Passionated by Physics, gradutated at the Autonomous University of Barcelona in 2019, with a strong enthusiasm for the fundations of Quantum Mechanics and its applications in the new era of technology, wishing to understand someday what is \(\psi\). Curious about other areas of physics like High Energy, Quantum Gravity or Complex Systems, even other topics like psicology or phylosophy.
Solid background in programming languages like Python and most of its common libraries for scientits (numpy, matplotlib) and data science (pandas). Also experienced in web applications (html, javascript, ReactJS, CSS…) and SQL management with SQLite and MySQL. Awarded with a Developer Certification in Android Development with Java and interested in promissing languages like Julia.
Adrià Labay-Mora, Eliana Fiorelli, Roberta Zambrini and Gian Luca Giorgi
Associative memory refers to the ability to relate a memory with an input and targets the restoration of corrupted patterns. It has been intensively studied in classical physical systems, as in neural networks where an attractor dynamics settles on stable solutions. Several extensions to the quantum domain have been recently reported, displaying different features. In this work, we develop a comprehensive framework for a quantum associative memory based on open quantum system dynamics, which allows us to compare existing models, identify the theoretical prerequisites for performing associative memory tasks, and extend it in different forms. The map that achieves an exponential increase in the number of stored patterns with respect to classical systems is derived. We establish the crucial role of symmetries and dissipation in the operation of quantum associative memory. Our theoretical analysis demonstrates the feasibility of addressing both quantum and classical patterns, orthogonal and non-orthogonal memories, stationary and metastable operating regimes, and measurement-based outputs. Finally, this opens up new avenues for practical applications in quantum computing and machine learning, such as quantum error correction or quantum memories.
Adrià Labay-Mora, Francisco Ferreira da Silva and Stephanie Wehner
We conduct a numerical investigation of fiber-based entanglement distribution over distances of up to 1600km using a chain of processing-node quantum repeaters. We determine minimal hardware requirements while simultaneously optimizing over protocols for entanglement generation and entanglement purification, as well as over strategies for entanglement swapping. Notably, we discover that through an adequate choice of protocols the hardware improvement cost scales linearly with the distance covered. Our results highlight the crucial role of good protocol choices in significantly reducing hardware requirements, such as employing purification to meet high-fidelity targets and adopting a SWAP-ASAP policy for faster rates. To carry out this analysis, we employ an extensive simulation framework implemented with NetSquid, a discrete-event-based quantum-network simulator, and a genetic-algorithm-based optimization methodology to determine minimal hardware requirements.
Adrià Labay-Mora, Roberta Zambrini and Gian Luca Giorgi
Quantum oscillators with nonlinear driving and dissipative terms have gained significant attention due to their ability to stabilize cat-states for universal quantum computation. Recently, superconducting circuits have been employed to realize such long-lived qubits stored in coherent states. We present a generalization of these oscillators, which are not limited to coherent states, in the presence of different nonlinearities in driving and dissipation, exploring different degrees. Specifically, we present an extensive analysis of the asymptotic dynamical features and of the storage of squeezed states. We demonstrate that coherent superpositions of squeezed states are achievable in the presence of a strong symmetry, thereby allowing for the storage of squeezed cat-states. In the weak symmetry regime, accounting for linear dissipation, we investigate the potential application of these nonlinear driven-dissipative resonators for quantum computing and quantum associative memory and analyze the impact of squeezing on their performance.
Adrià Labay-Mora, Roberta Zambrini and Gian Luca Giorgi
Algorithms for associative memory typically rely on a network of many connected units. The prototypical example is the Hopfield model, whose generalizations to the quantum realm are mainly based on open quantum Ising models. We propose a realization of associative memory with a single driven-dissipative quantum oscillator exploiting its infinite degrees of freedom in phase space. The model can improve the storage capacity of discrete neuron-based systems in a large regime and we prove successful state discrimination between $n$ coherent states, which represent the stored patterns of the system. These can be tuned continuously by modifying the driving strength, constituting a modified learning rule. We show that the associative-memory capacity is inherently related to the existence of a spectral gap in the Liouvillian superoperator, which results in a large timescale separation in the dynamics corresponding to a metastable phase.
Distribution of high-quality entanglement over long distances is a key step for the development of a future quantum internet. Exponential photon loss related to distance in optical fibers makes it impractical to connect two nodes directly. Furthermore, the impossibility of copying general quantum states forbids using the same solutions as in classical communication. Quantum repeaters can be used to extend entanglement to longer distances using teleportation; nonetheless, straightforward application still leads to an exponential decrease in the link quality. Entanglement purification probabilistically allows us to obtain a few high-quality links from many low-quality ones. Several protocols combining quantum repeaters with purification have been proposed. However, the hardware quality is still lacking. Moreover, it is unclear how an improvement over a certain hardware parameter affects the final link quality or entanglement generation rate. Analytical expressions are hard to find and usually, assumptions are needed, limiting their applicability. In this work, a realistic repeater chain is modeled using NetSquid, a discrete-event-based quantum network simulator. A genetic algorithm-based optimisation methodology is then applied to determine what entanglement distribution protocol allows for minimal improvement over current hardware, and what these improvements must be in order to achieve a target link quality and distribution rate. In this thesis, we aim to make the path toward scalable quantum repeaters clearer, as well as understand how entanglement purification can enable this goal. We conclude that quantum repeaters are necessary to connect distances larger than 200km. We also find that entanglement purification enables achieving target metrics with lower hardware cost when the internode distance is approximately 100km, where a balance is found between a low rate for longer separations and too-demanding hardware for shorter ones. Finally, we analyze the growth of the hardware cost with the distance showing that, with the best choice of protocols, it scales linearly. We believe that these results constitute a valuable stepping stone towards a blueprint for a pan-European quantum internet.
The Copenhaguen interpretation provides a mathematical framework that has proved useful to evaluate the probabilities for future events in terms of our previous knowledge of a system. However, it is a source of controversy since any physical intuition we want to give on the processes yields paradoxes like instantaneous collapse, spooky action at a distance… The goal of the relational interpretation is to solve some of them without changing the actual formalism, purely by focusing our attention on what is really the intrinsic property of Quantum Mechanics: discreteness.
The identification of abrupt changes in the behaviour of a system is of crucial importance in areas such as medicine, climatology, biology… Here we will discuss the problem in the quantum world, we will consider a source generating a certain state which suffers an alteration and suddenly changes to another. The question is to find the position of the change based on measures carried out on the states with the greatest possible probability of success. Recently, the solution to the problem was found when the two states, before and after the change, were pure. In this thesis, we will study the case in which the states are mixed and therefore the uncertainty in the system increases. We will use both analytical and numerical techniques to find the optimal measure that maximises the probability of correctly identifying the point of change.
The objective of this research project is to create a device capable of analysing air pollution using an Arduino and some sensors to measure temperature, humidity, liquefied petroleum gas, ethanol, hydrocarbon gases, carbon monoxide and carbon dioxide. The measurements are sent via a Bluetooth module to an Android mobile, where they are stored and presented. It is included in the Android application capabilities like speech recognition, speech synthesis and geolocation. Tailpipe emissions have been compared between diesel/gasoline and new/old cars.
*Unpublished
Conferences
General framework for quantum associative memories
QTYR Workshop (Madrid, Spain)
General framework for quantum associative memories
Quantum Matter (San Sebastian, Spain)
Associative memories in the quantum regime
Machine Learning and Quantum Physics Workshop (Obergurgl, Austria)
Quantum associative memory and storage properties of a driven-dissipative nonlinear oscillator
Quantum Techniques in Machine Learning (CERN, Switzerland)
Quantum associative memory and storage properties of a driven-dissipative nonlinear oscillator
XXIV Congreso de Física Estadística (FisEs 23) (Pamplona, Spain)
Quantum associative memory and storage properties of a driven-dissipative nonlinear oscillator
Quantum Information in Spain ICE-8 (Santiago de Compostela, Spain)
Quantum associative memory with a single driven-dissipative nonlinear oscillator
Conference on Complex Systems (Palma de Mallorca, Spain)
Quantum associative memory with a single driven-dissipative nonlinear oscillator
Quantum characterization and control of quantum complex systems (Lake Como School of Advanced Studies, Italy)
Quantum associative memory with a single driven-dissipative nonlinear oscillator
Quantum Matter (Barcelona, Catalunya)
Quantum associative memory with a single driven-dissipative nonlinear oscillator
Quantum Information in Spain ICE-7 (Granada, Spain)
Investigadors de l’IFISC (UIB-CSIC) han proposat un nou mètode per a la classificació de patrons utilitzant un sol oscil·lador quàntic no lineal en lloc d’una xarxa d’espins (bits). L’estudi, publicat a la prestigiosa revista Physical Review Letters, se centra en la implementació del mètode de memòria associativa i algorismes de classificació mitjançant IA.
Today, together with Àlex Giménez Romero we have released the UncValue library
for Python and Julia. This library allows to initialize a number with an uncertainty and propagate that
uncertainty under all the operations performed.
Language: en
physics
Quantum Field Theory
High Energy Physics
I don’t really know how to describe this notes, they are just a supplement to the main notes but well organised in my opinion and with multiple inputs from other books. Very few formulas will be derived, however the goal is to try to explain the physics of all of them.
Aquí podeu trobar un resum de l’assignatura de Termodinàmica i Mecànica Estadística del Grau en Física de la UAB.
Conté una introducció a la termodinàmica, enumerant les lleis i els diferents potencials que s’utilitzen. En segueix una introducció a la Mecànica Estadística on s’hi expliquen les 3 col·lectivitats (ensembles) més importants: microcanònica \(\Omega\), canònica \(Z\) i macrocanònica \(\Phi\). A continuació, s’estudien els canvis de fase, s’explica el significat del punt crític i s’introdueix la teoria de Landau que ens serà util per estudiar el comportament de sistemes magnètics. Concretament, a la 4a secció, veurem aquests sistemes des d’un punt de vist classic i quantic, així mateix, desenvoluparem el ben conegut model d’Ising que es pot resoldre exactament per una cadena unidimensional. Finalment, trobarem un apartat de gasos reals on veurem els efectes que surgen de la interacció de particules.
Aquí podeu trobar un resum de l’assignatura de Mecànica Clàssica del Grau en Física de la UAB. Conté una introducció a la Mecànica Netwoniana amb la teoria d’acreció de massa, oscilacions acoplades, forces centrals, moviment relatiu i solid rígid. També inclou una breu introducció a la relativitat especial on trobarem explicades les transformacions i el grup de Lorentz, el concepte de sistema propi i algun exemple de col·lisions relativistes. A continuació, canviem de formulisme per endinssar-nos a la Mecànica Analítica de Lagrange i Hamilton, explicarem els dos formulismes, la seva connexió i el principi variacional de Lagrange-Euler. També deduirem molts dels resultats trobats anteriorment amb la formulació Netwoniana i veurem que en la majoria dels cassos el nou mètode simplifica el procés. Per acabar, trobarem un apartat de transformacions canòniques que queda fora del temari de l’assignaturai està bassat completament en el Capítol 9 del Goldstein.
The Teogony by Hesiod, written between the 8th and 7th centure BC, is a poem based on the birth of Greek Gods. The name Teogony means by itself the “genealogy of Gods” and it represents a summary of a variety of Greek traditions, it explains how the kindgom of Gods was born form the Caos to the well-known Zeus.
In physics, the n-body problem is the problem of predicting the individual motions of a group of celestial objects interacting with each other gravitationally.