Aplicación
Estudio pormenorizado de las arquitecturas cuánticas y sus desafíos de software y hardware
Universidad Politécnica de Valencia (UPV)
Descripción del grupo:
El grupo en computación cuántica de la Universidad Politécnica de Valencia está liderado por la investigadora Carmen G. Almudéver. Su investigación se centra en diferentes aspectos de la computación cuántica, incluidos compiladores y lenguajes de programación cuántica, mapeo de algoritmos cuánticos, arquitectura y evaluación comparativa de computadoras cuánticas, corrección de errores cuánticos y computación cuántica tolerante a fallos.
Descripción de la actividad:
Esta actividad se centra en proveer soluciones arquitecturales de pila completa que permitan que los algoritmos cuánticos puedan ser ejecutados de la manera más fiable en los procesadores cuánticos actuales y en los que se desarrollarán en los próximos años.
Se hará especial énfasis en los algoritmos de aprendizaje automatizado (quantum machine learning algorithms), cuyos principales cuellos de botella provienen de su implementación en sistemas cuánticos reales. Para ello se realizarán las siguientes tareas:
1. Caracterización y taxonomía de los algoritmos a ejecutar en procesadores cuánticos de escala intermedia.
2. Desarrollo de soluciones arquitecturales que no sólo considerarán las limitaciones del hardware cuántico siguiendo un enfoque “bottom-up” sino que tendrán también en cuenta las aplicaciones o algoritmos a ejecutar en forma de soluciones software que son “algorithm-driven”.
Resultados
Duong Anh-Tai, T.; Fogarty, T.; de María-García, S.; Busch, T.; García-March, M. A.
Engineering impurity Bell states through coupling with a quantum bath Artículo de revista
En: Physical Review Research, 2024.
Resumen | BibTeX | Etiquetas: UPV
@article{nokey,
title = {Engineering impurity Bell states through coupling with a quantum bath},
author = {Duong Anh-Tai, T. and Fogarty, T. and de María-García, S. and Busch, T. and García-March, M.A.},
year = {2024},
date = {2024-10-16},
journal = {Physical Review Research},
abstract = {We theoretically demonstrate the feasibility of creating Bell states in multicomponent ultracold atomic gases by solely using the ability to control the interparticle interactions via Feshbach resonances. For this we consider two distinguishable impurities immersed in an atomic background cloud of a few bosons, with the entire system being confined in a one-dimensional harmonic trap. By analyzing the numerically obtained ground states we demonstrate that the two impurities can form spatially entangled bipolaron states due to mediated interactions from the bosonic bath. Our analysis is based on calculating the correlations between the two impurities in a two-mode basis, which is experimentally accessible by measuring the particle positions in the left or right sides of the trap. While interspecies interactions are crucial in order to create the strongly entangled impurity states, they can also inhibit correlations depending on the ordering of the impurities and three-body impurity-bath correlations. We show how these drawbacks can be mitigated by manipulating the properties of the bath, namely its size, mass, and intraspecies interactions, allowing one to create impurity Bell states over a wide range of impurity-impurity interactions.
},
keywords = {UPV},
pubstate = {published},
tppubtype = {article}
}
We theoretically demonstrate the feasibility of creating Bell states in multicomponent ultracold atomic gases by solely using the ability to control the interparticle interactions via Feshbach resonances. For this we consider two distinguishable impurities immersed in an atomic background cloud of a few bosons, with the entire system being confined in a one-dimensional harmonic trap. By analyzing the numerically obtained ground states we demonstrate that the two impurities can form spatially entangled bipolaron states due to mediated interactions from the bosonic bath. Our analysis is based on calculating the correlations between the two impurities in a two-mode basis, which is experimentally accessible by measuring the particle positions in the left or right sides of the trap. While interspecies interactions are crucial in order to create the strongly entangled impurity states, they can also inhibit correlations depending on the ordering of the impurities and three-body impurity-bath correlations. We show how these drawbacks can be mitigated by manipulating the properties of the bath, namely its size, mass, and intraspecies interactions, allowing one to create impurity Bell states over a wide range of impurity-impurity interactions.
Cirauqui, D.; García-March, M. A.; Guigó Corominas, G.; Graß, T.; Grzybowski, P. R.; Muñoz-Gil, G.; Saavedra, J. R. M.; Lewenstein, M.
Comparing pseudo- and quantum-random number generators with Monte Carlo simulations Editor’s Pick Artículo de revista
En: APL Quantum, 2024.
Resumen | Enlaces | BibTeX | Etiquetas: UPV
@article{nokey,
title = {Comparing pseudo- and quantum-random number generators with Monte Carlo simulations Editor’s Pick },
author = {Cirauqui, D. and García-March, M.A. and Guigó Corominas, G. and Graß, T. and Grzybowski, P.R. and Muñoz-Gil, G. and Saavedra, J.R.M. and Lewenstein, M.},
url = {https://pubs.aip.org/aip/apq/article/1/3/036125/3313392/Comparing-pseudo-and-quantum-random-number},
doi = {doi.org/10.1063/5.0199568},
year = {2024},
date = {2024-09-20},
journal = {APL Quantum},
abstract = {We study how the Monte Carlo simulations of the critical dynamics of two-dimensional Ising lattices are affected by the quality (as compared to true randomness) of the pseudo-randomness used in them by computing an observable known to be sensitive to it: the dynamic critical exponent z. To this end, we first present a review of the literature and then perform the same simulations with different pseudo-randomness sources. We control the quality of the random streams by physically reseeding the generators and observe that while the mean value of the measured observable is slightly affected by the correlations within them, its variance does get a severe impact. By studying this affectation and how such pseudo-random streams perform under standard randomness tests based on statistical analysis, we conclude that the new protocol is able to detect other types of correlations and can thus be used as an additional test. On the other hand, we present the first (to the best of our knowledge) computation of the dynamic critical exponent with a perfectly random quantum random number generator (QRNG) and hypothesize that the presented strategy may point toward a route to establish quantum advantage based on the quality of results as complementary to those strategies based on the speed of the computational task.},
keywords = {UPV},
pubstate = {published},
tppubtype = {article}
}
We study how the Monte Carlo simulations of the critical dynamics of two-dimensional Ising lattices are affected by the quality (as compared to true randomness) of the pseudo-randomness used in them by computing an observable known to be sensitive to it: the dynamic critical exponent z. To this end, we first present a review of the literature and then perform the same simulations with different pseudo-randomness sources. We control the quality of the random streams by physically reseeding the generators and observe that while the mean value of the measured observable is slightly affected by the correlations within them, its variance does get a severe impact. By studying this affectation and how such pseudo-random streams perform under standard randomness tests based on statistical analysis, we conclude that the new protocol is able to detect other types of correlations and can thus be used as an additional test. On the other hand, we present the first (to the best of our knowledge) computation of the dynamic critical exponent with a perfectly random quantum random number generator (QRNG) and hypothesize that the presented strategy may point toward a route to establish quantum advantage based on the quality of results as complementary to those strategies based on the speed of the computational task.
Piñol, E.; Mavrogordatos, Th. K.; Keys, D.; Veyron, R.; Sierant, P.; García-March, M. A.; Grandi, S.; Mitchell, M. W.; Wehr, J.
Telling different unravelings apart via nonlinear quantum-trajectory averages Artículo de revista
En: Physical Review Research, 2024.
Resumen | Enlaces | BibTeX | Etiquetas: UPV
@article{nokey,
title = {Telling different unravelings apart via nonlinear quantum-trajectory averages},
author = {Piñol, E. and Mavrogordatos, Th.K. and Keys, D. and Veyron, R. and Sierant, P. and García-March, M.A. and Grandi, S. and Mitchell, M.W. and Wehr, J. et al.},
url = {https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.6.L032057},
doi = {doi.org/10.1103/PhysRevResearch.6.L032057},
year = {2024},
date = {2024-09-06},
journal = {Physical Review Research},
abstract = {The Gorini-Kossakowski-Sudarshan-Lindblad master equation (ME) governs the density matrix of open quantum systems (OQSs). When an OQS is subjected to weak continuous measurement, its state evolves as a stochastic quantum trajectory, whose statistical average solves the ME. The ensemble of such trajectories is termed an unraveling of the ME. We propose a method to operationally distinguish unravelings produced by the same ME in different measurement scenarios, using nonlinear averages of observables over trajectories. We apply the method to the paradigmatic quantum nonlinear system of resonance fluorescence in a two-level atom. We compare the Poisson-type unraveling, induced by direct detection of photons scattered from the two-level emitter, and the Wiener-type unraveling, induced by phase-sensitive detection of the emitted field. We show that a quantum-trajectory-averaged variance is able to distinguish these measurement scenarios. We evaluate the performance of the method, which can be readily extended to more complex OQSs, under a range of realistic experimental conditions.
},
keywords = {UPV},
pubstate = {published},
tppubtype = {article}
}
The Gorini-Kossakowski-Sudarshan-Lindblad master equation (ME) governs the density matrix of open quantum systems (OQSs). When an OQS is subjected to weak continuous measurement, its state evolves as a stochastic quantum trajectory, whose statistical average solves the ME. The ensemble of such trajectories is termed an unraveling of the ME. We propose a method to operationally distinguish unravelings produced by the same ME in different measurement scenarios, using nonlinear averages of observables over trajectories. We apply the method to the paradigmatic quantum nonlinear system of resonance fluorescence in a two-level atom. We compare the Poisson-type unraveling, induced by direct detection of photons scattered from the two-level emitter, and the Wiener-type unraveling, induced by phase-sensitive detection of the emitted field. We show that a quantum-trajectory-averaged variance is able to distinguish these measurement scenarios. We evaluate the performance of the method, which can be readily extended to more complex OQSs, under a range of realistic experimental conditions.
Grzybowski, P. R.; Jankiewicz, A.; Piñol, E.; Cirauqui, D.; Grzybowska, D. H.; Petrykowski, P. M.; García-March, M. A.; Lewenstein, M.; Muñoz-Gil, G.; Pozas-Kerstjens, A.
Universal representation by Boltzmann machines with Regularised Axons Working paper
2023.
Resumen | Enlaces | BibTeX | Etiquetas: UPV
@workingpaper{nokey,
title = {Universal representation by Boltzmann machines with Regularised Axons},
author = {Grzybowski, P.R. and Jankiewicz, A. and Piñol, E. and Cirauqui, D. and Grzybowska, D.H. and Petrykowski, P.M. and García-March, M.A. and Lewenstein, M. and Muñoz-Gil, G. and Pozas-Kerstjens, A.},
url = {https://arxiv.org/abs/2310.14395},
doi = {doi.org/10.48550/arXiv.2310.14395 Focus to learn more},
year = {2023},
date = {2023-11-30},
abstract = {It is widely known that Boltzmann machines are capable of representing arbitrary probability distributions over the values of their visible neurons, given enough hidden ones. However, sampling -- and thus training -- these models can be numerically hard. Recently we proposed a regularisation of the connections of Boltzmann machines, in order to control the energy landscape of the model, paving a way for efficient sampling and training. Here we formally prove that such regularised Boltzmann machines preserve the ability to represent arbitrary distributions. This is in conjunction with controlling the number of energy local minima, thus enabling easy emph{guided} sampling and training. Furthermore, we explicitly show that regularised Boltzmann machines can store exponentially many arbitrarily correlated visible patterns with perfect retrieval, and we connect them to the Dense Associative Memory networks.
},
keywords = {UPV},
pubstate = {published},
tppubtype = {workingpaper}
}
It is widely known that Boltzmann machines are capable of representing arbitrary probability distributions over the values of their visible neurons, given enough hidden ones. However, sampling -- and thus training -- these models can be numerically hard. Recently we proposed a regularisation of the connections of Boltzmann machines, in order to control the energy landscape of the model, paving a way for efficient sampling and training. Here we formally prove that such regularised Boltzmann machines preserve the ability to represent arbitrary distributions. This is in conjunction with controlling the number of energy local minima, thus enabling easy emph{guided} sampling and training. Furthermore, we explicitly show that regularised Boltzmann machines can store exponentially many arbitrarily correlated visible patterns with perfect retrieval, and we connect them to the Dense Associative Memory networks.
