arXiv subjects

Sourish Dutta

Publications and source records attributed to Sourish Dutta.

At least 19 recordsLinked to original sources

arXiv2025

The Circular Flow Revisited: A Comparative Exposition of Leontief's Input-Output Analysis and Sraffa's Production of Commodities

This paper delves into the foundational contributions of Wassily Leontief and Piero Sraffa to the understanding of economic systems as circular processes of production. It provides a comprehensive analysis of Leontief's Input-Output (I-O) framework and Sraffa's model of "Production of Commodities by Means of Commodities," highlighting their distinct yet complementary perspectives on the structure of modern economies. By meticulously examining the mathematical underpinnings and economic assumptions of both models, this paper elucidates their respective treatments of prices, quantities, surplus, and the role of technology. The analysis extends to a comparative exploration of their approaches to value, distribution, and the representation of economic systems, drawing upon detailed examples and the theoretical frameworks presented in the foundational texts. The paper argues that a synergistic understanding of Leontief's empirical framework and Sraffa's theoretical critique offers profound insights into the intricate web of inter-industry relationships that characterise contemporary economies. The appendix part of this paper proposes a rigorous mathematical unification of the classical price theory of Piero Sraffa and the empirical input-output analysis of Wassily Leontief. While both frameworks model the economy as a circular process of production, their theoretical foundations and applications have often been treated separately. We demonstrate that they are two facets of a single, underlying algebraic structure.

econ.GN↗

arXiv2023

Horizontal and Vertical Differentiation: Approaching Endogenous Measurement in Intra-industry Trade

Studying intra-industry trade involves theoretical explanations and empirical methods to measure the phenomenon. Indicators have been developed to measure the intensity of intra-industry trade, leading to theoretical models explaining its determinants. It is essential to distinguish between horizontal and vertical differentiation in empirical analyses. The determinants and consequences of intra-industry trade depend on whether the traded products differ in quality. A method for distinguishing between vertical and horizontal differentiation involves comparing exports' unit value to imports for each industry's intra-industry trade. This approach has limitations, leading to the need for an alternative method.

econ.TH↗

arXiv2021

Commentary on World Development Report 2020: Trading for Development in the Age of Global Value Chains

The importance of trade to an economy needs no emphasis. You sell products or services that you are competitive at and buy those where you are not. Experience of countries such as South Korea and China demonstrate that resources required for development can be garnered through trade; thus, motivating many countries to embrace trade as a means for development. Simultaneously, emergence of 'Global Value Chain' or 'GVC' as they are popularly known has changed the way we trade. Though the concept of GVC was introduced in the early 2000s, there are examples of global value chains before the 1980s. However, the scale of the phenomenon and the way in which technological change, by lowering trade costs, has allowed fragmentation of production was not possible before (Hernandez et al., 2014). In this context, the World Bank has recently published its 'World Development Report 2020: Trading for Development in the Age of Global Value Chains' (WDR). The report prescribes that GVCs still offer developing countries a clear path to progress and that developing countries can achieve better outcomes by pursuing market-oriented reforms specific to their stage of development.

econ.GN↗

arXiv2021

Mechanistic Framework of Global Value Chains

Indeed, the global production (as a system of creating values) is eventually forming like a gigantic and complex network/web of value chains that explains the transitional structures of global trade and development of the global economy. It's truly a new wave of globalisation, and we term it as the global value chains (GVCs), creating the nexus among firms, workers and consumers around the globe. The emergence of this new scenario asks: how an economy's firms, producers and workers connect in the global economy. And how are they capturing the gains out of it in terms of different dimensions of economic development? This GVC approach is very crucial for understanding the organisation of the global industries and firms. It requires the statics and dynamics of diverse players involved in this complex global production network. Its broad notion deals with different global issues (including regional value chains also) from the top down to the bottom up, founding a scope for policy analysis (Gereffi & Fernandez-Stark 2011). But it is true that, as Feenstra (1998) points out, any single computational framework is not sufficient to quantification this whole range of economic activities. We should adopt an integrative framework for accurate projection of this dynamic multidimensional phenomenon.

econ.GN↗

arXiv2021

Research Methods of Assessing Global Value Chains

The global production (as a system of creating values) is eventually forming a vast web of value chains that explains the transitional structures of global trade and development of the world economy. It is truly a new wave of globalisation, and we can term it as the global value chains (GVCs), creating the nexus among firms, workers and consumers around the globe. The emergence of this new scenario is asking how an economy's businesses, producers and employees are connecting to the global economy and capturing the gains out of it regarding different dimensions of economic development. Indeed, this GVC approach is very crucial for understanding the organisation of the global industries (including firms) through analysing the statics and dynamics of different economic players involved in this complex global production network. Its widespread notion deals with various global issues (including regional value chains also) from the top down to the bottom up, founding a scope for policy analysis.

econ.GN↗

arXiv2021

Learning and Upgrading in Global Value Chains: An Analysis of India's Manufacturing Sector

The topic of my research is "Learning and Upgrading in Global Value Chains: An Analysis of India's Manufacturing Sector". To analyse India's learning and upgrading through position, functions, specialisation & value addition of manufacturing GVCs, it is required to quantify the extent, drivers, and impacts of India's Manufacturing links in GVCs. I have transformed this overall broad objective into three fundamental questions: (1) What is the extent of India's Manufacturing Links in GVCs? (2) What are the determinants of India's Manufacturing Links in GVCs? (3) What are the impacts of India's Manufacturing Links in GVCs? These three objectives represent my three chapters in my PhD thesis.

econ.GN↗

arXiv2021

Measurement of Global Value Chain (GVC) Participation in World Development Report 2020

As we can understand with the spread of GVCs, a lot of new questions emerge regarding the measurement of participation and positioning in the globalised production process. The World Development Report (WDR) 2020 explains the GVC phenomenon and then focus on participation and the prospects especially in a world of change in technology. From the overview section, we can figure out that nowadays, goods and services flow across borders as intermediate inputs rather than final goods. In traditional trade, we need two countries with the notions of export and import. However, in GVC trade, the goods and services cross borders multiple times requiring more than two countries. Remarkable improvements in information, communication, and transport technologies have made it possible to fragment production across national boundaries. So the question is: how to conceptualise this type of new trade to justify the measurement of participation.

econ.GN↗

arXiv2013

Cosmology with non-minimal derivative couplings: perturbation analysis and observational constraints

We perform a combined perturbation and observational investigation of the scenario of non-minimal derivative coupling between a scalar field and curvature. First we extract the necessary condition that ensures the absence of instabilities, which is fulfilled more sufficiently for smaller coupling values. Then using Type Ia Supernovae (SNIa), Baryon Acoustic Oscillations (BAO), and Cosmic Microwave Background (CMB) observations, we show that, contrary to its significant effects on inflation, the non-minimal derivative coupling term has a negligible effect on the universe acceleration, since it is driven solely by the usual scalar-field potential. Therefore, the scenario can provide a unified picture of early and late time cosmology, with the non-minimal derivative coupling term responsible for inflation, and the usual potential responsible for late-time acceleration. Additionally, the fact that the necessary coupling term does not need to be large, improves the model behavior against instabilities.

astro-ph.CO↗

arXiv2011

Horava-Lifshitz cosmology with generalized Chaplygin gas

We investigate cosmological scenarios of generalized Chaplygin gas in a universe governed by Horava-Lifshitz gravity. We consider both the detailed and non-detailed balance versions of the gravitational background, and we include the baryonic matter and radiation sectors. We use observational data from Type Ia Supernovae (SNIa), Baryon Acoustic Oscillations (BAO), and Cosmic Microwave Background (CMB), along with requirements of Big Bang Nucleosynthesis (BBN), to constrain the parameters of the model, and we provide the corresponding likelihood contours. We deduce that the present scenario is compatible with observations. Additionally, examining the evolution of the total equation-of-state parameter, we find in a unified way the succession of the radiation, matter, and dark energy epochs, consistently with the thermal history of the universe.

astro-ph.CO↗

arXiv2011

Matter Bounce Cosmology with the f(T) Gravity

We show that the f(T) gravitational paradigm, in which gravity is described by an arbitrary function of the torsion scalar, can provide a mechanism for realizing bouncing cosmologies, thereby avoiding the Big Bang singularity. After constructing the simplest version of an f(T) matter bounce, we investigate the scalar and tensor modes of cosmological perturbations. Our results show that metric perturbations in the scalar sector lead to a background-dependent sound speed, which is a distinguishable feature from Einstein gravity. Additionally, we obtain a scale-invariant primordial power spectrum, which is consistent with cosmological observations, but suffers from the problem of a large tensor-to-scalar ratio. However, this can be avoided by introducing extra fields, such as a matter bounce curvaton.

astro-ph.CO↗

arXiv2011

Slow-roll freezing quintessence

We examine the evolution of quintessence models with potentials satisfying (V'/V)^2<<1 and V"/V<<1, in the case where the initial field velocity is nonzero. We derive an analytic approximation for the evolution of the equation of state parameter, w, for the quintessence field. We show that such models are characterized by an initial rapid freezing phase, in which the equation of state parameter w decreases with time, followed by slow thawing evolution, for which w increases with time. These models resemble constant-V models at early times but diverge at late times. Our analytic approximation gives results in excellent agreement with exact numerical evolution.

astro-ph.CO↗

arXiv2010

f(T) gravity mimicking dynamical dark energy. Background and perturbation analysis

We investigate f(T) cosmology in both the background, as well as in the perturbation level, and we present the general formalism for reconstructing the equivalent one-parameter family of f(T) models for any given dynamical dark energy scenario. Despite the completely indistinguishable background behavior, the perturbations break this degeneracy and the growth histories of all these models differ from one another. As an application we reconstruct the f(T) equivalent for quintessence, and we show that the deviation of the matter overdensity evolution is strong for small scales and weak for large scales, while it is negligible for large redshifts.

astro-ph.CO↗

arXiv2010

Cosmological perturbations in f(T) gravity

We investigate the cosmological perturbations in f(T) gravity. Examining the pure gravitational perturbations in the scalar sector using a diagonal vierbien, we extract the corresponding dispersion relation, which provides a constraint on the f(T) ansatzes that lead to a theory free of instabilities. Additionally, upon inclusion of the matter perturbations, we derive the fully perturbed equations of motion, and we study the growth of matter overdensities. We show that f(T) gravity with f(T) constant coincides with General Relativity, both at the background as well as at the first-order perturbation level. Applying our formalism to the power-law model we find that on large subhorizon scales (O(100 Mpc) or larger), the evolution of matter overdensity will differ from LCDM cosmology. Finally, examining the linear perturbations of the vector and tensor sectors, we find that (for the standard choice of vierbein) f(T) gravity is free of massive gravitons.

astro-ph.CO↗

arXiv2010

Parametrization for the Scale Dependent Growth in Modified Gravity

We propose a scale dependent analytic approximation to the exact linear growth of density perturbations in Scalar-Tensor (ST) cosmologies. In particular, we show that on large subhorizon scales, in the Newtonian gauge, the usual scale independent subhorizon growth equation does not describe the growth of perturbations accurately, as a result of scale-dependent relativistic corrections to the Poisson equation. A comparison with exact linear numerical analysis indicates that our approximation is a significant improvement over the standard subhorizon scale independent result on large subhorizon scales. A comparison with the corresponding results in the Synchronous gauge demonstrates the validity and consistency of our analysis.

astro-ph.CO↗

arXiv2010

Big Bang nucleosynthesis with a stiff fluid

Models that lead to a cosmological stiff fluid component, with a density $ρ_S$ that scales as $a^{-6}$, where $a$ is the scale factor, have been proposed recently in a variety of contexts. We calculate numerically the effect of such a stiff fluid on the primordial element abundances. Because the stiff fluid energy density decreases with the scale factor more rapidly than radiation, it produces a relatively larger change in the primordial helium-4 abundance than in the other element abundances, relative to the changes produced by an additional radiation component. We show that the helium-4 abundance varies linearly with the density of the stiff fluid at a fixed fiducial temperature. Taking $ρ_{S10}$ and $ρ_{R10}$ to be the stiff fluid energy density and the standard density in relativistic particles, respectively, at $T = 10$ MeV, we find that the change in the primordial helium abundance is well-fit by $ΔY_p = 0.00024(ρ_{S10}/ρ_{R10})$. The changes in the helium-4 abundance produced by additional radiation or by a stiff fluid are identical when these two components have equal density at a "pivot temperature", $T_*$, where we find $T_* = 0.55$ MeV. Current estimates of the primordial $^4$He abundance give the constraint on a stiff fluid energy density of $ρ_{S10}/ρ_{R10} < 30$.

astro-ph.CO↗

arXiv2010

Decaying dark matter mimicking time-varying dark energy

A $Λ$CDM model with dark matter that decays into inert relativistic energy on a timescale longer than the Hubble time will produce an expansion history that can be misinterpreted as stable dark matter with time-varying dark energy. We calculate the corresponding spurious equation of state parameter, $\widetilde w_ϕ$, as a function of redshift, and show that the evolution of $\widetilde w_ϕ$ depends strongly on the assumed value of the dark matter density, erroneously taken to scale as $a^{-3}$. Depending on the latter, one can obtain models that mimic quintessence ($\widetilde w_ϕ> -1$), phantom models ($\widetilde w_ϕ< -1$) or models in which the equation of state parameter crosses the phantom divide, evolving from $\widetilde w_ϕ> -1$ at high redshift to $\widetilde w_ϕ< -1$ at low redshift. All of these models generically converge toward $\widetilde w_ϕ\approx -1$ at the present. The degeneracy between the $Λ$CDM model with decaying dark matter and the corresponding spurious quintessence model is broken by the growth of density perturbations.

astro-ph.CO↗

arXiv2010

Dark Energy, with Signatures

We propose a class of simple dark energy models which predict a late-time dark radiation component and a distinctive time-dependent equation of state $w(z)$ for redshift $z < 3$. The dark energy field can be coupled strongly enough to Standard Model particles to be detected in colliders, and the model requires only modest additional particle content and little or no fine-tuning other than a new energy scale of order milli-electron volts.

astro-ph.CO↗

arXiv2010

Overall observational constraints on the running parameter λof Horava-Lifshitz gravity

We use observational data from Type Ia Supernovae (SNIa), Baryon Acoustic Oscillations (BAO), and Cosmic Microwave Background (CMB), along with requirements of Big Bang Nucleosynthesis (BBN), to constrain the running parameter $λ$ of Horava-Lifshitz gravity, which determines the flow between the Ultra-Violet and the Infra-Red. We consider both the detailed and non-detailed balance versions of the gravitational sector, and we include the matter and radiation sectors. Allowing for variation of all the parameters of the theory, we construct the likelihood contours and we conclude that in $1σ$ confidence $λ$ is restricted to $|λ-1|\lesssim0.02$, while its best fit value is $|λ_{b.f}-1|\approx0.002$. Although this observational analysis restricts the running parameter $λ$ very close to its IR value 1, it does not enlighten the discussion about the theory's possible conceptual and theoretical problems.

hep-th↗