Flux Landscape Research Articles

Finiteness theorems and counting conjectures for the flux landscape

In this paper, we explore the string theory landscape obtained from type IIB and F-theory flux compactifications. We first give a comprehensive introduction to a number of mathematical finiteness theorems, indicate how they have been obtained, and clarify their implications for the structure of the locus of flux vacua. Subsequently, in order to address finer details of the locus of flux vacua, we propose three mathematically precise conjectures on the expected number of connected components, geometric complexity, and dimensionality of the vacuum locus. With the recent breakthroughs on the tameness of Hodge theory, we believe that they are attainable to rigorous mathematical tools and can be successfully addressed in the near future. The remainder of the paper is concerned with more technical aspects of the finiteness theorems. In particular, we investigate their local implications and explain how infinite tails of disconnected vacua approaching the boundaries of the moduli space are forbidden. To make this precise, we present new results on asymptotic expansions of Hodge inner products near arbitrary boundaries of the complex structure moduli space.

W0_sample = np.random.normal(0,1)?

In this note, we explore the distribution of vacuum expectation values of the superpotential W0 in explicit Type IIB flux compactifications. We show that the distribution can be approximated universally across geometries by a two-dimensional Gaussian with a model-dependent standard deviation. We identify this behaviour in 20 Calabi-Yau orientifold compactifications with between two and five complex structure moduli by constructing a total of O(107) flux vacua. We observe a characteristic scaling behaviour of the width σ of our distributions with respect to the D3-charge contributions Nflux from fluxes which can be approximated by σ∼Nflux. This W0 distribution implies that locating small values of |W0| as a preferred regime associated with classes of string theory solutions typically featuring hierarchies, simplifies to the basic statement of finding small Euclidean norms of normally distributed values. We also identify small modifications to this Gaussian behaviour in our samples, which might be seen as indications for the breakdown of the continuous flux approximation commonly used in the context of statistical analyses of the flux landscape.

Flux Landscape with enhanced symmetry not on SL(2, ℤ) elliptic points

We study structures of solutions for SUSY Minkowski F-term equations on two toroidal orientifolds with h2,1 = 1. Following our previous study [1], with fixed upper bounds of a flux D3-brane charge Nflux, we obtain a whole Landscape and a distribution of degeneracies of physically-distinct solutions for each case. In contrast to our previous study, we consider a non-factorizable toroidal orientifold and its Landscape on which SL(2, ℤ) is violated into a certain congruence subgroup, as it had been known in past studies. We find that it is not the entire duality group that a complex-structure modulus U enjoys but its outer semi-direct product with a “scaling” outer automorphism group. The fundamental region is enlarged to include the |U| < 1 region. In addition, we find that high degeneracy is observed at an elliptic point, not of SL(2, Z) but of the outer automorphism group. Furthermore, ℤ2-enhanced symmetry is realized on the elliptic point. The outer automorphism group is exceptional in the sense that it is consistent with a symplectic basis transformation of background three-cycles, as opposed to the outer automorphism group of SL(2, ℤ). We also compare this result with Landscape of another factorizable toroidal orientifold.

Norway's Climate Odyssey: Assessing Impacts, Mitigation Strategies, and Policy Responses in a Warming Arctic

Norway, a nation renowned for its dramatic landscapes, stands at the forefront of confronting the global climate crisis, particularly within the unique context of a warming Arctic. This article embarks on a comprehensive exploration of Norway's responses to the climate challenge, offering a nuanced assessment of climate change impacts, evaluation of mitigation strategies, and analysis of policy responses. The Arctic, with its iconic glaciers, fjords, and delicate ecosystems, bears witness to the unfolding narrative of climate transformation. Our assessment of climate change impacts reveals a landscape in flux, marked by melting glaciers, altered precipitation patterns, and shifting ecosystems. The article delves into the multifaceted implications of these changes, from their ecological consequences to their socio-economic effects on key sectors such as agriculture, fisheries, tourism, and infrastructure. Norway's proactive stance in mitigating climate change emerges through a rich tapestry of strategies. From the development of renewable energy sources to groundbreaking carbon capture and storage (CCS) projects, the nation has harnessed innovation and sustainability to navigate the path toward a low-carbon future. Emissions reduction targets, legislative frameworks, and international collaborations align Norway's climate policies with global agreements like the Paris Agreement.

Norway's Climate Odyssey: Assessing Impacts, Mitigation Strategies, and Policy Responses in a Warming Arctic

Norway, a nation renowned for its dramatic landscapes, stands at the forefront of confronting the global climate crisis, particularly within the unique context of a warming Arctic. This article embarks on a comprehensive exploration of Norway's responses to the climate challenge, offering a nuanced assessment of climate change impacts, evaluation of mitigation strategies, and analysis of policy responses. The Arctic, with its iconic glaciers, fjords, and delicate ecosystems, bears witness to the unfolding narrative of climate transformation. Our assessment of climate change impacts reveals a landscape in flux, marked by melting glaciers, altered precipitation patterns, and shifting ecosystems. The article delves into the multifaceted implications of these changes, from their ecological consequences to their socio-economic effects on key sectors such as agriculture, fisheries, tourism, and infrastructure. Norway's proactive stance in mitigating climate change emerges through a rich tapestry of strategies. From the development of renewable energy sources to groundbreaking carbon capture and storage (CCS) projects, the nation has harnessed innovation and sustainability to navigate the path toward a low-carbon future. Emissions reduction targets, legislative frameworks, and international collaborations align Norway's climate policies with global agreements like the Paris Agreement.

Regulation of plant carbon assimilation metabolism by post-translational modifications.

The flexibility of plant growth, development and stress responses is choreographed by an intricate network of signaling cascades and genetic programs. However, it is metabolism that ultimately executes these programs through the selective delivery of specific building blocks and energy. Photosynthetic carbon fixation is the central pillar of the plant metabolic network, the functioning of which is conditioned by environmental fluctuations. Hence, regulation of carbon assimilation metabolism must be particularly versatile and rapid to maintain efficiency and avoid dysfunction. While changes in gene expression can adjust the global inventory and abundance of relevant proteins, their specific characteristics are dynamically altered at the post-translational level. Here we highlight studies that show the extent of the regulatory impact by post-translational modification (PTM) on carbon assimilation metabolism. We focus on examples for which there has been empirical evidence of functional changes associated with a PTM, rather than just the occurrence of PTMs at specific sites in proteins, as regularly detected in proteomic studies. The examples indicate that we are only at the beginning of deciphering the PTM-based regulatory network that operates in plant cells. However, it is becoming increasingly clear that targeted exploitation of PTM engineering has the potential to control the metabolic flux landscape as a prerequisite for increasing crop yields, modifying metabolite composition, optimizing stress tolerance, and even executing novel growth and developmental programs.

Peruvian thanatoscape and posthumous biographies of prisoners: dispersion and re-appropriation of undesirable corpses

This article examines the necropolitical significance of the posthumous biographies of the inmates who were executed in the repression of the Santa Barbara, Lurigancho, and El Frontón prison riots of 1986 in Lima. Of the estimated 250 victims, only 22 have been handed over to their families. The path taken by the bodies is traced, along with the means employed by state agents to conceal them. We then analyze the modalities of their recovery, identification, and return (or otherwise), beginning in the 2000s. We coin the concept of “thanatoscape” to evoke the places and dynamics of a landscape in flux, encompassing the physical circulation of the deceased and the associated imaginary. The material dimension of the body is considered, along with how it is created symbolically by society and power relations. We discuss the means used to justify and legitimize whether these mortal remains deserved to be properly mourned or would remain missing and deprived of the opportunity to receive funeral rites. The management of these undesirable bodies can be better understood by studying the process of “de-citizenization” to which prisoners held for terrorism-related offenses were subjected, and which also extends to their families.

How can airports fully embrace multimodal and interoperable mobility ecosystems to deliver sustainability goals and offer a superior passenger experience?

The future of mobility will be fundamentally different from what we know today. While demand for mobility will thrive again after the pandemic, new means of transport and new market players will shape everyday customer mobility of the 2030s and 2040s. To overcome the challenges that the mobility market of 2050 will pose, airports need to fully embrace multimodal and interoperable mobility ecosystems in order to deliver sustainability goals and offer a superior passenger experience. Using the example of Frankfurt Airport, this article addresses the complexity of a mobility landscape in flux. It will be shown how intermodality can both address sustainability demands and provide a customer-centric approach to innovation and digitalisation with regard to mobility. The purpose of this paper is to present one possible approach to the set of challenges it describes: the mobility hub. Current mobility options and customer needs are analysed and, supported by the findings of a customer survey, focus areas allowing airports to evolve towards mobility ecosystems of the future are discovered. Two main goals are identified that support the airport's transformation into a mobility hub, thus suggesting and promoting a possible best practice and providing strategic direction: quality of connectivity and quantity of means of transport. For both, suggestions for fields of action are provided that range from short to long-term strategy.

Sharpening the boundaries between flux landscape and swampland by tadpole charge

We investigate the vacuum structure of four-dimensional effective theory arising from Type IIB flux compactifications on a mirror of the rigid Calabi-Yau threefold, corresponding to a T-dual of the DeWolfe-Giryavets-Kachru-Taylor model in Type IIA flux compactifications. By analyzing the vacuum structure of this interesting corner of string landscape, it turns out that there exist perturbatively unstable de Sitter (dS) vacua in addition to supersymmetric and non-supersymmetric anti-de Sitter vacua. On the other hand, the stable dS vacua appearing in the low-energy effective action violate the tadpole cancellation condition, indicating a strong correlation between the existence of dS vacua and the flux-induced D3-brane charge (tadpole charge). We also find analytically that the tadpole charge constrained by the tadpole cancellation condition emerges in the scalar potential in a nontrivial way. Thus, the tadpole charge would restrict the existence of stable dS vacua, and this fact underlies the statement of the dS conjecture. Furthermore, our analytical and numerical results exhibit that distributions of mathcal{O}(1) parameters in expressions of several swampland conjectures peak at specific values.

Moduli space holography and the finiteness of flux vacua

A holographic perspective to study and characterize field spaces that arise in string compactifications is suggested. A concrete correspondence is developed by studying two-dimensional moduli spaces in supersymmetric string compactifications. It is proposed that there exist theories on the boundaries of each moduli space, whose crucial data are given by a Hilbert space, an Sl(2, ℂ)-algebra, and two special operators. This boundary data is motivated by asymptotic Hodge theory and the fact that the physical metric on the moduli space of Calabi-Yau manifolds asymptotes near any infinite distance boundary to a Poincaré metric with Sl(2, ℝ) isometry. The crucial part of the bulk theory on the moduli space is a sigma model for group-valued matter fields. It is discussed how this might be coupled to a two-dimensional gravity theory. The classical bulk-boundary matching is then given by the proof of the famous Sl(2) orbit theorem of Hodge theory, which is reformulated in a more physical language. Applying this correspondence to the flux landscape in Calabi-Yau fourfold compactifications it is shown that there are no infinite tails of self-dual flux vacua near any co-dimension one boundary. This finiteness result is a consequence of the constraints on the near boundary expansion of the bulk solutions that match to the boundary data. It is also pointed out that there is a striking connection of the finiteness result for supersymmetric flux vacua and the Hodge conjecture.

A campus start-up ecosystem for mechanical engineering students: Challenges, approaches, catalysts and solutions

Start-up ecosystems are emerging rapidly worldwide. The speed of technology innovation and the diversity of business ideas keep the start-up landscape in constant flux. While many emerging start-ups are in the areas of electronics and information sciences, the field of mechanical engineering has huge potential that has yet to be exploited. Today’s mechanical engineering students need to be well positioned to recognize and seize potential start-up opportunities. This study examines the involvement of Indian mechanical engineering students in campus start-ups and the challenges they face in nascent entrepreneurship. Structural equation modelling was applied to a sample of 396 final-year undergraduate mechanical engineering students from the APJ Abdul Kalam Technological University in Kerala. Data collection was achieved through a questionnaire developed on the basis of existing literature, feedback and market research. The findings highlight the currently prevailing barriers and best practices, and recommendations are derived for leveraging the nascent entrepreneurship potential of the mechanical engineering discipline. The negative effects of the barriers are positively moderated by the activities of campus-based entrepreneurship centres. The study results provide insights into the role of universities, higher education departments and government agencies in promoting a sustainable campus start-up culture through entrepreneurial learning.

Quantifying the potential and flux landscapes for nonequilibrium multiverse, a new scenario for time arrow

We propose a new scenario of nonequilibirum multiverse. We quantified the potential landscape and the flux landscape for the multiverse. The potential landscape quantifies the weight of each universe. When the terminal vacuum with zero (flat) or negative cosmological constant (AdS) have a chance to tunnel back to the normal universes with positive cosmological constant (dS) through the bounce suggested by the recent studies, the detailed balance of the populations of the multiverse can be broken. We found that the degree of the detailed balance breaking can be quantified by the underlying average flux and associated flux landscape, which gives arise to the dynamical origin of irreversibility and the time arrow of the multiverse. We also showed that the steady state of the multiverse is maintained by the thermodynamic cost quantified by the entropy production rate which is associated to the flux. This gives arise to thermodynamic origin of time irreversibility. On the other hand, we show that the evolution dynamics of the multiverse is determined by both the potential landscape and flux landscape. While the potential landscape determines the weight of the universes in the multiverse and attracts the multiverse to the steady state basins, the flux landscape provides the cycles or loops associating certain universes together. We show that terminal vacuum universes can have dominant weights or lowest potentials giving arise to a funnel shaped potential landscape, while terminal vacuum universes together with other normal universes including ours can form dominant cycles giving arise to a funnel shaped cycle flux landscape. This indicates that even our universe may not be distinct from others based on the probability measure, it may lie in the dominant cycle(s), leading to higher chance of being found. This may provide an additional way beyond the anthropic principle for identifying our universe.

Landscape and flux quantify the stochastic transition dynamics for p53 cell fate decision.

The p53 transcription factor is a key mediator in cellular responses to various stress signals including DNA repair, cell cycle arrest, and apoptosis. In this work, we employ landscape and flux theory to investigate underlying mechanisms of p53-regulated cell fate decisions. Based on a p53 regulatory network, we quantified the potential landscape and probabilistic flux for the p53 system. The landscape topography unifies and quantifies three cell fate states, including the limit cycle oscillations (representing cell cycle arrest), high p53 state (characterizing apoptosis), and low p53 state (characterizing the normal proliferative state). Landscape and flux results provide a quantitative explanation for the biphasic dynamics of the p53 system. In the oscillatory phase (first phase), the landscape attracts the system into the ring valley and flux drives the system cyclically moving, leading to cell cycle arrest. In the fate decision-making phase (second phase), the ring valley shape of the landscape provides an efficient way for cells to return to the normal proliferative state once DNA damage is repaired. If the damage is unrepairable with larger flux, the system may cross the barrier between two states and switch to the apoptotic state with a high p53 level. By landscape-flux decomposition, we revealed a trade-off between stability (guaranteed by landscape) and function (driven by flux) in cellular systems. Cells need to keep a balance between appropriate speed to repair DNA damage and appropriate stability to survive. This is further supported by flux landscape analysis showing that flux may provide the dynamical origin of phase transition in a non-equilibrium system by changing landscape topography.

T -dualizing de Sitter no-go scenarios

In the context of realizing de Sitter vacua and the slow-roll inflation, several no-go conditions have been found in the framework of type IIA (generalized) flux compactifications. In this article, using our recently proposed $T$-dual dictionary [P. Shukla, A dictionary for the type II non-geometric flux compactifications, arXiv:1909.07391], we translate various such type IIA no-go conditions that subsequently lead to some interesting de Sitter no-go scenarios in the presence of (non)geometric fluxes on the dual type IIB side. We also present the relevance of using $K3/{\mathbb{T}}^{4}$-fibered Calabi Yau threefolds in order to facilitate one particular class of the de Sitter no-go conditions. This analysis helps in refining certain corners of the vast nongeometric flux landscape for the hunt of de Sitter vacua.

Searching for the Mechanisms of Mammalian Cellular Aging Through Underlying Gene Regulatory Networks

Aging attracts the attention throughout the history of humankind. However, it is still challenging to understand how the internal driving forces, for example, the fundamental building blocks of life, such as genes and proteins, as well as the environments work together to determine longevity in mammals. In this study, we built a gene regulatory network for mammalian cellular aging based on the experimental literature and quantify its underlying driving force for the dynamics as potential and flux landscape. We found three steady-state attractors: a fast-aging state attractor, slow-aging state attractor, and intermediate state attractor. The system can switch from one state attractor to another driven by the intrinsic or external forces through the genetics and the environment. We identified the dominant path from the slow-aging state directly to the fast-aging state. We also identified the dominant path from slow-aging to fast-aging through an intermediate state. We quantified the evolving landscape for revealing the dynamic characteristics of aging through certain regulation changes in time. We also predicted the key genes and regulations for fast-aging and slow-aging through the analysis of the stability for landscape basins. We also found the oscillation dynamics between fast-aging and slow-aging and showed that more energy is required to sustain such oscillations. We found that the flux is the dynamic cause and the entropy production rate the thermodynamic origin of the phase transitions or the bifurcations between the three-state phase and oscillation phase. The landscape quantification provides a global and physical approach to explore the underlying mechanisms of cellular aging in mammals.

Magnetic Recording of Superconducting States

Local polarization of magnetic materials has become a well-known and widely used method for storing binary information. Numerous applications in our daily life such as credit cards, computer hard drives, and the popular magnetic drawing board toy, rely on this principle. In this work, we review the recent advances on the magnetic recording of inhomogeneous magnetic landscapes produced by superconducting films. We summarize the current compelling experimental evidence showing that magnetic recording can be applied for imprinting in a soft magnetic layer the flux trajectory taking place in a superconducting layer at cryogenic temperatures. This approach enables the ex situ observation at room temperature of the imprinted magnetic flux landscape obtained below the critical temperature of the superconducting state. The undeniable appeal of the proposed technique lies in its simplicity and the potential to improve the spatial resolution, possibly down to the scale of a few vortices.

Deciphering bacterial xylose metabolism and metabolic engineering of industrial microorganisms for use as efficient microbial cell factories.

The goal of sustainable production of biochemicals and biofuels has driven the engineering of microbial cell as factories that convert low-value substrates to high-value products. Xylose is the second most abundant sugar substrate in lignocellulosic hydrolysates. We analyzed the mechanisms of xylose metabolism using genome sequencing data of 492 industrially relevant bacterial species in the mini-review. The analysis revealed the xylose isomerase and Weimberg pathways as the major routes across diverse routes of bacterial xylose metabolism. In addition, we discuss recent developments in metabolic engineering of xylose metabolism in industrial microorganisms. Genome-scale analyses have revealed xylose pathway-specific flux landscapes. Overall, a comprehensive understanding of bacterial xylose metabolism could be useful for the feasible development of microbial cell factories.

Funneled potential and flux landscapes dictate the stabilities of both the states and the flow: Fission yeast cell cycle.

Using fission yeast cell cycle as an example, we uncovered that the non-equilibrium network dynamics and global properties are determined by two essential features: the potential landscape and the flux landscape. These two landscapes can be quantified through the decomposition of the dynamics into the detailed balance preserving part and detailed balance breaking non-equilibrium part. While the funneled potential landscape is often crucial for the stability of the single attractor networks, we have uncovered that the funneled flux landscape is crucial for the emergence and maintenance of the stable limit cycle oscillation flow. This provides a new interpretation of the origin for the limit cycle oscillations: There are many cycles and loops existed flowing through the state space and forming the flux landscapes, each cycle with a probability flux going through the loop. The limit cycle emerges when a loop stands out and carries significantly more probability flux than other loops. We explore how robustness ratio (RR) as the gap or steepness versus averaged variations or roughness of the landscape, quantifying the degrees of the funneling of the underlying potential and flux landscapes. We state that these two landscapes complement each other with one crucial for stabilities of states on the cycle and the other crucial for the stability of the flow along the cycle. The flux is directly related to the speed of the cell cycle. This allows us to identify the key factors and structure elements of the networks in determining the stability, speed and robustness of the fission yeast cell cycle oscillations. We see that the non-equilibriumness characterized by the degree of detailed balance breaking from the energy pump quantified by the flux is the cause of the energy dissipation for initiating and sustaining the replications essential for the origin and evolution of life. Regulating the cell cycle speed is crucial for designing the prevention and curing strategy of cancer.

Quantifying the potential and flux landscapes of multi-locus evolution

Exploration of multi-locus evolution is critically important for understanding evolutionary dynamics. Recombination and epistasis lead to complex evolutionary dynamics. Quantifying the stability and function of such multi-locus evolutionary systems globally is a long-standing challenge for evolutionary biologists. The conventional Wright, Fisher and quasi-linkage equilibrium (QLE) theories can only be applied to highly restricted, simplified and special evolutionary scenarios. In this study, we developed a non-equilibrium potential and flux landscape theory to explore the multi-locus evolution beyond Wright, Fisher and the QLE. We found that the intrinsic potential landscape as a Lyapunov function under the zero noise limit can be used to describe the global stability of a deterministic multi-locus system. We identified and quantified two driving forces responsible for multi-locus evolution: the underlying landscape and the curl flux. We studied the evolution of different cases under recombination, epistasis and mutation. Recombination, frequency-dependent selection and mutation can give rise to non-zero curl flux. In particular, we investigated the dynamics of a simple example of a two-locus system. We explored the underlying potential landscape which shows stable basins attracting the system down to valleys and rotating curl flux, which aids the global communication under recombination, epistasis and mutation. Discontinuities in the first derivative of the non-equilibrium free energy functional shows the non-equilibrium phase transition as the recombination rate increases. We also explored the effect of epistasis on mono-stability and bi-stability evolution. Mutation may drive the system far from equilibrium and be another source of non-zero probability flux. Entropy production rate can quantify energy consumption or dissipation. We explained the origin of the Red Queen hypothesis for endless evolution using the curl flux. Our landscape and flux framework can be applied more generally to multi-locus evolutionary systems experiencing recombination and epistasis.

On the emergence of macroscopic transport barriers from staircase structures

This paper presents a theory for the formation and evolution of coupled density staircases and zonal shear profiles in a simple model of drift-wave turbulence. Density, vorticity, and fluctuation potential enstrophy are the fields evolved in this system. Formation of staircase structures is due to inhomogeneous mixing of generalized potential vorticity (PV), resulting in the sharpening of density and vorticity gradients in some regions, and weakening them in others. When the PV gradients steepen, the density staircase structure develops into a lattice of mesoscale “jumps,” and “steps,” which are, respectively, the regions of local gradient steepening and flattening. The jumps merge and migrate in radius, leading to the development of macroscale profile structures from mesoscale elements. The positive feedback process, which drives the staircase formation occurs via a Rhines scale dependent mixing length. We present extensive studies of bifurcation physics of the global state, including results on the global flux-gradient relations (flux landscapes) predicted by the model. Furthermore, we demonstrate that, depending on the sources and boundary conditions, either a region of enhanced confinement, or a region with strong turbulence can form at the edge. This suggests that the profile self-organization is a global process, though one which can be described by a local, but nonlinear model. This model is the first to demonstrate how the mesoscale condensation of staircases leads to global states of enhanced confinement.