585 research outputs found
A central limit theorem for the zeroes of the zeta function
On the assumption of the Riemann hypothesis, we generalize a central limit
theorem of Fujii regarding the number of zeroes of Riemann's zeta function that
lie in a mesoscopic interval. The result mirrors results of Soshnikov and
others in random matrix theory. In an appendix we put forward some general
theorems regarding our knowledge of the zeta zeroes in the mesoscopic regime.Comment: 22 pages. Incorporates referees suggestions. Contains minor
corrections to published versio
Coulomb integrals for the SL(2,R) WZNW model
We review the Coulomb gas computation of three-point functions in the SL(2,R)
WZNW model and obtain explicit expressions for generic states. These amplitudes
have been computed in the past by this and other methods but the analytic
continuation in the number of screening charges required by the Coulomb gas
formalism had only been performed in particular cases. After showing that ghost
contributions to the correlators can be generally expressed in terms of Schur
polynomials we solve Aomoto integrals in the complex plane, a new set of
multiple integrals of Dotsenko-Fateev type. We then make use of monodromy
invariance to analytically continue the number of screening operators and prove
that this procedure gives results in complete agreement with the amplitudes
obtained from the bootstrap approach. We also compute a four-point function
involving a spectral flow operator and we verify that it leads to the one unit
spectral flow three-point function according to a prescription previously
proposed in the literature. In addition, we present an alternative method to
obtain spectral flow non-conserving n-point functions through well defined
operators and we prove that it reproduces the exact correlators for n=3.
Independence of the result on the insertion points of these operators suggests
that it is possible to violate winding number conservation modifying the
background charge.Comment: Improved presentation. New section on spectral flow violating
correlators and computation of a four-point functio
Massive Scaling Limit of beta-Deformed Matrix Model of Selberg Type
We consider a series of massive scaling limits m_1 -> infty, q -> 0, lim m_1
q = Lambda_{3} followed by m_4 -> infty, Lambda_{3} -> 0, lim m_4 Lambda_{3} =
(Lambda_2)^2 of the beta-deformed matrix model of Selberg type (N_c=2, N_f=4)
which reduce the number of flavours to N_f=3 and subsequently to N_f=2. This
keeps the other parameters of the model finite, which include n=N_L and
N=n+N_R, namely, the size of the matrix and the "filling fraction". Exploiting
the method developed before, we generate instanton expansion with finite g_s,
epsilon_{1,2} to check the Nekrasov coefficients (N_f =3,2 cases) to the lowest
order. The limiting expressions provide integral representation of irregular
conformal blocks which contains a 2d operator lim frac{1}{C(q)} : e^{(1/2)
\alpha_1 \phi(0)}: (int_0^q dz : e^{b_E phi(z)}:)^n : e^{(1/2) alpha_2 phi(q)}:
and is subsequently analytically continued.Comment: LaTeX, 21 pages; v2: a reference adde
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
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
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 Selberg trace formula for Dirac operators
We examine spectra of Dirac operators on compact hyperbolic surfaces.
Particular attention is devoted to symmetry considerations, leading to
non-trivial multiplicities of eigenvalues. The relation to spectra of
Maass-Laplace operators is also exploited. Our main result is a Selberg trace
formula for Dirac operators on hyperbolic surfaces
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)
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]
The exceptional set for the number of primes in short intervals
We give upper bounds for the number of x up to X such that the interval (x, x+h) does not contain the expected quantity of primes. Here h is small with respect to x
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