16,876 research outputs found
The evolution of markets and the revolution of industry : a quantitative model of England’s development, 1300-2000
This paper argues that an economy's transition from Malthusian stagnation to modern growth requires markets to reach a critical size, and competition to reach a critical level of intensity. By allowing an economy to produce a greater variety of goods, a larger market makes goods more substitutable, raising the price elasticity of demand, and lowering mark-ups. Firms must then become larger to break even, which facilitates amortizing the fixed costs of innovation. We demonstrate our theory in a dynamic general equilibrium model calibrated to England's long-run development and explore how various factors affect the timing of takeoff.European Community's Seventh Framework ProgramFinancial aid from the European Commission (EFIGE Grant 225343 and HI-POD Grant 225551), the Comunidad de Madrid (PROCIUDAD-CM), and the Spanish Ministry of Science (ECO2008-01300) is acknowledged
Freed by interaction kinetic states in the Harper model
We study the problem of two interacting particles in a one-dimensional
quasiperiodic lattice of the Harper model. We show that a short or long range
interaction between particles leads to emergence of delocalized pairs in the
non-interacting localized phase. The properties of these Freed by Interaction
Kinetic States (FIKS) are analyzed numerically including the advanced Arnoldi
method. We find that the number of sites populated by FIKS pairs grows
algebraically with the system size with the maximal exponent , up to a
largest lattice size reached in our numerical simulations, thus
corresponding to a complete delocalization of pairs. For delocalized FIKS pairs
the spectral properties of such quasiperiodic operators represent a deep
mathematical problem. We argue that FIKS pairs can be detected in the framework
of recent cold atom experiments [M.~Schreiber {\it et al.} Science {\bf 349},
842 (2015)] by a simple setup modification. We also discuss possible
implications of FIKS pairs for electron transport in the regime of
charge-density wave and high superconductivity.Comment: 26 pages, 21 pdf and png figures, additional data and high quality
figures are available at http://www.quantware.ups-tlse.fr/QWLIB/fikspairs/ ,
parts of sections 2 and 3 moved to appendices, manuscript accepted for EPJ
Dynamical decoherence of a qubit coupled to a quantum dot or the SYK black hole
We study the dynamical decoherence of a qubit weakly coupled to a two-body
random interaction model (TBRIM) describing a quantum dot of interacting
fermions or the Sachdev-Ye-Kitaev (SYK) black hole model. We determine the
rates of qubit relaxation and dephasing for regimes of dynamical thermalization
of the quantum dot or of quantum chaos in the SYK model. These rates are found
to correspond to the Fermi golden rule and quantum Zeno regimes depending on
the qubit-fermion coupling strength. An unusual regime is found where these
rates are practically independent of TBRIM parameters. We push forward an
analogy between TBRIM and quantum small-world networks with an explosive
spreading over exponentially large number of states in a finite time being
similar to six degrees of separation in small-world social networks. We find
that the SYK model has approximately two-three degrees of separation.Comment: 17 pages, 15 pdf-figure
Poincar\'e recurrences and Ulam method for the Chirikov standard map
We study numerically the statistics of Poincar\'e recurrences for the
Chirikov standard map and the separatrix map at parameters with a critical
golden invariant curve. The properties of recurrences are analyzed with the
help of a generalized Ulam method. This method allows to construct the
corresponding Ulam matrix whose spectrum and eigenstates are analyzed by the
powerful Arnoldi method. We also develop a new survival Monte Carlo method
which allows us to study recurrences on times changing by ten orders of
magnitude. We show that the recurrences at long times are determined by
trajectory sticking in a vicinity of the critical golden curve and secondary
resonance structures. The values of Poincar\'e exponents of recurrences are
determined for the two maps studied. We also discuss the localization
properties of eigenstates of the Ulam matrix and their relation with the
Poincar\'e recurrences.Comment: 11 pages, 14 figures, high resolution figures and video mpeg files
available at: http://www.quantware.ups-tlse.fr/QWLIB/ulammethod
The Evolution of Markets and the Revolution of Industry: A Unified Theory of Growth
This paper puts forth a unified theory of growth that captures a number of relevant features of countries transitions from stagnant, predominantly rural economies to vibrant, industrialized economies that have been overlooked by the literature. In our theory, increasing variety of consumer goods and increasing firm size, which are the consequence of a gradual expansion in the market, sow the seeds for process innovation and an economy’s take-off. We demonstrate this mechanism in a dynamic general equilibrium model calibrated to England’s long-run development, and explore how various factors affected the timing of its take-off.Uni�ed Growth Theory, Industrial Revolution, Innovation, Competition, Market Revolution
Bigger is better: Market size, demand elasticity and innovation
This paper proposes a novel mechanism whereby larger markets increase competition and facilitate process innovation. Larger markets, in the sense of more people or more open trade, support a larger variety of goods, resulting in a more crowded product space. This raises the price elasticity of demand and lowers mark-ups. Firms, therefore, become larger to break even. This facilitates process innovation as larger firms can amortize R&D costs over more goods. We demonstrate this mechanism in a standard model of process and product innovation. In doing so, we question some important results in the new trade and endogenous growth literatures.trade; population; price elasticity; competition; innovation; firm-size; scale effects; Dixit-Stiglitz; Hotelling
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