Home << 1 >>
List View
 | 
Citations
 | 
Details
   web
Records
Author (up) Angles-Castillo, A.; Perez, A.; Roldan, E.
Title Bright and dark solitons in a photonic nonlinear quantum walk: lessons from the continuum Type Journal Article
Year 2024 Publication New Journal of Physics Abbreviated Journal New J. Phys.
Volume 26 Issue 2 Pages 023004 - 16pp
Keywords quantum walks; soliton; non-linear optics
Abstract We propose a nonlinear quantum walk model inspired in a photonic implementation in which the polarization state of the light field plays the role of the coin-qubit. In particular, we take profit of the nonlinear polarization rotation occurring in optical media with Kerr nonlinearity, which allows to implement a nonlinear coin operator, one that depends on the state of the coin-qubit. We consider the space-time continuum limit of the evolution equation, which takes the form of a nonlinear Dirac equation. The analysis of this continuum limit allows us to gain some insight into the existence of different solitonic structures, such as bright and dark solitons. We illustrate several properties of these solitons with numerical calculations, including the effect on them of an additional phase simulating an external electric field.
Address [Angles-Castillo, Andreu; Perez, Armando] Univ Valencia, Dept Fis Teor & IFIC, CSIC, Burjassot 46100, Valencia, Spain, Email: andreu.angles-castillo@uv.es
Corporate Author Thesis
Publisher IOP Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1367-2630 ISBN Medium
Area Expedition Conference
Notes WOS:001156767400001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 5929
Permanent link to this record
 
 
Author (up) Arnault, P.; Macquet, A.; Angles-Castillo, A.; Marquez-Martin, I.; Pina-Canelles, V.; Perez, A.; Di Molfetta, G.; Arrighi, P.; Debbasch, F.
Title Quantum simulation of quantum relativistic diffusion via quantum walks Type Journal Article
Year 2020 Publication Journal of Physics A Abbreviated Journal J. Phys. A
Volume 53 Issue 20 Pages 205303 - 39pp
Keywords noisy quantum walks; noisy quantum systems; decoherence; Lindblad equation; quantum simulation; relativistic diffusions; telegraph equation
Abstract Two models are first presented, of a one-dimensional discrete-time quantum walk (DTQW) with temporal noise on the internal degree of freedom (i.e., the coin): (i) a model with both a coin-flip and a phase-flip channel, and (ii) a model with random coin unitaries. It is then shown that both these models admit a common limit in the spacetime continuum, namely, a Lindblad equation with Dirac-fermion Hamiltonian part and, as Lindblad jumps, a chirality flip and a chirality-dependent phase flip, which are two of the three standard error channels for a two-level quantum system. This, as one may call it, Dirac Lindblad equation, provides a model of quantum relativistic spatial diffusion, which is evidenced both analytically and numerically. This model of spatial diffusion has the intriguing specificity of making sense only with original unitary models which are relativistic in the sense that they have chirality, on which the noise is introduced: the diffusion arises via the by-construction (quantum) coupling of chirality to the position. For a particle with vanishing mass, the model of quantum relativistic diffusion introduced in the present work, reduces to the well-known telegraph equation, which yields propagation at short times, diffusion at long times, and exhibits no quantumness. Finally, the results are extended to temporal noises which depend smoothly on position.
Address [Arnault, Pablo; Angles-Castillo, Andreu; Marquez-Martin, Ivan; Pina-Canelles, Vicente; Perez, Armando; Di Molfetta, Giuseppe] Univ Valencia, Dept Fis Teor, Dr Moliner 50, Burjassot 46100, Spain, Email: pablo.arnault@ic.uv.es
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1751-8113 ISBN Medium
Area Expedition Conference
Notes WOS:000531359000001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4390
Permanent link to this record
 
 
Author (up) Di Molfetta, G.; Perez, A.
Title Quantum walks as simulators of neutrino oscillations in a vacuum and matter Type Journal Article
Year 2016 Publication New Journal of Physics Abbreviated Journal New J. Phys.
Volume 18 Issue Pages 103038 - 8pp
Keywords quantum walks; neutrino oscillations; quantum simulation
Abstract We analyze the simulation of Dirac neutrino oscillations using quantum walks, both in a vacuum and in matter. We show that this simulation, in the continuum limit, reproduces a set of coupled Dirac equations that describe neutrino flavor oscillations, and we make use of this to establish a connection with neutrino phenomenology, thus allowing one to fix the parameters of the simulation for a given neutrino experiment. We also analyze how matter effects for neutrino propagation can be simulated in the quantum walk. In this way, important features, such as the MSW effect, can be incorporated. Thus, the simulation of neutrino oscillations with the help of quantum walks might be useful to illustrate these effects in extreme conditions, such as the solar interior or supernovae.
Address [Di Molfetta, G.] Univ Valencia, CSIC, Dept Fis Teor, Dr Moliner 50, E-46100 Burjassot, Spain, Email: giuseppe.dimolfetta@lif.univ-mrs.fr
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1367-2630 ISBN Medium
Area Expedition Conference
Notes WOS:000386816100004 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2846
Permanent link to this record
 
 
Author (up) 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 Thesis
Publisher Amer Scientific Publishers Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1546-1955 ISBN Medium
Area Expedition Conference
Notes WOS:000322605800014 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1529
Permanent link to this record
 
 
Author (up) Jay, G.; Arnault, P.; Debbasch, F.
Title Dirac quantum walks with conserved angular momentum Type Journal Article
Year 2021 Publication Quantum Studies-Mathematics and Foundations Abbreviated Journal Quantum Stud. Math. Found.
Volume 8 Issue Pages 419-430
Keywords Quantum walks; Quantum simulation; Lattice field theory
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.
Address [Jay, Gareth] Univ Western Australia, Phys Dept, Perth, WA 6009, Australia, Email: gareth.jay@uwa.edu.au;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2196-5609 ISBN Medium
Area Expedition Conference
Notes WOS:000697709700001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4975
Permanent link to this record
 
 
Author (up) Nzongani, U.; Zylberman, J.; Doncecchi, C.E.; Perez, A.; Debbasch, F.; Arnault, P.
Title Quantum circuits for discrete-time quantum walks with position-dependent coin operator Type Journal Article
Year 2023 Publication Quantum Information Processing Abbreviated Journal Quantum Inf. Process.
Volume 22 Issue 7 Pages 270 - 46pp
Keywords Quantum walks; Quantum circuits; Quantum simulation
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).
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;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1570-0755 ISBN Medium
Area Expedition Conference
Notes WOS:001022408900002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5587
Permanent link to this record
 
 
Author (up) 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 Thesis
Publisher Amer Scientific Publishers Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1546-1955 ISBN Medium
Area Expedition Conference
Notes WOS:000322605800007 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1528
Permanent link to this record