Ultracold heteronuclear molecules and ferroelectric superfluids

We analyze the possibility of a ferroelectric transition in heteronuclear molecules consisting of Bose-Bose, Bose-Fermi or Fermi-Fermi atom pairs. This transition is characterized by the appearance of a spontaneous electric polarization below a critical temperature. We discuss the existence of a ferroelectric Fermi liquid phase for Fermi molecules and the existence of a ferroelectric superfluid phase for Bose molecules characterized by the coexistence of ferroelectric and superfluid orders. Lastly, we propose an experiment to detect ferroelectric correlations through the observation of coherent dipole radiation pulses during time of flight.Comment: 4 pages and 3 figure

Lepton Flavor Violation and Collider Searches in a Type I + II Seesaw Model

Neutrino are massless in the Standard Model. The most popular mechanism to generate neutrino masses are the type I and type II seesaw, where right-handed neutrinos and a scalar triplet are augmented to the Standard Model, respectively. In this work, we discuss a model where a type I + II seesaw mechanism naturally arises via spontaneous symmetry breaking of an enlarged gauge group. Lepton flavor violation is a common feature in such setup and for this reason, we compute the model contribution to the $\mu \rightarrow e\gamma$ and $\mu \rightarrow 3e$ decays. Moreover, we explore the connection between the neutrino mass ordering and lepton flavor violation in perspective with the LHC, HL-LHC and HE-LHC sensitivities to the doubly charged scalar stemming from the Higgs triplet. Our results explicitly show the importance of searching for signs of lepton flavor violation in collider and muon decays. The conclusion about which probe yields stronger bounds depends strongly on the mass ordering adopted, the absolute neutrino masses and which much decay one considers. In the 1-5 TeV mass region of the doubly charged scalar, lepton flavor violation experiments and colliders offer orthogonal and complementary probes. Thus if a signal is observed in one of the two new physics searches, the other will be able to assess whether it stems from a seesaw framework.Comment: 41 pages, 1 figure, 2 table

F-wave versus P-wave Superconductivity in Organic Conductors

Current experimental results suggest that some organic quasi-one-dimensional superconductors exhibit triplet pairing symmetry. Thus, we discuss several potential triplet order parameters for the superconducting state of these systems within the functional integral formulation. We compare weak spin-orbit coupling $f_{xyz}$, $p_x$, $p_y$ and $p_z$ symmetries via several thermodynamic quantities. For each symmetry, we analyse the temperature dependences of the order parameter, condensation energy, specific heat, and superfluid density tensor.Comment: 5 pages, 4 figure

On the nature of Lithium-rich giant stars: constraints from Beryllium abundances

We have derived beryllium abundances for 7 Li-rich giant (A(Li) > 1.5) stars and 10 other Li-normal giants, with the aim of investigating the origin of the Lithium in the Li-rich giants. In particular, we test the predictions of the engulfment scenario proposed by Siess & Livio (1999), where the engulfment of a brown dwarf or one or more giant planets would lead to a simultaneous enrichment of 7Li and 9Be. We show that regardless their nature, none of the stars studied in this paper were found to have detectable beryllium. Using simple dilution arguments we show that the engulfment of an external object as the sole source of Li enrichment is ruled out by the Li and Be abundance data. The present results favor the idea that Li has been produced in the interior of the stars by a Cameron-Fowler process and brought up to the surface by an extra mixing mechanism.Comment: Accepted in A&

Nonzero orbital angular momentum superfluidity in ultracold Fermi gases

We analyze the evolution of superfluidity for nonzero orbital angular momentum channels from the Bardeen-Cooper-Schrieffer (BCS) to the Bose-Einstein condensation (BEC) limit in three dimensions. First, we analyze the low energy scattering properties of finite range interactions for all possible angular momentum channels. Second, we discuss ground state ($T = 0$) superfluid properties including the order parameter, chemical potential, quasiparticle excitation spectrum, momentum distribution, atomic compressibility, ground state energy and low energy collective excitations. We show that a quantum phase transition occurs for nonzero angular momentum pairing, unlike the s-wave case where the BCS to BEC evolution is just a crossover. Third, we present a gaussian fluctuation theory near the critical temperature ($T = T_{\rm c}$), and we analyze the number of bound, scattering and unbound fermions as well as the chemical potential. Finally, we derive the time-dependent Ginzburg-Landau functional near $T_{\rm c}$, and compare the Ginzburg-Landau coherence length with the zero temperature average Cooper pair size.Comment: 28 pages and 24 figure

Simbiose micorrízica em plantas forrageiras.

Esse projeto teve como objetivos: verificar a condição micorrízica em plantas forrageiras nas condições do semi-árido, avaliar a eficiência de fungos micorrízicos arbusculares em promover o crescimento vegetal e o teor nutricional de plantas de Cajanus cajan var. Petrolina, passível de utilização na alimentação animal, e conhecer o potencial dessas forragens em incrementar a propagação desses fungos no solo