A new determination of the electromagnetic nucleon form factors from QCD Sum Rules

We obtain the electromagnetic form factors of the nucleon, in the space-like region, using three-point function Finite Energy QCD Sum Rules. The QCD calculation is performed to leading order in perturbation theory in the chiral limit, and also to leading order in the non-perturbative power corrections. For the Dirac form factor, $F_1(q^2)$, we get a very good agreement with the data for both the proton and the neutron, in the currently accessible experimental region of momentum transfers. Unfortunately this is not the case, though, for the Pauli form factor $F_2(q^2)$, which has a soft $q^2$-dependence proportional to the quark condensate $$.Comment: 4 pages, 3 figures. Presented at QCD 05: 12th International QCD Conference, Montpellier, France, 4-9 July 200

Optical circular dichroism of single-wall carbon nanotubes

The circular dichroism (CD) spectra of single-wall carbon nanotubes are calculated using a dipole approximation. The calculated CD spectra show features that allow us to distinguish between nanotubes with different angles of chirality, and diameters. These results provide theoretical support for the quantification of chirality and its measurement, using the CD lineshapes of chiral nanotubes. It is expected that this information would be useful to motivate further experimental studies.Comment: Submitted to Phys. Rev.

Global well-posedness and asymptotic behavior for Navier-Stokes-Coriolis equations in homogeneous Besov spaces

We are concerned with the $3$D-Navier-Stokes equations with Coriolis force. Existence and uniqueness of global solutions in homogeneous Besov spaces are obtained for large speed of rotation. In the critical case of the regularity, we consider a suitable initial data class whose definition is based on the Stokes-Coriolis semigroup and Besov spaces. Moreover, we analyze the asymptotic behavior of solutions in that setting as the speed of rotation goes to infinity.Comment: 19 page

On the 3D Euler equations with Coriolis force in borderline Besov spaces

We consider the 3D Euler equations with Coriolis force (EC) in the whole space. We show long-time solvability in Besov spaces for high speed of rotation $\Omega$ and arbitrary initial data. For that, we obtain $\Omega$-uniform estimates and a blow-up criterion of BKM type in our framework. Our initial data class is larger than previous ones considered for (EC) and covers borderline cases of the regularity. The uniqueness of solutions is also discussed.Comment: 18 page

Solutions of the Schr\"odinger equation given by solutions of the Hamilton--Jacobi equation

We find the form of the potential depending on the coordinates and the time such that a solution, $S$, of the Hamilton--Jacobi equation yields an exact solution, $\exp ({\rm i} S/\hbar)$, of the corresponding Schr\"odinger equation

Transformation of a wavefunction under changes of reference frame

A simple procedure to derive the transformation of a wavefunction under a change of reference frame is applied to some examples and its relation with the transformation of the Hamilton principal function is studied

Extending the applicability of Redfield theories into highly non-Markovian regimes

We present a new, computationally inexpensive method for the calculation of reduced density matrix dynamics for systems with a potentially large number of subsystem degrees of freedom coupled to a generic bath. The approach consists of propagation of weak-coupling Redfield-like equations for the high frequency bath degrees of freedom only, while the low frequency bath modes are dynamically arrested but statistically sampled. We examine the improvements afforded by this approximation by comparing with exact results for the spin-boson model over a wide range of parameter space. The results from the method are found to dramatically improve Redfield dynamics in highly non--Markovian regimes, at a similar computational cost. Relaxation of the mode-freezing approximation via classical (Ehrenfest) evolution of the low frequency modes results in a dynamical hybrid method. We find that this Redfield-based dynamical hybrid approach, which is computationally more expensive than bare Redfield dynamics, yields only a marginal improvement over the simpler approximation of complete mode arrest.Comment: 10 pages, 5 figure

The Relationship between Centaurs and Jupiter Family Comets with Implications for K-Pg-type Impacts

Centaurs--icy bodies orbiting beyond Jupiter and interior to Neptune--are believed to be dynamically related to Jupiter Family Comets (JFCs), which have aphelia near Jupiter's orbit and perihelia in the inner Solar System. Previous dynamical simulations have recreated the Centaur/JFC conversion, but the mechanism behind that process remains poorly described. We have performed a numerical simulation of Centaur analogues that recreates this process, generating a dataset detailing over 2.6 million close planet/planetesimal interactions. We explore scenarios stored within that database and, from those, describe the mechanism by which Centaur objects are converted into JFCs. Because many JFCs have perihelia in the terrestrial planet region, and since Centaurs are constantly resupplied from the Scattered Disk and other reservoirs, the JFCs are an ever-present impact threat.Comment: Companion paper to "It's Complicated: A Big Data Approach to Exploring Planetesimal Evolution in the Presence of Jovian Planets" in The Astronomical Journal: https://doi.org/10.3847/1538-3881/aae09

Polynomial Heisenberg algebras, multiphoton coherent states and geometric phases

In this paper we will realize the polynomial Heisenberg algebras through the harmonic oscillator. We are going to construct then the Barut-Girardello coherent states, which coincide with the so-called multiphoton coherent states, and we will analyze the corresponding Heisenberg uncertainty relation and Wigner distribution function for some particular cases. We will show that these states are intrinsically quantum and cyclic, with a period being a fraction of the oscillator period. The associated geometric phases will be as well evaluated.Comment: 27 pages, 20 figure

Critical Nucleation in Colossal Magnetoresistance

Critical exponents have been obtained for a 3D spin particle system. Clusters are formed and system reaches a critical behavior when fragment size distribution follows a power law, as predicted by Fisher Liquid Droplet Model. Also, spontaneous magnetization critical temperature is in agreement with other theoretical studies. System evolution is reproduced via a genetic algorithm that performs minimal genetic fluctuations until a stationary state is attained. Critical exponents are in the range of those belonging to Heavy Ion collisions previously reported, and therefore belong to the same universality class.Comment: 13 pages, 6 figures. Contributed paper for the National Congress of the Sociedad Mexicana de Fisica at Leon (Mexico), Oct. 28- Oct.31, 200