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Author |
Athenodorou, A.; Binosi, D.; Boucaud, P.; De Soto, F.; Papavassiliou, J.; Rodriguez-Quintero, J.; Zafeiropoulos, S. |
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Title |
On the zero crossing of the three-gluon vertex |
Type |
Journal Article |
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Year |
2016 |
Publication  |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
761 |
Issue |
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Pages |
444-449 |
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Keywords |
Lattice simulations; Three-gluon vertex; Zero crossing; Schwinger-Dyson equations |
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Abstract |
We report on new results on the infrared behavior of the three-gluon vertex in quenched Quantum Chromodynamics, obtained from large-volume lattice simulations. The main focus of our study is the appearance of the characteristic infrared feature known as 'zero crossing', the origin of which is intimately connected with the nonperturbative masslessness of the Faddeev-Popov ghost. The appearance of this effect is clearly visible in one of the two kinematic configurations analyzed, and its theoretical origin is discussed in the framework of Schwinger-Dyson equations. The effective coupling in the momentum subtraction scheme that corresponds to the three-gluon vertex is constructed, revealing the vanishing of the effective interaction at the exact location of the zero crossing. |
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Address |
[Athenodorou, A.] Univ Cyprus, Dept Phys, POB 20537, CY-1678 Nicosia, Cyprus, Email: binosi@ectstar.eu |
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Publisher |
Elsevier Science Bv |
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English |
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ISSN |
0370-2693 |
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Conference |
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Notes |
WOS:000384469900063 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2939 |
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Author |
Nzongani, U.; Zylberman, J.; Doncecchi, C.E.; Perez, A.; Debbasch, F.; Arnault, P. |
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Title |
Quantum circuits for discrete-time quantum walks with position-dependent coin operator |
Type |
Journal Article |
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Year |
2023 |
Publication |
Quantum Information Processing |
Abbreviated Journal |
Quantum Inf. Process. |
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Volume |
22 |
Issue |
7 |
Pages |
270 - 46pp |
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Keywords |
Quantum walks; Quantum circuits; Quantum simulation |
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Abstract |
The aim of this paper is to build quantum circuits that implement discrete-time quantum walks having an arbitrary position-dependent coin operator. The position of the walker is encoded in base 2: with n wires, each corresponding to one qubit, we encode 2(n) position states. The data necessary to define an arbitrary position-dependent coin operator is therefore exponential in n. Hence, the exponentiality will necessarily appear somewhere in our circuits. We first propose a circuit implementing the position-dependent coin operator, that is naive, in the sense that it has exponential depth and implements sequentially all appropriate position-dependent coin operators. We then propose a circuit that “transfers” all the depth into ancillae, yielding a final depth that is linear in n at the cost of an exponential number of ancillae. Themain idea of this linear-depth circuit is to implement in parallel all coin operators at the different positions. Reducing the depth exponentially at the cost of having an exponential number of ancillae is a goal which has already been achieved for the problem of loading classical data on a quantum circuit (Araujo in Sci Rep 11:6329, 2021) (notice that such a circuit can be used to load the initial state of the walker). Here, we achieve this goal for the problem of applying a position-dependent coin operator in a discrete-time quantum walk. Finally, we extend the result of Welch (New J Phys 16:033040, 2014) from position-dependent unitaries which are diagonal in the position basis to position-dependent 2 x 2-block-diagonal unitaries: indeed, we show that for a position dependence of the coin operator (the block-diagonal unitary) which is smooth enough, one can find an efficient quantum-circuit implementation approximating the coin operator up to an error epsilon (in terms of the spectral norm), the depth and size of which scale as O(1/epsilon). A typical application of the efficient implementation would be the quantum simulation of a relativistic spin-1/2 particle on a lattice, coupled to a smooth external gauge field; notice that recently, quantum spatial-search schemes have been developed which use gauge fields as the oracle, to mark the vertex to be found (Zylberman in Entropy 23:1441, 2021), (Fredon arXiv:2210.13920). A typical application of the linear-depth circuit would be when there is spatial noise on the coin operator (and hence a non-smooth dependence in the position). |
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Address |
[Nzongani, Ugo; Doncecchi, Carlo-Elia; Arnault, Pablo] Univ Paris Saclay, CNRS, INRIA, Lab Methodes Formelles,ENS Paris Saclay, F-91190 Gif Sur Yvette, France, Email: ugo.nzongani@universite-paris-saclay.fr; |
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Springer |
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English |
Summary Language |
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Edition |
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ISSN |
1570-0755 |
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Conference |
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Notes |
WOS:001022408900002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5587 |
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Author |
Jay, G.; Arnault, P.; Debbasch, F. |
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Title |
Dirac quantum walks with conserved angular momentum |
Type |
Journal Article |
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Year |
2021 |
Publication |
Quantum Studies-Mathematics and Foundations |
Abbreviated Journal |
Quantum Stud. Math. Found. |
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Volume |
8 |
Issue |
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Pages |
419-430 |
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Keywords |
Quantum walks; Quantum simulation; Lattice field theory |
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Abstract |
A quantum walk (QW) simulating the flat (1+2)D Dirac equation on a spatial polar grid is constructed. Because fermions are represented by spinors, which do not constitute a representation of the rotation group SO(3), but rather of its double cover SU(2), the QW can only be defined globally on an extended spacetime where the polar angle extends from 0 to 4 pi. The coupling of the QW with arbitrary electromagnetic fields is also presented. Finally, the cylindrical relativistic Landau levels of the Dirac equation are computed explicitly and simulated by the QW. |
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Address |
[Jay, Gareth] Univ Western Australia, Phys Dept, Perth, WA 6009, Australia, Email: gareth.jay@uwa.edu.au; |
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Springer |
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English |
Summary Language |
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Series Editor |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2196-5609 |
ISBN |
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Conference |
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Notes |
WOS:000697709700001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4975 |
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Author |
n_TOF Collaboration (Alcayne, V. et al); Balibrea-Correa, J.; Domingo-Pardo, C.; Lerendegui-Marco, J.; Babiano-Suarez, V.; Ladarescu, I. |
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Title |
A Segmented Total Energy Detector (sTED) optimized for (n,γ) cross-section measurements at n_TOF EAR2 |
Type |
Journal Article |
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Year |
2024 |
Publication |
Radiation Physics and Chemistry |
Abbreviated Journal |
Radiat. Phys. Chem. |
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Volume |
217 |
Issue |
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Pages |
11pp |
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Keywords |
Neutron capture; PHWT; Scintillation detectors; Monte Carlo simulation |
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Abstract |
The neutron time-of-flight facility nTOF at CERN is a spallation source dedicated to measurements of neutroninduced reaction cross-sections of interest in nuclear technologies, astrophysics, and other applications. Since 2014, Experimental ARea 2 (EAR2) is operational and delivers a neutron fluence of similar to 4 center dot 10(7) neutrons per nominal proton pulse, which is similar to 50 times higher than the one of Experimental ARea 1 (EAR1) of similar to 8 center dot 10(5) neutrons per pulse. The high neutron flux at EAR2 results in high counting rates in the detectors that challenged the previously existing capture detection systems. For this reason, a Segmented Total Energy Detector (sTED) has been developed to overcome the limitations in the detector's response, by reducing the active volume per module and by using a photo-multiplier (PMT) optimized for high counting rates. This paper presents the main characteristics of the sTED, including energy and time resolution, response to gamma-rays, and provides as well details of the use of the Pulse Height Weighting Technique (PHWT) with this detector. The sTED has been validated to perform neutron-capture cross-section measurements in EAR2 in the neutron energy range from thermal up to at least 400 keV. The detector has already been successfully used in several measurements at nTOF EAR2. |
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Address |
[Alcayne, V.; Cano-Ott, D.; Garcia, J.; Gonzalez-Romero, E.; Martinez, T.; de Rada, A. Perez; Plaza, J.; Sanchez-Caballero, A.; Mendoza, E.] Ctr Invest Energet Medioambient & Tecnol CIEMAT, Madrid, Spain, Email: victor.alcayne@ciemat.es |
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Publisher |
Pergamon-Elsevier Science Ltd |
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Language |
English |
Summary Language |
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Original Title |
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Abbreviated Series Title |
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Edition |
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ISSN |
0969-806x |
ISBN |
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Conference |
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Notes |
WOS:001185584800001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5999 |
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Author |
Martin-Luna, P.; Esperante, D.; Prieto, A.F.; Fuster-Martinez, N.; Rivas, I.G.; Gimeno, B.; Ginestar, D.; Gonzalez-Iglesias, D.; Hueso, J.L.; Llosa, G.; Martinez-Reviriego, P.; Meneses-Felipe, A.; Riera, J.; Regueiro, P.V.; Hueso-Gonzalez, F. |
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Title |
Simulation of electron transport and secondary emission in a photomultiplier tube and validation |
Type |
Journal Article |
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Year |
2024 |
Publication |
Sensors and Actuators A-Physical |
Abbreviated Journal |
Sens. Actuator A-Phys. |
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Volume |
365 |
Issue |
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Pages |
114859 - 10pp |
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Keywords |
Photomultiplier tube; Photodetector; Proton therapy; Monte Carlo simulation; Measurement |
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Abstract |
The electron amplification and transport within a photomultiplier tube (PMT) has been investigated by developing an in-house Monte Carlo simulation code. The secondary electron emission in the dynodes is implemented via an effective electron model and the Modified Vaughan's model, whereas the transport is computed with the Boris leapfrog algorithm. The PMT gain, rise time and transit time have been studied as a function of supply voltage and external magnetostatic field. A good agreement with experimental measurements using a Hamamatsu R13408-100 PMT was obtained. The simulations have been conducted following different treatments of the underlying geometry: three-dimensional, two-dimensional and intermediate (2.5D). The validity of these approaches is compared. The developed framework will help in understanding the behavior of PMTs under highly intense and irregular illumination or varying external magnetic fields, as in the case of prompt gamma-ray measurements during pencil-beam proton therapy; and aid in optimizing the design of voltage dividers with behavioral circuit models. |
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Address |
[Martin-Luna, Pablo; Esperante, Daniel; Fuster-Martinez, Nuria; Gimeno, Benito; Gonzalez-Iglesias, Daniel; Llosa, Gabriela; Martinez-Reviriego, Pablo; Meneses-Felipe, Alba; Hueso-Gonzalez, Fernando] CSIC UV, Inst Fis Corpuscular IFIC, C Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: pablo.martin@uv.es |
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Publisher |
Elsevier Science Sa |
Place of Publication |
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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 |
0924-4247 |
ISBN |
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Expedition |
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Conference |
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Notes |
WOS:001131902700001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
5876 |
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