Time-dependent and Non-BPS Solutions in N=6 Superconformal Chern-Simons Theory

We study a class of classical solutions of three-dimensional N=6 superconformal Chern-Simons theory coupled with U(N) \times U(N) bi-fundamental matter fields. Especially, time evolutions of fuzzy spheres are discussed for both massless and massive cases. For the massive case, there are a variety of solutions having different behaviors according to the value of the mass. In addition to the time-dependent solutions, we analyze non-BPS static solutions which represent parallel M5/M5 or M5/anti-M5-branes suspended by multiple M2-branes. These solutions are similar to the fundamental strings connecting two parallel (anti) Dp-branes in perturbative string theory. A moving M5-brane and domain wall solutions with constant velocity that are obtained by the Lorentz boost of the known BPS solutions are briefly addressed.Comment: 27 pages, 9 figures, published version in JHE

Correction: A gold isocyanide complex with a pendant carboxy group: orthogonal molecular arrangements and hypsochromically shifted luminescent mechanochromism

Correction for 'A gold isocyanide complex with a pendant carboxy group: orthogonal molecular arrangements and hypsochromically shifted luminescent mechanochromism' by Tomohiro Seki et al., Chem. Commun., 2018, 54, 11136–11139

Effects of Microalloying on the Impact Toughness of Ultrahigh-Strength TRIP-Aided Martensitic Steels

The effects of the addition of Cr, Mo, and/or Ni on the Charpy impact toughness of a 0.2 pct C-1.5 pct Si-1.5 pct Mn-0.05 pct Nb transformation-induced plasticity (TRIP)-aided steel with a lath-martensite structure matrix (i.e., a TRIP-aided martensitic steel or TM steel) were investigated with the aim of using the steel in automotive applications. In addition, the relationship between the toughness of the various alloyed steels and their metallurgical characteristics was determined. When Cr, Cr-Mo, or Cr-Mo-Ni was added to the base steel, the TM steel exhibited a high upper-shelf Charpy impact absorbed value that ranged from 100 to 120 J/cm2 and a low ductile–brittle fracture appearance transition temperature that ranged from 123 K to 143 K (−150 °C to −130 °C), while also exhibiting a tensile strength of about 1.5 GPa. This impact toughness of the alloyed steels was far superior to that of conventional martensitic steel and was caused by the presence of (i) a softened wide lath-martensite matrix, which contained only a small amount of carbide and hence had a lower carbon concentration, (ii) a large amount of finely dispersed martensite-retained austenite complex phase, and (iii) a metastable retained austenite phase of 2 to 4 vol pct in the complex phase, which led to plastic relaxation via strain-induced transformation and played an important role in the suppression of the initiation and propagation of voids and/or cleavage cracks.ArticleMETALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE. 44A(11):5006-5017 (2013)journal articl

Hamiltonian analysis of Linearized Extension of Ho\v{r}ava-Lifshitz gravity

We investigate the Hamiltonian structure of linearized extended Ho\v{r}ava- Lifshitz gravity in a flat cosmological background following the Faddeev-Jackiw's Hamiltonian reduction formalism. The Hamiltonian structure of extended Ho\v{r}ava-Lifshitz gravity is similar to that of the projectable version of original Ho\v{r}ava-Lifshitz gravity, in which there is one primary constraint and so there are two physical degrees of freedom. We also find that extra scalar graviton mode in an inflationary background can be decoupled from the matter field in the infrared (IR) limit, but it is coupled to the matter field in a general cosmological background. But it is necessary to go beyond linear order in order to draw any conclusion of the strong coupling problem.Comment: 11page

Cosmological perturbations in a healthy extension of Horava gravity

In Horava's theory of gravity, Lorentz symmetry is broken in exchange for renormalizability, but the original theory has been argued to be plagued with problems associated with a new scalar mode stemming from the very breaking of Lorentz symmetry. Recently, Blas, Pujolas, and Sibiryakov have proposed a healthy extension of Horava gravity, in which the behavior of the scalar mode is improved. In this paper, we study scalar modes of cosmological perturbations in extended Horava gravity. The evolution of metric and density perturbations is addressed analytically and numerically. It is shown that for vanishing non-adiabatic pressure of matter the large scale evolution of cosmological perturbations converges to that described by a single constant, $\zeta$, which is an analog of a curvature perturbation on the uniform-density slicing commonly used in usual gravitational theories. The subsequent evolution is thus determined completely by the value of $\zeta$.Comment: 10 pages, 4 figures; v2: published versio

Constraining the Detailed Balance Condition in Horava Gravity with Cosmic Accelerating Expansion

In 2009 Ho\v{r}ava proposed a power-counting renormalizable quantum gravity theory. Afterwards a term in the action that softly violates the detailed balance condition has been considered with the attempt of obtaining a more realistic theory in its IR-limit. This term is proportional to $\omega R^{(3)}$, where $\omega$ is a constant parameter and $R^{(3)}$ is the spatial Ricci scalar. In this paper we derive constraints on this IR-modified Ho\v{r}ava theory using the late-time cosmic accelerating expansion observations. We obtain a lower bound of $|\omega|$ that is nontrivial and depends on $\Lambda_W$, the cosmological constant of the three dimensional spatial action in the Ho\v{r}ava gravity. We find that to preserve the detailed balance condition, one needs to fine-tune $\Lambda_W$ such that - 2.29\times 10^{-4}< (c^2 \Lambda_W)/(H^2_0 \currentDE) - 2 < 0 , where $H_0$ and \currentDE are the Hubble parameter and dark energy density fraction in the present epoch, respectively. On the other hand, if we do not insist on the detailed balance condition, then the valid region for $\Lambda_W$ is much relaxed to -0.39< (c^2 \Lambda_W)/(H^2_0 \currentDE) - 2 < 0.12. We find that although the detailed balance condition cannot be ruled out, it is strongly disfavored.Comment: 22 pages with 7 figures, references adde

Non-gaussianity from the trispectrum and vector field perturbations

We use the \delta N formalism to study the trispectrum T_\zeta of the primordial curvature perturbation \zeta when the latter is generated by vector field perturbations, considering the tree-level and one-loop contributions. The order of magnitude of the level of non-gaussianity in the trispectrum, \tau_{NL}, is calculated in this scenario and related to the order of magnitude of the level of non-gaussianity in the bispectrum, f_{NL}, and the level of statistical anisotropy in the power spectrum, g_\zeta. Such consistency relations will put under test this scenario against future observations. Comparison with the expected observational bound on \tau_{NL} from WMAP, for generic inflationary models, is done.Comment: LaTeX file, 12 pages, no figures. v2: Minor changes, conclusions unchanged. v3: Version accepted for publication in Physics Letters

The Unified First law in "Cosmic Triad" Vector Field Scenario

In this letter, we try to apply the unified first law to the "cosmic triad" vector field scenario both in the minimal coupling case and in the non-minimalcoupling case. After transferring the non-minimally coupling action in Jordan frame to Einstein frame, the correct dynamical equation (Friedmann equation) is gotten in a thermal equilibrium process by using the already existing entropy while the entropy in the non-minimal coupled "cosmic triad" scenario has not been derived. And after transferring the variables back to Jordan frame, the corresponding Friedmann equation is demonstrated to be correct. For complete arguments, we also calculate the related Misner-Sharp energy in Jordan and Einstein frames.Comment: 19 pages, no figure