We formulate a classical fields method for the description of relativistic interacting bosonic particles at nonzero temperatures. The method relies on the assumption that at low temperatures the Bose field can be described by a $c$-number function. We discuss a very important role of the cutoff momentum which divides the field into a dominant classical part and a small quantum correction. We illustrate the method by studying the thermodynamics of a relativistic Bose field which is governed by the Klein-Gordon equation with a $\lambda {\psi }^4$ term responsible for the interactions.

In this paper we study the possibility of sustaining an evolving wormhole via exotic matter made of phantom energy in the presence of a cosmological constant. We derive analytical evolving wormhole geometries by supposing that the radial tension of the phantom matter, which is negative to the radial pressure, and the pressure measured in the tangential directions have barotropic equations of state with constant state parameters. In this case the presence of a cosmological constant ensures accelerated expansion of the wormhole configurations. More specifically, for positive cosmological constant we have wormholes which expand forever and, for negative cosmological constant we have wormholes which expand to a maximum value and then recollapse. At spatial infinity the energy density and the pressures of the anisotropic phantom matter threading the wormholes vanish; thus these evolving wormholes are asymptotically vacuum $\Lambda$-Friedmann models with either open or closed or flat topologies.

We make preliminary estimates to assess whether the recently reported flyby anomaly can be attributed to dark matter interactions. We consider both elastic and exothermic inelastic scattering from dark matter constituents; for isotropic dark matter velocity distributions, the former decrease, while the latter increase, the final flyby velocity. The fact that the observed flyby velocity anomaly shows examples with both positive and negative signs, requires the dominance of different dark matter scattering processes along different flyby trajectories. The magnitude of the observed anomalies requires dark matter densities many orders of magnitude greater than the galactic halo density. Such a large density could result from an accumulation cascade, in which the solar system-bound dark matter density is much higher than the galactic halo density, and the earth-bound density is much higher than the solar system-bound density. We discuss a number of strong constraints on the hypothesis of a dark matter explanation for the flyby anomaly. These require dark matter to be non-self-annihilating, with the dark matter scattering cross section on nucleons much larger, and the dark matter mass much lighter, than usually assumed.

We correct the mistaken claim made by Guzey and Polyakov [Eur. Phys. J. C 46, 151 (2006) ] and Guzey and Teckentrup [Phys. Rev. D 74, 054027 (2006)] that the minimal model of the dual parametrization of nucleon generalized parton distributions gives a good, essentially model-independent description of high-energy data on deeply virtual Compton scattering (DVCS). In the implementation of the dual parametrization by Guzey-Polyakov and Guzey-Teckentrup (see above), the numerical prefactor of two in front of the DVCS amplitude was missing. We show that the corrected minimal model of the dual parametrization significantly overestimates the Hadron Electron Ring Accelerator data (H1 and ZEUS experiments) on the DVCS cross section.

$CP$-violating effects in the time-dependent angular distribution of the $B_s^0\to J/\psi [\to {\ell }^{+}{\ell }^{-}]\varphi [\to K^{+}{K}^{-}]$ decay products play a key rôle for the search of new physics. The hadronic standard-model uncertainties are related to doubly Cabibbo-suppressed penguin contributions and are usually assumed to be negligibly small. In view of recent results from the Tevatron and the quickly approaching start of the data taking at the LHC, we have a critical look at the impact of these terms, which could be enhanced through long-distance QCD phenomena, and explore the associated uncertainty for the measurement of the $CP$-violating $B_s^0-{\overline{B}}_s^0$ mixing phase. We point out that these effects can actually be controlled by means of an analysis of the time-dependent angular distribution of the $B_s^0\to J/\psi [\to {\ell }^{+}{\ell }^{-}]{\overline{K}}^{*0}[\to {\pi }^{+}{K}^{-}]$ decay products and illustrate this through numerical studies. Moreover, we discuss $SU(3)$-breaking effects, which limit the theoretical accuracy of our method, and suggest internal consistency checks of $SU(3)$.

We derive the general form for a three-dimensional scale-invariant field theory with $\mathcal{N}=6$ supersymmetry, $SU(4)$ R-symmetry and a $U(1)$ global symmetry. The results can be written in terms of a 3-algebra in which the triple product is not antisymmetric. For a specific choice of 3-algebra we obtain the $\mathcal{N}=6$ theories that have been recently proposed as models for M2-branes in an ${\mathbb{R}}^8/{\mathbb{Z}}_k$ orbifold background.

In the context of two-time physics in $4+2$ dimensions we construct the most general $N=2$, 4 supersymmetric Yang-Mills gauge theories for any gauge group G. This builds on our previous work for $N=1$ supersymmetry (SUSY). The action, the conserved SUSY currents, and the SU(N) covariant SUSY transformation laws are presented for both $N=2$ and $N=4$. When the equations of motion are used the SUSY transformations close to the supergroup $\mathrm{SU}(2,2|N)$ with $N=1$, 2, 4. The $\mathrm{SU}(2,2)=\mathrm{SO}(4,2)$ subsymmetry is realized linearly on $4+2$ dimensional flat spacetime. All fields, including vectors and spinors, are in $4+2$ dimensions. The extra gauge symmetries in 2T field theory, together with the kinematic constraints that follow from the action, remove all the ghosts to give a unitary theory. By choosing gauges and solving the kinematic equations, the 2T field theory in $4+2$ flat spacetime can be reduced to various shadows in various $3+1$ dimensional (generally curved) spacetimes. These shadows are related to each other by dualities. The conformal shadows of our theories in flat $3+1$ dimensions coincide with the well known counterpart $N=1$, 2, 4 supersymmetric massless renormalizable field theories in $3+1$ dimensions. It is expected that our more symmetric new structures in $4+2$ spacetime may be useful for nonperturbative or exact solutions of these theories.

We investigate the radiation emitted from a scalar source in circular orbit around a Reissner-Nordström black hole. Particle and energy emission rates are analytically calculated in the low- and high-frequency regimes and shown to be in full agreement with a numerical calculation. A brief comment connecting the present work with a recent discussion on the cosmic censorship conjecture is included at the end.

The first spectral numerical simulations of 16 orbits, merger, and ringdown of an equal-mass nonspinning binary black hole system are presented. Gravitational waveforms from these simulations have accumulated numerical phase errors through ringdown of $\lesssim 0.1\mathrm{radian}$ when measured from the beginning of the simulation, and $\lesssim 0.02\mathrm{radian}$ when waveforms are time and phase shifted to agree at the peak amplitude. The waveform seen by an observer at infinity is determined from waveforms computed at finite radii by an extrapolation process accurate to $\lesssim 0.01\mathrm{radian}$ in phase. The phase difference between this waveform at infinity and the waveform measured at a finite radius of $r=100M$ is about half a radian. The ratio of final mass to initial mass is $M_f/M=0.95162\pm 0.00002$, and the final black hole spin is $S_f/M_f^2=0.68646\pm 0.00004$.

Assuming that the dilaton is the dark matter of the Universe, we propose an experiment to detect the relic dilaton using the electromagnetic resonant cavity, based on the dilaton-photon conversion in strong electromagnetic background. We calculate the density of the relic dilaton, and estimate the dilaton mass for which the dilaton becomes the dark matter of the Universe. With this we calculate the dilaton detection power in the resonant cavity, and compare it with the axion detection power in a similar resonant cavity experiment.

Inflation is now an accepted paradigm in standard cosmology, with its predictions consistent with observations of the cosmic microwave background. It lacks, however, a firm physical theory, with many possible theoretical origins beyond the simplest, canonical, slow-roll inflation, including Dirac-Born-Infeld inflation and k-inflation. We discuss how a hierarchy of Hubble flow parameters, extended to include the evolution of the inflationary sound speed, can be applied to compare a general, single field inflationary action with cosmological observational data. We show that it is important to calculate the precise scalar and tensor primordial power spectra by integrating the full flow and perturbation equations, since values of observables can deviate appreciably from those obtained using typical second-order Taylor expanded approximations in flow parameters. As part of this, we find that a commonly applied approximation for the tensor-to-scalar ratio, $r\approx 16c_sϵ$, becomes poor (deviating by as much as 50%) as $c_s$ deviates from 1 and hence the Taylor expansion including next-to-leading order contribution terms involving $c_s$ is required. By integrating the full flow equations, we use a Monte-Carlo-Markov-Chain approach to impose constraints on the parameter space of general single field inflation, and reconstruct the properties of such an underlying theory in light of recent cosmic microwave background and large-scale structure observations.

The effect of quintessence perturbations on the integrated Sachs-Wolfe (ISW) effect is studied for a mixed dynamical scalar field dark energy (DDE) and pressureless perfect fluid dark matter. A new and general methodology is developed to track the growth of the perturbations, which uses only the equation of state (EoS) parameter $w_{\mathrm{DDE}}(z)\equiv p_{\mathrm{DDE}}/{\rho }_{\mathrm{DDE}}$ of the scalar field DDE, and the initial values of the relative entropy perturbation (between the matter and DDE) and the intrinsic entropy perturbation of the scalar field DDE as inputs. We also derive a relation between the rest-frame sound speed ${\widehat{c}}_{s,\mathrm{DDE}}^2$ of an arbitrary scalar field DDE component and its EoS $w_{\mathrm{DDE}}(z)$. We show that the ISW signal differs from that expected in a $\Lambda \mathrm{CDM}$ cosmology by as much as $+20\%$ to $-80\%$ for parametrizations of $w_{\mathrm{DDE}}$ consistent with SNIa data, and about $\pm 20\%$ for parametrizations of $w_{\mathrm{DDE}}$ consistent with $\mathrm{SNIa}+\mathrm{CMB}+\mathrm{BAO}$ data, at 95% confidence. Our results indicate that, at least in principle, the ISW effect can be used to phenomenologically distinguish a cosmological constant from DDE.

The observed mass pattern of scalar resonances below 1 GeV suggests a tetraquark assignment over the conventional $\overline{q}q$ assignment for these states. We present a search for tetraquarks with isospins 0, $1/2$, 1 in lattice QCD, where the isospin channels $1/2$ and 1 have not been studied before. We determine three energy levels in each isospin channel using the variational method. The scattering states and possible tetraquark states are distinguished by considering the volume dependence of spectral weights and by considering the time dependence of correlators near $t\simeq T/2$. We find no indication for light tetraquarks at our range of pion masses, $344–576\mathrm{MeV}$. However, our simulation does not exclude a possibility of finding tetraquarks in a simulation with smaller pion masses or a different interpolator basis.

Bottom baryon masses are calculated based on a $2+1$ flavor dynamical lattice QCD simulation. The gauge field configurations were computed by the CP-PACS and JLQCD collaborations using an improved clover action. The bottom quark is described using lattice NRQCD. Results are presented for single and double-$b$ baryons at one lattice spacing. Comparison with experimental values is discussed.

We investigate the effect of the electric-charge neutrality in $\beta$ equilibrium on the chiral phase transition by solving the chiral and diquark condensates in the two-flavor Nambu–Jona-Lasinio model. We demonstrate that the electric-charge neutrality plays a similar role as the repulsive vector interaction; they both weaken the first-order chiral phase transition in the high-density and low-temperature region. The first-order chiral phase transition is not affected, however, at finite temperatures where the diquark condensate melts. In this way the chiral phase transition could be second order at intermediate temperatures if the diquark effects overwhelm the chiral dynamics, while the first-order transition may survive at lower and higher temperatures. The number of the critical points appearing on the phase diagram can vary from zero to three, which depends on the relative strength of the chiral and diquark couplings. We systematically study the possibility of the phase structure with multiple QCD critical points and evaluate the Meissner screening mass to confirm that our conclusion is not overturned by chromomagnetic instability.

We investigate here the BCS-BEC crossover in relativistic systems using a variational construct for the ground state and the minimization of the thermodynamic potential. This is first studied in a four-fermion point interaction model and with a BCS type ansatz for the ground state with fermion pairs. It is shown that the antiparticle degrees of freedom play an important role in the BCS-BEC crossover physics, even when the ratio of Fermi momentum to the mass of the fermion is small. We also consider the phase structure for the case of fermion pairing with imbalanced populations. Within the ansatz, thermodynamically stable gapless modes for both fermions and antifermions are seen for strong coupling in the Bose-Einstein condensation (BEC) regime. We further investigate the effect of fluctuations of the condensate field by treating it as a dynamical field and generalize the BCS ansatz to include quanta of the condensate field also in a boson-fermion model with quartic self-interaction of the condensate field. It is seen that the critical temperature decreases with inclusion of fluctuations.

We present a calculation of $\eta /s$ for the meson gas (zero baryon number), with the viscosity computed within unitarized next-to-leading-order chiral perturbation theory, and confirm the observation that $\eta /s$ decreases towards the possible phase transition to a quark-gluon plasma/liquid. The value is somewhat higher than previously estimated in leading-order $\chi \mathrm{PT}$. We also examine the case of atomic Argon gas to check the discontinuity of $\eta /s$ across a first-order phase transition. Our results suggest employing this dimensionless number, sometimes called KSS number (in analogy with other ratios in fluid mechanics such as Reynolds number or Prandtl number) to pin down the phase transition and critical end point to a crossover in strongly interacting nuclear matter between the hadron gas and quark and gluon plasma/liquid.

We have developed a model for neutrino-induced coherent pion production off nuclei in the energy regime of interest for present and forthcoming neutrino oscillation experiments. It is based on a microscopic model for pion production off the nucleon that, besides the dominant $\Delta$ pole contribution, takes into account the effect of background terms required by chiral symmetry. Moreover, the model uses a reduced nucleon-to-$\Delta$ resonance axial coupling, which leads to coherent pion production cross sections around a factor of 2 smaller than most of the previous theoretical estimates. In the coherent production, the main nuclear effects, namely, medium corrections on the $\Delta$ propagator and the final pion distortion, are included. We have improved on previous similar models by taking into account the nucleon motion and employing a more sophisticated optical potential. As found in previous calculations the modification of the $\Delta$ self-energy inside the nuclear medium strongly reduces the cross section, while the final pion distortion mainly shifts the peak position to lower pion energies. The angular distribution profiles are not much affected by nuclear effects. Nucleon motion increases the cross section by $\sim 15\%$ at neutrino energies of 650 MeV, while Coulomb effects on charged pions are estimated to be small. Finally, we discuss at length the deficiencies of the Rein-Sehgal pion coherent production model for neutrino energies below 2 GeV, and, in particular, for the MiniBooNE and T2K experiments. We also predict flux-averaged cross sections for these two latter experiments and K2K.

In the framework of three light Majorana neutrinos, we show how to reconstruct, through the use of $3\times 3$ unitarity, the full PMNS matrix from six independent Majorana-type phases. In particular, we express the strength of Dirac-type $CP$ violation in terms of these Majorana-type phases by writing the area of the unitarity triangles in terms of these phases. We also study how these six Majorana phases appear in $CP$-odd weak-basis invariants as well as in leptonic asymmetries relevant for flavored leptogenesis.

The main aim of this study is the comparison of gravitational waveforms obtained from numerical simulations which employ different numerical evolution approaches and different wave-extraction techniques. For this purpose, we evolve an oscillating, nonrotating, polytropic neutron-star model with two different approaches: a full nonlinear relativistic simulation (in three dimensions) and a linear simulation based on perturbation theory. The extraction of the gravitational-wave signal is performed via three methods: the gauge-invariant curvature-perturbation theory based on the Newman-Penrose scalar ${\psi }_4$; the gauge-invariant Regge-Wheeler-Zerilli-Moncrief metric-perturbation theory of a Schwarzschild space-time; some generalization of the quadrupole emission formula.