We consider folded $(S,J)$ spinning strings in ${\mathrm{AdS}}_5\times S^5$ (with one spin component in ${\mathrm{AdS}}_5$ and a one in $S^5$) corresponding to the $\mathrm{Tr}(D^S{\Phi }^J)$ operators in the $sl(2)$ sector of the $\mathcal{N}=4$ super Yang-Mills theory in the special scaling limit in which both the string mass $\sim \sqrt{\lambda }\ln S$ and $J$ are sent to infinity with their ratio fixed. Expanding in the parameter $\ell =\frac{J}{\sqrt{\lambda }\ln S}$ we compute the 2-loop string sigma-model correction to the string energy and show that it agrees with the expression proposed by Alday and Maldacena [J. High Energy Phys. 11 (2007) 019]. We suggest that a resummation of the logarithmic ${\ell }^2{ln}^n\ell$ terms is necessary in order to establish an interpolation to the weakly coupled gauge-theory results. In the process, we set up a general framework for the calculation of higher loop corrections to the energy of multispin string configurations. In particular, we find that in addition to the direct 2-loop term in the string energy there is a contribution from lower loop order due to a finite “renormalization” of the relation between the parameters of the classical solution and the fixed spins, i.e., the charges of the $SO(2,4)\times SO(6)$ symmetry.

Metastable, supersymmetry-breaking configurations can be created in flux geometries by placing antibranes in warped throats. Via gauge/gravity duality, such configurations should have an interpretation as supersymmetry-breaking states in the dual field theory. In this paper, we perturbatively determine the asymptotic supergravity solutions corresponding to $\overline{\mathrm{D}3}$-brane probes placed at the tip of the cascading warped deformed conifold geometry, which is dual to an $SU(N+M)\times SU(N)$ gauge theory. The backreaction of the antibranes has the effect of introducing imaginary anti-self-dual flux, squashing the compact part of the space and forcing the dilaton to run. Using the generalization of holographic renormalization to cascading geometries, we determine the expectation values of operators in the dual field theory in terms of the asymptotic values of the supergravity fields.

We demonstrate that amplitudes describing scattering of longitudinally polarized massive vector bosons present in non-Abelian Lee-Wick gauge theory do not grow with energy and, hence, satisfy the constraints imposed by perturbative unitarity. This result contrasts with the widely known violation of perturbative unitarity in the standard model with a very heavy Higgs boson. Our conclusions are valid to all orders of perturbation theory and depend on the existence of a formulation of the theory in which all operators are of dimension four or less. This can be thought of as a restriction on the kinds of higher dimension operator which can be included in the higher derivative formulation of the theory.

We study compactified pure gauge/gravitational theories with gauge-fixing terms and show that these theories possess quantum mechanical supersymmetriclike symmetries between unphysical degrees of freedom. These residual symmetries are global symmetries and generated by quantum mechanical $\mathcal{N}=2$ supercharges. Also, we establish a new one-parameter family of gauge choices for higher-dimensional gravity and calculate as a check of its validity one graviton exchange amplitude in the lowest tree-level approximation. We confirm that the result is indeed $\xi$ independent and the cancellation of the $\xi$ dependence is ensured by the residual symmetries. We also give a simple interpretation of the van Dam-Veltman-Zakharov discontinuity, which arises in the lowest tree-level approximation, from the supersymmetric point of view.

In previous work we proposed a field theory model for multiple M2-branes based on an algebra with a totally antisymmetric triple product. In this paper we gauge a symmetry that arises from the algebra’s triple product. We then construct a supersymmetric theory that is consistent with all the symmetries expected of a multiple M2-brane theory: 16 supersymmetries, conformal invariance, and an $SO(8)$ R-symmetry that acts on the eight transverse scalars. The gauge field is not dynamical. The result is a new type of maximally supersymmetric gauge theory in three dimensions.

The perturbative effective potential $V$ in the massless $\lambda {\varphi }^4$ model with a global $O(N)$ symmetry is uniquely determined to all orders by the renormalization group functions alone when the Coleman-Weinberg renormalization condition $\frac{d^{4}V}{d{\varphi }^4}{|}_{\varphi =\mu }=\lambda$ is used, where $\mu$ represents the renormalization scale. Systematic methods are developed to express the $n$-loop effective potential in the Coleman-Weinberg scheme in terms of the known $n$-loop minimal-subtraction (MS) renormalization group functions. Moreover, it also proves possible to sum the leading- and subsequent-to-leading-logarithm contributions to $V$. An essential element of this analysis is a conversion of the renormalization group functions in the Coleman-Weinberg scheme to the renormalization group functions in the MS scheme. As an example, the explicit five-loop effective potential is obtained from the known five-loop MS renormalization group functions and we explicitly sum the leading-logarithm, next-to-leading-logarithm, and further subleading-logarithm contributions to $V$. Extensions of these results to massless scalar QED are also presented. Because massless scalar QED has two couplings, conversion of the renormalization group functions from the MS scheme to the Coleman-Weinberg scheme requires the use of multiscale renormalization group methods.

We study the collapse of a spherically symmetric dust distribution in $d$-dimensional AdS spacetime. We investigate the role of dimensionality, and the presence of a negative cosmological constant, in determining the formation of trapped surfaces and the end state of gravitational collapse. We obtain the self-similar solution for the case of zero cosmological constant, and show that one cannot construct a self-similar solution when a cosmological constant is included.

Using the Kerr-Schild formalism to solve the Einstein-Maxwell equations, we study energy transport due to time-dependent electromagnetic perturbations around a Kerr black hole, which may work as a mechanism to illuminate a disk located on the equatorial plane. For such a disk-hole system it is found that the energy extraction from the hole can occur under the well-known superradiance condition for wave frequency, even though the energy absorption into the hole should be rather dominant near the polar region of the horizon. We estimate the efficiency of the superradiant amplification of the disk illumination. Further we calculate the time-averaged energy density distribution to show explicitly the existence of a negative energy region near the horizon and to discuss the possible generation of a hot spot on the disk.

We study identical mass black hole binaries with spins perpendicular to the binary’s orbital plane. These binaries have individual spins ranging from $s/m^2=-0.90$ to 0.90, ($s_1=s_2$ in all cases) which is near the limit possible with standard Bowen-York puncture initial data. The extreme cases correspond to the largest initial spin simulations to date. Our results expand the parameter space covered by Rezzolla et al., and when combining both data sets, we obtain estimations for the minimum and maximum values for the intrinsic angular momenta of the remnant of binary black hole mergers of $J/M^2=0.341\pm 0.004$ and $0.951\pm 0.004$, respectively. Note, however, that these values are reached through extrapolation to the singular cases $|s_1|=|s_2|=1$ and thus remain as estimates until full-fledged numerical simulations provide confirmation.

We report on a search for gravitational waves from the coalescence of compact binaries during the third and fourth LIGO science runs. The search focused on gravitational waves generated during the inspiral phase of the binary evolution. In our analysis, we considered three categories of compact binary systems, ordered by mass: (i) primordial black hole binaries with masses in the range $0.35M_{\odot }<m_1$, $m_2<1.0M_{\odot }$, (ii) binary neutron stars with masses in the range $1.0M_{\odot }<m_1$, $m_2<3.0M_{\odot }$, and (iii) binary black holes with masses in the range $3.0M_{\odot }<m_1$, $m_2<m_{\max }$ with the additional constraint $m_1+m_2<m_{\max }$, where $m_{\max }$ was set to $40.0M_{\odot }$ and $80.0M_{\odot }$ in the third and fourth science runs, respectively. Although the detectors could probe to distances as far as tens of Mpc, no gravitational-wave signals were identified in the 1364 hours of data we analyzed. Assuming a binary population with a Gaussian distribution around $0.75-0.75M_{\odot }$, $1.4-1.4M_{\odot }$, and $5.0-5.0M_{\odot }$, we derived 90%-confidence upper limit rates of $4.9{\mathrm{yr}}^{-1}{L}_{10}^{-1}$ for primordial black hole binaries, $1.2{\mathrm{yr}}^{-1}{L}_{10}^{-1}$ for binary neutron stars, and $0.5{\mathrm{yr}}^{-1}{L}_{10}^{-1}$ for stellar mass binary black holes, where $L_{10}$ is ${10}^{10}$ times the blue-light luminosity of the Sun.

We present the concept design of a new class of acoustic detectors of gravitational waves (GWs), which feature a wideband sensitivity. The main novelty relies in the geometry of the test mass, which is equipped with integrated whips. This tapering provides more resonant modes with favorable cross-section to GWs to achieve a large bandwidth. Moreover, the whips act as displacement concentrators and ensure a high mechanical gain at the sensing surfaces. The resulting decrease in mechanical stiffness allows us to achieve the noise matching condition with reasonable operating parameters of the displacement transducer. The performances of the detector are modeled taking into account the quantum and thermal noise sources in the case of a capacitive transducer with a SQUID amplifier. This class of detectors can be designed to target GWs in the frequency range above 1 kHz at a sensitivity comparable to that predicted for future long baseline interferometric detectors. After showing how to scale the design for different constructing materials and target frequencies, we discuss the predicted sensitivity to specific astrophysical signal waveforms.

The standard $\Lambda \mathrm{CDM}$ paradigm is complemented with a magnetized contribution whose effects on the anisotropies of the cosmic microwave background are assessed by means of a dedicated numerical approach. The accuracy on the temperature and polarization correlations stems from the inclusion of the large-scale magnetic fields both at the level of the initial conditions and at the level of the Einstein-Boltzmann hierarchy which is consistently embedded in a generalized magnetohydrodynamical framework. Examples of the calculations of the temperature and polarization angular power spectra are illustrated and discussed. The reported results and the described numerical tools set the groundwork for a consistent inclusion of a magnetized contribution in current strategies of cosmological parameter estimation.

We discuss the relation between remnant fragmentation in inelastic high-energy hadronic interactions and muon production in extensive cosmic ray air showers. Using a newly developed tool, a simple and flexible hadronic event generator, we analyze the forward region of hadronic interactions. We show that measurements of the Feynman-$x$ distribution in the beam fragmentation region at LHCf will be key to understanding muon production in air showers quantitatively.

Relying on Dirac neutrinos allows an infinity of anomaly-free discrete gauge symmetries to be imposed on the supersymmetric standard model, some of which are grand unified theory (GUT)-compatible.

We analyze the LHC phenomenology of $\lambda \mathrm{SUSY}$—a version of the next-to-minimal supersymmetric standard model with a large-ish $S{H}_1{H}_2$ coupling. The scalar spectrum of the model contains a 200–300 GeV Higgs boson $h$ with standard-model like properties, and heavy $CP$-even and $CP$-odd Higgs bosons $H$ and $A$ with masses in 500–800 GeV range. We study the discovery potential of $H$ and $A$ in the decay chains $H\to hh\to 4V\to 2l6j$ and $A\to Zh\to Z2V\to 2l4j$. The dominant backgrounds are the diffuse $Z6j$ and $Z4j$ productions, which can be suppressed by demanding reconstruction of $V$’s and $h$’s in intermediate states. The excess of signal events allows for a discovery of both $H$ and $A$ with over $5\sigma$ significance for $100{\mathrm{fb}}^{-1}$ of integrated luminosity.

We discuss the quark condensate of the vacuum inside the baryon. We analyze the $1+1$-dimensional chiral bag in analogy with the realistic $1+3$-dimensional one. The Nambu–Jona-Lasinio (NJL) type interaction is used to investigate the quark condensate in the chiral bag. Considering the strong meson-quark coupling, we solve the mean field solution to the scalar and pseudoscalar channels. Extracting the finite values of the chiral Casimir energy and the quark condensate by proper regularization, the resulting self-consistent equation allows a generation of a finite dynamical quark mass inside the bag.

We present a search for the associated production of charginos and neutralinos in $\mathrm{p}\overline{\mathrm{p}}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$. The data were collected at the Collider Detector at Fermilab (CDF II) and correspond to integrated luminosities between 0.7 and $1.0{\mathrm{fb}}^{-1}$. We look for final states with one high-$p_{\mathrm{T}}$ electron or muon, and two additional leptons. Our results are consistent with the standard model expectations, and we set limits on the cross section as a function of the chargino mass in three different supersymmetric scenarios. For a specific minimal supersymmetric standard model scenario with no slepton mixing, we set a 95% C.L. limit at $151\mathrm{GeV}/c^2$.

The Polyakov loop extended Nambu–Jona-Lasinio (PNJL) model with imaginary chemical potential is studied. The model possesses the extended ${\mathbb{Z}}_3$ symmetry that QCD does. Quantities invariant under the extended ${\mathbb{Z}}_3$ symmetry, such as the partition function, the chiral condensate, and the modified Polyakov loop, have Roberge-Weiss periodicity. The phase diagram of confinement/deconfinement transition derived with the PNJL model is consistent with the Roberge-Weiss prediction on it and the results of lattice QCD. The phase diagram of chiral transition is also presented by the PNJL model.

We discuss the intriguing possibility that dark energy may change its equation of state in situations where large dark energy fluctuations are present. We show indications of this dynamical mutation in some generic models of dark energy.