Publications (2023)
Total peer-reviewed articles: 111
Variational Quantum Simulators Based on Waveguide QED
Authors: Tabares, C.; de las Heras, A. Munoz; Tagliacozzo, L.; Porras, D.; Gonzalez-Tudela, A.
Journal: PHYSICAL REVIEW LETTERS
Publication date: 2023/08/14
DOI: 10.1103/PhysRevLett.131.073602
Abstract: Waveguide QED simulators are analog quantum simulators made by quantum emitters interacting with one-dimensional photonic band gap materials. One of their remarkable features is that they can be used to engineer tunable-range emitter interactions. Here, we demonstrate how these interactions can be a resource to develop more efficient variational quantum algorithms for certain problems. In particular, we illustrate their power in creating wave function Ansatze that capture accurately the ground state of quantum critical spin models (XXZ and Ising) with fewer gates and optimization parameters than other variational Ansatze based on nearest-neighbor or infinite-range entangling gates. Finally, we study the potential advantages of these waveguide Ansatze in the presence of noise. Overall, these results evidence the potential of using the interaction range as a variational parameter and place waveguide QED simulators as a promising platform for variational quantum algorithms.
Photodissociation dynamics of methylamine in the blue edge of the A-band. II. The NH2 + CH3 channel
Authors: Cachon, Javier; Recio, Pedro; Zanchet, Alexandre; Marggi Poullain, Sonia; Banares, Luis
Journal: JOURNAL OF CHEMICAL PHYSICS
Publication date: 2023/08/14
DOI: 10.1063/5.0159855
Abstract: The photodissociation dynamics leading to the C-N bond cleavage in methylamine (CH3NH2) are investigated upon photoexcitation in the blue edge of the first absorption A-band, in the 198-204 nm range. Velocity map images of the generated methyl (CH3) fragment detected in specific vibrational modes, i.e., nu = 0,. nu(1) = 1, and nu(2) = 1, through resonance enhanced multiphoton ionization, are presented along with the corresponding translational energy distributions and the angular analysis. The experimental results are complemented by high-level ab initio calculations of potential energy curves as a function of the C-N bond distance. While a similar single Boltzmann-type contribution is observed in all the translational energy distributions measured, the speed-dependent anisotropy parameter obtained through the angular analysis reveals the presence of two different mechanisms. Prompt dissociation through the conical intersection between the (A) over tilde (1)A’ first excited state and the ground state located in the exit channel is, indeed, revealed as a minor channel. In contrast, slow dissociation on the ground state, presumably from frustrated N-H bond cleavage trajectories, constitutes the major reaction pathway leading to the methyl formation.
Ar+ ArH+ Reactive Collisions of Astrophysical Interest: The Case of 36Ar
Authors: de Oca-Estevez, Maria Judit Montes; Darna, Beatriz; Garcia-Ruiz, Borja; Prosmiti, Rita; Gonzalez-Lezana, Tomas; Koner, Debasish
Journal: CHEMPHYSCHEM
Publication date: 2023/08/11
Abstract: The reactive collision between Ar-36 and the (ArH+)-Ar-36 species has been investigated by means of quantum mechanical (QM), quasiclassical trajectories (QCT) and statistical quantum mechanical (SQM) approaches. Reaction probabilities, cross sections as a function of the energy and rate constants in terms of the temperature have been obtained. Cumulative distributions as a function of the collision time and the inspection of selected QCT corresponding to specific dynamical mechanisms have been analysed. Predictions by means of the SQM method are in good agreement with the QM results, thus supporting the complex-forming nature of the process.
An ab initio study of the photodissociation of CH2I and CH2I+
Authors: Bouallagui, A.; Zanchet, A.; Banares, L.; Garcia-Vela, A.
Journal: PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Publication date: 2023/08/02
DOI: 10.1039/d3cp01460f
Abstract: Photodissociation of the CH2I radical and the CH2I+ cation is studied by means of high-level ab initio calculations, including spin-orbit effects. Potential-energy curves (PEC) along the dissociating bond distances involved in some fragmentation pathways of these species are computed for the ground and several excited electronic states. Based on the PECs obtained, the possible photodissociation mechanisms are analyzed and suggested. Significant differences are found between the fragmentation dynamics of the neutral radical and that of the cation. While a relatively simple dissociation dynamics is predicted for CH2I, more complex fragmentation mechanisms involving internal conversion and couplings between different excited electronic states are expected for CH2I+. The species studied here are relevant to atmospheric chemistry, and the present work can help to understand better how their photodissociation may affect chemical processes in the atmosphere.
Evaluated electron scattering cross section dataset for gaseous benzene in the energy range 0.1-1000 eV
Authors: Garcia-Abenza, A.; Lozano, A. I.; Alvarez, L.; Oller, J. C.; Rosado, J.; Blanco, F.; Limao-Vieira, P.; Garcia, G.
Journal: PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Publication date: 2023/08/02
DOI: 10.1039/d3cp01908j
Abstract: In this study, a complete and self-consistent cross section dataset for electron transport simulations through gaseous benzene in the energy range 0.1-1000 eV has been critically compiled. Its reliability has been evaluated through a joint experimental and computational procedure. To accomplish this, the compiled dataset has been used as input for event-by-event Monte Carlo simulations of the magnetically confined electron transport through gaseous benzene, and the simulated transmitted intensity has been compared with the experimental one for different incident energies and benzene gas pressures.
Cooling microwave fields into general multimode Gaussian states
Authors: Yazdi, Nahid; Garcia-Ripoll, Juan Jose; Porras, Diego; Navarrete-Benlloch, Carlos
Journal: NEW JOURNAL OF PHYSICS
Publication date: 2023/08/01
Abstract: We show that a collection of lossy multichromatic modulated qubits can be used to dissipatively engineer arbitrary Gaussian states of a set of bosonic modes. Our ideas are especially suited to superconducting-circuit architectures, where all the required ingredients are experimentally available. The generation of such multimode Gaussian states is necessary for many applications, most notably measurement-based quantum computation. We build upon some of our previous proposals, where we showed how to generate single-mode and two-mode squeezed states through cooling and lasing. Special care must be taken when extending these proposals to many bosonic modes, and we discuss here how to overcome all the limitations and hurdles that naturally appear. For the sake of illustration, we work out two examples of Gaussian-state families consisting of Greenberger-Horne-Zeilinger and cluster states, which allow us to show that it is possible to use a set of N lossy qubits to cool down a bosonic chain of N modes to any desired Gaussian state.
The role of dimers in complex forming reactions at low temperature: full dimension potential and dynamics of (H2CO)2+OH reaction
Authors: del Mazo-Sevillano, Pablo; Aguado, Alfredo; Zanchet, Alexandre; Roncero, Octavio
Journal: CHEMPHYSCHEM
Publication date: 2023/08/01
Abstract: The (H 2 ${{}_{2}}$ CO) 2 ${{}_{2}}$ +OH and H 2 ${{}_{2}}$ CO-OH+H 2 ${{}_{2}}$ CO reaction dynamics are studied theoretically for temperatures below 300 K. For this purpose, a full dimension potential energy surface is built, which reproduces well accurate ab initio calculations. The potential presents a submerged reaction barrier, as an example of the catalytic effect induced by the presence of the third molecule. However, quasi-classical and ring polymer molecular dynamics calculations show that the dominant channel is the dimer-exchange mechanism below 200 K, and that the reactive rate constant tends to stabilize at low temperatures, because the effective dipole of either dimer is reduced with respect to that of formaldehyde alone. The reaction complex formed at low temperatures does not live long enough to produce complete energy relaxation, as assumed in statistical theories. These results show that the reactivity of the dimers cannot explain the large rate constants measured at temperatures below 100 K.
Electron Scattering from 1-Methyl-5-Nitroimidazole: Cross-Sections for Modeling Electron Transport through Potential Radiosensitizers
Authors: Lozano, Ana I.; Alvarez, Lidia; Garcia-Abenza, Adrian; Guerra, Carlos; Kossoski, Fabris; Rosado, Jaime; Blanco, Francisco; Oller, Juan Carlos; Hasan, Mahmudul; Centurion, Martin; Weber, Thorsten; Slaughter, Daniel S.; Mootheril, Deepthy M.; Dorn, Alexander; Kumar, Sarvesh; Limao-Vieira, Paulo; Colmenares, Rafael; Garcia, Gustavo
Journal: INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Publication date: 2023/08/01
Abstract: In this study, we present a complete set of electron scattering cross-sections from 1-Methyl-5-Nitroimidazole (1M5NI) molecules for impact energies ranging from 0.1 to 1000 eV. This information is relevant to evaluate the potential role of 1M5NI as a molecular radiosensitizers. The total electron scattering cross-sections (TCS) that we previously measured with a magnetically confined electron transmission apparatus were considered as the reference values for the present analysis. Elastic scattering cross-sections were calculated by means of two different schemes: The Schwinger multichannel (SMC) method for the lower energies (below 15 eV) and the independent atom model-based screening-corrected additivity rule with interferences (IAM-SCARI) for higher energies (above 15 eV). The latter was also applied to calculate the total ionization cross-sections, which were complemented with experimental values of the induced cationic fragmentation by electron impact. Double differential ionization cross-sections were measured with a reaction microscope multi-particle coincidence spectrometer. Using a momentum imaging spectrometer, direct measurements of the anion fragment yields and kinetic energies by the dissociative electron attachment are also presented. Cross-sections for the other inelastic channels were derived with a self-consistent procedure by sampling their values at a given energy to ensure that the sum of the cross-sections of all the scattering processes available at that energy coincides with the corresponding TCS. This cross-section data set is ready to be used for modelling electron-induced radiation damage at the molecular level to biologically relevant media containing 1M5NI as a potential radiosensitizer. Nonetheless, a proper evaluation of its radiosensitizing effects would require further radiobiological experiments.
Laboratory and astronomical discovery of the cyanovinyl radical H2CCCN
Authors: Cabezas, C.; Tang, J.; Agundez, M.; Seiki, K.; Sumiyoshi, Y.; Ohshima, Y.; Tercero, B.; Marcelino, N.; Fuentetaja, R.; de Vicente, P.; Endo, Y.; Cernicharo, J.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2023/07/31
DOI: 10.1051/0004-6361/202347385
Abstract: We report the first laboratory and interstellar detection of the ff-cyano vinyl radical (H2CCCN). This species was produced in the laboratory by an electric discharge of a gas mixture of vinyl cyanide, CH2CHCN, and Ne. Its rotational spectrum was characterized using a Balle-Flygare narrowband-type Fourier-transform microwave spectrometer operating in the frequency region of 8-40 GHz. The observed spectrum shows a complex structure due to tunneling splittings between two torsional sublevels of the ground vibronic state, 0(+) and 0(-), derived from a large-amplitude inversion motion. In addition, the presence of two equivalent hydrogen nuclei makes it necessary to discern between ortho- and para-H2CCCN. A least-squares analysis reproduces the observed transition frequencies with a standard deviation of ca. 3 kHz. Using the laboratory predictions, this radical was detected in the cold dark cloud TMC-1 using the Yebes 40m telescope and the QUIJOTE(1) line survey. The 4(0,4)-3(0,3) and 5(0,5)-4(0,4) rotational transitions, composed of several hyperfine components, were observed in the 31.0-50.4 GHz range. Adopting a rotational temperature of 6 K, we derived a column density of (1.4 +/- 0.2) x10(11) cm(-2) and (1.1 +/- 0.2)x10(11) cm(-2) for ortho-H2CCCN and para-H2CCCN, respectively. The reaction of C + CH3CN emerges as the most likely route to H2CCCN in TMC-1, and possibly that of N + CH2CCH as well.
Discovery of H2CCCH+ in TMC-1?
Authors: Silva, W. G. D. P.; Cernicharo, J.; Schlemmer, S.; Marcelino, N.; Loison, J. -C.; Agundez, M.; Gupta, D.; Wakelam, V.; Thorwirth, S.; Cabezas, C.; Tercero, B.; Domenech, J. L.; Fuentetaja, R.; Kim, W. -J.; de Vicente, P.; Asvany, O.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2023/07/25
DOI: 10.1051/0004-6361/202347174
Abstract: Based on a novel laboratory method, 14 millimeter-wave lines of the molecular ion H2CCCH+ have been measured in high resolution, and the spectroscopic constants of this asymmetric rotor determined with high accuracy. Using the Yebes 40 m and IRAM 30 m radio telescopes, we detected four lines of H2CCCH+ toward the cold dense core TMC-1. With a dipole moment of about 0.55 D obtained from high-level ab initio calculations, we derive a column density of 5.4 & PLUSMN;1×10(11) cm(-2) and 1.6 & PLUSMN;0.5×10(11) cm(-2) for the ortho and para species, respectively, and an abundance ratio N(H2CCC)/N(H2CCCH+) = 2.8 & PLUSMN;0.7. The chemistry of H2CCCH+ is modeled using the most recent chemical network for the reactions involving the formation of H2CCCH+. We find a reasonable agreement between model predictions and observations, and new insights into the chemistry of C-3-bearing species in TMC-1 were obtained.
Rotational spectra and astronomical search of five ethynyl derivatives of propene
Authors: Cabezas, Carlos; Agundez, Marcelino; Liu, Yi-Ting; Endo, Yasuki; Cernicharo, Jose
Journal: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Publication date: 2023/07/04
Abstract: The interstellar discovery of the five cyano derivatives of propene brings interest in analogous molecules that could be detected in similar astronomical environments. In this context, ethynyl-propene derivatives are good candidates to be observed in the Taurus Molecular Cloud (TMC-1), where other cyano and ethynyl derivatives of hydrocarbons such as ethane, allene, propene, and cyclopentadiene, among others, have been detected. We have investigated the pure rotational spectra of the five ethynyl-propene derivatives to enable their interstellar detections. These molecular species have been produced by an electric discharge and their rotational spectra were characterized using a Balle-Flygare narrow band-type Fourier-transform microwave spectrometer operating in the frequency region of 4-40 GHz. The spectral analysis allowed us to derive accurate spectroscopic parameters to obtain reliable frequency predictions for astronomical searches. We do not detect any of these species in TMC-1 but we derive upper limits for the abundances for the five isomers.
AGN feedback in action in the molecular gas ring of the Seyfert galaxy NGC 7172
Authors: Herrero, A. Alonso; Garcia-Burillo, S.; Pereira-Santaella, M.; Shimizu, T.; Combes, F.; Hicks, E. K. S.; Davies, R.; Almeida, C. Ramos; Garcia-Bernete, I.; Honig, S. F.; Levenson, N. A.; Packham, C.; Bellocchi, E.; Hunt, L. K.; Imanishi, M.; Ricci, C.; Roche, P.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2023/07/04
DOI: 10.1051/0004-6361/202346074
Abstract: We present new ALMA observations of the CO(3-2) transition and associated 854 ?& mu;m continuum at 0.06 – 0.3 & DPRIME; resolution, together with new VLT/SINFONI observations of NGC 7172. This is a luminous (bolometric luminosity of & SIME;10(44) erg s(-1)) Seyfert galaxy that belongs to the Galaxy Activity, Torus, and Outflow Survey (GATOS). The ALMA CO(3-2) observations reveal the presence of a highly inclined cold molecular gas ring with an approximate radius of 3 – 4 & DPRIME;?& SIME;?540 – 720 pc, which is likely associated with an inner Lindblad resonance of a putative stellar bar. There are noncircular motions in the VLT/SINFONI [Si VI]& lambda;1.96 ?& mu;m and H-2 at 2.12 ?& mu;m, and ALMA CO(3-2) velocity fields. After subtracting the stellar velocity field, we detected [Si VI] blueshifted velocities of a few hundred km s(-1) to the south of the active galactic nucleus (AGN) position. They trace outflowing ionized gas outside the plane of the galaxy and out to projected distances of & SIME;200 pc. The CO(3-2) position-velocity diagram along the kinematic minor axis displays noncircular motions with observed velocities of up to & SIM;150 km s(-1). Assuming that these are taking place in the disk of the galaxy, the observed velocity signs imply that the molecular gas ring is not only rotating but also outflowing. We derived an integrated cold molecular gas mass outflow rate of & SIM;40 ?M-& ODOT; yr(-1) for the ring. Using the ALMA 854 ?& mu;m extended emission map, we resolved a 32 pc radius torus with a gas mass of 8 x 10(5)?M-& ODOT;. These torus properties are similar to other Seyfert galaxies in the GATOS sample. We measured a decreased cold molecular gas concentration in the nuclear-torus region relative to the circumnuclear region when compared to other less luminous Seyfert galaxies. We conclude that the effects of AGN feedback in NGC 7172, which are likely caused by the AGN wind and/or the moderate luminosity radio jet, are seen as a large-scale outflowing molecular gas ring and accompanying redistribution of molecular gas in the nuclear regions.
Inelastic N2+H2 collisions and quantum-classical rate coefficients: large datasets and machine learning predictions
Authors: Hong, Qizhen; Storchi, Loriano; Bartolomei, Massimiliano; Pirani, Fernando; Sun, Quanhua; Coletti, Cecilia
Journal: EUROPEAN PHYSICAL JOURNAL D
Publication date: 2023/07/01
DOI: 10.1140/epjd/s10053-023-00688-4
Abstract: Rate coefficients for vibrational energy transfer are calculated for collisions between molecular nitrogen and hydrogen in a wide range of temperature and of initial vibrational states (v = 40 for N-2 and w = 10 for H-2). These data are needed for the modelling of discharges in N-2/H-2 plasma or of atmospheric and interstellar medium chemistry in different temperature ranges. The calculations were performed by a mixed quantum-classical method, to recover quantum effects associated with the vibrational motion, on a refined potential energy surface. The obtained rates present striking discrepancies with those evaluated by first-order perturbation theories, like the SSH (Schwartz, Slavsky, Herzfeld) theory, which are often adopted in kinetic modelling. In addition, we present a detailed, though preliminary, analysis on the performance of different Machine Learning models based on the Gaussian Process or Neural Network techniques to produce complete datasets of inelastic scattering rate coefficients. Eventually, by using the selected models, we give the complete dataset (i.e., covering the whole vibrational ladder) of rate coefficients for the N-2(v) + H-2(0) ? N-2(v – ?v) + H-2(0), ?v = 1, 2, 3 processes.
Dependence of Induced Biological Damage on the Energy Distribution and Intensity of Clinical Intra-Operative Radiotherapy Electron Beams
Authors: Colmenares, Rafael; Carrion-Marchante, Rebeca; Martin, M. Elena; Munoz, Laura Salinas; Garcia-Bermejo, Maria Laura; Oller, Juan C.; Munoz, Antonio; Blanco, Francisco; Rosado, Jaime; Lozano, Ana I.; alvarez, Sofia; Garcia-Vicente, Feliciano; Garcia, Gustavo
Journal: INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Publication date: 2023/07/01
Abstract: The survival fraction of epithelial HaCaT cells was analysed to assess the biological damage caused by intraoperative radiotherapy electron beams with varying energy spectra and intensities. These conditions were achieved by irradiating the cells at different depths in water using nominal 6 MeV electron beams while consistently delivering a dose of 5 Gy to the cell layer. Furthermore, a Monte Carlo simulation of the entire irradiation procedure was performed to evaluate the molecular damage in terms of molecular dissociations induced by the radiation. A significant agreement was found between the molecular damage predicted by the simulation and the damage derived from the analysis of the survival fraction. In both cases, a linear relationship was evident, indicating a clear tendency for increased damage as the averaged incident electron energy and intensity decreased for a constant absorbed dose, lowering the dose rate. This trend suggests that the radiation may have a more pronounced impact on surrounding healthy tissues than initially anticipated. However, it is crucial to conduct additional experiments with different target geometries to confirm this tendency and quantify the extent of this effect.
A radio-jet-driven outflow in the Seyfert 2 galaxy NGC 2110?
Authors: de Arriba, L. Peralta; Alonso-Herrero, A.; Garcia-Burillo, S.; Garcia-Bernete, I.; Villar-Martin, M.; Garcia-Lorenzo, B.; Davies, R.; Rosario, D. J.; Hoenig, S. F.; Levenson, N. A.; Packham, C.; Almeida, C. Ramos; Pereira-Santaella, M.; Audibert, A.; Bellocchi, E.; Hicks, E. K. S.; Labiano, A.; Ricci, C.; Rigopoulou, D.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2023/06/30
DOI: 10.1051/0004-6361/202245408
Abstract: We present a spatially resolved study of the ionized gas in the central 2 kpc of the Seyfert 2 galaxy NGC 2110 and investigate the role of its moderate-luminosity radio jet (kinetic radio power of P-jet ?=?2.3 x 10(43)?erg ?s(-1)). We used new optical integral-field observations taken with the MEGARA spectrograph at the Gran Telescopio Canarias, which cover the 4300 – 5200 & ANGS; and 6100 – 7300 & ANGS; ranges with a spectral resolution of R ?& SIME;?5000 – 5900. We fitted the emission lines with a maximum of two Gaussian components, except at the position of the active galactic nucleus (AGN), where we used three. Aided by existing stellar kinematics, we used the observed velocity and velocity dispersion (& sigma;) of the emission lines to classify the different kinematic components. The disk component is characterized by lines with & sigma;?& SIME;?60 – 200 ?km ?s(-1). The outflow component has typical values of & sigma;?& SIME;?700 ?km ?s(-1) and is confined to the central 2.5 & DPRIME;?& SIME;?400 ?pc, which is coincident with the linear part of the radio jet detected in NGC 2110. At the AGN position, the [O III]& lambda;5007 line shows high velocity components that reach at least 1000 ?km ?s(-1). This and the high velocity dispersions indicate the presence of outflowing gas outside the galaxy plane. Spatially resolved diagnostic diagrams reveal mostly low ionization (nuclear) emitting region-like excitation in the outflow and some regions in the disk, which could be due to the presence of shocks. However, there is also Seyfert-like excitation beyond the bending of the radio jet, which probably traces the edge of the ionization cone that intercepts with the disk of the galaxy. NGC 2110 follows the observational trends between the outflow properties and the jet radio power found for a few nearby Seyfert galaxies. All these pieces of information suggest that part of the observed ionized outflow in NGC 2110 might be driven by the radio jet. However, the radio jet was bent at radial distances of & SIM;200 ?pc (in projection) from the AGN, and beyond there, most of the gas in the galaxy disk is rotating.