We compute the radiation pressure force on a moving mirror, in the nonrelativistic approximation, assuming the field to be at temperature T. At high temperature, the force has a dissipative component proportional to the mirror velocity, which results from the Doppler shift of the reflected thermal photons. In the case of a scalar field, the force has also a dispersive component associated with a mass correction $\Delta m.\mathrm{}$ In the electromagnetic case, the separate contributions to the mass correction from the two polarizations cancel. We also derive explicit results in the low temperature regime, and present numerical results for the general case. As an application, we compute the dissipation and decoherence rates for a mirror in a harmonic potential well.

We reinvestigate the interesting phenomenon of symmetry nonrestoration at high temperature in the multifield ${O(N}_1{\left)XO\right(N}_2)$ model. We apply modified self-consistent resummation (MSCR) in order to obtain the scalar dressed masses and find in what circumstances a resummed multifield theory which has symmetry (non)restoration can be renormalized. It is shown that, aside from the consistency of the MSCR method, the basic ingredient that guarantees the renormalization of a multifield model within a resummation approach is the $T^2$ mass behavior of field theory at high temperature.

Much effort has been devoted to the study of the phenomenology in particle physics with extra dimensions. We propose degenerate fermion stars with extra dimensions and study the features characterized by the size of the extra dimensions that should appear in their structure. We find that Kaluza-Klein excited modes arise for the larger scale of extra dimensions and examine the conditions under which different layers should be caused in the inside of the stars. We expound on how the extra dimensions affect the physical quantities.

We investigate the possible total radiated energy produced by a binary black hole system containing nonvanishing total angular momentum. For the scenarios considered we find that the total radiated energy does not exceed $1\%.$ Additionally we explore the gravitational radiation field and the variation of angular momentum in the process. After the formation of the final black hole, the model uses the Robinson-Trautman (RT) spacetimes as background. The evolution of perturbed RT geometries is carried out numerically.

Time dependent orbifolds with spacelike or null singularities have recently been studied as simple models of cosmological singularities. We show that their apparent simplicity is an illusion: the introduction of a single particle causes the spacetime to collapse to a strong curvature singularity (a big crunch), even in regions arbitrarily far from the particle.

We present a fast Markov chain Monte Carlo exploration of cosmological parameter space. We perform a joint analysis of results from recent cosmic microwave background (CMB) experiments and provide parameter constraints, including ${\sigma }_8,$ from the CMB independent of other data. We next combine data from the CMB, HST Key Project, 2dF galaxy redshift survey, supernovae type Ia and big-bang nucleosynthesis. The Monte Carlo method allows the rapid investigation of a large number of parameters, and we present results from 6 and 9 parameter analyses of flat models, and an 11 parameter analysis of non-flat models. Our results include constraints on the neutrino mass ${(m}_{\nu }\lesssim 0.3\mathrm{eV}),$ equation of state of the dark energy, and the tensor amplitude, as well as demonstrating the effect of additional parameters on the base parameter constraints. In a series of appendixes we describe the many uses of importance sampling, including computing results from new data and accuracy correction of results generated from an approximate method. We also discuss the different ways of converting parameter samples to parameter constraints, the effect of the prior, assess the goodness of fit and consistency, and describe the use of analytic marginalization over normalization parameters.

The evolution of primordial fluctuations in a Brans-Dicke type scalar-tensor gravity theory is comprehensively investigated. The harmonic attractor model, in which the scalar field has its harmonic effective potential in the Einstein conformal frame and the theory relaxes toward Einstein gravity with time, is considered. The evolution of adiabatic initial perturbations in flat SCDM models is examined from the radiation-dominated epoch up to the present. We discuss how the scalar-tensor gravity affects the evolution of metric and matter perturbations, mainly focusing on the observational consequences, i.e., the matter power spectrum and the power spectrum of cosmic microwave background temperature. We find that the early time deviation is characterized only by the large static gravitational constant while the late time behavior is qualitatively different from that in Einstein gravity because the time variation of the gravitational constant and its fluctuation have non-negligible effects. The attracting scalar-tensor gravity affects only small scale modes due to its attracting nature, the degree of which is far beyond the post-Newtonian deviation at the present epoch.

We discuss the possibility to directly reconstruct the cosmic microwave background (CMB) polarization field at the last scattering surface by accounting for modifications imposed by the gravitational lensing effect. The suggested method requires a tracer field of the large scale structure lensing potentials that deflected propagating CMB photons from the last scattering surface. This required information can come from a variety of observations on the large scale structure matter distribution, including the convergence reconstructed from lensing shear studies involving galaxy shapes. In the case of so-called curl, or B modes of CMB polarization, the reconstruction allows one to identify the distinct signature of inflationary gravitational waves.

We present a method for measuring the cosmic matter budget without assumptions about speculative early Universe physics, and for measuring the primordial power spectrum $P_{*}\mathrm{}\left(k\right)\mathrm{}$ nonparametrically, either by combining CMB and LSS information or by using CMB polarization. Our method complements currently fashionable “black box” cosmological parameter analysis, constraining cosmological models in a more physically intuitive fashion by mapping measurements of CMB, weak lensing and cluster abundance into k space, where they can be directly compared with each other and with galaxy and $\mathrm{Ly}\alpha$ forest clustering. Including the new CBI results, we find that CMB measurements of $P\left(k\right)\mathrm{}$ overlap with those from 2dF galaxy clustering by over an order of magnitude in scale, and even overlap with weak lensing measurements. We describe how our approach can be used to raise the ambition level beyond cosmological parameter fitting as data improves, testing rather than assuming the underlying physics.

We argue for a “parametrized post-Friedmannian” approach to linear cosmology, where the history of expansion and perturbation growth is measured without assuming that the Einstein field equations hold. As an illustration, a model-independent analysis of 92 type Ia supernovae demonstrates that the curve giving the expansion history has the wrong shape to be explained without some form of dark energy or modified gravity. We discuss how upcoming lensing, galaxy clustering, cosmic microwave background and $\mathrm{Ly}\alpha$ forest observations can be combined to pursue this program, and forecast the accuracy that the proposed SNAP satellite can attain.

Ultrahigh energy cosmic neutrinos are incisive probes of both astrophysical sources and new TeV-scale physics. Such neutrinos would create extensive air showers deep in the atmosphere. The absence of such showers implies upper limits on incoming neutrino fluxes and cross sections. Combining the exposures of the Akeno Giant Air Shower Array, the largest existing ground array, with the exposure of the Fly’s Eye fluorescence detector integrated over all its operating epochs, we derive 95% confidence level bounds that substantially improve existing limits. We begin with model-independent bounds on astrophysical fluxes, assuming standard model cross sections, and model-independent bounds on new physics cross sections, assuming a conservative cosmogenic flux. We then derive model-dependent constraints on new components of neutrino flux for several assumed power spectra, and we update bounds on the fundamental Planck scale $M_D$ in extra dimension scenarios from black hole production. For large numbers of extra dimensions, we find $M_D>2.0\mathrm{}\hspace{0.5em}\mathrm{}\left(1.1\right)\mathrm{}\mathrm{TeV}$ for $M_{\mathrm{BH}}^{\min }{=M}_D{(5M}_D),$ comparable to or exceeding the most stringent constraints to date.

It has recently been argued that bubble nucleation in ekpyrotic and cyclic cosmological scenarios can lead to unacceptable inhomogeneities unless certain constraints are satisfied. In this paper we show that this is not the case. We find that bubble nucleation is completely negligible in realistic models.

We investigate in a phenomenological way direct $\mathrm{CP}$ violation in the hadronic decays $B^{\pm ,0\mathrm{}}\to {\pi }^{+}{\pi }^{-}{K}^{\pm ,0\mathrm{}}$ where the effect of $\rho -\omega$ mixing is included. If $N_c^{\mathrm{eff}}$ (the effective parameter associated with factorization) is constrained using the most recent experimental branching ratios (to ${\rho }^0{K}^0,$ ${\rho }^{\pm }{K}^{\mp },$ ${\rho }^{\pm }{K}^0,$ ${\rho }^0{K}^{\pm }$ and $\omega K^{\pm })$ from the BABAR, BELLE and CLEO Collaborations, we get a maximum $\mathrm{CP}$ violating asymmetry $a_{\max }$ in the range $-25\%$ to $+49\%$ for $B^{-}\to {\pi }^{+}{\pi }^{-}{K}^{-}$ and $-24\%$ to $+55\%$ for $B^0\to {\pi }^{+}{\pi }^{-}{K}^0.$ We also find that $\mathrm{CP}$ violation is strongly dependent on the Cabibbo-Kobayashi-Maskawa matrix elements. Finally, we show that the sign of $\sin \delta$ is always positive in the allowed range of $N_c^{\mathrm{eff}}$ and hence, a measurement of direct $\mathrm{CP}$ violation in $B^{\pm ,0\mathrm{}}\to {\pi }^{+}{\pi }^{-}{K}^{\pm ,0\mathrm{}}$ would remove the $\mathrm{mod}\left(\pi \right)$ ambiguity in $\arg \left[-V_{\mathrm{ts}}{V}_{\mathrm{tb}}^{\star }{/V}_{\mathrm{us}}{V}_{\mathrm{ub}}^{\star }\right].$

The SU(2) and SU(3) chiral phase transitions in a gas made of pions, kaons, and etas are studied within the framework of chiral perturbation theory. We describe the temperature dependence of the quark condensates by using the meson meson scattering phase shifts in a second order virial expansion. In particular, the SU(3) formalism yields a somewhat lower melting temperature for the nonstrange condensates than within SU(2), and also predicts that the strange condensate melting is slower than that of the nonstrange, due to the different strange and nonstrange quark masses.

Well-known and newly developed renormalization schemes for $\tan \beta$ are analyzed in view of three desirable properties: gauge independence, process independence, and numerical stability in perturbation theory. Arguments are provided that no scheme can meet all three requirements, and, as an illustration, a “no-go-theorem” for the renormalization of $\tan \beta$ is established. Nevertheless, two particularly attractive schemes emerge. A discussion about which scheme might be the best compromise in practice is given.

A new approach towards the composite structure of quarks and leptons in the context of the higher dimensional unified theories is proposed. Because of certain strong dynamics much like ordinary QCD, every possible vectorlike set of composites appears in higher dimensional bulk space-time. However, through a proper Sherk-Schwarz compactification only chiral multiplets of composite quarks and leptons survive as the massless states in four dimensions. In this scenario restrictions related to ’t Hooft’s anomaly matching condition turn out to be avoided and, as a result, the composite models look rather simple and economical. We demonstrate our approach by an explicit construction of a model of preons and their composites unified in the supersymmetric $\mathrm{SU}\left(5\right)\mathrm{}$ GUT in five space-time dimensions. The model predicts precisely three families of composite quarks and leptons being the triplets of the chiral horizontal symmetry ${\mathrm{SU}\left(3\right)\mathrm{}}_h$ which automatically appears in the composite spectrum when going to ordinary four dimensions.

We construct a four dimensional realization of a higher dimensional model, Yukawa deflected gauge mediation, in which supersymmetry breaking is communicated to the visible sector through both gauge and Yukawa interactions. The reduction to four dimensions is achieved by “deconstructing” or “latticizing” the extra dimension. Three sites (gauge groups) are sufficient to reproduce the spectrum of the higher dimensional model. The characteristic features of Yukawa deflected gauge mediation, in particular, alignment of squarks and quarks, and a natural solution to the mu problem, carry over to the deconstructed version of the model. We comment on the implications of our results for a solution of the mu problem in the context of deconstructed gaugino mediation.

We discuss issues in a scenario where hierarchical Yukawa couplings are generated through the strong dynamics of superconformal field theories (SCFTs). Independently of the mediation mechanism of supersymmetry breaking, the infrared convergence property of SCFTs can provide an interesting solution to the supersymmetric flavor problem; sfermion masses are suppressed around the decoupling scale of SCFTs and eventually become degenerate to some degree, thanks to family-independent radiative corrections governed by the gaugino masses of the minimal supersymmetric standard model (MSSM). We discuss under what conditions the degeneracy of the sfermion mass can be estimated in a simple manner. We also discuss the constraints from lepton flavor violations. We then explicitly study sfermion mass degeneracy within the framework of grand unified theories coupled to SCFTs. It is found that the degeneracy for right-handed sleptons becomes worse in the conventional SU(5) model than in the MSSM. On the other hand, in the flipped $\mathrm{SU}\mathrm{}\left(5\right)\mathrm{}\times \mathrm{U}\mathrm{}\left(1\right)\mathrm{}$ model, each right-handed lepton is still an SU(5) singlet, whereas the B-ino mass $M_1$ is determined by two independent gaugino masses of $\mathrm{SU}\mathrm{}\left(5\right)\mathrm{}\times \mathrm{U}\mathrm{}\left(1\right).$ These two properties enable us to have an improved degeneracy for the right-handed sleptons. We also speculate on how further improvement can be obtained in the SCFT approach.

We study the low-lying eigenmodes of the lattice overlap Dirac operator for $\mathrm{SU}{(N}_c)$ gauge theories with $N_c=2,$ 3, 4 and 5 colors. We define a fermionic topological charge from the zero modes of this operator and show that, as $N_c$ grows, any disagreement with the topological charge obtained by cooling the fields becomes rapidly less likely. By examining the fields where there is a disagreement, we are able to show that the Dirac operator does not resolve instantons below a critical size of about $\rho \simeq 2.5a,$ but resolves the larger, more physical instantons. We investigate the local chirality of the near-zero modes and how it changes as we go to larger $N_c.$ We observe that the local chirality of these modes, which is prominent for SU(2) and SU(3), becomes rapidly weaker for larger $N_c$ and is consistent with disappearing entirely in the limit of $N_c=\infty .$ We find that this is not simply due to the observed disappearance of small instantons at larger $N_c.$

Compact U(1) theory in four dimensions is used to compare the modified iterative and Laplacian fixing to the lattice Landau gauge in a controlled setting, since in the Coulomb phase the lattice theory must reproduce the perturbative prediction. It turns out that on either side of the phase transition clear differences show up and in the Coulomb phase the ability to remove double Dirac sheets proves vital on a small lattice.