IF - Artigos publicados em periódicos

URI Permanente para esta coleçãohttp://200.137.215.59//handle/ri/1359

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Diffractive Lugiato-Lefever equation driven by a double tightly focused pump
(2025) Santos, Mateus Calixto Pereira dos; Kumar, Shatrughna; Cardoso, Wesley Bueno; Malomed, Boris A.
We introduce a model of an optical cavity based on the one-dimensional Lugiato-Lefever (LL) equation, which includes the pump represented by a symmetric pair of tightly localized “hot spots” (HSs) with phase shift 𝜒 between them, and self-focusing or defocusing cubic nonlinearity. Families of bound states, pinned to the double HS, are found in the system's parameter space. They feature the effect of the symmetry breaking (SB) between peaks pinned to individual HSs, provided that the phase shift takes values 0<𝜒<𝜋, and the LL equation includes the loss term. The SB, which is explained analytically, takes place in the full LL model and its linearized version alike. The same phenomenology is also explored in the framework of the LL equation with the double HS and quintic self-focusing. In that case, there are stable symmetric and asymmetric bound states, in spite of the presence of the background instability driven by the critical collapse.
Spontaneous symmetry breaking induced by nonlinear interaction in a coupler supported by fractional diffraction
(2025) Santos, Mateus Calixto Pereira dos; Cardoso, Wesley Bueno
In this paper we introduce a one-dimensional model of coupled fractional nonlinear Schrödinger equations with a double-well potential applied to one component. This study examines ground state (GS) solitons, observing spontaneous symmetry breaking (SSB) in both the actuated field and the partner component due to nonlinear coupling. Numerical simulations reveal symmetric and asymmetric profiles arising from a slightly asymmetric initial condition. Asymmetry is influenced by nonlinearities, potential depth, and coupling strength, with self-focusing systems favoring greater asymmetry. Fractional diffraction affects the amplitude and localization of symmetric profiles and the stability of asymmetric ones. We identify critical Lévy index values for generating coupled GS solitons. Stability analysis of unstable, centrally asymmetric GS solitons demonstrates oscillatory dynamics, providing new insights into SSB in fractional systems and half-trapped solitons.
Inducing localized solutions via interaction in a self-defocusing system with localized pumping
(2025) Cardoso, Wesley Bueno; Santos, Mateus Calixto Pereira dos
We investigate the emergence of induced localized coupled modes in passive cavities with both loss and gain. Our model is based on linearly coupled Lugiato-Lefever equations, where a Gaussian pump beam is applied to only one mode. Through numerical simulations, we demonstrate that self-defocusing systems are capable of supporting the formation of localized stationary modes in the partner field. The characteristics of these induced modes are determined by key parameters, including coupling strength, cavity decay rate, detuning effects, and the pump beam's intensity and width.
Alternative split-step method for solving linearly coupled nonlinear Schrödinger equations
(2025) Cardoso, Wesley Bueno
In this paper we introduce an alternative method for solving linearly coupled nonlinear Schrödinger equations by using a split-step approach. This methodology involves approximating the nonlinear part of the evolution operator, allowing it to be solved exactly, which significantly enhances computational efficiency. The dispersive component is addressed using a spectral method, ensuring accuracy in the treatment of linear terms. As a reference, we compare our results with those obtained using the Runge-Kutta method implemented using a pseudo-spectral technique. Our findings indicate that the proposed split-step method achieves precision comparable to that of the Runge-Kutta method while nearly doubling computational efficiency. Numerical simulations include the evolution of a single soliton in each field and a collision between two solitons, demonstrating the robustness and effectiveness of our approach.
Development and spectroscopy study of YPO4:Tm3+ nanopowders
(2025) Torquato, Francisco Alisson da Silva; Santana, Ricardo Costa de; Maia, Lauro June Queiroz
The Y1-xTmxPO4 nanopowders were successfully synthesized via the coprecipitation method assisted by slow evaporation under basic conditions (pH = 10), yielding particles with an average length of about 26 nm ± 8 nm observed by Transmission Electron Microscopy images. The diffuse reflectance spectra (DRS) show higher reflectance of powdered samples in the visible range, and optical bandgaps (Eg) values were obtained using the Kubelka-Munk approach, which ranged from 4.5 to 4.7 eV, indicating an insulator nature. The powders displayed remarkably intense blue emission centred at 452 nm, originating from the 1D2 → 3H6 transition under 361.5 nm excitation. This emission was accompanied by a residual contribution from a near-infrared emission band at approximately 783 nm, which was attributed to the 1G4 → 3H5 and 3H4 → 3H6 transitions due to residual multiphonon decay and cross-relaxation mechanisms, respectively. The lifetimes of the 1D2 state range from 42 to 35 µs, displaying monoexponential behaviour as the concentration rises from 0.25 % mol to 2 % mol. The dipole-dipole interaction between ions is confirmed for blue emission using the Dexter model, which has a critical distance of ∼ 24 Å. The same behaviour is also observed for the lifetimes from the 1G4 state, decreasing from 422 µs (0.25 mol. %) to 170 µs (2 mol. %), with a bi-exponential behaviour due to the more effective cross-relaxation mechanisms. The relative changes between 1D2 and 1G4 energy levels allow for tuning the emission colour from blue to cyan by adjusting the delay time. Additionally, the CIE chromaticity coordinates of steady-state PL spectra indicate that the samples have a colour purity of above 93 % for x > 0.01 in the deep blue region, indicating the Y1-xTmxPO4 nanopowders as a versatile blue to cyan emitter component for W-LED applications.
Improvement of electronic structure calculations for the interpretation of the emission spectrum for NdIII complexes
(2025) Gil Sánchez, Yolimar; Maldonado, María José; Santana, Ricardo Costa de; Vega, Andrés; Fuentealba, Pablo; Aravena, Daniel
A protocol to correct ab initio calculated luminescence spectra of NdIII complexes is proposed. The emission spectrum of [NdIII(bipy)(tta)3] was measured to calibrate the optimal correction for the Racah parameters on top of a CASSCF calculation to attain the best energetic placement of the 4F3/2 → 4I13/2−9/2 emission lines. As interelectronic repulsion is the most important source of error in this calculation, this straightforward correction results in an accurate placement of transitions, allowing the assignment of a complex spectral shape in terms of its underlying transitions. Finally, the correction derived for [NdIII(bipy)(tta)3] was directly applied to a different NdIII complex, demonstrating the broad use of this approach.
Trichromatic color tuning strategy for emission of heterometallic EuIII/TbIII coordination polymers with triazolyl-substituted 4-methyl-phenoxo ligand
(2025) Pérez Obando, Juliana; Manzur Saffie, Jorge Alberto; Fuentealba, Pablo; Morales Alfaro, Jeannette; Vega, Andrés; Santana, Ricardo Costa de; Carneiro Neto, Albano Neto; Spodine, Evgenia
This study presents the microwave-assisted synthesis and characterization of a series of heterometallic coordination polymers (HMCPs) with a 4-methyl-2,6-di[(1H-1,2,4-triazol-1-yl)]phenoxo ligand with varying EuIII/TbIII ratios. Single crystal X-ray diffraction reveals a double-chain structure bridged by triazolyl groups. Powder X-ray diffraction confirms the isostructural nature of the synthesized HMCPs. The photophysical properties depend on lanthanide ion concentration and excitation wavelength, leading to a color shift from green to blue as the proportion of TbIII decreases and EuIII increases. White light generation is achieved in the 8/2 EuIII/TbIII HMCP (CIE: 0.293, 0.326) under 335 nm excitation. The study suggests energy transfer from TbIII to EuIII, but both experimental and theoretical calculations indicate that this transfer is orders of magnitude lower than the sensitization through ligand states.
Anti-thermal quenching in NdIII molecular near-infrared thermometers operating at physiological temperatures
(2025) Maldonado, María José; Farías Carreño, Patricia; Gil Sánchez, Yolimar; Vega, Andrés; Santana, Ricardo Costa de; Aravena, Daniel; Brites, Carlos D. S.; Carlos, Luis Dias; Carneiro Neto, Albano Neto; Vetrone, Fiorenzo
Examples of molecular complexes acting as thermometers operating at room temperature in near infrared region are scarce, therefore this work showcases the anti-thermal quenching effect on neodymium(III) molecular thermometers working in biological windows within the physiological temperature range. A mononuclear complex, [Nd(L)(NO3)3] (1Nd), where L is a macrocyclic ligand, was synthesized and used as a precursor to develop two novel species: a dinuclear, [(Nd(L)(NO3))2(µ-BDC)](NO3)2·H2O (2Nd), linked by 1,4-benzenedicarboxylate (BDC), and a hexameric, [(Nd(L))(µ-BTC)(H2O)]6·35H2O (6Nd), linked with 1,3,5-benzenetricarboxylate (BTC). Thermometric properties were studied in the physiological temperature range (292-332 K), utilizing 804 nm laser excitation (first biological window) and monitoring emissions in the second biological window (908, 1065, and 1340 nm) associated with the 4F3/2 → 4I9/2, 4I11/2, 4I13/2 transitions, respectively. Among the complexes, the hexamer 6Nd exhibited exceptional performance, with Sr of 2.4%K−1 at 293 K, when luminescence intensity ratio (LIR) of two Stark components of the 4F3/2 → 4I11/2 emission was used, positioning it as a high-performance NdIII-based thermometer. All complexes displayed anti-thermal quenching behavior, surpassing the current molecular-based thermometers in the near-infrared region. Theoretical calculations using complete active space self consistent field (CASSCF) and Boltzmann population models between Kramers doublets of the 4F3/2 level were performed to rationalize the anti-thermal behavior.
Measurements of pion and muon nuclear capture at rest on argon in the LArIAT experiment
(2025) Hernandez Morquecho, Miguel Angel; Acciarri, Roberto; Asaadi, Jonathan Abraham; Backfish, Michael; Badgett, William Farris; Basque, Vincent Marc; Blaszczyk, F. D. M.; Foreman, William; Gomes, Ricardo Avelino; Gramellini, Elena
We report the measurement of the final-state products of negative pion and muon nuclear capture at rest on argon by the LArIAT experiment at the Fermilab Test Beam Facility. We measure a population of isolated MeV-scale energy depositions, or blips, in 296 LArIAT events containing tracks from stopping low-momentum pions and muons. The average numbers of visible blips are measured to be 0.74 ±0.19 and 1.86 ±0.17 near muon and pion track endpoints, respectively. The 3.6⁢𝜎 statistically significant difference in blip content between muons and pions provides the first demonstration of a new method of pion-muon discrimination in neutrino liquid argon time projection chamber experiments. LArIAT Monte Carlo simulations predict substantially higher average blip counts for negative muon (1.22 ±0.08) and pion (2.34 ±0.09) nuclear captures. We attribute this difference to geant4’s inaccurate simulation of the nuclear capture process.
The track-length extension fitting algorithm for energy measurement of interacting particles in liquid argon TPCs and its performance with ProtoDUNE-SP data
(2025) Abud, Adam Abed; Abi, Babak; Acciarri, Roberto; Acero Ortega, Mario Andrés; Adames, Márcio Rostirolla; Adamov, George; Adamowski, Mark; Adams, David; Adinolfi, Marco; Adriano, Cris; Gomes, Ricardo Avelino
This paper introduces a novel track-length extension fitting algorithm for measuring the kinetic energies of inelastically interacting particles in liquid argon time projection chambers (LArTPCs). The algorithm finds the most probable offset in track length for a track-like object by comparing the measured ionization density as a function of position with a theoretical prediction of the energy loss as a function of the energy, including models of electron recombination and detector response. The algorithm can be used to measure the energies of particles that interact before they stop, such as charged pions that are absorbed by argon nuclei. The algorithm's energy measurement resolutions and fractional biases are presented as functions of particle kinetic energy and number of track hits using samples of stopping secondary charged pions in data collected by the ProtoDUNE-SP detector, and also in a detailed simulation. Additional studies describe the impact of the dE/dx model on energy measurement performance. The method described in this paper to characterize the energy measurement performance can be repeated in any LArTPC experiment using stopping secondary charged pions.
Neutrino interaction vertex reconstruction in DUNE with Pandora deep learning
(2025) Abud, Adam Abed; Acciarri, Roberto; Acero Ortega, Mario Andrés; Adames, Márcio Rostirolla; Adamov, George; Adamowski, Mark; Adams, David; Adinolfi, Marco; Adriano, Cris; Aduszkiewicz, Antoni; Gomes, Ricardo Avelino
The Pandora Software Development Kit and algorithm libraries perform reconstruction of neutrino interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at the Deep Underground Neutrino Experiment, which will operate four large-scale liquid argon time projection chambers at the far detector site in South Dakota, producing high-resolution images of charged particles emerging from neutrino interactions. While these high-resolution images provide excellent opportunities for physics, the complex topologies require sophisticated pattern recognition capabilities to interpret signals from the detectors as physically meaningful objects that form the inputs to physics analyses. A critical component is the identification of the neutrino interaction vertex. Subsequent reconstruction algorithms use this location to identify the individual primary particles and ensure they each result in a separate reconstructed particle. A new vertex-finding procedure described in this article integrates a U-ResNet neural network performing hit-level classification into the multi-algorithm approach used by Pandora to identify the neutrino interaction vertex. The machine learning solution is seamlessly integrated into a chain of pattern-recognition algorithms. The technique substantially outperforms the previous BDT-based solution, with a more than 20% increase in the efficiency of sub-1 cm vertex reconstruction across all neutrino flavours.
First observation of antiproton annihilation at rest on argon in the LArIAT experiment
(2025) Basque, Vincent Marc; Acciarri, Roberto; Asaadi, Jonathan Abraham; Backfish, Michael; Badgett, William Farris; Cavanna, F.; Flanagan, W.; Foreman, William; Gomes, Ricardo Avelino
We report the first observation and measurement of antiproton annihilation at rest on argon track and shower multiplicities and particle identification conducted with the LArIAT experiment. Stopping antiprotons from the Fermilab Test Beam Facility’s charged particle test beam are identified using beamline instrumentation and LArIAT’s liquid argon time projection chamber (LArTPC). The charged particle multiplicity from the annihilation vertex is manually evaluated via hand scanning, yielding a mean of 3.2 ±0.4 tracks and a standard deviation of 1.3 tracks, consistent with a semiautomated reconstruction resulting in 2.8 ±0.4 tracks and a standard deviation of 1.2 tracks. Both methods are consistent with Monte Carlo simulations within statistical uncertainty. The shower multiplicities and particle identification for outgoing tracks are also consistent with geant4 model predictions. These results, obtained from a low-statistics sample, provide a foundation for higher-statistics studies in larger LArTPCs, which could refine modeling of intranuclear annihilation on argon and inform scenarios such as neutron-antineutron oscillations.
Surface palladium nanoparticles in ionic liquids modified with phosphorus ligands for enhanced catalytic semi-hydrogenation
(2025) Qadir, Muhammad Irfan; Chacon Rosales, Gustavo Javier; Ebersol, Camila Porto; Abarca Anjari, Gabriel Nelson; Matias, Pedro Henrique Ferreira; Oliveira, Heibbe Cristhian Benedito de; Pontes, Renato Borges; Stieler, Rafael; Dupont, Jairton
Thermodynamic stability of nanoparticles necessitates the use of stabilizing agents to provide steric and electronic protection. However, their activity and selectivity remain suboptimal under moderate reaction conditions. In this study, we present high-performance Pd nanoparticles featuring a distinctive Pd–phosphine surface, akin to a “quasi nano-frustrated Lewis pair” architecture. In this system, electron donation from ionophilic phosphine species enhances the electron density of the Pd nanoparticles, contributing to their improved performance. Solid-state NMR and XPS analyses disclose the strong coordination of phosphine species on the Pd NPs. DFT calculations reveal the geometry and conformations of the coordinated phosphine, showing that one of the phenyl rings aligns nearly parallel to the nanoparticle facets. This interaction occurs through the six carbon atoms of the π system. We investigate the structure–activity relationships (SARs) exhibited by these NPs in the efficient semi-hydrogenation of phenylacetylene (TOF = 3.85 s−1), 2-cyclohexen-1-one (TOF = 0.8 s−1), and 1,3-cyclohexadiene (TOF = 12.82 s−1) at 40 °C and 2–4 bar of H2 in BMIm·NTF2 ionic liquid. The enhanced activity and selectivity are attributed to (i) the formation of ionic liquid cages/membranes around the NPs akin to catalytically active membranes that tune the diffusion affinity of reactants, reactive intermediates, and products for catalytically active sites and (ii) the steric hindrance provided by the Pd–P bonds.
Photodynamic inactivation of KPC-producing Klebsiella pneumoniae difficult-to-treat resistance (DTR) by a cationic porphyrin
(2025) Freitas, Alysson Benite de; Rezende, Hanstter Hallison Alves; Souza, Guilherme Rocha Lino de; Gonçalves, Pablo José
The global rise of difficult-to-treat resistance (DTR) bacteria, such as Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae (KPC-Kp), poses a critical challenge in controlling infections and curbing the spread of antimicrobial resistance genes. Antimicrobial photodynamic inactivation (aPDI) offers a promising alternative to traditional antimicrobials by effectively targeting extensively drug-resistant pathogens and mitigating antimicrobial resistance. This study investigated the in vitro photodynamic efficacy of the cationic porphyrin 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin (TMPyP) against planktonic cultures of KPC-Kp. The minimum effective concentration (MEC) of TMPyP for significant photodynamic activity was determined to be 0.8 μM under an irradiance of 314 ± 11 mW/cm2, delivering a total light dose of 189 J/cm2. At the same concentration, bacterial suspensions exposed to a lower irradiance of 107 ± 7 mW/cm2 achieved a > 99.997 % reduction in viability with a lethal light dose of 51.4 J/cm2. Scanning electron microscopy (SEM) revealed oxidative damage to the bacterial cell wall induced by aPDI. Hemolysis assays confirmed the safety of TMPyP, with no significant cytotoxicity or photocytotoxicity observed, and a selectivity index (SI) greater than 8, indicating a favorable therapeutic window. These findings underscore the potential of TMPyP-based aPDI as a therapeutic strategy to combat KPC-Kp infections. Further studies are warranted to explore its clinical applications and optimize treatment protocols for DTR bacterial infections.
Quantum features of the thermal two-qubit quantum rabi model in ultra- and deep-strong regimes
(2025) Diniz, Ciro Micheletti; Damas, Gabriella Gonçalves; Almeida, Norton Gomes de; Villas Bôas, Celso Jorge; Moraes Neto, Gentil Dias de
Quantum correlations and non-classical states are indispensable resources for advancing quantum technologies, and their resilience at finite temperatures is crucial for practical experimental implementations. The two-qubit quantum Rabi model (2QQRM), a natural extension of the quantum Rabi model, describes two qubits coupled to a single bosonic mode and is extensively studied in cavity quantum electrodynamics, superconducting circuits, and quantum information science. In this work, the persistence of quantum correlations and non-classical states in the 2QQRM at thermal equilibrium is investigated, focusing on the ultrastrong and deep strong coupling regimes. Through a systematic analysis of quantumness quantifiers, the emergence of long-lived quantum correlations is demonstrated, even in the presence of thermal noise. Notably, striking phenomena arising from the interplay between detuning and deep strong-coupling are uncovered: in the high-frequency limit, where the qubit energy exceeds the cavity-mode energy, quantum criticality emerges, leading to a high degree of photon squeezing. In contrast, the opposite regime is characterized by robust qubit–qubit quantum correlations. Importantly, it is shown that both dispersive regimes exhibit quantum features that are remarkably robust to parameter fluctuations, making them advantageous for maintaining quantum coherence. These results highlight the exceptional resilience of quantum resources in the 2QQRM and provide valuable insights for developing quantum technologies operating under realistic, finite-temperature conditions.
Supernova pointing capabilities of DUNE
(2025) Abud, Adam Abed; Abi, Babak; Acciarri, Roberto; Acero Ortega, Mario Andrés; Adames, Márcio Rostirolla; Adamov, George; Adamowski, Mark; Adams, David; Adinolfi, Marco; Adriano, Cris; Gomes, Ricardo Avelino
The determination of the direction of a stellar core collapse via its neutrino emission is crucial for the identification of the progenitor for a multimessenger follow-up. A highly effective method of reconstructing supernova directions within the Deep Underground Neutrino Experiment (DUNE) is introduced. The supernova neutrino pointing resolution is studied by simulating and reconstructing electron-neutrino charged-current absorption on 40 Ar and elastic scattering of neutrinos on electrons. Procedures to reconstruct individual interactions, including a newly developed technique called “brems flipping,” as well as the burst direction from an ensemble of interactions are described. Performance of the burst direction reconstruction is evaluated for supernovae happening at a distance of 10 kpc for a specific supernova burst flux model. The pointing resolution is found to be 3.4 degrees at 68% coverage for a perfect interaction-channel classification and a fiducial mass of 40 kton, and 6.6 degrees for a 10 kton fiducial mass respectively. Assuming a 4% rate of charged-current interactions being misidentified as elastic scattering, DUNE’s burst pointing resolution is found to be 4.3 degrees (8.7 degrees) at 68% coverage.
Measurement of 𝜈𝜇 charged-current inclusive 𝜋0 production in the NOvA near detector
(2023) Acero Ortega, Mario Andrés; Adamson, P.; Agam, Gady; Aliaga, L.; Alion, T.; Allakhverdian, V.; Altakarli, Sef; Anfimov, Nikolay; Antoshkin, Alexander Igorevich
Cross sections for the interaction 𝜈𝜇⁢𝐴 →𝜇−⁢𝜋0⁢𝑋 with neutrino energies between 1 and 5 GeV are measured using a sample of 165,000 selected events collected in the NOvA experiment’s near detector, a hydrocarbon-based detector exposed to the Neutrinos from the Main Injector beam at the Fermi National Accelerator Laboratory. Results are presented as a flux-averaged total cross section and as differential cross sections in the momenta and angles of the outgoing muon and 𝜋0, the total four-momentum transfer, and the invariant mass of the hadronic system. Comparisons are made with predictions from a reference version of the genie neutrino interaction generator. The measured total cross section of (3.57 ±0.44)×10−39 cm2 is 7.5% higher than the genie prediction, but is consistent within experimental errors.
Monte Carlo method for constructing confidence intervals with unconstrained and constrained nuisance parameters in the NOvA experiment
(2025) Acero Ortega, Mario Andrés; Acharya, Bishnu; Adamson, P.; Aliaga, L.; Anfimov, Nikolay; Antoshkin, Alexander Igorevich; Asquith, Lily; Arrieta Diaz, Enrique; Aurisano, Adam; Back, A.; Gomes, Ricardo Avelino
Measuring observables to constrain models using maximum-likelihood estimation is fundamental to many physics experiments. Wilks' theorem provides a simple way to construct confidence intervals on model parameters, but it only applies under certain conditions. These conditions, such as nested hypotheses and unbounded parameters, are often violated in neutrino oscillation measurements and other experimental scenarios. Monte Carlo methods can address these issues, albeit at increased computational cost. In the presence of nuisance parameters, however, the best way to implement a Monte Carlo method is ambiguous. This paper documents the method selected by the NOvA experiment, the profile construction. It presents the toy studies that informed the choice of method, details of its implementation, and tests performed to validate it. It also includes some practical considerations which may be of use to others choosing to use the profile construction.
Dual-baseline search for active-to-sterile neutrino oscillations in NOvA
(2025) Acero Ortega, Mario Andrés; Acharya, Bibhudendra; Adamson, P.; Anfimov, Nikolay; Antoshkin, Alexander Igorevich; Arrieta Diaz, Enrique; Asquith, Lily; Aurisano, Adam J.; Back, A.; Balashov, Nikita; Gomes, Ricardo Avelino
We report a search for neutrino oscillations to sterile neutrinos under a model with three active and one sterile neutrinos (3+1 model). This analysis uses the NOvA detectors exposed to the NuMI beam, running in neutrino mode. The data exposure, 13.6×1020 protons on target, doubles that previously analyzed by NOvA, and the analysis is the first to use 𝜈𝜇 charged-current interactions in conjunction with neutral-current interactions. Neutrino samples in the near and far detectors are fitted simultaneously, enabling the search to be carried out over a Δ⁢𝑚2 41 range extending 2 (3) orders of magnitude above (below) 1 eV2. NOvA finds no evidence for active-to-sterile neutrino oscillations under the 3+1 model at 90% confidence level. New limits are reported in multiple regions of parameter space, excluding some regions currently allowed by IceCube at 90% confidence level. We additionally set the most stringent limits for anomalous 𝜈𝜏 appearance for Δ⁢𝑚2 41≤3 eV2.
Quantum thermodynamics as a gauge theory
(2025) Melo, Gabriel Fernandez Ferrari; Rudnicki, Łukasz; Celeri, Lucas Chibebe
Thermodynamics is based on a coarse-grained approach, from which its fundamental variables emerge, effectively erasing the complicated details of the microscopic dynamics within a macroscopic system. The strength of thermodynamics lies in the universality provided by this paradigm. In contrast, quantum mechanics focuses on describing the dynamics of microscopic systems, aiming to make predictions about experiments we perform, a goal shared by all fundamental physical theories, which are often framed as gauge theories in modern physics. Recently, a gauge theory for quantum thermodynamics was introduced, defining gauge-invariant work and heat, and exploring their connections to quantum phenomena. In this work, we extend that theory in two significant ways. First, we incorporate energy spectrum degeneracies, which were previously overlooked. Additionally, we define gauge-invariant entropy, exploring its properties and connections to other physical and informational quantities. This results in a complete framework for quantum thermodynamics grounded in the principle of gauge invariance. To demonstrate some implications of this theory, we apply it to well-known critical systems.

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