I. Pérez Castillo

Publications (2)0 Total impact

• Source

  Available from: ArXiv

  Article: The two-spinon transverse structure factor of the gapped Heisenberg antiferromagnetic chain

  J. -S. Caux, J. Mossel, I. Pérez Castillo
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  ABSTRACT: We consider the transverse dynamical structure factor of the anisotropic Heisenberg spin-1/2 chain (XXZ model) in the gapped antiferromagnetic regime ($\Delta > 1$). Specializing to the case of zero field, we use two independent approaches based on integrability (one valid for finite size, the other for the infinite lattice) to obtain the exact two-spinon part of this correlator. We discuss in particular its asymmetry with respect to the $\pi/2$ momentum line, its overall anisotropy dependence, and its contribution to sum rules. Comment: 19 pages, 6 figures
  06/2008;
• Source

  Available from: arxiv.org

  Article: Typical properties of large random economies with linear activities

  A. De Martino, M. Marsili, I. Pérez Castillo
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  ABSTRACT: We study the competitive equilibrium of large random economies with linear activities using methods of statistical mechanics. We focus on economies with $C$ commodities, $N$ firms, each running a randomly drawn linear technology, and one consumer. We derive, in the limit $N,C\to\infty$ with $n=N/C$ fixed, a complete description of the statistical properties of typical equilibria. We find two regimes, which in the limit of efficient technologies are separated by a phase transition, and argue that endogenous technological change drives the economy close to the critical point.
  10/2003;