3,029 research outputs found

### Charged three-body system with arbitrary masses near conformal invariance

Within an adiabatic approximation to the three-body Coulomb system, we study
the strength of the leading order conformaly invariant attractive dipole
interaction produced when a slow charged particle $q_3$ (with mass $m_3$) is
captured by the first excited state of a dimer [with individual masses and
charges $(m_1,q_1$) and ($m_2,q_2=-q_1$)]. The approach leads to a universal
mass-charge critical condition for the existence of three-body level
condensation, ${(m_1^{-1}+m_2^{-1})}/ {[(m_1+m_2)^{-1}+m_3^{-1}]}>|{q_1}/(24
q_3)|$, as well as the ratio between the geometrically scaled energy levels.
The resulting expressions can be relevant in the analysis of recent
experimental setups with charged three-body systems, such as the interactions
of excitons, or other matter-antimatter dimers, with a slow charged particle.Comment: 5 pages, 1 figure, to appear in Physical Review

### Nuclear Matter Properties in Derivative Coupling Models Beyond Mean - Field Approximation

The structure of infinite nuclear matter is studied with two of the Zimanyi -
Moszkowski (ZM) models in the framework of a relativistic approximation which
takes into account Hartree terms and beyond and is compared with the results
which come out of the relativistic Hartree - Fock approach in the linear
Walecka model. The simple treatment applied to these models can be used in
substitution to the more complicated Dirac - Brueckner - Hartree - Fock method
to perform future calculations in finite nuclei.Comment: 11 pages including 1 table, 1 figure (available upon request

### Four-boson scale near a Feshbach resonance

We show that an independent four-body momentum scale $\mu_{(4)}$ drives the
tetramer binding energy for fixed trimer energy (or three-body scale
$\mu_{(3)}$) and large scattering length ($a$). The three- and four-body forces
from the one-channel reduction of the atomic interaction near a Feshbach
resonance disentangle $\mu_{(4)}$ and $\mu_{(3)}$. The four-body independent
scale is also manifested through a family of Tjon-lines, with slope given by
$\mu_{(4)}/\mu_{(3)}$ for $a^{-1}=0$. There is the possibility of a new
renormalization group limit cycle due to the new scale

### Form factors in the Bullough-Dodd related models: The Ising model in a magnetic field

We consider particular modification of the free-field representation of the
form factors in the Bullough-Dodd model. The two-particles minimal form factors
are excluded from the construction. As a consequence, we obtain convenient
representation for the multi-particle form factors, establish recurrence
relations between them and study their properties. The proposed construction is
used to obtain the free-field representation of the lightest particles form
factors in the $\Phi_{1,2}$ perturbed minimal models. As a significant example
we consider the Ising model in a magnetic field. We check that the results
obtained in the framework of the proposed free-field representation are in
agreement with the corresponding results obtained by solving the bootstrap
equations.Comment: 20 pages; v2: some misprints, textual inaccuracies and references
corrected; some references and remarks adde

### Finite temperature results on the 2d Ising model with mixed perturbation

A numerical study of finite temperature features of thermodynamical
observables is performed for the lattice 2d Ising model. Our results support
the conjecture that the Finite Size Scaling analysis employed in the study of
integrable perturbation of Conformal Field Theory is still valid in the present
case, where a non-integrable perturbation is considered.Comment: 9 pages, Latex, added references and improved introductio

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