21,052 research outputs found
Quantum Unique Ergodicity for maps on the torus
When a map is classically uniquely ergodic, it is expected that its
quantization will posses quantum unique ergodicity. In this paper we give
examples of Quantum Unique Ergodicity for the perturbed Kronecker map, and an
upper bound for the rate of convergence.Comment: 17 pages Added a construction of non diophantine irrationals with
arbitrary slow rate of convergenc
CHANGES IN MEXICAN AGRICULTURAL POLICIES, 2001-2003
Several changes in agricultural policies in Mexico have taken place during the administration of President Fox, which started in December 2000. For the fist time in modern history an opposition party won the Presidential election in July of that year. The new government has shown a new attitude towards agriculture, seeing to the greatest possible extent market oriented policies and is pushing hard to change the attitude of Mexican farmers, in order to foster their entrepreneurial skills. Traditionally most farmers have relied heavily in government guidance for their production and marketing decisions. In contrast, the largest farmer organizations, with strong political ties to the former governing Party, do not share a large the new policy orientations. Moreover, the Fox administration does not hold a majority in Congress. Even though all political parties state that agriculture is one of their main priorities, a common view is lacking. Policy developments during the last two years should be analyzed under the perspective of compromise between the major players involved.Agricultural and Food Policy,
Scarred eigenstates for arithmetic toral point scatterers
We investigate eigenfunctions of the Laplacian perturbed by a delta potential
on the standard tori in dimensions .
Despite quantum ergodicity holding for the set of "new" eigenfunctions we show
that there is scarring in the momentum representation for , as well as
in the position representation for (i.e., the eigenfunctions fail to
equidistribute in phase space along an infinite subsequence of new
eigenvalues.) For , scarred eigenstates are quite rare, but for
scarring in the momentum representation is very common --- with denoting the counting function for the new eigenvalues below
, there are eigenvalues corresponding to momentum
scarred eigenfunctions.Comment: 31 pages, 1 figur
The Galois group of random elements of linear groups
Let F be a finitely generated field of characteristic zero and \Gamma<GL_n(F)
a finitely generated subgroup. For an element g in \Gamma, let Gal(F(g)/ F) be
the Galois group of the splitting field of the characteristic polynomial of g
over F. We show that the structure of Gal(F(g)/ F) has a typical behaviour
depending on F, and on the geometry of the Zariski closure of \Gamma (but not
on \Gamma)
Risk, Implicit Contracts and the Family in Rural Areas of Low-Income Countries
In this paper the role of family structure in mitigating income volatility in the absence of income insurance in low-income agricultural environments is discussed. Hypotheses concerning the relationship between the membership, size and composition of households and insurance-based income transfers are tested using longitudinal data from India. A test is also performed of whether a household's ability to reduce risk ex post via family arrangements affects its willingness tobear risk ex ante through its selection of formal tenancy contracts. The results support these hypotheses concerning the risk-mitigating roles of both household structure and share contracts, and indicate as well the importance of heterogeneity in risk-aversion across households.Consumer/Household Economics,
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