Publications (2025)
Microsolvation of cationic alkali dimers in helium: quantum delocalization and solid-like/liquid-like behaviors of He shells
Authors: Yanes-Rodriguez, Raquel; Villarreal, Pablo; Prosmiti, Rita
Journal: PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Publication date: 2025/04/16
DOI: 10.1039/d5cp00318k
Abstract: We performed path-integral molecular dynamics (PIMD) simulations in the NVT ensemble to investigate the quantum solvation of Li2+ in He nanoclusters at a low temperature of 2 K. The interaction potentials were modeled using a sum-of-potentials approach, incorporating automated learning ab initio-based models up to three-body terms. Additionally, the semiclassical quadratic Feynman-Hibbs approach was applied to incorporate quantum effects into classical computations effectively, enabling the study of HeNLi2+ complexes with up to 50 He atoms. The quantum simulations revealed strong evidence of local solid-like behavior in the He atoms within the first solvation shell surrounding the Li2+ dimer cation. In contrast, the second and third solvation shells displayed delocalized He densities, allowing for the interchange of He atoms between these layers, indicative of a liquid-like structure. Our findings align with earlier studies of He-doped clusters, particularly in systems where the charged impurity interacts strongly with the solvent medium, significantly impacting the helium environment at the microscopic level.
Non-adiabatic photodissociation dynamics of vinyl iodide from n?* and n?* transitions
Authors: Murillo-Sanchez, Marta L.; Poullain, Sonia Marggi; Limao-Vieira, Paulo; Zanchet, Alexandre; de Oliveira, Nelson; Gonzalez-Vazquez, Jesus; Banares, Luis
Journal: PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Publication date: 2025/04/16
DOI: 10.1039/d5cp00236b
Abstract: The photodissociation dynamics of vinyl iodide upon photoexcitation at 199.2 and 200 nm are investigated in a joint theoretical and experimental study. The gas-phase absorption spectrum measured by Fourier transform spectroscopy along with the use of synchrotron radiation is reported and a reassignment of the excited electronic states responsible for the absorption at the energy range of interest is proposed. Femtosecond time-resolved velocity map imaging in conjunction with resonance enhanced multiphoton ionization detection of the I(2P3/2) and I*(2P1/2) photofragments have been carried out. The experimental results are discussed in view of high-level ab initio calculations including potential energy curves and semiclassical dynamics. Three conical intersections (CIs) governing the dynamics are identified in a search for stationary points using spin-orbit gradients. Based on these results, a complete picture of the photodissociation dynamics of vinyl iodide is obtained. Photoexcitation at 200 nm, associated with a nI(perpendicular to)sigma* transition, leads to a fast dissociation occurring in a repulsive potential energy surface, which is mediated by a CI with a low-lying excited electronic state. This mechanism resembles the typical dissociation of alkyl iodides in the first absorption A-band. In contrast, one-photon excitation at 199.2 nm into a well-defined vibronic structure of the absorption spectrum is assigned to a nI(& Vert;)pi* transition. The subsequent dissociation dynamics from that state features an ultrafast electronic predissociation with sub-200 femtosecond reaction time. State-switching at a first CI with a low-lying electronic state governing the mechanism involves states of completely different character, occurring in less than 20 fs. This remarkably fast process takes place through an initial stretch of the C 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 C bond, followed by a C-I elongation with subsequent vibrational activity in the CC stretch mode.
On unveiling buried nuclei with JWST: A technique for hunting the most obscured galaxy nuclei from local to high redshift
Authors: Garcia-Bernete, I.; Donnan, F. R.; Rigopoulou, D.; Pereira-Santaella, M.; Gonzalez-Alfonso, E.; Thatte, N.; Aalto, S.; Konig, S.; Maksymowicz-Maciata, M.; Smith, M. W. R.; Huang, J. -s.; Magdis, G. E.; Roche, P. F.; Devriendt, J.; Slyz, A.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2025/04/10
DOI: 10.1051/0004-6361/202452455
Abstract: We analyze JWST NIRSpec+MIRI/MRS observations of the infrared (IR) polycyclic aromatic hydrocarbon (PAH) features in the central regions (similar to 0.26 ” at 6 mu m; similar to 50-440 pc depending on the source) of local luminous IR galaxies. In this work, we examine the effect of nuclear obscuration on the PAH features of deeply obscured nuclei, predominantly found in local luminous IR galaxies, and we compare these nuclei with normal star-forming regions. We extend previous work to include shorter wavelength PAH ratios now available with the NIRSpec+MIRI/MRS spectral range. We introduce a new diagnostic diagram for selecting deeply obscured nuclei based on the 3.3 and 6.2 mu m PAH features and/or mid-IR continuum ratios at similar to 3 and 5 mu m. We find that the PAH equivalent width ratio of the brightest PAH features at shorter wavelengths (at 3.3 and 6.2 mu m) is impacted by nuclear obscuration. Although the sample of luminous IR galaxies used in this analysis is relatively small, we find that sources exhibiting a high silicate absorption feature cluster tightly in a specific region of the diagram, whereas star-forming regions experiencing lower extinction levels occupy a different area in the diagram. This demonstrates the potential of this technique to identify buried nuclei. To leverage the excellent sensitivity of the MIRI imager on board JWST, we extend our method of identifying deeply obscured nuclei at higher redshifts using a selection of MIRI filters. Specifically, the combination of various MIRI JWST filters enables the identification of buried sources beyond the local Universe and up to z similar to 3, where other commonly used obscuration tracers such as the 9.7 mu m silicate band, are out of the spectral range of MRS. Our results pave the way for identifying distant deeply obscured nuclei with JWST.
Majorana bound states from cavity embedding in an interacting two-site Kitaev chain
Authors: Gomez-Leon, Alvaro; Schiro, Marco; Dmytruk, Olesia
Journal: PHYSICAL REVIEW B
Publication date: 2025/04/09
DOI: 10.1103/PhysRevB.111.155410
Abstract: Poor man’s Majorana bound states (MBS) arise in minimal Kitaev chains when the parameters are fine-tuned to a sweet spot. We consider an interacting two-site Kitaev chain coupled to a single-mode cavity and show that the sweet spot condition can be controlled with the cavity frequency and the hopping between sites. Furthermore, we demonstrate that photon-mediated effective interactions can be used to screen intrinsic interactions, improving the original quality of the MBS. We describe experimental signatures in the cavity transmission to detect their presence and quality. Our work proposes a new way to tune poor man’s MBS in a quantum dot array coupled to a cavity.
Digital simulation of zero-temperature spontaneous symmetry breaking in a superconducting lattice processor
Authors: Hu, Chang-Kang; Xie, Guixu; Poulsen, Kasper; Zhou, Yuxuan; Chu, Ji; Liu, Chilong; Zhou, Ruiyang; Yuan, Haolan; Shen, Yuecheng; Liu, Song; Zinner, Nikolaj T.; Tan, Dian; Santos, Alan C.; Yu, Dapeng
Journal: NATURE COMMUNICATIONS
Publication date: 2025/04/07
DOI: 10.1038/s41467-025-57812-8
Abstract: Quantum simulators are ideal platforms to investigate quantum phenomena that are inaccessible through conventional means, such as the limited resources of classical computers to address large quantum systems or due to constraints imposed by fundamental laws of nature. Here, through a digitized adiabatic evolution, we report an experimental simulation of antiferromagnetic (AFM) and ferromagnetic (FM) phase formation induced by spontaneous symmetry breaking (SSB) in a three-generation Cayley tree-like superconducting lattice. We develop a digital quantum annealing algorithm to mimic the system dynamics, and observe the emergence of signatures of SSB-induced phase transition through a connected correlation function. We demonstrate that the signature of a transition from classical AFM to quantum FM-like phase state happens in systems undergoing zero-temperature adiabatic evolution with only nearest-neighbor interacting systems, the shortest range of interaction possible. By harnessing properties of the bipartite R & eacute;nyi entropy as an entanglement witness, we observe the formation of entangled quantum FM and AFM phases. Our results open perspectives for new advances in condensed matter physics and digitized quantum annealing.
New sub-millimetre HCN lasers in carbon-rich evolved stars
Authors: Yang, W.; Wong, K. T.; Wiesemeyer, H.; Menten, K. M.; Gong, Y.; Cernicharo, J.; De Beck, E.; Klein, B.; Duran, C. A.
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2025/04/04
DOI: 10.1051/0004-6361/202453136
Abstract: Context. Strong laser emission from hydrogen cyanide (HCN) at 805 and 891 GHz has been discovered towards carbon-rich (C-rich) asymptotic giant branch (AGB) stars. Both lines belong to the Coriolis-coupled system between the (1,11e,0) and (0,40,0) vibrational states, which has been extensively studied in early molecular spectroscopy in the laboratory. However, the other lines in this system with frequencies above similar to 900 GHz, which are challenging to observe with ground-based telescopes, have remained unexplored in astronomical contexts. Aims. We aim to (1) search for new HCN transitions that show laser activity in the (0,40,0), J = 10-9 line at 894 GHz, the (1,11e,0)-(0,40,0), J = 11-10 line at 964 GHz, the (1,11e,0), J = 11-10 at 968 GHz, and the (1,11e,0), J = 12-11 line at 1055 GHz towards C-rich AGB stars; (2) study the variability of multiple HCN laser lines, including the two known lasers at 805 and 891 GHz; and (3) construct a complete excitation scenario to the Coriolis-coupled system. Methods. We conducted SOFIA/4GREAT observations and combined our data with Herschel/HIFI archival data to construct a sample of eight C-rich AGB stars, covering six HCN transitions (i.e. the 805, 891, 894, 964, 968, and 1055 GHz lines) in the Coriolis-coupled system. Results. We report the discovery of HCN lasers at 964, 968, and 1055 GHz towards C-rich AGB stars. Laser emission in the 805, 891, and 964 GHz HCN lines was detected in seven C-rich stars, while the 968 GHz laser was detected in six stars and the 1055 GHz laser in five stars. Notably, the 894 GHz line emission was not detected in any of the targets. Among the detected lasers, the emission of the cross-ladder line at 891 GHz is always the strongest, with typical luminosities of a few 1044 photons s-1. The cross vibrational state 964 GHz laser emission, which is like a twin of the 891 GHz line, is the second strongest. The 1055 GHz laser emission always has a stronger 968 GHz counterpart. Towards IRC+10216, all five HCN laser transitions were observed in six to eight epochs and exhibited significant variations in line profiles and intensities. The 891 and 964 GHz lines exhibit similar variations, and their intensity changes do not follow the near-infrared light curve (i.e. they have non-periodic variations). In contrast, the variations in the 805, 968, and 1055 GHz lines appear to be quasi-periodic, with a phase lag of 0.1-0.2 relative to the near-infrared light curve. A comparative analysis indicates that these HCN lasers may be seen as analogues to vibrationally excited SiO and H2O masers in oxygen-rich stars. Conclusions. We suggest that chemical pumping and radiative pumping could play an important role in the production of the cross-ladder HCN lasers, while the quasi-periodic behaviour of the rotational HCN laser lines may be modulated by additional collisional and radiative pumping driven by periodic shocks and variations in infrared luminosity.
Scalable quantum eraser with superconducting integrated circuits
Authors: Diniz, Ciro Micheletti; Villas-Boas, Celso J.; Santos, Alan C.
Journal: QUANTUM SCIENCE AND TECHNOLOGY
Publication date: 2025/04/01
Abstract: A fast and scalable scheme for multi-qubit resetting in superconducting quantum processors is proposed by exploiting the feasibility of frequency-tunable transmon qubits and transmon-like couplers to engineer a full programmable superconducting erasing head. We demonstrate the emergence of collective effects that lead to a decoherence-free subspace during the erasing process. The presence of such a subspace negatively impacts the device’s performance and has been overlooked in other multi-qubit chips. To circumvent this issue and pave the way to the device’s scalability, we employ tunable frequency couplers to identify a specific set of parameters that enables us to erase even those states within this subspace, ensuring the simultaneous multi-qubit resetting, verified here for the two-qubit case. In contrast, we show that collectivity effects can also emerge as an ingredient to speed up the erasing process. To end, we offer a proposal to build up integrated superconducting processors that can be efficiently connected to erasure heads in a scalable way.
Long-Range Interactions in Weyl-Dense Atomic Arrays Protected from Dissipation and Disorder
Authors: Garcia-Elcano, Inaki; Huidobro, Paloma A.; Bravo-Abad, Jorge; Gonzalez-Tudela, Alejandro
Journal: PHYSICAL REVIEW LETTERS
Publication date: 2025/03/28
DOI: 10.1103/PhysRevLett.134.123602
Abstract: Long-range interactions are a key resource in many quantum phenomena and technologies. Free-space photons mediate power-law interactions but lack tunability and suffer from decoherence processes due to their omnidirectional emission. Engineered dielectrics can yield tunable and coherent interactions, but typically at the expense of making them both shorter ranged and sensitive to material disorder and photon loss. Here, we propose a platform that can circumvent all these limitations based on three-dimensional subwavelength atomic arrays subjected to magnetic fields. Our key result is to show how to design the polaritonic bands of these atomic metamaterials to feature a pair of frequency-isolated Weyl points, i.e., points in reciprocal space around which the bands disperse linearly and defining monopoles of the Berry curvature. As predicted by recent works, such Weyl excitations can mediate interactions that are simultaneously long range, due to their gapless nature; robust, due to the topological protection of Weyl points; and decoherence-free, due to their subradiant character. We demonstrate the robustness of these isolated Weyl points for a large regime of interatomic distances and magnetic field values and characterize the emergence of their corresponding Fermi arcs surface states. The latter can lead to two-dimensional, nonreciprocal atomic interactions with no analogue in other chiral quantum optical setups.
Exact Quantization of Nonreciprocal Quasilumped Electrical Networks
Authors: Parra-Rodriguez, A.; Egusquiza, I. L.
Journal: PHYSICAL REVIEW X
Publication date: 2025/03/28
DOI: 10.1103/PhysRevX.15.011072
Abstract: Following a consistent geometrical description previously introduced [Quantum 8, 1466 (2024)], we present an exact method for obtaining canonically quantizable Hamiltonian descriptions of nonlinear, nonreciprocal quasilumped electrical networks. We identify and classify singularities arising in the quest for Hamiltonian descriptions of general quasilumped element networks via the Faddeev-Jackiw technique. We offer systematic solutions to cases previously considered singular-a major challenge in the context of canonical circuit quantization. The solution relies on the correct identification of the reduced classical circuit-state manifold, i.e., a mix of flux and charge fields and functions. Starting from the geometrical description of the transmission line, we provide a complete program including lines coupled to one-port lumped-element networks, as well as multiple lines connected to multiport nonreciprocal lumped-element networks, with intrinsic ultraviolet cutoff. On the way, we naturally extend the canonical quantization of transmission lines coupled through frequency-dependent, nonreciprocal linear systems, such as practical circulators. Additionally, we demonstrate how our method seamlessly facilitates the characterization of general nonreciprocal, dissipative linear environments. This is achieved by extending the Caldeira-Leggett formalism, using continuous limits of series of immittance matrices. We provide a tool in the analysis and design of electrical circuits and of special interest in the context of canonical quantization of superconducting networks. For instance, this work provides a solid ground for a precise nondivergent inputoutput theory in the presence of nonreciprocal devices, e.g., within (chiral) waveguide QED platforms.
Dipole-dipole interactions mediated by a photonic flat band
Authors: Di Benedetto, Enrico; Gonzalez-Tudela, Alejandro; Ciccarello, Francesco
Journal: QUANTUM
Publication date: 2025/03/25
Abstract: Flat bands (FBs) are energy bands with zero group velocity, which in electronic systems were shown to favor strongly correlated phenomena. Indeed, a FB can be spanned with a basis of strictly localized states, the so called compact localized states (CLSs), which are yet generally non-orthogonal. Here, we study emergent dipole-dipole interactions between emitters dispersively coupled to the photonic analogue of a FB, a setup within reach in state-of the-art experimental platforms. We show that the strength of such photon-mediated interactions decays exponentially with distance with a characteristic localization length which, unlike typical behaviours with standard bands, saturates to a finite value as the emitter’s energy approaches the FB. Remarkably, we find that the localization length grows with the overlap between CLSs according to an analytically-derived universal scaling law valid for a large class of FBs both in 1D and 2D. Using giant atoms (non-local atomfield coupling) allows to tailor interaction potentials having the same shape of a CLS or a superposition of a few of these.
The large PAH sumanene: laboratory rotational spectroscopy and astronomical search
Authors: Moran, Jose R.; Cabezas, Carlos; Hussain, Farha S.; Perez, Cristobal; Cernicharo, Jose; Steber, Amanda L.; Pena, Isabel
Journal: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Publication date: 2025/03/24
Abstract: The recent interstellar detection of individual polycyclic aromatic hydrocarbons (PAHs) in the Taurus Molecular Cloud (TMC-1) brings with it interest in related species that could be present in this astronomical environment. The interstellar PAHs detected in TMC-1 consist of a few pure PAHs while the majority that have been detected are their cyano-derivative counterparts due to their larger dipole moment components. Bowl-shaped PAHs, such as sumanene (C21H12), represent another important target for radio astronomy as they are very polar species, in spite of their high symmetry, increasing their chances of detection. Here, we present the laboratory rotational spectroscopic study of the PAH sumanene, characterized in the gas-phase using a chirped-pulse Fourier-transform microwave spectrometer operating between 2 and 8 GHz. Accurate spectroscopic parameters are derived from the spectral analysis and compared to those obtained for corannulene. These parameters have been employed to achieve reliable frequency predictions for their astronomical search in TMC-1. We do not detect either sumanene or corannulene in our QUIJOTE line survey of TMC-1 but upper limits to their abundance in this source are derived.
The many faces of vibrational energy relaxation in N2(v) + O(1D) collisions: Dynamics on 1? and 1? potential energy surfaces
Authors: Hong, Qizhen; Bartolomei, Massimiliano; Pirani, Fernando; Sun, Quanhua; Coletti, Cecilia
Journal: JOURNAL OF CHEMICAL PHYSICS
Publication date: 2025/03/21
DOI: 10.1063/5.0255380
Abstract: Complete datasets of rate coefficients for the vibrational quenching of molecular nitrogen by collision with electronically excited atomic oxygen O(D-1) over a wide temperature range are calculated for the first time. Such data are important ingredients in the modeling of non-local thermal equilibrium conditions that characterize the atmosphere, media of astronomical interest, and cold and hot plasmas, where O(D-1), also formed when O-2 molecules break, represents a significant fraction of the gas mixture. To this end, we developed analytical potential energy surfaces (PESs) for the (1)Pi and (1)Delta electronic states of the N-2-O(D-1) system to accurately describe the interaction in the long, medium, and first repulsive range of intermolecular distances, the most effective regions in inelastic collisions under a variety of conditions of interest. The derived PESs are used to calculate the vibration-to-translation (V-T) and vibration-to-electronic (V-E) energy transfer rates by mixed quantum-classical dynamics and by the Landau-Zener formulation, respectively. In addition, the datasets are extended to cover the entire N-2 vibrational ladder by using the Gaussian process regression. The results show that at low temperatures, where V-E relaxation dominates, N-2 vibrational quenching by O(D-1) collisions is faster than by O(P-3) collisions.
Hydrogenation of HOCO and formation of interstellar CO2: a not so straightforward relation
Authors: Molpeceres, German; Enrique-Romero, Joan; Ishibashi, Atsuki; Oba, Yasuhiro; Hidaka, Hiroshi; Lamberts, Thanja; Aikawa, Yuri; Watanabe, Naoki
Journal: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Publication date: 2025/03/18
Abstract: Carbon dioxide (CO2) is one of the most important interstellar molecules. While it is considered that it forms on the surface of interstellar dust grains, the exact contribution of different chemical mechanisms is still poorly constrained. Traditionally it is deemed that the CO + OH reaction occurring on top of ices is the main reaction path for its formation. Recent investigations showed that in reality the reaction presents a more complex mechanism, requiring an additional H-abstraction step. Building on our previous works, we carried out a detailed investigation of such H abstraction reactions with the hydrogen atom as a reactant for the abstraction reaction. We found an unconventional chemistry for this reaction, markedly depending on the isomeric form of the HOCO radical prior to reaction. The favoured reactions are t-HOCO + H -> CO + H2O, c-HOCO + H -> CO2 + H-2, and t/c-HOCO + H -> c/t-HCOOH. We estimate bounds for the rate constants of the less favoured reaction channels, t-HOCO + H -> CO2 + H and c-HOCO + H -> CO + H2O, to be approximately 10(4-6)s(-1). However, these estimates should be interpreted cautiously due to the significant role of quantum tunnelling in these reactions and the complex electronic structure of the involved molecules, which complicates their study. Our findings underscore the need for detailed investigation into the chemistry of interstellar CO2 and pave the way for a re-evaluation of its primary formation mechanisms in the interstellar medium.
Hydroxylamine in astrophysical ices: Infrared spectra and cosmic-ray-induced radiolytic chemistry
Authors: Mate, Belen; Pelaez, Ramon J.; Molpeceres, German; Racz, Richard; Mifsud, Duncan V.; Ortigoso, Juan; Rivilla, Victor M.; Lakatos, Gergo; Sulik, Bela; Herczku, Peter; Ioppolo, Sergio; Biri, Sandor; Juhasz, Zoltan
Journal: ASTRONOMY & ASTROPHYSICS
Publication date: 2025/03/13
DOI: 10.1051/0004-6361/202453312
Abstract: Context. Gas-phase hydroxylamine (NH2OH) has recently been detected within dense clouds in the interstellar medium. However, it is also likely present within interstellar ices, as well as on the icy surfaces of outer Solar System bodies, where it may react to form more complex prebiotic molecules such as amino acids. Aims. In this work, we aim to provide infrared spectra of NH2OH in astrophysical ice analogues that will help in the search for this molecule in various astrophysical environments. Furthermore, we aim to provide quantitative information on the stability of NH2OH upon exposure to ionising radiation analogous to cosmic rays, as well as on the ensuing chemistry and potential formation of complex prebiotic molecules. Methods. Ices composed of NH2 OH, H2O, and CO were prepared by vapour deposition, and infrared spectra were acquired between 4000-500 cm(-1) (2.5-20 mu m) prior to and during irradiation using 15 keV protons. Results. Our spectroscopic characterisations determine that NH2OH ices deposited at 10-20 K adopt an amorphous structure, which begins to crystallise upon warming to temperatures greater than 150 K. In interstellar ice analogues, the most prominent infrared absorption band of NH2OH is that at about 1188 cm(-1), which may be a good candidate to use in searches for this species in icy space environments. Calculated effective destruction cross-sections and G-values for the NH2 OH-rich ices studied show that NH2OH is rapidly destroyed upon exposure to ionising radiation (more rapidly than a number of previously studied organic molecules) and that this destruction is slightly enhanced when it is mixed with other icy species. The irradiation of a NH2OH:H2O:CO ternary ice mixture leads to a rich chemistry that includes the formation of simple inorganic molecules such as NH3, CO2, OCN-, and H2O2, as well as ammonium salts and, possibly, complex organic molecules relevant to life such as formamide, formic acid, urea, and glycine.
RIOJA. Complex Dusty Starbursts in a Major Merger B14-65666 at z=7.15
Authors: Sugahara, Yuma; alvarez-Marquez, Javier; Hashimoto, Takuya; Colina, Luis; Inoue, Akio K.; Costantin, Luca; Fudamoto, Yoshinobu; Mawatari, Ken; Ren, Yi W.; Arribas, Santiago; Bakx, Tom J. L. C.; Blanco-Prieto, Carmen; Ceverino, Daniel; Crespo Gomez, Alejandro; Hagimoto, Masato; Hashigaya, Takeshi; Marques-Chaves, Rui; Matsuo, Hiroshi; Nakazato, Yurina; Pereira-Santaella, Miguel; Tamura, Yoichi; Usui, Mitsutaka; Yoshida, Naoki
Journal: ASTROPHYSICAL JOURNAL
Publication date: 2025/03/10
Abstract: We present JWST NIRCam imaging of B14-65666 (Big Three Dragons), a bright Lyman-break galaxy system (MUV = -22.5 mag) at z = 7.15. The high angular resolution of NIRCam reveals the complex morphology of two galaxy components: galaxy E has a compact core (E-core), surrounded by diffuse, extended, rest-frame optical emission, which is likely to be tidal tails; and galaxy W has a clumpy and elongated morphology with a blue UV slope (beta UV = -2.2 +/- 0.1). The flux excess, F356W – F444W, peaks at the E-core ( 1.05-0.09+0.08 mag), tracing the presence of strong [O iii] lambda lambda 4960,5008 emission. Atacama Large Millimeter/submillimeter Array archival data show that the bluer galaxy W is brighter in dust continua than the redder galaxy E, while the tails are bright in [O iii] 88 mu m. The UV/optical and submillimeter spectral energy distribution (SED) fitting confirms that B14-65666 is a major merger in a starburst phase as derived from the stellar mass ratio (3:1 to 2:1) and the star formation rate, similar or equal to 1 dex higher than the star formation main sequence at the same redshift. Galaxy E is a dusty (AV = 1.2 +/- 0.1 mag) starburst with a possible high dust temperature (>= 63-68 K). Galaxy W would have a low dust temperature (<= 27-33 K) or patchy stellar-and-dust geometry, as suggested by the IR excess and beta UV diagram. The high optical-to-far-IR [O iii] line ratio of the E-core shows its lower gas-phase metallicity (similar or equal to 0.2-0.4 Z circle dot) than galaxy W. These results agree with a scenario where major mergers disturb morphology and induce nuclear dusty starbursts triggered by less-enriched inflows. B14-65666 shows a picture of complex stellar buildup processes during major mergers in the epoch of reionization.