Departamento de Electromagnetismo y Física de la Materiahttp://hdl.handle.net/10481/310182022-08-08T00:28:56Z2022-08-08T00:28:56ZA model of interacting quantum neurons with a dynamic synapseTorres Agudo, JoaquínManzano Diosdado, Danielhttp://hdl.handle.net/10481/763882022-07-27T11:36:01ZA model of interacting quantum neurons with a dynamic synapse
Torres Agudo, Joaquín; Manzano Diosdado, Daniel
Motivated by recent advances in neuroscience, in this work, we explore the emergent behaviour of
quantum systems with a dynamical biologically-inspired qubits interaction. We use a minimal
model of two interacting qubits with an activity-dependent dynamic interplay as in classical
dynamic synapses that induces the so-called synaptic depression, that is, synapses that present
synaptic fatigue after heavy presynaptic stimulation. Our study shows that in absence of synaptic
depression the two-qubits quantum system shows typical Rabi oscillations whose frequency
decreases when synaptic depression is introduced, so one can trap excitations for a large period of
time. This creates a population imbalance between the qubits even though the Hamiltonian is
Hermitian. This imbalance can be sustained in time by introducing a small energy shift between
the qubits. In addition, we report that long time entanglement between the two qubits raises
naturally in the presence of synaptic depression. Moreover, we propose and analyse a plausible
experimental setup of our two-qubits system which demonstrates that these results are robust and
can be experimentally obtained in a laboratory.
Comment on “Loss-Free Excitonic Quantum Battery”Tejero, ÁlvaroManzano Diosdado, Danielhttp://hdl.handle.net/10481/727932022-02-11T09:26:38ZComment on “Loss-Free Excitonic Quantum Battery”
Tejero, Álvaro; Manzano Diosdado, Daniel
Quantum batteries have primarily been modeled as an
ensemble of isolated systems that store energy and from
which work can be extracted by applying unitary transformations.
1 Only recently have investigations begun in the
direction of dissipative quantum batteries2−4 wherein the
charge of the battery is protected against a dissipative
environment.
Solar Wind—Magnetosphere Coupling During Radial Interplanetary Magnetic Field Conditions: Simultaneous Multi-Point ObservationsToledo Redondo, S.Fornieles Callejón, Jesús Franciscohttp://hdl.handle.net/10481/720252021-12-13T08:20:04ZSolar Wind—Magnetosphere Coupling During Radial Interplanetary Magnetic Field Conditions: Simultaneous Multi-Point Observations
Toledo Redondo, S.; Fornieles Callejón, Jesús Francisco
In-situ spacecraft missions are powerful assets to study processes that occur in space plasmas. One of their main limitations, however, is extrapolating such local measurements to the global scales of the system. To overcome this problem at least partially, multi-point measurements can be used. There are several multi-spacecraft missions currently operating in the Earth's magnetosphere, and the simultaneous use of the data collected by them provides new insights into the large-scale properties and evolution of magnetospheric plasma processes. In this work, we focus on studying the Earth's magnetopause (MP) using a conjunction between the Magnetospheric Multiscale and Cluster fleets, when both missions skimmed the MP for several hours at distant locations during radial interplanetary magnetic field (IMF) conditions. The observed MP positions as a function of the evolving solar wind conditions are compared to model predictions of the MP. We observe an inflation of the magnetosphere (similar to 0.7 R-E), consistent with magnetosheath pressure decrease during radial IMF conditions, which is less pronounced on the flank (<0.2 R-E). There is observational evidence of magnetic reconnection in the subsolar region for the whole encounter, and in the dusk flank for the last portion of the encounter, suggesting that reconnection was extending more than 15 R-E. However, reconnection jets were not always observed, suggesting that reconnection was patchy, intermittent or both. Shear flows reduce the reconnection rate up to similar to 30% in the dusk flank according to predictions, and the plasma beta enhancement in the magnetosheath during radial IMF favors reconnection suppression by the diamagnetic drift.
S. Toledo-Redondo and J. Fornieles acknowledge support of the Ministry of Economy and Competitiveness (MINECO) of Spain (grant FIS2017-90102-R) and of Ministry of Science and Innovation (grant PID2020-112805GA-I00). Research at IRAP was supported by CNRS, CNES, and the University of Toulouse. We acknowledge support of the ISSI teams MMS and Cluster observations of magnetic reconnection and Cold plasma of ionospheric in the Earth's magnetosphere, and of the ESAC Science faculty.
Phenotypic-dependent variability and the emergence of tolerance in bacterial populationsMateu Camacho, JoséSireci, MatteoMuñoz Martínez, Miguel Ángelhttp://hdl.handle.net/10481/710382021-11-02T09:37:39ZPhenotypic-dependent variability and the emergence of tolerance in bacterial populations
Mateu Camacho, José; Sireci, Matteo; Muñoz Martínez, Miguel Ángel
Ecological and evolutionary dynamics have been historically regarded as unfolding at broadly separated timescales. However, these two types of processes are nowadays well-documented to intersperse much more tightly than traditionally assumed, especially in communities of microorganisms. Advancing the development of mathematical and computational approaches to shed novel light onto eco-evolutionary problems is a challenge of utmost relevance. With this motivation in mind, here we scrutinize recent experimental results showing evidence of rapid evolution of tolerance by lag in bacterial populations that are periodically exposed to antibiotic stress in laboratory conditions. In particular, the distribution of single-cell lag times-i.e., the times that individual bacteria from the community remain in a dormant state to cope with stress-evolves its average value to approximately fit the antibiotic-exposure time. Moreover, the distribution develops right-skewed heavy tails, revealing the presence of individuals with anomalously large lag times. Here, we develop a parsimonious individual-based model mimicking the actual demographic processes of the experimental setup. Individuals are characterized by a single phenotypic trait: their intrinsic lag time, which is transmitted with variation to the progeny. The model-in a version in which the amplitude of phenotypic variations grows with the parent's lag time-is able to reproduce quite well the key empirical observations. Furthermore, we develop a general mathematical framework allowing us to describe with good accuracy the properties of the stochastic model by means of a macroscopic equation, which generalizes the Crow-Kimura equation in population genetics. Even if the model does not account for all the biological mechanisms (e.g., genetic changes) in a detailed way-i.e., it is a phenomenological one-it sheds light onto the eco-evolutionary dynamics of the problem and can be helpful to design strategies to hinder the emergence of tolerance in bacterial communities. From a broader perspective, this work represents a benchmark for the mathematical framework designed to tackle much more general eco-evolutionary problems, thus paving the road to further research avenues.
Author summary
Problems in which ecological and evolutionary changes occur at similar timescales and feedback into each other are ubiquitous and of outmost importance, especially in microbiology. A particularly relevant problem is that of the emergence of tolerance to antibiotics by lag, that has been recently shown to emerge very fast in bacterial (E. coli) populations under controlled laboratory conditions. Here, we present a computational individual-based model, allowing us to reproduce empirical observations and, also, introduce a very general analytical framework to rationalize such results. We believe that our combined computational and analytical approach may inform the development of well-informed strategies to mitigate the emergence of bacterial tolerance and resistance to antibiotics and, more generally, can help shedding light onto more general eco-evolutionary problems.
1. MAM and MS acknowledge funding from the Spanish Ministry and Agencia Estatal de investigacion (AEI) through (European Regional Development Fund)", Grant numer grant FIS201784256-P http://www.aei.gob.es/as well as from the Consejeria de Conocimiento, Investigacion Universidad, Junta de Andalucia and European Regional Development Fund. https://www.juntadeandalucia.es/organismos/transformacione conomicaindustriaconocimientoyuniv7e12 rsidades. Grant number Ref. A-FQM-175-UGR18. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Degenerated Liouvillians and steady-state reduced density matrices EMBARGO HASTA 07/07/2022Thingna, JuzarManzano Diosdado, Danielhttp://hdl.handle.net/10481/710092021-10-20T09:45:50ZDegenerated Liouvillians and steady-state reduced density matrices EMBARGO HASTA 07/07/2022
Thingna, Juzar; Manzano Diosdado, Daniel
Symmetries in an open quantum system lead to degenerated Liouvillians that physically imply the existence of multiple steady states. In
such cases, obtaining the initial condition independent steady states is highly nontrivial since any linear combination of the true asymptotic
states, which may not necessarily be a density matrix, is also a valid asymptote for the Liouvillian. Thus, in this work, we consider different
approaches to obtain the true steady states of a degenerated Liouvillian. In the ideal scenario, when the open system symmetry operators
are known, we show how these can be used to obtain the invariant subspaces of the Liouvillian and hence the steady states. We then discuss
two other approaches that do not require any knowledge of the symmetry operators. These could be powerful numerical tools to deal with
quantum many-body complex open systems. The first approach that is based on Gram–Schmidt orthonormalization of density matrices
allows us to obtain all the steady states, whereas the second one based on large deviations allows us to obtain the non-degenerated maximum
and minimum current carrying states. We discuss the symmetry-decomposition and the orthonormalization methods with the help of an
open para-benzene ring and examine interesting scenarios such as the dynamical restoration of Hamiltonian symmetries in the long-time
limit and apply the method to study the eigenspacing statistics of the nonequilibrium steady state.
J.T. acknowledges support by the Institute for Basic Science in Republic of Korea (No. IBS-R024-Y2). D.M. acknowledges the Spanish Ministry and the Agencia Espanola de Investigacion (AEI) for financial support under Grant No. FIS2017-84256-P (FEDER funds). We would like to thank Sai Vinjanampathy for discussions and constructive comments on our manuscript.
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