency, while the ANN-based method is able to increase the efficiency up to unity, the ideal value, at the cost of increasing the random fraction. Images reconstructed using ANN sorted data (no compensation for randoms) present better contrast, and those image features which are more affected by randoms are enhanced. For the image quality phantom used in the paper, the ANN method decreases the spill-over ratio by a factor of 18%. |
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Summary Language |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0018-9499 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000325827200027 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1611 |
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| Author |
Barrientos, D.; Gonzalez, V.; Bellato, M.; Gadea, A.; Bazzacco, D.; Blasco, J.M.; Bortolato, D.; Egea, F.J.; Isocrate, R.; Pullia, A.; Rampazzo, G.; Sanchis, E.; Triossi, A. |
| Title |
Multiple Register Synchronization With a High-Speed Serial Link Using the Aurora Protocol |
Type |
Journal Article |
| Year |
2013 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
| Volume |
60 |
Issue |
5 |
Pages |
3521-3525 |
| Keywords |
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| Abstract |
In this work, the development and characterization of a multiple synchronous registers interface communicating with a high-speed serial link and using the Aurora protocol is presented. A detailed description of the developing process and the characterization methods and hardware test benches are also included. This interface will implement the slow control buses of the digitizer cards for the second generation of electronics for the Advanced GAmma Tracking Array (AGATA). |
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Place of Publication |
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Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0018-9499 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000325827700014 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1612 |
| Permanent link to this record |
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| Author |
Egea, F.J. et al; Gadea, A.; Barrientos, D.; Huyuk, T. |
| Title |
Design and Test of a High-Speed Flash ADC Mezzanine Card for High-Resolution and Timing Performance in Nuclear Structure Experiments |
Type |
Journal Article |
| Year |
2013 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
| Volume |
60 |
Issue |
5 |
Pages |
3526-3531 |
| Keywords |
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| Abstract |
This work describes new electronics for the EX-OGAM2 (HP-Ge detector array) and NEDA (BC501A-based neutron detector array). A new digitizing card with high resolution has been designed for gamma-ray and neutron spectroscopy experiments. The higher bandwidth requirement of the NEDA signals, together with the necessity for accuracy, require a high sampling rate in order to preserve the shape for real-time Pulse Shape Analysis (PSA). The PSA is of paramount importance for the NEDA to discriminate between neutrons and gamma-ray signals. Both high resolution and high speed parameters are often difficult to achieve in a single electronic unit. These constraints, together with the need to build new digitizing electronics to improve performance and flexibility of signal analysis in nuclear physics experiments, led to the development a new FADC mezzanine card. In this work, the design and development are described, including the characterization procedure and the preliminary measurement results. |
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Series Issue |
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Edition |
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| ISSN |
0018-9499 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000325827700015 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1613 |
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| Author |
Boronat, M.; Marinas, C.; Frey, A.; Garcia, I.; Schwenker, B.; Vos, M.; Wilk, F. |
| Title |
Physical Limitations to the Spatial Resolution of Solid-State Detectors |
Type |
Journal Article |
| Year |
2015 |
Publication |
IEEE Transactions on Nuclear Science |
Abbreviated Journal |
IEEE Trans. Nucl. Sci. |
| Volume |
62 |
Issue |
1 |
Pages |
381-386 |
| Keywords |
Charged particle tracking; silicon detectors; solid state devices |
| Abstract |
In this paper we explore the effect of delta-ray emission and fluctuations in the signal deposition on the detection of charged particles in silicon-based detectors. We show that these two effects ultimately limit the resolution that can be achieved by interpolation of the signal in finely segmented position-sensitive solid-state devices. |
| Address |
[Boronat, M.; Garcia, I.; Vos, M.] IFIC UVEG CSIC, E-46980 Valencia, Spain, Email: marcel.vos@ific.uv.es |
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Thesis |
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| Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0018-9499 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
WOS:000349672900025 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2140 |
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| Author |
Clausse, A.; Soto, L.; Tarifeño-Saldivia, A. |
| Title |
Influence of the Anode Length on the Neutron Emission of a 50 J Plasma Focus: Modeling and Experiment |
Type |
Journal Article |
| Year |
2015 |
Publication |
IEEE Transactions on Plasma Science |
Abbreviated Journal |
IEEE Trans. Plasma Sci. |
| Volume |
43 |
Issue |
2 |
Pages |
629-636 |
| Keywords |
Anode; fusion neutrons; modeling; plasma focus (PF); plasma pinch |
| Abstract |
A comprehensive set of electric data measured in a small plasma focus (PF) device of 50 J correlated with the corresponding neutron emissions is taken as the base for developing a semiempirical model of the current sheet dynamics and the neutron yield. The model is able to explain the dependence of the neutron yield with the pressure and anode length with good accuracy, and suggests a physical interpretation of the drive parameter commonly used in PF design. |
| Address |
[Clausse, Alejandro] Natl Univ Cent Buenos Aires, Natl Atom Energy Commiss, Natl Sci & Tech Res Council, RA-7000 Tandil, Argentina, Email: clausse@exa.unicen.edu.ar; |
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Thesis |
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| Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
0093-3813 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
WOS:000352084400021 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2186 |
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| Author |
Mendoza, S.; Olmo, G.J. |
| Title |
Astrophysical constraints and insights on extended relativistic gravity |
Type |
Journal Article |
| Year |
2015 |
Publication |
Astrophysics and Space Science |
Abbreviated Journal |
Astrophys. Space Sci. |
| Volume |
357 |
Issue |
2 |
Pages |
133 - 6pp |
| Keywords |
Gravitation; Relativistic processes; Gravitational lensing: weak |
| Abstract |
We give precise details to support that observations of gravitational lensing at scales of individual, groups and clusters of galaxies can be understood in terms of nonNewtonian gravitational interactions with a relativistic structure compatible with the Einstein Equivalence Principle. This result is derived on very general grounds without knowing the underlying structure of the gravitational field equations. As such, any developed gravitational theory built to deal with these astrophysical scales needs to reproduce the obtained results of this article. |
| Address |
[Mendoza, S.] Univ Nacl Autonoma Mexico, Inst Astron, Mexico City 04510, DF, Mexico, Email: sergio@astro.unam.mx; |
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Thesis |
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| Publisher |
Springer |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0004-640x |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
WOS:000354392900038 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2234 |
| Permanent link to this record |
