arXiv subjects

Cesar Damian

Publications and source records attributed to Cesar Damian.

At least 19 recordsLinked to original sources

arXiv2026

Double fibration in G-theory and the cobordism conjecture

We investigate Type IIB compactifications with spatially varying fluxes and dilaton profiles in the setting of dynamical cobordism. In particular, we analyze a G-theory motivated compactification in which the fluxes and the dilaton depend on coordinates of a complex two-dimensional plane. From the equations of motion, we deduce the existence of End of the World branes. In a cohomological interpretation, these branes appear precisely in order to trivialize the relevant cohomology class. Furthermore, we compute the associated bordism group and show that additional non-perturbative objects are needed to cancel the class, while retaining the cohomological contribution as a subgroup. This suggests a mathematical structure that connects energy scales with the emergence of perturbative and non-perturbative physics.

hep-th↗

arXiv2026

The Hagedorn Temperature as a Nonequilibrium Dynamical Bottleneck in String Thermodynamics

We revisit the Hagedorn regime of string theory from a nonequilibrium perspective using Steepest-Entropy-Ascent Quantum Thermodynamics (SEAQT), which formulates thermodynamic evolution directly on the state manifold without requiring a globally well-defined canonical ensemble. Treating the inverse temperature as an instantaneous, state-dependent quantity, we derive its exact scalar evolution equation, governed in the commuting limit by higher-order fluctuation moments. In an open-system extension we prove that the inverse-temperature mobility equals unity identically on the quasi-canonical family: a divergent Hagedorn variance is necessary but not sufficient for slowing-down. Sustained Hagedorn pinning requires a definite energy-injection topology, realized by a two-sector construction in which the reservoir couples only to light quasi-particle modes; the mobility then collapses, the intensive variable freezes at the Hagedorn scale, and energy condenses into the long-string sector at a finite rate. Promoting the Hagedorn scale to a moduli-dependent quantity along emergent-string limits yields a finite critical distance $\Delta_*$ beyond which pinning activates, with thermodynamic inertia diverging as $(\Delta_*-\Delta)^{a-3}$ for $1<a<3$, a thermodynamic discriminant between emergent-string and decompactification limits.

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arXiv2024

An effective description of the instability of coherent states of gravitons in string theory

We study the dynamics of a coherent state of closed type II string gravitons within the framework of the Steepest Entropy Ascent Quantum Thermodynamics, an effective model where the quantum evolution is driven by a maximal increase of entropy. We find that by perturbing the pure coherent state of gravitons by the presence of other coherent fields in the string spectrum, there exists conditions upon which the system undergoes decoherence by reaching thermodynamical equilibrium. Following the proposal by Dvali, et al., this suggests the instability of the classical dS space. We identify the time scale it takes the system to reach equilibrium consisting of a mixed state of fields in the string spectrum and compare it with the quantum-break time. Also we find that in such final state the quantum-break time seems to be larger than the classical break-time, in agreement with the Swampland conjectures about the dS solution in string theory.

hep-th↗

arXiv2024

Non-equilibrium and equilibrium thermodynamic foundations of the 2D toric code within the SEAQT framework

The 2D toric code is a prototypical example that exhibits non-trivial topological properties and a ground state possessing a non-trivial topological order. Until now, all the cases studied in the literature have been in the stable equilibrium regime, leaving the relaxation towards this state unexplored. In the present work, the dynamics of the toric code towards stable equilibrium is explored within the steepest-entropy-ascent quantum thermodynamic (SEAQT) framework. Under these dynamics, information correlations such as the relative entropy, logarithmic negativity, magnetization, coherent information, and geometric entropy are described out of equilibrium, permitting a connection to be made between the out-of-equilibrium dynamics and these information measures.

quant-ph↗

arXiv2024

Model for Predicting Adsorption Isotherms and the Kinetics of Adsorption via Steepest-Entropy-Ascent Quantum Thermodynamics

This work outlines the foundations for being able to do a first-principle study of the adsorption process using the steepest-entropy-ascent quantum thermodynamic (SEAQT) framework, a framework able to predict the unique non-equilibrium path taken by a system from some initial state to stable equilibrium. To account for the process of multi-component adsorption, the SEAQT framework incorporates the particle number operator for each absorbed species directly into its equation of motion. The theoretical models developed are validated via some initial comparisons with experimental data found in the literature, demonstrating good agreement. The findings reveal that this framework can be an effective tool for describing the adsorption process out of equilibrium. It is able to do so without $a \; priori$ knowledge of the specific adsorption mechanism(s) involved. It also aligns well with the anticipated predictions of equilibrium models. In addition, within this framework, all intensive thermodynamic properties are characterized by out-of-equilibrium fluctuations, highlighting the significance of non-equilibrium thermodynamics in predicting measurable physical quantities.

physics.chem-ph↗

arXiv2024

Steepest-Entropy-Ascent Framework for Predicting Arsenic Adsorption on Graphene Oxide Surfaces -- A Case Study

Water contamination by arsenic(V) constitutes a major public-health concern, underscoring the need for models that capture both equilibrium and transient adsorption behaviour. A framework that can do so is the steepest-entropy-ascent quantum thermodynamic (SEAQT) framework, which is used here to describe the uptake of As(V) on graphene oxide (GO) across pollutant concentrations of 25-350 mg/L. A non-equilibrium equation of motion derived from the steepest-entropy-ascent principle for a five-component system (water, arsenic, two GO functional groups, and protons is solved with an energy eigenstructure generated by a Replica-Exchange Wang-Landau algorithm and then extrapolated to relevant contaminant concentrations via an artificial neural network. Without recourse to empirical rate laws, the model predicts the time-dependent adsorption capacity, the stable-equilibrium arsenic concentration, and the pH dependence of removal efficiency. Equilibrium capacities are reproduced within 5 % of experimental isotherms, and the characteristic adsorption time aligns with the reported kinetics. These results indicate that SEAQT framework provides a thermodynamically consistent, fully predictive tool for designing and optimising adsorbent-based water-treatment technologies.

physics.chem-ph↗

arXiv2024

Modeling the effects of perturbations and steepest entropy ascent on the time evolution of entanglement

This work presents an analysis of the evolution of perturbed Bell diagonal states using the equation of motion of steepest-entropy-ascent quantum thermodynamics (SEAQT), the Lindblad equation, and various measures of loss of entanglement. First, a brief derivation is presented showing that Bell diagonal states are stationary states that are not stable equilibrium states relative to the SEAQT equation of motion, highlighting the need for the development of perturbation methods to study the evolutions of nearby states. This contrasts with the Lindblad equation of motion for which only some of the Bell diagonal states are stationary. Next, two perturbation methods are presented. The first is a weighted-average method for perturbing bi-partite system states and the second is a general bi-partite method based on a set of unitary operations that are constrained to hold the system energy and system entropy constant. Sets of density operators are randomly generated with each method and the resulting time-varying characteristics of the system's entanglement are analyzed using the SEAQT and Lindblad frameworks. The findings reveal that the evolutions associated with the constrained perturbations accurately predict the loss of non-locality and align well with the measured concurrence. In addition, using the SEAQT framework, the deep connection between the thermodynamic states of the state evolution of the system and the loss of non-locality is quantitatively demonstrated.

quant-ph↗

arXiv2023

Galois groups of uplifted de Sitter vacua

We compute the Galois group of a polynomial whose roots are determined by the critical points of a scalar potential in type IIB compactifications. We focus our study on certain perturbative models where it is feasible to construct a de Sitter vacuum within the effective theory by introducing non-geometric fluxes, D-branes, or non-BPS states. Our findings clearly show that all de Sitter vacua derived from lifting AdS stable vacua are associated with an unsolvable Galois group. This suggests a deeper connection between the fundamental principles of Galois theory and its applications in the construction of dS vacua.

hep-th↗

arXiv2022

Metastable vacua from torsion and machine learning

By implementing an error function on a Machine Learning algorithm we look for minimal conditions to construct stable Anti de Sitter and de Sitter vacua from dimensional type IIB String theory compactifcation on K\"ahler manifolds with torsion. This allows to have contributions to the scalar potential from the five-form flux and from D-branes wrapping torsional cycles, interpreted as non-BPS states. The former implies the possibility to construct stable AdS vacua while the later constitutes a mechanism to uplift AdS to dS vacua. Particularly we consider $\hat{D5}$ non-BPS states to uplift the stable AdS vacua to an (apparently) stable dS minimum. Both results -- the generation of an AdS vacuum and the corresponding uplifting to a dS one -- are restricted to certain type of configurations, specifically with the number of O3 orientifolds bounded from below by the number of D3-branes and fluxes. Under these conditions we report over 170 dS (classical) stable vacua. In all of them, the uplifted effective potential becomes very flat indicating the presence of possible source of instabilities. We comment about their relation with the Swampland Conjectures.

hep-th↗

arXiv2021

Inflationary implications of the Covariant Entropy Bound and the Swampland de Sitter Conjectures

We present a proposal to relate the de Sitter Conjecture (dSC) to the Covariant Entropy Bound (CEB). By assuming an early phase of accelerated expansion where the CEB is satisfied, we take into account a contribution from extra-dimensions to the four-dimensional entropy which restricts the values of the usual slow-roll parameters. We show in this context that the dSC inequalities follow from the CEB -- including their mutual exclusion -- in both single and multi-field inflationary scenarios. We also observe that the order one constants, c and c' in the conjecture are given in terms of physical quantities such as the change in entropy over time, the Hubble constant and the dynamics of the effective scalar fields. Finally, we give a simple example to illustrate a possible contribution to the four-dimensional entropy from a flux string scenario.

hep-th↗

arXiv2020

Testing Swampland Conjectures with Machine Learning

We consider Type IIB compactifications on an isotropic torus $T^6$ threaded by geometric and non geometric fluxes. For this particular setup we apply supervised machine learning techniques, namely an artificial neural network coupled to a genetic algorithm, in order to obtain more than sixty thousand flux configurations yielding to a scalar potential with at least one critical point. We observe that both stable AdS vacua with large moduli masses and small vacuum energy as well as unstable dS vacua with small tachyonic mass and large energy are absent, in accordance to the Refined de Sitter Conjecture. Moreover, by considering a hierarchy among fluxes, we observe that perturbative solutions with small values for the vacuum energy and moduli masses are favored, as well as scenarios in which the lightest modulus mass is much greater than the corresponding AdS vacuum scale. Finally we apply some results on Random Matrix Theory to conclude that the most probable mass spectrum derived from this string setup is that satisfying the Refined de Sitter and AdS scale conjectures.

hep-th↗

arXiv2019

Some remarks on the dS conjecture, fluxes and K-theory in IIB toroidal compactifications

In this note, we present a scenario in which the existence of dS vacua is jeopardized by topological transitions between non-BPS branes and fluxes in type IIB toroidal compactifications. We focus our study on a six-dimensional torus compactification modded out by an orientifold three-plane. In particular, we consider the presence of non-BPS five branes, which allows the construction of apparent stable dS vacua. Since moduli stabilization requires the presence of NS-NS fluxes, we also describe the minimal required conditions to avoid the appearance of Freed-Witten anomalies. Cancellation of these anomalies implies a topological transformation between non-BPS states and fluxes with the same discrete K- theory charge. After the transition, we observe that the scalar potential undergoes major changes, implying that the dS vacua are unstable. We discuss a scenario in which, even if the discrete K-theory charge is globally cancelled, the above transitions could still be relevant, allowing the existence of short-lived dS minima. We briefly comment on how these implications seem to be in concordance with the Refined de Sitter and Trans-Planckian Censorship Conjectures.

hep-th↗

arXiv2019

Leaving the Swampland: Non-geometric fluxes and the Distance Conjecture

We study a Type IIB isotropic toroidal compactification with non-geometric fluxes. Under the assumption of a hierarchy on the moduli, an effective scalar potential is constructed showing a runaway direction on the real part of the K\"ahler modulus while the rest of the moduli are stabilized. For the effective model to be consistent it is required that displacements in the field space are finite. Infinite distances in field space would imply a breakdown in the hierarchy assumption on the moduli. In this context, the Swampland Distance Conjecture is satisfied suggesting the possibility of leaving or entering the Swampland by a parametric control of the fluxes. This is achieved upon allowing the non-geometric fluxes to take fractional values. In the process we are able to compute the cut-off scale below which the theory is valid, completely depending on the flux configuration. We also report on the appearance of a discrete spectrum of values for the string coupling at the level of the effective theory.

hep-th↗

arXiv2018

Two-field axion inflation and the swampland constraint in the flux-scaling scenario

Based on the flux-scaling scenario we study a model consisting on Type IIB string theory compactified on a Calabi-Yau manifold with a frozen complex structure in the presence of generic fluxes. The model contains (meta)stable Minkowski and de Sitter vacua as well as inflationary directions driven by two independent linear combination of axions. Due to a numerical control by fluxes, we show that cosmological parameters as the spectral index, tensor-to-scalar ratio and non-Gaussianities can be kept within observed bounds while preserving the desired hierarchies on physical scales. Moreover we compute the deviation of the inflationary trajectories from geodesics on field space in terms of the fluxes showing that for some regions, they fulfill the recent proposed swampland criterion for multi-field scenarios.

hep-th↗

arXiv2017

Meromorphic Flux Compactification

We present exact solutions of four-dimensional Einstein's equations related to Minkoswki vacuum constructed from Type IIB string theory with non-trivial fluxes. Following recent works, we study a non-trivial flux compactification on a fibered product by a four-dimensional torus and a two-dimensional sphere punctured by 5- and 7-branes. By considering only 3-form fluxes and the dilaton, as functions on the internal sphere coordinates, we show that these solutions correspond to a family of supersymmetric solutions constructed by the use of G-theory. Meromorphicity on functions constructed in terms of fluxes and warping factors guarantees that flux and 5-brane contributions to the scalar curvature vanish while fulfilling stringent constraints as tadpole cancellation and Bianchi identities. Different Einstein's solutions are shown to be related by U-dualities. We present three supersymmetric non-trivial Minkowski vacuum solutions and compute the corresponding soft terms. We also construct a non-supersymmetric solution and study its stability.

hep-th↗

arXiv2015

The Flux-Scaling Scenario: De Sitter Uplift and Axion Inflation

Non-geometric flux-scaling vacua provide promising starting points to realize axion monodromy inflation via the F-term scalar potential. We show that these vacua can be uplifted to Minkowski and de Sitter by adding an anti D3-brane or a D-term containing geometric and non-geometric fluxes. These uplifted non-supersymmetric models are analyzed with respect to their potential to realize axion monodromy inflation self-consistently. Admitting rational values of the fluxes, we construct examples with the required hierarchy of mass scales.

hep-th↗

arXiv2015

Type IIB flux vacua from G-theory II

We find analytic solutions of type IIB supergravity on geometries that locally take the form $\text{Mink}\times M_4\times \mathbb{C}$ with $M_4$ a generalised complex manifold. The solutions involve the metric, the dilaton, NSNS and RR flux potentials (oriented along the $M_4$) parametrised by functions varying only over $\mathbb{C}$. Under this assumption, the supersymmetry equations are solved using the formalism of pure spinors in terms of a finite number of holomorphic functions. Alternatively, the solutions can be viewed as vacua of maximally supersymmetric supergravity in six dimensions with a set of scalar fields varying holomorphically over $\mathbb{C}$. For a class of solutions characterised by up to five holomorphic functions, we outline how the local solutions can be completed to four-dimensional flux vacua of type IIB theory. A detailed study of this global completion for solutions with two holomorphic functions has been carried out in the companion paper [1]. The fluxes of the global solutions are, as in F-theory, entirely codified in the geometry of an auxiliary $K3$ fibration over $\mathbb{CP}^1$. The results provide a geometric construction of fluxes in F-theory.

hep-th↗

arXiv2015

Type IIB flux vacua from G-theory I

We construct non-perturbatively exact four-dimensional Minkowski vacua of type IIB string theory with non-trivial fluxes. These solutions are found by gluing together, consistently with U-duality, local solutions of type IIB supergravity on $T^4 \times \mathbb{C}$ with the metric, dilaton and flux potentials varying along $\mathbb{C}$ and the flux potentials oriented along $T^4$. We focus on solutions locally related via U-duality to non-compact Ricci-flat geometries. More general solutions and a complete analysis of the supersymmetry equations are presented in the companion paper [1]. We build a precise dictionary between fluxes in the global solutions and the geometry of an auxiliary $K3$ surface fibered over $\mathbb{CP}^1$. In the spirit of F-theory, the flux potentials are expressed in terms of locally holomorphic functions that parametrize the complex structure moduli space of the $K3$ fiber in the auxiliary geometry. The brane content is inferred from the monodromy data around the degeneration points of the fiber.

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