Publications (2025)
On the role of true and false chirality in producing parity-violating energy differences
Authors: Martinez-Gil, Daniel; Bargueno, Pedro; Miret-Artes, Salvador
Journal: PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
Publication date: 2025/02/05
Abstract: In this work, we tackle the problem of showing which type of influences can lift the degeneracy between truly and falsely chiral systems, showing that only when both systems and influences are both truly (falsely) chiral, a parity violating energy difference between left-handed (L) and right-handed (R) systems can be produced. In particular, after considering the enantiomers of a chiral molecule as paradigmatic truly chiral systems, we rigorously show, under a quantum field theoretical approach, that only a truly chiral influence such as the Z0-mediated electroweak interaction can lift the degeneracy between enantiomers. Indeed, we explicitly show that a falsely chiral influence, such as an axion-mediated interaction in chiral molecules, cannot lift the aforementioned degeneracy. These results extend Barron’s seminal ideas (L. D. Barron, True and false chirality and parity violation, Chem. Phys. Lett. 123, 423 (1986). (doi:10.1016/0009-2614(86)80035-5)) to a quantum-field-theory- (QFT)-based approach.
Scan Quantum Mechanics: Quantum Inertia Stops Superposition
Authors: Gato-Rivera, Beatriz
Journal: UNIVERSE
Publication date: 2025/02/01
Abstract: Scan Quantum Mechanics (SQM) is a novel interpretation in which the superposition of states is only an approximate effective concept due to lack of time resolution. Quantum systems scan all possible states in the apparent superpositions and switch randomly and very rapidly among them. A crucial property that we postulate is quantum inertia Iq, that increases whenever a constituent is added, or the system is perturbed with all kinds of interactions. Once the quantum inertia reaches a critical value Icr for an observable, the switching among its eigenvalues stops and the corresponding superposition comes to an end. Consequently, increasing the quantum inertia of a quantum system by increasing its mass, its temperature, or the strength of the electric, magnetic and gravitational fields in its environment, can lead to the end of the superpositions for all the observables, the quantum system transmuting into a classical one, as a result. This process could be reversible, however, by decreasing the size of the system, its temperature, etc. SQM also implies a radiation mechanism from astrophysical objects with very strong gravitational fields that could contribute to neutron star formation. Future experiments might determine the critical quantum inertia Icr corresponding to different observables, which translates into critical masses, critical temperatures and critical electric, magnetic and gravitational fields.
The Galaxy Activity, Torus, and Outflow Survey (GATOS). VII. The 20-214 ?m Imaging Atlas of Active Galactic Nuclei Using SOFIA
Authors: Fuller, Lindsay; Lopez-Rodriguez, Enrique; Garcia-Bernete, Ismael; Ramos Almeida, Cristina; Alonso-Herrero, Almudena; Packham, Chris; Zhang, Lulu; Leist, Mason; Levenson, Nancy A.; Imanishi, Masatoshi; Hoenig, Sebastian; Stalevski, Marko; Ricci, Claudio; Hicks, Erin; Bellocchi, Enrica; Combes, Francoise; Davies, Ric; Garcia Burillo, Santiago; Gonzalez Martin, Omaira; Izumi, Takuma; Labiano, Alvaro; Pereira Santaella, Miguel; Rigopoulou, Dimitra; Rosario, David; Rouan, Daniel; Shimizu, Taro; Ward, Martin
Journal: ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
Publication date: 2025/02/01
Abstract: We present a 19.7-214 mu m imaging atlas of local (4-181 Mpc; median 43 Mpc) active galactic nuclei (AGN) observed with FORCAST and HAWC+ on board the SOFIA telescope with angular resolutions similar to 3 ”-20 ”. This atlas comprises 22 Seyferts (17 Type 2 and five Type 1) with a total of 69 images, 41 of which have not been previously published. The AGN span a range of luminosities of log10(L-bol[erg s(-1)])=[42,46] with a median of log10(L-bol[erg s(-1)])=44.1 +/- 1.0. We provide the total fluxes of our sample using aperture photometry for point-source objects and a 2D Gaussian fitting for objects with extended host galaxy emission, which was used to estimate the unresolved nuclear component. Most galaxies in our sample are pointlike sources; however, four sources (Centaurus A, Circinus, NGC 1068, and NGC 4388) show extended emission in all wavelengths. The 30-40 mu m extended emission in NGC 4388 is coincident with the narrow-line region at PA similar to 50 degrees, while the dusty extension at longer wavelengths arises from the host galaxy at PA similar to 90 degrees. Our new observations allow us to construct the best-sampled parsec-scales (spectral energy distributions, SEDs) available between 30 and 500 mu m for a sample of nearby AGN. We estimate that the average peak wavelength of the nuclear SEDs is similar to 40 mu m in nu F-nu, which we associate with an unresolved extended dusty region heated by the AGN.
Linear response theory for cavity QED materials at arbitrary light-matter coupling strengths
Authors: Roman-Roche, Juan; Gomez-Leon, Alvaro; Luis, Fernando; Zueco, David
Journal: PHYSICAL REVIEW B
Publication date: 2025/01/31
DOI: 10.1103/PhysRevB.111.035156
Abstract: We develop a linear response theory for materials collectively coupled to a cavity that is valid in all regimes of light-matter coupling, including symmetry-broken phases. We present and compare two different approaches. First, we use a coherent path-integral formulation for the partition function to obtain thermal Green’s functions. This approach relies on a saddle-point expansion for the action that can be truncated in the thermodynamic limit. Second, we formulate the equations of motion for the retarded Green’s functions and solve them. We use a mean-field decoupling of high-order Green’s functions to obtain a closed, solvable system of equations. Both approaches yield identical results in the calculation of response functions for the cavity and material. These are obtained in terms of the bare cavity and material responses. In combination, the two techniques clarify the validity of a mean-field decoupling in correlated light-matter systems and provide complementary means to compute finite-size corrections to the thermodynamic limit. The theory is formulated for a general model that encompasses most of the systems typically considered in the field of cavity QED materials. Finally, we provide a detailed application of the theory to the quantum Hall effect and to a collection of spin models.
The Galaxy Activity, Torus, and Outflow Survey (GATOS) VI. Black hole mass estimation using machine learning
Authors: Poitevineau, R.; Combes, F.; Garcia-Burillo, S.; Cornu, D.; Herrero, A. Alonso; Almeida, C. Ramos; Audibert, A.; Bellocchi, E.; Boorman, P. G.; Bunker, A. J.; Davies, R.; Diaz-Santos, T.; Garcia-Bernete, I.; Garcia-Lorenzo, B.; Gonzalez-Martin, O.; Hicks, E. K. S.; Hoenig, S. F.; Hunt, L. K.; Imanishi, M.; Pereira-Santaella, M.; Ricci, C.; Rigopoulou, D.; Rosario, D. J.; Rouan, D.; Martin, M. Villar; Ward, M.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2025/01/29
DOI: 10.1051/0004-6361/202347566
Abstract: The detailed feeding and feedback mechanisms of active galactic nuclei (AGNs) are not yet well known. For low-luminosity AGNs, obscured AGNs, and late-type galaxies, the masses of their central black holes (BH) are difficult to determine precisely. Our goal with the GATOS sample is to study the circum-nuclear regions and, in the present work, to better determine their BH mass, with more precise and accurate estimations than those obtained from scaling relations. We used the high spatial resolution of ALMA to resolve the CO(3-2) emission within similar to 100 pc around the supermassive black hole (SMBH) of seven GATOS galaxies and try to estimate their BH mass when enough gas is present in the nuclear regions. We studied the seven bright (L-AGN(14 – 150 keV)>= 10(42) erg/s) and nearby (< 28 Mpc) galaxies from the GATOS core sample. For the sake of comparison, we first searched the literature for previous BH mass estimations. We also made additional estimations using the M-BH-sigma relation and the fundamental plane of BH activity. We developed a new method using supervised machine learning to estimate the BH mass either from position-velocity diagrams or from first-moment maps computed from ALMA CO(3-2) observations. We used numerical simulations with a large range of parameters to create the training, validation, and test sets. Seven galaxies had sufficient gas detected, thus, we were able to make a BH estimation from the ALMA data: NGC 4388, NGC 5506, NGC 5643, NGC 6300, NGC 7314, NGC 7465, and NGC 7582. Our BH masses range from 6.39 to 7.18 log(M-BH/M-circle dot) and are consistent with the previous estimations. In addition, our machine learning method has the advantage of providing a robust estimation of errors with confidence intervals. The method has also more growth potential than scaling relations. This work represents the first step toward an automatized method for estimating M-BH using machine learning.
Detection of thioacetaldehyde (CH3CHS) in TMC-1: Sulfur-oxygen differentiation along the hydrogenation sequence?
Authors: Agundez, M.; Molpeceres, G.; Cabezas, C.; Marcelino, N.; Tercero, B.; Fuentetaja, R.; de Vicente, P.; Cernicharo, J.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2025/01/28
DOI: 10.1051/0004-6361/202453459
Abstract: In recent years, the chemistry of sulfur in the interstellar medium has experienced renewed interest due to the detection of a large variety of molecules containing sulfur. We report the first identification in space of a new S-bearing molecule, thioacetaldehyde (CH3CHS), which is the sulfur counterpart of acetaldehyde (CH3CHO). The astronomical observations are part of QUIJOTE, a Yebes 40 m Q-band line survey of the cold dense cloud TMC-1. We detected seven individual lines corresponding to A and E components of the four most favorable rotational transitions of CH3CHS covered in the Q band (31.0-50.3 GHz). Assuming a rotational temperature of 9 K, we derive a column density of 9.8 x 10(10) cm(-2) for CH3CHS, which implies that it is 36 times less abundant than its oxygen counterpart CH3CHO. By comparing the column densities of the O- and S-bearing molecules detected in TMC-1, we find that as molecules increase their degree of hydrogenation, sulfur-bearing molecules become less abundant than their oxygen analog. That is, hydrogenation seems to be less favored for S-bearing molecules than for O-bearing ones in cold sources such as TMC-1. We explored potential formation pathways to CH3CHS and implemented them into a chemical model, which underestimates the observed abundance of thioacetaldehyde by several orders of magnitude, however. Quantum chemical calculations carried out for one of the potential formation pathways, the S + C2H5 reaction, indicate that formation of CH3CHS is only a minor channel in this reaction.
Photon antibunching in single-molecule vibrational sum-frequency generation
Authors: Kalarde, Fatemeh Moradi; Ciccarello, Francesco; Munoz, Carlos Sanchez; Feist, Johannes; Galland, Christophe
Journal: NANOPHOTONICS
Publication date: 2025/01/21
Abstract: Sum-frequency generation (SFG) enables the coherent upconversion of electromagnetic signals and plays a significant role in mid-infrared vibrational spectroscopy for molecular analysis. Recent research indicates that plasmonic nanocavities, which confine light to extremely small volumes, can facilitate the detection of vibrational SFG signals from individual molecules by leveraging surface-enhanced Raman scattering combined with mid-infrared laser excitation. In this article, we compute the degree of second order coherence (g (2)(0)) of the upconverted mid-infrared field under realistic parameters and accounting for the anharmonic potential that characterizes vibrational modes of individual molecules. On the one hand, we delineate the regime in which the device should operate in order to preserve the second-order coherence of the mid-infrared source, as required in quantum applications. On the other hand, we show that an anharmonic molecular potential can lead to antibunching of the upconverted photons under coherent, Poisson-distributed mid-infrared and visible drives. Our results therefore open a path toward bright and tunable source of indistinguishable single photons by leveraging vibrational blockade in a resonantly and parametrically driven molecule, without the need for strong light-matter coupling.
JWST Discovery of a Very Fast Biconical Outflow of Warm Molecular Gas in the Nearby Ultraluminous Infrared Galaxy F08572+3915 NW
Authors: Dan, Kylie Yui; Seebeck, Jerome; Veilleux, Sylvain; Rupke, David; Gonzalez-Alfonso, Eduardo; Garcia-Bernete, Ismael; Liu, Weizhe; Lutz, Dieter; Melendez, Marcio; Santaella, Miguel Pereira; Sturm, Eckhard; Tombesi, Francesco
Journal: ASTROPHYSICAL JOURNAL
Publication date: 2025/01/20
Abstract: We present new James Webb Space Telescope (JWST) Mid-Infrared Instrument Medium-Resolution Spectrometer observations of the nearby ultraluminous infrared galaxy (ULIRG) F08572+3915 NW. These integral field spectroscopic (IFS) data reveal a kpc-scale warm-molecular rotating disk and biconical outflow traced by the H2 nu = 0-0 S(1), S(2), S(3), and S(5) rotational transitions. The outflow maintains a relatively constant median (maximum) projected velocity of 1100 km s-1 (3000 km s-1) out to similar to 1.4 kpc from the nucleus. The outflowing H2 material is slightly warmer (640-700 K) than the rotating disk material (460-520 K), perhaps due to shock heating in the highly turbulent outflowing material. This outflow shares the same kinematics and orientation as the sub-kiloparsec scale warm H2 outflow traced by the rovibrational H2 lines in Keck AO near-infrared IFS data. However, this warm H2 outflow is significantly faster than the sub-kiloparsec-scale cold molecular outflow derived from multi-transition far-infrared OH observations with Herschel and the greater than or equivalent to kiloparsec-scale cold molecular outflow mapped by millimeter-wave interferometric CO 1-0 observations with IRAM-PdBI and NOEMA. The new JWST data bolster the scenario where the buried quasar in this ULIRG is excavating the dust screen, accelerating perhaps as much as 60% of the dusty warm molecular material to velocities beyond the escape velocity, and thus influencing the evolution of the host galaxy.
Molecular gas stratification and disturbed kinematics in the Seyfert galaxy MCG-05-23-16 revealed by JWST and ALMA
Authors: Esparza-Arredondo, D.; Almeida, C. Ramos; Audibert, A.; Pereira-Santaella, M.; Garcia-Bernete, I.; Garcia-Burillo, S.; Shimizu, T.; Davies, R.; Munoz, L. Hermosa; Alonso-Herrero, A.; Combes, F.; Speranza, G.; Zhang, L.; Campbell, S.; Bellocchi, E.; Bunker, A. J.; Diaz-Santos, T.; Garcia-Lorenzo, B.; Gonzalez-Martin, O.; Hicks, E. K. S.; Labiano, A.; Levenson, N. A.; Ricci, C.; Rosario, D.; Hoenig, S.; Packham, C.; Stalevski, M.; Fuller, L.; Izumi, T.; Lopez-Rodriguez, E.; Rigopoulou, D.; Rouan, D.; Ward, M.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2025/01/15
DOI: 10.1051/0004-6361/202452488
Abstract: Understanding the processes that drive the morphology and kinematics of molecular gas in galaxies is crucial for comprehending star formation and, ultimately, galaxy evolution. Using data from the Galactic Activity, Torus and Outflow Survey (GATOS) obtained with the James Webb Space Telescope (JWST) and the archival data from the Atacama Large Millimeter/submillimeter Array (ALMA), we study the behavior of the warm molecular gas at temperatures of hundreds of Kelvin and the cold molecular gas at tens of Kelvin in the galaxy MCG-05-23-16, which hosts an active galactic nucleus (AGN). Hubble Space Telescope (HST) images of this spheroidal galaxy, classified in the optical as S0, show a dust lane resembling a nuclear spiral and a surrounding ring. These features are also detected in CO(2-1) and H-2, and their morphologies and kinematics are consistent with rotation plus local inward gas motions along the kinematic minor axis in the presence of a nuclear bar. The H2 transitions 0-0 S(3), 0-0 S(4), and 0-0 S(5), which trace warmer and more excited gas, show more disrupted kinematics than 0-0 S(1) and 0-0 S(2), including clumps of high velocity dispersion (of up to similar to 160 km s(-1)), in regions devoid of CO(2-1). The kinematics of one of these clumps, located similar to 350 pc westward of the nucleus, are consistent with outflowing gas, possibly driven by localized star formation traced by polycyclic aromatic hydrocarbon emission at 11.3 mu m. Overall, we observe a stratification of the molecular gas, with the colder gas located in the nuclear spiral, ring, and connecting arms, and most of the warmer gas with a higher velocity dispersion filling the inter-arm space. The compact jet, approximately 200 pc in size, detected with Very Large Array (VLA) observations, does not appear to significantly affect the distribution and kinematics of the molecular gas, possibly due to its limited intersection with the molecular gas disk.
Inelastic H + H3+ collision rates and their impact on the determination of the excitation temperature of H3+
Authors: Felix-Gonzalez, Daniel; del Mazo-Sevillano, Pablo; Aguado, Alfredo; Roncero, Octavio; Le Bourlot, Jacques; Roueff, Evelyne; Le Petit, Franck; Bron, Emeric
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2025/01/15
DOI: 10.1051/0004-6361/202452977
Abstract: Context. In diffuse interstellar clouds, the excitation temperature derived from the lowest levels of H3+ is systematically lower than that derived from H2. The differences may be attributed to the lack of state-specific formation and destruction rates of H3+, which are needed to thermalize the two species.Aims. In this work, we aim to investigate the possible influence of rotational excitation collisions of H3+ with atomic hydrogen on its excitation temperature.Methods. We used a time-independent close-coupling method to calculate the state-to-state rate coefficients, incorporating a very accurate and full-dimensional potential energy surface recently developed for H4+. We take a symmetric top approach to describe a frozen H3+ as an equilateral triangle.Results. We derive rotational excitation collision rate coefficients of H3+ with atomic hydrogen in a temperature range corresponding to diffuse interstellar conditions up to (J, K, +/-) = (7, 6, +) and (J, K, +/-) = (6, 4, +) for its ortho and para forms. This allows us to obtain a consistent set of collisional excitation rate coefficients and to improve on a previous study that included speculations regarding these contributions.Conclusions. The new state-specific inelastic H3+ + H rate coefficients yield differences of up to 20% in the excitation temperature, and their impact increases with decreasing molecular fraction. We also confirm the impact of chemical state-to-state destruction reactions on the excitation balance of H3+, and that reactive H + H3+ collisions are also needed to account for possible further ortho to para transitions.
Identification of the interstellar 1-cyano propargyl radical (HCCCHCN) in TMC-1
Authors: Cabezas, C.; Agundez, M.; Marcelino, N.; Chang, C. H.; Fuentetaja, R.; Tercero, B.; Nakajima, M.; Endo, Y.; de Vicente, P.; Cernicharo, J.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2025/01/13
DOI: 10.1051/0004-6361/202453419
Abstract: We report the first detection in interstellar medium of the 1-cyano propargyl radical, HC3HCN. This species is an isomer of the 3-cyano propargyl radical (CH2C3N), which was recently discovered in TMC-1. The 1-cyano propargyl radical was observed in the cold dark cloud TMC-1 using data from the ongoing QUIJOTE line survey, which is being carried out with the Yebes 40m telescope. A total of seven rotational transitions with multiple hyperfine components were detected in the 31.0-50.4 GHz range. We derived a column density of (2.2 +/- 0.2) x 10(11) cm(-2) and a rotational temperature of 7 +/- 1 K. The abundance ratio between HC3HCN and CH2C3N is 1.4. The almost equal abundance of these isomers indicates that the two species may be produced in the same reaction with a similar efficiency, probably in the reaction C + CH2CHCN and perhaps also in the reaction C-2 + CH3CN and the dissociative recombination with electrons of CH2C3NH+.
Encoding quantum bits in bound electronic states of a graphene nanotorus
Authors: Furtado, J.; Ramos, A. C. A.; Silva, J. E. G.; Bachelard, R.; Santos, Alan C.
Journal: ANNALS OF PHYSICS
Publication date: 2025/01/01
DOI: 10.1016/j.aop.2024.169862
Abstract: We propose to use the quantum states of an electron trapped on the inner surface of a graphene nanotorus to realize as a new kind of physical quantum bit, which can be used to encode quantum information. Fundamental tasks for quantum information processing, such as the qubit initialization and the implementation of arbitrary single qubit gates, can then be performed using external magnetic and electric fields. We also analyze the robustness of the device again systematic errors, which can be suppressed by a suitable choice of the external control fields. These findings open new prospects for the development an alternative platform for quantum computing, the scalability of which remains to be determined.
Quantum steering ellipsoids and quantum obesity in critical systems
Authors: Rosario, Pedro; Santos, Alan c.
Journal: EPL
Publication date: 2025/01/01
Abstract: – Quantum obesity (QO) is a novel function introduced to quantify quantum correlations that go beyond traditional measures like entanglement, while also functioning as an entanglement witness. One of the key strengths of QO lies in its analyticity for arbitrary states of bipartite systems, making it a more accessible and versatile tool compared to other measures of quantum correlations, such as quantum discord. In this work, we highlight the importance of QO as a fundamental quantity for identifying signatures of quantum phase transitions, which are critical changes in the ground state of quantum systems driven by quantum fluctuations. We introduce a mechanism based on local filtering operations designed to enhance the critical behavior of QO near phase transition points, providing a deeper understanding of these phenomena. Furthermore, we present a theorem that characterizes how QO transforms under local quantum operations and classical communications (LOCC), which broadens its applicability to a wider range of quantum systems. This opens new avenues for exploring quantum criticality and other novel quantum phenomena by leveraging the analytically computable, pairwise QO, thus offering both theoretical insights and practical applications in quantum information science.
Adsorption of molecular hydrogen on extended graphene prototypes decorated with sodium: a quantum-mechanical study
Authors: Garcia-Arroyo, Esther; Bartolomei, Massimiliano; Hernandez, Marta, I; Gonzalez-Lezana, Tomas; Mella, Massimo; Campos-Martinez, Jose
Journal: PHYSICA SCRIPTA
Publication date: 2025/01/01
Abstract: This paper presents a study of sodium-decorated circumcircumcoronene, a large polycyclic aromatic hydrocarbon (PAH) regarded as a graphene prototype, and the complexes formed upon aggregation of hydrogen molecules on this substrate. Accurate force fields based on high level electronic structure calculations have been built using a rigid rotor model for the hydrogen molecules as well as a corresponding pseudo-atom approximation, aimed to pursue larger compounds where a simpler treatment could be helpful. Structural and energy features of the hydrogen adsorption have been then analyzed by means of quantum Monte Carlo methods. A large stabilization of the adsorption energy is found for up to four H2 molecules attached to the alkali atom, in agreement with conclusions reached from previous studies on smaller Na-decorated PAHs. Adsorption patterns are examined in detail as the number of attached molecules is increased, comparing with results on smaller substrates and analyzing the effects of rotational orientation by contrasting the rigid rotor versus pseudo-atom approaches.
Laser-assisted motional-mode spectroscopy in a Penning trap and the generalized invariance theorem
Authors: Berrocal, J.; Hernandez, A.; Porras, D.; Rodriguez, D.
Journal: PHYSICAL REVIEW A
Publication date: 2025/01/01
DOI: 10.1103/PhysRevA.110.063107
Abstract: In this paper we measure all the motional-mode frequencies (common and stretch) of a balanced and an unbalanced two-ion Coulomb crystal in a 7-tesla Penning trap using an electric-dipole transition in 40Ca+. The three common modes of the balanced crystal were obtained using a laser-pulse measurement technique developed in a previous work for a single ion, whereas the stretch mode frequencies were measured in a stationary state while applying laser cooling. Due to the Coulomb interaction, and the heating of the crystal, nonlinearities appear in the oscillators, which are treated analytically and numerically to obtain the experimental frequency values. The generalized invariance theorem has been tested yielding a relative shift of -1.0 x 10-6 with a relative uncertainty of 4 x 10-6. Single-ion frequency measurements are used to assess its validity.