| Records |
Author  |
Arnault, P.; Perez, A.; Arrighi, P.; Farrelly, T. |
| Title |
Discrete-time quantum walks as fermions of lattice gauge theory |
Type |
Journal Article |
| Year |
2019 |
Publication |
Physical Review A |
Abbreviated Journal |
Phys. Rev. A |
| Volume |
99 |
Issue |
3 |
Pages |
032110 - 16pp |
| Keywords |
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| Abstract |
It is shown that discrete-time quantum walks can be used to digitize, i.e., to time discretize fermionic models of continuous-time lattice gauge theory. The resulting discrete-time dynamics is thus not only manifestly unitary, but also ultralocal, i.e., the particle's speed is upper bounded, as in standard relativistic quantum field theories. The lattice chiral symmetry of staggered fermions, which corresponds to a translational invariance, is lost after the requirement of ultralocality of the evolution; this fact is an instance of Meyer's 1996 no-go results stating that no nontrivial scalar quantum cellular automaton can be translationally invariant [D. A. Meyer, J. Stat. Phys. 85, 551 (1996); Phys. Lett. A 223, 337 (1996)]. All results are presented in a single-particle framework and for a (1+1)-dimensional space-time. |
| Address |
[Arnault, Pablo; Perez, Armando] Univ Valencia, Dept Fis Teor, Dr Moliner 50, E-46100 Burjassot, Spain, Email: pablo.arnault@ific.uv.es |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
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 |
2469-9926 |
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:000461896700002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3950 |
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| Author |
Arrechea, J.; Delhom, A.; Jimenez-Cano, A. |
| Title |
Inconsistencies in four-dimensional Einstein-Gauss-Bonnet gravity |
Type |
Journal Article |
| Year |
2021 |
Publication |
Chinese Physics C |
Abbreviated Journal |
Chin. Phys. C |
| Volume |
45 |
Issue |
1 |
Pages |
013107 - 8pp |
| Keywords |
alternative theories of gravity; singularities; Einstein-Gauss-Bonnet |
| Abstract |
We attempt to clarify several aspects concerning the recently presented four-dimensional Einstein-Gauss-Bonnet gravity. We argue that the limiting procedure outlined in [Phys. Rev. Lett. 124, 081301 (2020)] generally involves ill-defined terms in the four dimensional field equations. Potential ways to circumvent this issue are discussed, alongside remarks regarding specific solutions of the theory. We prove that, although linear perturbations are well behaved around maximally symmetric backgrounds, the equations for second-order perturbations are ill-defined even around a Minkowskian background. Additionally, we perform a detailed analysis of the spherically symmetric solutions and find that the central curvature singularity can be reached within a finite proper time. |
| Address |
[Arrechea, Julio] CSIC, Inst Astrofis Andalucia, Granada, Spain, Email: arrechea@iaa.es; |
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Thesis |
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| Publisher |
Iop Publishing Ltd |
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 |
1674-1137 |
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:000606026400001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
4676 |
| Permanent link to this record |
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| Author |
Arrighi, P.; Di Molfetta, G.; Marquez-Martin, I.; Perez, A. |
| Title |
From curved spacetime to spacetime-dependent local unitaries over the honeycomb and triangular Quantum Walks |
Type |
Journal Article |
| Year |
2019 |
Publication |
Scientific Reports |
Abbreviated Journal |
Sci Rep |
| Volume |
9 |
Issue |
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Pages |
10904 - 10pp |
| Keywords |
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| Abstract |
A discrete-time Quantum Walk (QW) is an operator driving the evolution of a single particle on the lattice, through local unitaries. In a previous paper, we showed that QWs over the honeycomb and triangular lattices can be used to simulate the Dirac equation. We apply a spacetime coordinate transformation upon the lattice of this QW, and show that it is equivalent to introducing spacetime-dependent local unitaries-whilst keeping the lattice fixed. By exploiting this duality between changes in geometry, and changes in local unitaries, we show that the spacetime-dependent QW simulates the Dirac equation in (2 + 1)-dimensional curved spacetime. Interestingly, the duality crucially relies on the non linear-independence of the three preferred directions of the honeycomb and triangular lattices: The same construction would fail for the square lattice. At the practical level, this result opens the possibility to simulate field theories on curved manifolds, via the quantum walk on different kinds of lattices. |
| Address |
[Arrighi, Pablo; Di Molfetta, Giuseppe; Marquez-Martin, Ivan] Univ Toulon & Var, Aix Marseille Univ, CNRS, LIS, Marseille, France, Email: pablo.arrighi@univ-amu.fr; |
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| Publisher |
Nature Publishing Group |
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 Issue |
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Edition |
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| ISSN |
2045-2322 |
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:000477701800007 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4081 |
| Permanent link to this record |
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| Author |
Arrighi, P.; Di Molfetta, G.; Marquez-Martin, I.; Perez, A. |
| Title |
Dirac equation as a quantum walk over the honeycomb and triangular lattices |
Type |
Journal Article |
| Year |
2018 |
Publication |
Physical Review A |
Abbreviated Journal |
Phys. Rev. A |
| Volume |
97 |
Issue |
6 |
Pages |
062111 - 5pp |
| Keywords |
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| Abstract |
A discrete-time quantum walk (QW) is essentially an operator driving the evolution of a single particle on the lattice, through local unitaries. Some QWs admit a continuum limit, leading to well-known physics partial differential equations, such as the Dirac equation. We show that these simulation results need not rely on the grid: the Dirac equation in (2 + 1) dimensions can also be simulated, through local unitaries, on the honeycomb or the triangular lattice, both of interest in the study of quantum propagation on the nonrectangular grids, as in graphene-like materials. The latter, in particular, we argue, opens the door for a generalization of the Dirac equation to arbitrary discrete surfaces. |
| Address |
[Arrighi, Pablo; Di Molfetta, Giuseppe; Marquez-Martin, Ivan] Aix Marseille Univ, Univ Toulon, LIS, CNRS, Marseille, France, Email: pablo.arrighi@univ-amu.fr; |
| Corporate Author |
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Thesis |
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| Publisher |
Amer Physical Soc |
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 |
2469-9926 |
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:000435076800001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
3624 |
| Permanent link to this record |
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| Author |
Asai, M.; Cortes-Giraldo, M.A.; Gimenez-Alventosa, V.; Gimenez, V.; Salvat, F. |
| Title |
The PENELOPE Physics Models and Transport Mechanics. Implementation into Geant4 |
Type |
Journal Article |
| Year |
2021 |
Publication |
Frontiers in Physics |
Abbreviated Journal |
Front. Physics |
| Volume |
9 |
Issue |
|
Pages |
738735 - 20pp |
| Keywords |
coupled electron-photon transport; Monte Carlo simulation; PENELOPE code system; random-hinge method; Geant4 toolkit |
| Abstract |
A translation of the penelope physics subroutines to C++, designed as an extension of the Geant4 toolkit, is presented. The Fortran code system penelope performs Monte Carlo simulation of coupled electron-photon transport in arbitrary materials for a wide energy range, nominally from 50 eV up to 1 GeV. Penelope implements the most reliable interaction models that are currently available, limited only by the required generality of the code. In addition, the transport of electrons and positrons is simulated by means of an elaborate class II scheme in which hard interactions (involving deflection angles or energy transfers larger than pre-defined cutoffs) are simulated from the associated restricted differential cross sections. After a brief description of the interaction models adopted for photons and electrons/positrons, we describe the details of the class-II algorithm used for tracking electrons and positrons. The C++ classes are adapted to the specific code structure of Geant4. They provide a complete description of the interactions and transport mechanics of electrons/positrons and photons in arbitrary materials, which can be activated from the G4ProcessManager to produce simulation results equivalent to those from the original penelope programs. The combined code, named PenG4, benefits from the multi-threading capabilities and advanced geometry and statistical tools of Geant4. |
| Address |
[Asai, Makoto] SLAC Natl Accelerator Lab, Menlo Pk, CA USA, Email: miancortes@us.es; |
| Corporate Author |
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Thesis |
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| Publisher |
Frontiers Media Sa |
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 |
2296-424x |
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:000742889400001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5080 |
| Permanent link to this record |
