We discuss an extension of the Standard Model with a new vector boson decaying predominantly into a multiphoton final state through intermediate light degrees of freedom. The model has a distinctive phase in which the photons are collimated. As such, they would fail the isolation requirements of standard multiphoton searches, but group naturally into a novel object, the “photon-jet”. Once defined, the photon-jet object facilitates more inclusive searches for similar phenomena. We present a concrete model, discuss photon jets more generally, and outline some strategies that may prove useful when searching for such objects.

We calculate perturbative contributions of Wilson loops of various sizes up to order 20 in $SU(3)$ pure lattice gauge theory at different lattice sizes for the Wilson gauge action using the technique of numerical stochastic perturbation theory. This allows us to investigate the perturbative series for various Wilson loops at high orders of the perturbation theory. We observe differences in the behavior of the series as a function of the loop order $n$. Up to $n=20$ we do not find evidence for the factorial growth of the expansion coefficients often assumed to characterize an asymptotic series. Based on the actually observed behavior we sum the series in a model parametrized by hypergeometric functions. For Wilson loops of moderate sizes the summed series in boosted perturbation theory reach stable plateaus for moderate perturbative order already. The coefficients in the boosted series become much more stable in the result of smoothing the coefficients of the original series effected by the hypergeometric model. We introduce generalized ratios of Wilson loops of different sizes. Together with the corresponding Wilson loops from standard Monte Carlo measurements they enable us to assess their nonperturbative parts.

We report on a search for low-energy ($E<20\mathrm{keV}$) WIMP-induced nuclear recoils using data collected in 2009–2010 by EDELWEISS from four germanium detectors equipped with thermal sensors and an electrode design (ID) which allows to efficiently reject several sources of background. The data indicate no evidence for an exponential distribution of low-energy nuclear recoils that could be attributed to WIMP elastic scattering after an exposure of $113\mathrm{kg}·\mathrm{d}$. For weakly interacting massive particles (WIMPs) of mass 10 GeV, the observation of one event in the WIMP search region results in a 90% C.L. limit of $1.0\times {10}^{-5}\mathrm{pb}$ on the spin-independent WIMP-nucleon scattering cross-section, which constrains the parameter space associated with the findings reported by the CoGeNT, DAMA and CRESST experiments.

We study the one loop correction to the closed bosonic string propagator, including the possible presence of D-branes, by discretizing the lightcone worldsheet on an $M\times N$ rectangular lattice, with $M\propto P^{+}$ and $N+1\propto i{x}^{+}$. The integrals over the moduli then become sums which we evaluate numerically. The main purpose of this study is to assess the reliability of the worldsheet lattice as a regulator of the divergences in string perturbation theory. There are two natural geometrical counterterms for the lightcone worldsheet, one proportional to the area of the worldsheet and the other proportional to the length of worldsheet boundaries, tracing the ends of open strings. We show that the divergences in the closed string self-energy can be cancelled by the area counterterm and a renormalization of the Regge slope parameter. The residual finite part is compatible with Lorentz invariance, provided a novel regularization, natural to the lightcone worldsheet lattice and described in this article, is employed.

Nonlocal order parameters for deconfinement, such as the entanglement entropy and Wilson loops, depend on spatial surfaces $\Sigma$. These observables are given holographically by the area of a certain bulk spatial surface $\Gamma$ ending on $\Sigma$. At finite charge density it is natural to consider the electric flux through the bulk surface $\Gamma$ in addition to its area. We show that this flux provides a refined order parameter that can distinguish “fractionalized” phases, with charged horizons, from what we term “cohesive” phases, with charged matter in the bulk. Fractionalization leads to a volume law for the flux through the surface, the flux for deconfined but cohesive phases is between a boundary and a volume law, while finite density confined phases have vanishing flux through the surface. We suggest two possible field theoretical interpretations for this order parameter. The first is as information extracted from the large $N$ reduced density matrix associated with $\Sigma$. The second is as surface operators dual to polarized bulk “D-branes,” carrying an electric dipole moment.

We show how recent progress in real space renormalization group methods can be used to define a generalized notion of holography inspired by holographic dualities in quantum gravity. The generalization is based upon organizing information in a quantum state in terms of scale and defining a higher-dimensional geometry from this structure. While states with a finite correlation length typically give simple geometries, the state at a quantum critical point gives a discrete version of anti-de Sitter space. Some finite temperature quantum states include black hole-like objects. The gross features of equal time correlation functions are also reproduced.

In the large $N_c$ limit, gauge theories with different gauge groups and matter content sometimes turn out to be “large $N_c$ equivalent,” in the sense of having a set of coincident correlation functions. Large $N_c$ equivalence has mainly been explored in the glueball and meson sectors. However, a recent proposal to dodge the fermion sign problem of QCD with a quark number chemical potential using large $N_c$ equivalence motivates investigating the applicability of large $N_c$ equivalence to correlation functions involving baryon operators. Here we present evidence that large $N_c$ equivalence extends to the baryon sector, under the same type of symmetry realization assumptions as in the meson sector, by adapting the classic Witten analysis of large $N_c$ baryons.

We apply Zwanziger formalism to Cho restricted $SU(2)$ theory to obtain the potential in a static quark-antiquark pair. Cho restricted theory is a self-consistent subset of a non-Abelian $SU(2)$ gauge theory which tries to describe the infrared regime of Yang-Mills gauge theories. In Zwanziger formalism, a local Lagrangian depending on two electric and magnetic gauge fields is constructed for the theories where both electric and magnetic charges exist. Based on this local Lagrangian the propagator and then the potential between quarks is calculated in two limits: $m_{C}r\ll 1$ and $m_{C}r\gg 1$, where $m_C$ is the mass of the dual gauge boson and $r$ is the distance between the quark and the antiquark.

Systematizing our results on $r$ duality obtained previously we focus on comparing $r$ duality with the generalized Seiberg duality in the $r$ vacua of $\mathcal{N}=2$ and $\mathcal{N}=1$ super-Yang-Mills theories with the $\mathrm{U}(N)$ gauge group and $N_f$ matter flavors ($N_f>N$). The number of condensed (s)quarks $r$ is assumed to be in the interval $\frac{2}{3}{N}_f<r\le N$. To pass to $\mathcal{N}=1$ we introduce an $\mathcal{N}=2$-breaking deformation, a mass term $\mu$ for the adjoint matter, eventually decoupling the adjoint matter in the limit of large $\mu$. If one starts from a large value of the parameter $\xi \sim \mu m$, where the original theory is at weak coupling, and let $\xi$ decrease, one hits a crossover transition from weak to strong coupling (here $m$ is a typical value of the quark masses). Below this transition the original theory is described in terms of a weakly coupled infrared-free $r$ dual theory with the $\mathrm{U}(N_f-r)$ gauge group and $N_f$ light quarklike dyon flavors. Dyon condensation leads to confinement of monopoles, defying a naive expectation of quark confinement. The quarks and gauge bosons of the original theory are in an “instead-of-confinement” phase. The $r$ and Seiberg dualities are demonstrated to coincide in the $r=N$ vacua. In the $\frac{2}{3}{N}_f<r<N$ vacua two dualities do not match. In this window Seiberg’s dual is at strong coupling while our $r$-dual model is at weak coupling. Thus, we can speak of triality. Seiberg’s dual solution at weak coupling reappears again at $r<N_f-N<\frac{1}{3}{N}_f$.

In the framework of the truncated Dyson-Schwinger equation for the fermion propagator, we investigate the chiral and fermion number susceptibility at finite temperature and chemical potential in quantum electrodynamics in ($2+1$) dimensions (${\mathrm{QED}}_3$). The critical end point in the phase diagram of ${\mathrm{QED}}_3$ is identified, and the behavior of these two susceptibilities around the critical end point is highlighted.

Supersymmetric (SUSY) unified theories which incorporate a renormalizable Type I seesaw mechanism for small neutrino masses can also provide slow-roll inflection-point inflation along a flat direction associated with a gauge-invariant combination of the Higgs, slepton, and right handed sneutrino superfields. Inflationary parameters are related to the Majorana and Dirac couplings responsible for neutrino masses with the scale of inflation set by a right-handed neutrino mass $M_{{\nu }^c}\sim {10}^6–{10}^{12}\mathrm{GeV}$. Tuning of the neutrino Dirac and Majorana superpotential couplings and soft SUSY-breaking parameters is required to enforce flatness of the inflationary potential. In contrast to previous inflection-point inflation models, the cubic term is dominantly derived from superpotential couplings rather than soft $A$-terms. Thus, since $M_{{\nu }^c}\gg M_{\mathrm{Susy}}$, the tuning condition is almost independent of the soft supersymmetry-breaking parameters and therefore more stable. The required fine-tuning is also less stringent than for minimal SUSY standard model (MSSM) inflation or Dirac neutrino “$A$-term” inflation scenarios due to the much larger value of the inflaton mass. Reheating proceeds via ”instant preheating” which rapidly dumps all the inflaton energy into a MSSM-mode radiation bath giving a high reheat temperature $T_{\mathrm{rh}}\approx M_{{\nu }^c}^{(3/4)}{10}^6\mathrm{GeV}\sim {10}^{11}–{10}^{15}\mathrm{GeV}$. Thus, our scenario requires large gravitino $\mathrm{\text{mass}}>50\mathrm{TeV}$ to avoid a gravitino problem. The instant preheating and Higgs component of the inflaton also imply a ”nonthermal” contribution to leptogenesis due to facilitated production of right-handed neutrinos during inflaton decay. We derive the tuning conditions for the scenario to work in the realistic new minimal SUSY SO(10) grand unified theory and show that they can be satisfied by realistic fits.

We develop the quantum theory of a scalar field on loop quantum cosmology Bianchi I geometry. In particular, by considering only the single modes of the field, the evolution equation is derived from the quantum scalar constraint: it is shown that the same equation can be obtained from quantum field theory on a “classical” effective geometry. We then study the dependence of this effective space-time on the wave vector of the modes (which could in principle generate a deformation in local Lorentz symmetry), by analyzing the dispersion relation for propagation of the test field on the resulting geometry. We show that when we disregard the backreaction no Lorentz violation is present, despite the effective metric being different than the classical Bianchi I. Furthermore, a preliminary analysis of the correction due to inclusion of backreaction is briefly discussed in the context of Born-Oppenheimer approximation.

Recently, a new spin-$1/2$ fermionic quantum field with mass dimension one in four dimensions–Elko field $\lambda$ was introduced as a candidate of dark matter. In this paper, we investigate the localization of 5D Elko spinors on Minkowski branes by presenting the equation of the Elko KK modes. For the 5D free massless Elko field, the zero mode can be localized on Randall-Sundrum thin branes but cannot be localized on the majority of thick branes. There do not exist bound massive KK modes on all these branes. If the 5D mass term is introduced, there will exist a bound Elko zero mode in the Randall-Sundrum brane model. And when we introduce the Yukawa type coupling $\eta {\varphi }^2\stackrel{\neg }{\lambda }\lambda$ with $\varphi$ the background scalar field, the Elko zero mode can be localized on some special thick branes with a particular coupling constant $\eta$. Nevertheless, the massive KK modes still cannot be localized on these branes. These results are very different from that of the conventional Dirac spinor field and the scalar field.

We analyze the possibility that due to their superfluid properties some compact astrophysical objects may contain a significant part of their matter in the form of a Bose-Einstein condensate. To study the condensate we use the Gross-Pitaevskii equation with arbitrary nonlinearity. By introducing the Madelung representation of the wave function, we formulate the dynamics of the system in terms of the continuity and hydrodynamic Euler equations. The nonrelativistic and Newtonian Bose-Einstein gravitational condensate can be described as a gas, whose density and pressure are related by a barotropic equation of state. In the case of a condensate with quartic nonlinearity, the equation of state is polytropic with index one. In the framework of the Thomas-Fermi approximation the structure of the Newtonian gravitational condensate is described by the Lane-Emden equation, which can be exactly solved. The case of the rotating condensate is briefly discussed. General relativistic configurations with quartic nonlinearity are studied numerically with both nonrelativistic and relativistic equations of state, and the maximum mass of the stable configuration is determined. Condensates with particle masses of the order of two neutron masses (Cooper pair) and scattering length of the order of 10–20 fm have maximum masses of the order of $2M_{\odot }$, maximum central density of the order of $0.1–0.3\times {10}^{16}\mathrm{g}/{\mathrm{cm}}^3$ and minimum radii in the range of 10–20 km. In this way we obtain a large class of stable astrophysical objects, whose basic astrophysical parameters (mass and radius) sensitively depend on the mass of the condensed particle, and on the scattering length. We also propose that the recently observed neutron stars with masses in the range of $2–2.4M_{\odot }$ are Bose-Einstein condensate stars. We discuss the connection of our results with previous boson star models based on scalar field theory.

We consider the class of $d=4$ conformal field theories at finite temperature and chemical potential that are holographically described within $D=5$ Einstein-Maxwell theory with a Chern-Simons term. The high temperature phase, which is spatially homogeneous and isotropic, is dual to the AdS-Reissner-Nördstrom black brane solution. For sufficiently large Chern-Simons coupling, we construct new electrically charged AdS black hole solutions that are dual to the low temperature, spatially modulated phase. In this phase the current, associated with the Abelian global symmetry, spontaneously acquires a helical order. The new black holes are stationary and also have Bianchi ${\mathrm{VII}}_0$ symmetry.

Standard puncture initial data have been widely used for numerical binary black hole evolutions despite their shortcomings, most notably the inherent lack of gravitational radiation at the initial time that is later followed by a burst of spurious radiation. We study the evolution of three alternative initial data schemes. Two of the three alternatives are based on post-Newtonian expansions that contain realistic gravitational waves. The first scheme is based on a second-order post-Newtonian expansion in Arnowitt, Deser, and Misner transverse-traceless (ADMTT) gauge that has been resummed to approach standard puncture data at the black holes. The second scheme is based on asymptotic matching of the 4-metrics of two tidally perturbed Schwarzschild solutions to a first-order post-Newtonian expansion in ADMTT gauge away from the black holes. The final alternative is obtained through asymptotic matching of the 4-metrics of two tidally perturbed Schwarzschild solutions to a second-order post-Newtonian expansion in harmonic gauge away from the black holes. When evolved, the second scheme fails to produce quasicircular orbits (and instead leads to a nearly head-on collision). This failure can be traced back to inaccuracies in the extrinsic curvature due to low-order matching. More encouraging is that the latter two alternatives lead to quasicircular orbits and show gravitational radiation from the onset of the evolution, as well as a reduction of spurious radiation. Current deficiencies compared to standard punctures data include more eccentric trajectories during the inspiral and larger constraint violations, since the alternative data sets are only approximate solutions of Einstein’s equations. The eccentricity problem can be ameliorated by adjusting the initial momentum parameters.

We study time-reversal and parity—on the physical manifold and in internal space—in covariant loop gravity. We consider a minor modification of the Holst action which makes it transform coherently under such transformations. The classical theory is not affected but the quantum theory is slightly different. In particular, the simplicity constraints are slightly modified and this restricts orientation flips in a spin foam to occur only across degenerate regions, thus reducing the sources of potential divergences.

This is a supplement to an earlier paper [Phys. Rev. D 84, 023510 (2011)], where those shearfree normal cosmological models were identified, in which all light rays have repeatable paths. All of them are conformally flat, but less general than the Stephani model and more general than Robertson-Walker. In this paper, their defining feature is identified: in each of them, in comoving coordinates, the time dependence factors out so that the cofactor is a static metric. An example is given of a congruence of test observers and sources in the Minkowski spacetime that displays nonrepeatable light paths.

Tidal stripping of dark matter from subhalos falling into the Milky Way produces narrow, cold tidal streams as well as more spatially extended “debris flows” in the form of shells, sheets, and plumes. Here we focus on the debris flow in the Via Lactea II simulation, and show that this incompletely phase-mixed material exhibits distinctive high velocity behavior. Unlike tidal streams, which may not necessarily intersect the Earth’s location, debris flow is spatially uniform at 8 kpc and thus guaranteed to be present in the dark matter flux incident on direct detection experiments. At Earth-frame speeds greater than 450 km/s, debris flow comprises more than half of the dark matter at the Sun’s location, and up to 80% at even higher speeds. Therefore, debris flow is most important for experiments that are particularly sensitive to the high speed tail of the dark matter distribution, such as searches for light or inelastic dark matter or experiments with directional sensitivity. We show that debris flow yields a distinctive recoil energy spectrum and a broadening of the distribution of incidence direction.

We study the Wheeler-DeWitt quantum cosmology of a spatially flat Friedmann cosmological model with a free massless scalar field. We compare the consistent histories approach with the de Broglie–Bohm theory when applied to this simple model under two different quantization schemes: the Schrödinger-like quantization, which essentially takes the square root of the resulting Klein-Gordon equation through the restriction to positive frequencies and their associated Newton-Wigner states, or the induced Klein-Gordon quantization, that allows both positive and negative frequencies together. We show that the consistent histories approach can give a precise answer to the question concerning the existence of a quantum bounce if and only if one takes the single frequency approach within a single family of histories; namely, a family containing histories concerning properties of the quantum system at only two specific moments of time: the infinity past and the infinity future. In that case, as shown by Craig and Singh [Phys. Rev. D 82, 123526 (2010)], there is no quantum bounce. In any other situation, the question concerning the existence of a quantum bounce has no meaning in the consistent histories approach. On the contrary, we show that if one considers the de Broglie–Bohm theory, there are always states where quantum bounces occur in both quantization schemes. Hence, the assertion that the Wheeler-DeWitt quantization does not solve the singularity problem in cosmology is not precise. To address this question, one must specify not only the quantum interpretation adopted but also the quantization scheme chosen.