468 research outputs found
A Reprise of Warrants, Probable Cause, and Articulable Suspicion in Immigration Enforcement—LaDuke v. Nelson, 762 F.2d 1318 (9th Cir. 1985)
This Note analyzes LaDuke v. Nelson, in which the Ninth Circuit held that the farm and ranch check practices of the INS violated the fourth amendment in that seizures were made without warrants, probable cause, or articulable suspicion of illegal alienage. The court\u27s alternative holding criticized the INS for conducting searches without warrants, probable cause, or effective consent. For LaDuke to stand it must be carefully distinguished from the Supreme Court\u27s most recent fourth amendment decisions, which juxtapose the individual\u27s interest in privacy and security with the government\u27s interest in effective law enforcement. LaDuke should stand because it provides an appropriate standard for cases which involve searches and seizures for the purpose of apprehending farm workers who are illegal aliens. That standard prevents the INS from harassing citizens and lawfully present aliens based on their racial or ethnic characteristics. It also prohibits the INS from harassing citizens and legal aliens based on their presumed proximity to illegal aliens
Representations of integers by certain positive definite binary quadratic forms
We prove part of a conjecture of Borwein and Choi concerning an estimate on
the square of the number of solutions to n=x^2+Ny^2 for a squarefree integer N.Comment: 8 pages, submitte
Random matrix theory, the exceptional Lie groups, and L-functions
There has recently been interest in relating properties of matrices drawn at
random from the classical compact groups to statistical characteristics of
number-theoretical L-functions. One example is the relationship conjectured to
hold between the value distributions of the characteristic polynomials of such
matrices and value distributions within families of L-functions. These
connections are here extended to non-classical groups. We focus on an explicit
example: the exceptional Lie group G_2. The value distributions for
characteristic polynomials associated with the 7- and 14-dimensional
representations of G_2, defined with respect to the uniform invariant (Haar)
measure, are calculated using two of the Macdonald constant term identities. A
one parameter family of L-functions over a finite field is described whose
value distribution in the limit as the size of the finite field grows is
related to that of the characteristic polynomials associated with the
7-dimensional representation of G_2. The random matrix calculations extend to
all exceptional Lie groupsComment: 14 page
The nonrelativistic limit of the Magueijo-Smolin model of deformed special relativity
We study the nonrelativistic limit of the motion of a classical particle in a
model of deformed special relativity and of the corresponding generalized
Klein-Gordon and Dirac equations, and show that they reproduce nonrelativistic
classical and quantum mechanics, respectively, although the rest mass of a
particle no longer coincides with its inertial mass. This fact clarifies the
meaning of the different definitions of velocity of a particle available in DSR
literature. Moreover, the rest mass of particles and antiparticles differ,
breaking the CPT invariance. This effect is close to observational limits and
future experiments may give indications on its effective existence.Comment: 10 pages, plain TeX. Discussion of generalized Dirac equation and CPT
violation adde
Advection of vector fields by chaotic flows
We have introduced a new transfer operator for chaotic flows whose leading
eigenvalue yields the dynamo rate of the fast kinematic dynamo and applied
cycle expansion of the Fredholm determinant of the new operator to evaluation
of its spectrum. The theory hs been tested on a normal form model of the vector
advecting dynamical flow. If the model is a simple map with constant time
between two iterations, the dynamo rate is the same as the escape rate of
scalar quantties. However, a spread in Poincar\'e section return times lifts
the degeneracy of the vector and scalar advection rates, and leads to dynamo
rates that dominate over the scalar advection rates. For sufficiently large
time spreads we have even found repellers for which the magnetic field grows
exponentially, even though the scalar densities are decaying exponentially.Comment: 12 pages, Latex. Ask for figures from [email protected]
Some recursive formulas for Selberg-type integrals
A set of recursive relations satisfied by Selberg-type integrals involving
monomial symmetric polynomials are derived, generalizing previously known
results. These formulas provide a well-defined algorithm for computing
Selberg-Schur integrals whenever the Kostka numbers relating Schur functions
and the corresponding monomial polynomials are explicitly known. We illustrate
the usefulness of our results discussing some interesting examples.Comment: 11 pages. To appear in Jour. Phys.
The trace of the heat kernel on a compact hyperbolic 3-orbifold
The heat coefficients related to the Laplace-Beltrami operator defined on the
hyperbolic compact manifold H^3/\Ga are evaluated in the case in which the
discrete group \Ga contains elliptic and hyperbolic elements. It is shown
that while hyperbolic elements give only exponentially vanishing corrections to
the trace of the heat kernel, elliptic elements modify all coefficients of the
asymptotic expansion, but the Weyl term, which remains unchanged. Some physical
consequences are briefly discussed in the examples.Comment: 11 page
Wigner quantization of some one-dimensional Hamiltonians
Recently, several papers have been dedicated to the Wigner quantization of
different Hamiltonians. In these examples, many interesting mathematical and
physical properties have been shown. Among those we have the ubiquitous
relation with Lie superalgebras and their representations. In this paper, we
study two one-dimensional Hamiltonians for which the Wigner quantization is
related with the orthosymplectic Lie superalgebra osp(1|2). One of them, the
Hamiltonian H = xp, is popular due to its connection with the Riemann zeros,
discovered by Berry and Keating on the one hand and Connes on the other. The
Hamiltonian of the free particle, H_f = p^2/2, is the second Hamiltonian we
will examine. Wigner quantization introduces an extra representation parameter
for both of these Hamiltonians. Canonical quantization is recovered by
restricting to a specific representation of the Lie superalgebra osp(1|2)
A random matrix decimation procedure relating to
Classical random matrix ensembles with orthogonal symmetry have the property
that the joint distribution of every second eigenvalue is equal to that of a
classical random matrix ensemble with symplectic symmetry. These results are
shown to be the case of a family of inter-relations between eigenvalue
probability density functions for generalizations of the classical random
matrix ensembles referred to as -ensembles. The inter-relations give
that the joint distribution of every -st eigenvalue in certain
-ensembles with is equal to that of another
-ensemble with . The proof requires generalizing a
conditional probability density function due to Dixon and Anderson.Comment: 19 pages, 1 figur
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