Showing papers on "Planck force published in 2014"

Planck 2013 results

Abstract: In this volume, we proudly present a special feature on science results from the data that ESA Planck mission gathered over its first 15 months and which ESA and the Planck Collaboration released in March 2013. This collection of 31 articles presents the initial scientific results extracted from this first Planck dataset, which measures the cosmic microwave background (CMB) with the highest accuracy to date. It provides major new advances in different domains of cosmology and astrophysics. We thank Jan Tauber and the Planck Science Team for coordinating this special feature.

Cosmology from gravitational lens time delays and Planck data

Abstract: Under the assumption of a flat Lambda CDM cosmology, recent data from the Planck satellite point toward a Hubble constant that is in tension with that measured by gravitational lens time delays and by the local distance ladder. Prosaically, this difference could arise from unknown systematic uncertainties in some of the measurements. More interestingly-if systematics were ruled out-resolving the tension would require a departure from the flat Lambda CDM cosmology, introducing, for example, a modest amount of spatial curvature, or a non-trivial dark energy equation of state. To begin to address these issues, we present an analysis of the gravitational lens RXJ1131-1231 that is improved in one particular regard: we examine the issue of systematic error introduced by an assumed lens model density profile. We use more flexible gravitational lens models with baryonic and dark matter components, and find that the exquisite Hubble Space Telescope image with thousands of intensity pixels in the Einstein ring and the stellar velocity dispersion of the lens contain sufficient information to constrain these more flexible models. The total uncertainty on the time-delay distance is 6.6% for a single system. We proceed to combine our improved time-delay distance measurement with the WMAP9 and Planck posteriors. In an open Lambda CDM model, the data for RXJ1131-1231 in combination with Planck favor a flat universe with Omega(k) = 0.00(-0.02)(+0.01) (68% credible interval (CI)). In a flat wCDM model, the combination of RXJ1131-1231 and Planck yields w = -1.52 (+0.19)(-0.20) (68% CI).

Reconstruction of the primordial power spectra with Planck and BICEP2 data

Abstract: By using the cubic spline interpolation method, we reconstruct the shape of the primordial scalar and tensor power spectra from the recently released Planck temperature and BICEP2 polarization cosmic microwave background data. We find that the vanishing scalar index running (dn(s)= d ln k) model is strongly disfavored at more than 3 sigma confidence level on the k = 0.0002 Mpc(-1) scale. Furthermore, the power-law parametrization gives a blue-tilt tensor spectrum, no matter using only the first five bandpowers n(t) = 1.20(-0.64)(+0.56) (95% C.L.) or the full nine bandpowers nt 1.24(-0.58)(+0.51) (95% C.L.) of BICEP2 data sets. Unlike the large tensor-to-scalar ratio value (r similar to 0.20) under the scale-invariant tensor spectrum assumption, our interpolation approach gives r(0.002) < 0.060 (95% C.L.) by using the first five bandpowers of BICEP2 data. After comparing the results with/without BICEP2 data, we find that Planck temperature with small tensor amplitude signals and BICEP2 polarization data with large tensor amplitude signals dominate the tensor spectrum reconstruction on the large and small scales, respectively. Hence, the resulting blue tensor tilt actually reflects the tension between Planck and BICEP2 data.

Planck scale boundary conditions in the standard model with singlet scalar dark matter

Abstract: We investigate Planck scale boundary conditions on the Higgs sector of the standard model with a gauge singlet scalar dark matter. We will find that vanishing selfcoupling and Veltman condition at the Planck scale are realized with the 126 GeV Higgs mass and top pole mass, 172 GeV ≲ M t ≲ 173.5 GeV, where a correct abundance of scalar dark matter is obtained with mass of 300 GeV ≲ m S ≲ 1 TeV. It means that the Higgs potential is flat at the Planck scale, and this situation can not be realized in the standard model with the top pole mass.

Inflationary generalized Chaplygin gas and dark energy in light of the Planck and BICEP2 experiments

Abstract: In this work, we study an inflationary scenario in the presence of generalized Chaplygin gas (GCG). We show that in Einstein gravity, GCG is not a suitable candidate for inflation; but in a five-dimensional brane-world scenario, it can work as a viable inflationary model. We calculate the relevant quantities such as ${n}_{s}$, $r$, and ${A}_{s}$ related to the primordial scalar and tensor fluctuations, and using their recent bounds from Planck and BICEP2, we constrain the model parameters as well as the five-dimensional Planck mass. But as a slow-roll inflationary model with a power-law type scalar primordial power spectrum, GCG as an inflationary model cannot resolve the tension between results from BICEP2 and Planck with a concordance $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ Universe. We show that by going beyond the concordance $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model and incorporating more general dark energy behavior, we may ease this tension. We also obtain the constraints on the ${n}_{s}$ and $r$ and the GCG model parameters using $\text{Planck}+\mathrm{WP}+\mathrm{BICEP}2$ data considering the CPL dark energy behavior.

Effect of transitions in the Planck mass during inflation on primordial power spectra

Abstract: We study the effect of sudden transitions in the effective Planck mass during inflation on primordial power spectra. Specifically, we consider models in which this variation results from the nonminimal coupling of a Brans-Dicke type scalar field. We find that the scalar power spectra develop features at the scales corresponding to those leaving the horizon during the transition. In addition, we observe that the tensor perturbations are largely unaffected, so long as the variation of the Planck mass is below the percent level. Otherwise, the tensor power spectra exhibit damped oscillations over the same scales. Due to significant features in the scalar power spectra, the tensor-to-scalar ratio $r$ shows variation over the corresponding scales. Thus, by studying the spectra of both scalar and tensor perturbations, one can constrain sudden but small variations of the Planck mass during inflation. We illustrate these effects with a number of benchmark single- and two-field models. In addition, we comment on their implications and the possibility to alleviate the tension between the observations of the tensor-to-scalar ratio performed by the Planck and BICEP2 experiments.

Negative Running of the Spectral Index, Hemispherical Asymmetry and the Consistency of Planck with Large $r$

Abstract: Planck favours a negative running of the spectral index, with the likelihood being dominated by low multipoles $l \lesssim 50$ and no preference for running at higher $l$. A negative spectral index is also necessary for the 2-$\sigma$ Planck upper bound on the tensor-to-scalar ratio $r$ to be consistent with values significantly larger than 0.1. Planck has also observed a hemispherical asymmetry of the CMB power spectrum, again mostly at low multipoles. Here we consider whether the physics responsible for the hemispherical asymmetry could also account for the negative running of the spectral index and the consistency of Planck with a large value of $r$. A negative running of the spectral index can be generated if the hemispherical asymmetry is due to a scale- and space-dependent modulation which suppresses the CMB power spectrum at low multipoles. We show that the observed hemispherical asymmetry at low $l$ can be generated while satisfying constraints on the asymmetry at higher $l$ and generating a negative spectral index of the right magnitude to account for the Planck observation and to allow Planck to be consistent with a large value of $r$.

Constraints on the cosmological parameters from BICEP2, Planck and WMAP

Abstract: In this paper we constrain the cosmological parameters, in particular the tilt of tensor power spectrum, by adopting Background Imaging of Cosmic Extragalactic Polarization (B2), Planck released in 2013 (P13) and Wilkinson Microwaves Anisotropy Probe 9-year Polarization (WP) data. We find that a blue tilted tensor power spectrum is preferred at more than $3\sigma$ confidence level if the data from B2 are assumed to be totally interpreted as the relic gravitational waves, but a scale invariant tensor power spectrum is consistent with the data once the polarized dust is taken into account. The recent Planck 353 GHz HFI dust polarization data imply that the B2 data are perfectly consistent with there being no gravitational wave signal.

Constraints on cosmological parameters from Planck and BICEP2 data

Abstract: We show that the tension introduced by the detection of large amplitude gravitational wave power by the BICEP2 experiment with temperature anisotropy measurements by the Planck mission is alleviated in models where extra light species contribute to the effective number of relativistic degrees of freedom. We also show that inflationary models based on S-dual potentials are in agreement with Planck and BICEP2 data.

GCG Inflation in the light of Planck and BICEP2

Abstract: In this work, we study an inflationary scenario in the presence of Generalized Chaplygin Gas (GCG). We show that in Einstein gravity, GCG is not a suitable candidate for inflation; but in a five dimensional brane world scenario, it can work as a viable inflationary model. We calculate the relevant quantities such as $n_{s}$, $r$ and $A_{s}$ related to the primordial scalar and tensor fluctuations, and using their recent bounds from Planck and BICEP2, we constrain the model parameters as well as the five-dimensional Planck mass. But as a slow-roll inflationary model with a power-law type scalar primordial power spectrum, GCG as an inflationary model can not resolve the tension between results from BICEP2 and Planck with a concordance $\Lambda$CDM universe. We show that with a phantom type dark energy equation of state, this tension may be eased.

Quantum Smearing in Hybrid Inflation with Chaotic Potentials

Abstract: We study the impact of one-loop radiative corrections in a non-supersymmetric model of hybrid inflation with chaotic (polynomial-like) potential, $V_0 + \lambda_p \phi^p$. These corrections can arise from the possible couplings of inflaton with other fields which may play active role in the reheating process. The tree-level predictions of these models are shown to lie outside of the Planck's latest bounds on the scalar spectral index $n_s$ and the tensor to scalar ratio $r$. However, the radiatively corrected version of these models, $ V_0 + \lambda_p \phi^p + A \phi^4 \ln \phi$, is fully consistent with the Planck's data. More specifically, fermionic radiative correction ($A<0$) reduces the tensor to scalar ratio significantly and a red-tilted spectral index $n_s<1$, consistent with Planck's data, is obtained even for sub-Planckian field-values.

Experimental set for measuring the planck’s constant using LED

Abstract: The key parameter for determination of Planck’s constant using LED is the voltage required to turn on an LED. Many experiments have been used a voltmeter to measure the voltage. The accuracy of voltage obtained depends on experience of experimenter in deciding when the LED stared to emit. Therefore, in this work, we have proposed a computer based approach that utilizes curve fitting to determine the voltage required to switch on an LED. The experimental setup consists of a circuit with a 6 V dc source, a 100 Ω resistor, a variable resistor (0-100 Ω), a capacitor (0.14 F), and five LEDs. A voltage probe connected to MultiLogPro Data Logger and a computer are used for monitoring the voltage across the capacitor during the discharge of capacitor through each LED. Then, the threshold voltage which is the minimum voltage to turn on the LED obtains from curve fitting. By plotting the graph of photon energy versus frequency for the five LEDs, the Planck’s constant is achieved from its slope. The Planck’s constant from our experiment was found to be (6.625 ± 0.003) × 10 -34 J•s. It can be concluded that this method is reliable and accurate with a percentage error of 0.015. Keyword: Planck’s constant, LED, physics education

Emergent gravity by tuning the effective Planck length in Bose-Einstein Condensate

Abstract: We show that at lowest energy nonlocal interactions, the tuning of s-wave scattering length can enable a systematic control over the quantum pressure term in a Bose-Einstein condensate (BEC). We derive the equation for the massless free excitations in an analogue curved space-time by controlling the effective Planck length. Our controlled derivation indicates a breakdown of this dynamics at length scales comparable to effective Planck length. We also specify the correction that one has to take into account at a larger length scale in a flat space-time due to the emergent gravity at intermediate length scales.

The Planck Relation is a Geometric Mean Equation

Abstract: We show that the Planck relation is a geometric mean equation, supporting the idea that the universe is undergoing a geometric mean expansion.

Will Planck Observe Gravity Waves

Abstract: Assume that inflation is driven by a gauge singlet scalar field with a Higgs potential. The tensor to scalar ratio r, a canonical measure of gravity waves generated during inflation, turns out in this case to be & 0.02, provided the scalar spectral index ns ≥ 0.96. Thus, Planck or some other comparable experiment should observe r sooner or later. In minimal supersymmetric hybrid inflation, on the other hand, r ∼ 10−10, and therefore lies well below the reach of Planck and any foreseeable experiment. Observable r values, ∼ 0.02 or so, are

On the Origin of Nuclear Charge Radius & Planck’s Constant

Abstract: In this paper the authors made an attempt to fit and understand the origin of the nuclear charge radius, the Planck’s constant and the strong coupling constant by introducing the unified mass unit in a unified approach. This approach connects gravity and strong interaction via the electromagnetic and gravitational force ratio of proton and electron. Finally, by considering the proton rest energy the authors made an attempt to fit the semi-empirical mass formula energy coefficients in a very simple way.

Cosmology with Planck

Abstract: The European Space Agency (hereafter ESA) Planck satellite was launched on May 2009 and has been surveying the microwave and the submillimeter sky since August 2009. In March 2013, ESA and the Planck Collaboration publicly released the initial cosmology products based on the first 15.5 months of Planck operations. In this contribution we present the first cosmological results based on Planck measurements of the Cosmic Microwave Radiation temperature and lensing-potential power spectra. The Planck spectra at high multipoles are well described by the standard Lambda Cold Dark Matter (?CDM) cosmological model based on six parameters. We find a low value of the Hubble parameter, H 0 = 67.3 ± 1.2 km/s/Mpc, and, consequently, an high value of the matter parameter density Ω m = 0.315±0.017 (±1σ errors), in agreement with the measurements of baryon acoustic oscillation (BAO) surveys. We also present results from several possible extensions of the standard cosmological model, by using astrophysical datasets in addition to the Planck data. None of these models are favored significantly over the standard ?CDM. Using BAO and CMB data, we find N eff = 3.30 ± 0.27 for the effective number of relativistic degrees of freedom, and an upper limit of 0.25 eV for the summed neutrino mass.