Implications of the spectrum of dynamically generated string tension theories

The string tension does not have to be put in by hand, it can be dynamically generated, as in the case when we formulate string theory in the modified measure formalism, and other formulations as well. Then string tension appears, but as an additional dynamical degree of freedom. It can be seen however that this string tension is not universal, but rather each string generates its own string tension, which can have a different value for each string. We also define a new Tension scalar background field which change locally the value of the string tension along the world sheets of the strings. When there are many strings with different string tensions this Tension field can be determined from the requirement of world sheet conformal invariance and for two types of string tensions depending on the relative sign of the tensions we obtain nonsingular cosmologies and warp space scenarios and when the two string tensions are positive, we obtain scenarios where the Hagedorn temperature is avoided in the early universe or in regions of warped space time where the string tensions become very big.

Subsystem domination influence on magnetization reversal in designed magnetic patterns in ferrimagnetic Tb/Co multilayers

Recent results showed that the ferrimagnetic compensation point and other characteristic features of Tb/Co ferrimagnetic multilayers can be tailored by He+ ion bombardment. With appropriate choices of the He+ ion dose, we prepared two types of lattices composed of squares with either Tb or Co domination. The magnetization reversal of the first lattice is similar to that seen in ferromagnetic heterostructures consisting of areas with different switching fields. However, in the second lattice, the creation of domains without accompanying domain walls is possible. These domain patterns are particularly stable because they simultaneously lower the demagnetizing energy and the energy associated with the presence of domain walls (exchange and anisotropy). For both lattices, studies of magnetization reversal show that this process takes place by the propagation of the domain walls. If they are not present at the onset, the reversal starts from the nucleation of reversed domains and it is followed by domain wall propagation. The magnetization reversal process does not depend significantly on the relative sign of the effective magnetization in areas separated by domain walls.

Interference effect on resonance studies in searches of heavy particles

The interference between resonance signal and continuum background can be either constructive or destructive, depending on the relative sign of couplings between the signal and background amplitudes. Different interference schemes lead to asymmetric distortions of the resonance line shape, which could be distinguished in experiments, when the internal resonance width is larger than the detector resolution. Interpreting the ATLAS diboson excesses by means of a toy [Formula: see text] model as an illustrative example (though it is disfavored by the 13 TeV data), we find that the signs of resonance couplings can only be revealed in the line shape measurements up to a high confidence level at a high luminosity, which could bring us further information on the underlying theory beyond resonance searches at future lepton and hadron colliders.

Spectroscopy of pendular molecules in strong parallel electric and magnetic fields

We report high-resolution laser-induced fluorescence spectra of the A3Π1, [Formula: see text] ν″ = 0 system of ICl subjected to strong parallel electric and magnetic fields, scanned independently up to 50 kV cm−1 and 0.7 T. Either field induces coherent superposition or hybridization of the rotational states within the A3Π1 electronic state, which possesses both an electric and a magnetic dipole moment along the internuclear axis. Only the electric field induces such hybridization within the ground state [Formula: see text], since it is polar but diamagnetic. Comparisons with computed spectra illustrate several salient features. The hybridization creates directional pendular states in which the molecular axis is confined to librate over a limited angular range about the field direction. For a polar paramagnetic electronic state, such as the A state, parallel electric and magnetic fields conjoin in producing hybridization for half of the ensemble but they counteract for the other half. For the latter component, the electric and magnetic effects can be tuned to balance out, yet the concomitant field-induced hyperfine splitting remains, despite the resulting free rotation of the molecule. The dependence of the transition intensities on the combined fields provides an unequivocal means to determine the relative sign of the electric dipole moments in the upper and lower electronic states. We find that the sign is the same for the X and A states (chlorine more negative than iodine).