Brane Bremsstrahlung in DBI Inflation
Brax, Philippe
2010-01-01
We consider the effect of trapped branes on the evolution of a test brane whose motion generates DBI inflation along a warped throat. The coupling between the inflationary brane and a trapped brane leads to the radiation of non-thermal particles on the trapped brane. We calculate the Gaussian spectrum of the radiated particles and their backreaction on the DBI motion of the inflationary brane. Radiation occurs for momenta lower than the speed of the test brane when crossing the trapped brane. The slowing down effect is either due to a parametric resonance when the interaction time is small compared to the Hubble time or a tachyonic resonance when the interaction time is large. In both cases the motion of the inflationary brane after the interaction is governed by a chameleonic potential,which tends to slow it down. We find that a single trapped brane can hardly slow down a DBI inflaton whose fluctuations lead to the Cosmic Microwave Background spectrum. A more drastic effect is obtained when the DBI brane enc...
Multifield DBI Inflation and Non-Gaussianities
Huang, Min-xin; Underwood, Bret
2008-01-01
We analyze the trajectories for multifield DBI inflation, which can arise in brane inflation models, and show that the trajectories are the same as in typical slow roll inflation. We calculate the power spectrum and find that the higher derivative terms of the DBI action lead to a suppression of the contribution from the isocurvature perturbations. We also calculate the bispectrum generated by the isocurvature perturbation, and find that it leads to distinctive features.
Primordial non-Gaussian features from DBI Galileon inflation
International Nuclear Information System (INIS)
Choudhury, Sayantan; Pal, Supratik
2015-01-01
We have studied primordial non-Gaussian features of a model of potential-driven single field DBI Galileon inflation. We have computed the bispectrum from the three-point correlation function considering all possible cross correlations between the scalar and tensor modes of the proposed setup. Further, we have computed the trispectrum from a four-point correlation function considering the contribution from contact interaction, and scalar and graviton exchange diagrams in the in-in picture. Finally we have obtained the non-Gaussian consistency conditions from the four-point correlator, which results in partial violation of the Suyama-Yamaguchi four-point consistency relation. This further leads to the conclusion that sufficient primordial non-Gaussianities can be obtained from DBI Galileon inflation. (orig.)
Non-Gaussianities in multifield DBI inflation with a waterfall phase transition
Kidani, Taichi; Koyama, Kazuya; Mizuno, Shuntaro
2012-10-01
We study multifield Dirac-Born-Infeld (DBI) inflation models with a waterfall phase transition. This transition happens for a D3 brane moving in the warped conifold if there is an instability along angular directions. The transition converts the angular perturbations into the curvature perturbation. Thanks to this conversion, multifield models can evade the stringent constraints that strongly disfavor single field ultraviolet (UV) DBI inflation models in string theory. We explicitly demonstrate that our model satisfies current observational constraints on the spectral index and equilateral non-Gaussianity as well as the bound on the tensor to scalar ratio imposed in string theory models. In addition, we show that large local type non-Gaussianity is generated together with equilateral non-Gaussianity in this model.
Amani, Roonak; Rezazadeh, Kazem; Abdolmaleki, Asrin; Karami, Kayoomars
2018-02-01
We investigate the power-law, intermediate, and logamediate inflationary models in the framework of DBI non-canonical scalar field with constant sound speed. In the DBI setting, we first represent the power spectrum of both scalar density and tensor gravitational perturbations. Then, we derive different inflationary observables including the scalar spectral index n s , the running of the scalar spectral index {{dn}}s/d{ln}k, and the tensor-to-scalar ratio r. We show that the 95% CL constraint of the Planck 2015 T + E data on the non-Gaussianity parameter {f}{NL}{DBI} leads to the sound speed bound {c}s≥slant 0.087 in the DBI inflation. Moreover, our results imply that, although the predictions of the power-law, intermediate, and logamediate inflations in the standard canonical framework (c s = 1) are not consistent with the Planck 2015 data, in the DBI scenario with constant sound speed {c}srunning of the scalar spectral index and find that it is compatible with the 95% CL constraint from the Planck 2015 TT,TE,EE+lowP data.
Warm inflation in the stochastic inflation formalism
International Nuclear Information System (INIS)
Silva, Leandro A. da; Ramos, Rudnei O.
2011-01-01
Full text: The basic assumption of stochastic inflation is the splitting, through the definition of a appropriate window function, of the quantum inflaton field in a long wavelength part (modes outside of the de Sitter horizon) and in a short wavelength (modes inside the de Sitter horizon) part. The inflationary mechanism then continuously shifts more and more modes of the bath field into the system stretching their physical wavelengths beyond the de Sitter horizon size, what generates an effective system-bath interaction. Therefore, the system field develops a stochastic dynamics driven by the bath field, that plays the role of noise source. The resulting equation of motion (EoM) is a Langevin-like equation. Applying this formalism to Warm Inflation scenario (where, alternatively to the cold inflation, we assume that the inflaton evolves in a thermal bath and through a dissipative process continuously generates radiation, thus avoiding the necessity of a reheating mechanism), we contrast the exact numerical solution of thermal power spectrum and two approximations currently used in the literature, and compare this to the quantum power spectrum at horizon crossing. Finally, we consider a more realistic model based on microscopic derivations to estimate the effects of non-Markovianity on the inflaton dynamics and on the thermal power spectrum. (author)
Stochastic effects in hybrid inflation
Martin, Jérôme; Vennin, Vincent
2012-02-01
Hybrid inflation is a two-field model where inflation ends due to an instability. In the neighborhood of the instability point, the potential is very flat and the quantum fluctuations dominate over the classical motion of the inflaton and waterfall fields. In this article, we study this regime in the framework of stochastic inflation. We numerically solve the two coupled Langevin equations controlling the evolution of the fields and compute the probability distributions of the total number of e-folds and of the inflation exit point. Then, we discuss the physical consequences of our results, in particular, the question of how the quantum diffusion can affect the observable predictions of hybrid inflation.
Stochastic dynamics of new inflation
International Nuclear Information System (INIS)
Nakao, Ken-ichi; Nambu, Yasusada; Sasaki, Misao.
1988-07-01
We investigate thoroughly the dynamics of an inflation-driving scalar field in terms of an extended version of the stochastic approach proposed by Starobinsky and discuss the spacetime structure of the inflationary universe. To avoid any complications which might arise due to quantum gravity, we concentrate our discussions on the new inflationary universe scenario in which all the energy scales involved are well below the planck mass. The investigation is done both analytically and numerically. In particular, we present a full numerical analysis of the stochastic scalar field dynamics on the phase space. Then implications of the results are discussed. (author)
Stochastic inflation and nonlinear gravity
International Nuclear Information System (INIS)
Salopek, D.S.; Bond, J.R.
1991-01-01
We show how nonlinear effects of the metric and scalar fields may be included in stochastic inflation. Our formalism can be applied to non-Gaussian fluctuation models for galaxy formation. Fluctuations with wavelengths larger than the horizon length are governed by a network of Langevin equations for the physical fields. Stochastic noise terms arise from quantum fluctuations that are assumed to become classical at horizon crossing and that then contribute to the background. Using Hamilton-Jacobi methods, we solve the Arnowitt-Deser-Misner constraint equations which allows us to separate the growing modes from the decaying ones in the drift phase following each stochastic impulse. We argue that the most reasonable choice of time hypersurfaces for the Langevin system during inflation is T=ln(Ha), where H and a are the local values of the Hubble parameter and the scale factor, since T is the natural time for evolving the short-wavelength scalar field fluctuations in an inhomogeneous background
Solving stochastic inflation for arbitrary potentials
International Nuclear Information System (INIS)
Martin, Jerome; Musso, Marcello
2006-01-01
A perturbative method for solving the Langevin equation of inflationary cosmology in the presence of backreaction is presented. In the Gaussian approximation, the method permits an explicit calculation of the probability distribution of the inflaton field for an arbitrary potential, with or without the volume effects taken into account. The perturbative method is then applied to various concrete models, namely, large field, small field, hybrid, and running mass inflation. New results on the stochastic behavior of the inflaton field in those models are obtained. In particular, it is confirmed that the stochastic effects can be important in new inflation while it is demonstrated they are negligible in (vacuum dominated) hybrid inflation. The case of stochastic running mass inflation is discussed in some details and it is argued that quantum effects blur the distinction between the four classical versions of this model. It is also shown that the self-reproducing regime is likely to be important in this case
Multiple fields in stochastic inflation
Energy Technology Data Exchange (ETDEWEB)
Assadullahi, Hooshyar [Institute of Cosmology & Gravitation, University of Portsmouth,Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); Firouzjahi, Hassan [School of Astronomy, Institute for Research in Fundamental Sciences (IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Noorbala, Mahdiyar [Department of Physics, University of Tehran,P.O. Box 14395-547, Tehran (Iran, Islamic Republic of); School of Astronomy, Institute for Research in Fundamental Sciences (IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Vennin, Vincent; Wands, David [Institute of Cosmology & Gravitation, University of Portsmouth,Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom)
2016-06-24
Stochastic effects in multi-field inflationary scenarios are investigated. A hierarchy of diffusion equations is derived, the solutions of which yield moments of the numbers of inflationary e-folds. Solving the resulting partial differential equations in multi-dimensional field space is more challenging than the single-field case. A few tractable examples are discussed, which show that the number of fields is, in general, a critical parameter. When more than two fields are present for instance, the probability to explore arbitrarily large-field regions of the potential, otherwise inaccessible to single-field dynamics, becomes non-zero. In some configurations, this gives rise to an infinite mean number of e-folds, regardless of the initial conditions. Another difference with respect to single-field scenarios is that multi-field stochastic effects can be large even at sub-Planckian energy. This opens interesting new possibilities for probing quantum effects in inflationary dynamics, since the moments of the numbers of e-folds can be used to calculate the distribution of primordial density perturbations in the stochastic-δN formalism.
Stochastic approaches to inflation model building
International Nuclear Information System (INIS)
Ramirez, Erandy; Liddle, Andrew R.
2005-01-01
While inflation gives an appealing explanation of observed cosmological data, there are a wide range of different inflation models, providing differing predictions for the initial perturbations. Typically models are motivated either by fundamental physics considerations or by simplicity. An alternative is to generate large numbers of models via a random generation process, such as the flow equations approach. The flow equations approach is known to predict a definite structure to the observational predictions. In this paper, we first demonstrate a more efficient implementation of the flow equations exploiting an analytic solution found by Liddle (2003). We then consider alternative stochastic methods of generating large numbers of inflation models, with the aim of testing whether the structures generated by the flow equations are robust. We find that while typically there remains some concentration of points in the observable plane under the different methods, there is significant variation in the predictions amongst the methods considered
Recursive stochastic effects in valley hybrid inflation
Levasseur, Laurence Perreault; Vennin, Vincent; Brandenberger, Robert
2013-10-01
Hybrid inflation is a two-field model where inflation ends because of a tachyonic instability, the duration of which is determined by stochastic effects and has important observational implications. Making use of the recursive approach to the stochastic formalism presented in [L. P. Levasseur, preceding article, Phys. Rev. D 88, 083537 (2013)], these effects are consistently computed. Through an analysis of backreaction, this method is shown to converge in the valley but points toward an (expected) instability in the waterfall. It is further shown that the quasistationarity of the auxiliary field distribution breaks down in the case of a short-lived waterfall. We find that the typical dispersion of the waterfall field at the critical point is then diminished, thus increasing the duration of the waterfall phase and jeopardizing the possibility of a short transition. Finally, we find that stochastic effects worsen the blue tilt of the curvature perturbations by an O(1) factor when compared with the usual slow-roll contribution.
MEASURING INFLATION THROUGH STOCHASTIC APPROACH TO INDEX NUMBERS FOR PAKISTAN
Directory of Open Access Journals (Sweden)
Zahid Asghar
2010-09-01
Full Text Available This study attempts to estimate the rate of inflation in Pakistan through stochastic approach to index numbers which provides not only point estimate but also confidence interval for the rate of inflation. There are two types of approaches to index number theory namely: the functional economic approaches and the stochastic approach. The attraction of stochastic approach is that it estimates the rate of inflation in which uncertainty and statistical ideas play a major roll of screening index numbers. We have used extended stochastic approach to index numbers for measuring inflation by allowing for the systematic changes in the relative prices. We use CPI data covering the period July 2001--March 2008 for Pakistan.
Portfolio Management with Stochastic Interest Rates and Inflation Ambiguity
DEFF Research Database (Denmark)
Munk, Claus; Rubtsov, Alexey Vladimirovich
We solve a stock-bond-cash portfolio choice problem for a risk- and ambiguity-averse investor in a setting where the inflation rate and interest rates are stochastic. The expected inflation rate is unobservable, but the investor may learn about it from realized inflation and observed stock and bond......-Jacobi-Bellman equation in closed form and derive and illustrate a number of interesting properties of the solution. For example, ambiguity aversion affects the optimal portfolio through the correlation of price level with the stock index, a bond, and the expected inflation rate. Furthermore, unlike other settings...
Portfolio Management with Stochastic Interest Rates and Inflation Ambiguity
DEFF Research Database (Denmark)
Munk, Claus; Rubtsov, Alexey Vladimirovich
We solve a stock-bond-cash portfolio choice problem for a risk- and ambiguity-averse investor in a setting where the inflation rate and interest rates are stochastic. The expected inflation rate is unobservable, but the investor may learn about it from realized inflation and observed stock and bond...... prices. The investor is aware that his model for the observed inflation is potentially misspecified, and he seeks an investment strategy that maximizes his expected utility from real terminal wealth and is also robust to inflation model misspecification. We solve the corresponding robust Hamilton......-Jacobi-Bellman equation in closed form and derive and illustrate a number of interesting properties of the solution. For example, ambiguity aversion affects the optimal portfolio through the correlation of price level with the stock index, a bond, and the expected inflation rate. Furthermore, unlike other settings...
STOCHASTIC MODELING OF INFLATION IN NIGERIA
African Journals Online (AJOL)
2006-04-04
Apr 4, 2006 ... In this paper, we adopt a time series approach in modeling inflation in ... KEYWORDS: Buys-Ballot table; Quadratic trend; Seasonal multiplicative model, ..... Basic Statistics for Business and Economics, 2nd ed, Irwin, USA.
Stochastic inflation: Quantum phase-space approach
International Nuclear Information System (INIS)
Habib, S.
1992-01-01
In this paper a quantum-mechanical phase-space picture is constructed for coarse-grained free quantum fields in an inflationary universe. The appropriate stochastic quantum Liouville equation is derived. Explicit solutions for the phase-space quantum distribution function are found for the cases of power-law and exponential expansions. The expectation values of dynamical variables with respect to these solutions are compared to the corresponding cutoff regularized field-theoretic results (we do not restrict ourselves only to left-angle Φ 2 right-angle). Fair agreement is found provided the coarse-graining scale is kept within certain limits. By focusing on the full phase-space distribution function rather than a reduced distribution it is shown that the thermodynamic interpretation of the stochastic formalism faces several difficulties (e.g., there is no fluctuation-dissipation theorem). The coarse graining does not guarantee an automatic classical limit as quantum correlations turn out to be crucial in order to get results consistent with standard quantum field theory. Therefore, the method does not by itself constitute an explanation of the quantum to classical transition in the early Universe. In particular, we argue that the stochastic equations do not lead to decoherence
Stochastic inflation as a time-dependent random walk
International Nuclear Information System (INIS)
Kandrup, H.E.
1989-01-01
This paper exploits the ''stochastic inflation'' paradigm introduced by Starobinskii to study the evolution of long-wavelength modes for a free scalar field Phi in an inflationary Universe. By relaxing the assumption of a ''slow roll,'' it becomes obvious that the well-known late-time infrared divergence of the vacuum for a massless field in de Sitter space may be viewed as a consequence of the fluctuation-dissipation theorem. This stochastic model is also extended to allow for nonvacuum states and power-law inflation, situations where the fluctuation-dissipation theorem no longer holds. One recovers the correct late-time form for the expectation value 2 > in these cases as well, corroborating thereby the intuitive picture that, quite generally, the long-wavelength modes of the field evolve in a thermal ''bath'' provided by the shorter-wavelength modes
Stochastic inflation in phase space: is slow roll a stochastic attractor?
Energy Technology Data Exchange (ETDEWEB)
Grain, Julien [Institut d' Astrophysique Spatiale, UMR8617, CNRS, Univ. Paris Sud, Université Paris-Saclay, Bt. 121, Orsay, F-91405 (France); Vennin, Vincent, E-mail: julien.grain@ias.u-psud.fr, E-mail: vincent.vennin@port.ac.uk [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO13FX (United Kingdom)
2017-05-01
An appealing feature of inflationary cosmology is the presence of a phase-space attractor, ''slow roll'', which washes out the dependence on initial field velocities. We investigate the robustness of this property under backreaction from quantum fluctuations using the stochastic inflation formalism in the phase-space approach. A Hamiltonian formulation of stochastic inflation is presented, where it is shown that the coarse-graining procedure—where wavelengths smaller than the Hubble radius are integrated out—preserves the canonical structure of free fields. This means that different sets of canonical variables give rise to the same probability distribution which clarifies the literature with respect to this issue. The role played by the quantum-to-classical transition is also analysed and is shown to constrain the coarse-graining scale. In the case of free fields, we find that quantum diffusion is aligned in phase space with the slow-roll direction. This implies that the classical slow-roll attractor is immune to stochastic effects and thus generalises to a stochastic attractor regardless of initial conditions, with a relaxation time at least as short as in the classical system. For non-test fields or for test fields with non-linear self interactions however, quantum diffusion and the classical slow-roll flow are misaligned. We derive a condition on the coarse-graining scale so that observational corrections from this misalignment are negligible at leading order in slow roll.
Gratton, Steven
2011-09-01
In this paper we present a path integral formulation of stochastic inflation. Volume weighting can be naturally implemented from this new perspective in a very straightforward way when compared to conventional Langevin approaches. With an in-depth study of inflation in a quartic potential, we investigate how the inflaton evolves and how inflation typically ends both with and without volume weighting. The calculation can be carried to times beyond those accessible to conventional Fokker-Planck approaches. Perhaps unexpectedly, complex histories sometimes emerge with volume weighting. The reward for this excursion into the complex plane is an insight into how volume-weighted inflation both loses memory of initial conditions and ends via slow roll. The slow-roll end of inflation mitigates certain “Youngness Paradox”-type criticisms of the volume-weighted paradigm. Thus it is perhaps time to rehabilitate proper-time volume weighting as a viable measure for answering at least some interesting cosmological questions.
International Nuclear Information System (INIS)
Gratton, Steven
2011-01-01
In this paper we present a path integral formulation of stochastic inflation. Volume weighting can be naturally implemented from this new perspective in a very straightforward way when compared to conventional Langevin approaches. With an in-depth study of inflation in a quartic potential, we investigate how the inflaton evolves and how inflation typically ends both with and without volume weighting. The calculation can be carried to times beyond those accessible to conventional Fokker-Planck approaches. Perhaps unexpectedly, complex histories sometimes emerge with volume weighting. The reward for this excursion into the complex plane is an insight into how volume-weighted inflation both loses memory of initial conditions and ends via slow roll. The slow-roll end of inflation mitigates certain ''Youngness Paradox''-type criticisms of the volume-weighted paradigm. Thus it is perhaps time to rehabilitate proper-time volume weighting as a viable measure for answering at least some interesting cosmological questions.
Stochastic quantum inflation for a canonical scalar field with linear self-interaction potential
Energy Technology Data Exchange (ETDEWEB)
Panotopoulos, Grigoris [CENTRA, Instituto Superior Tecnico, Universidade de Lisboa, Lisboa (Portugal)
2017-10-15
We apply Starobinsky's formalism of stochastic inflation to the case of a massless minimally coupled scalar field with linear self-interaction potential. We solve the corresponding Fokker-Planck equation exactly, and we obtain analytical expressions for the stochastic expectation values. (orig.)
Portfolio Management with Stochastic Interest Rates and Inflation Ambiguity
DEFF Research Database (Denmark)
Munk, Claus; Rubtsov, Alexey Vladimirovich
2014-01-01
prices. The investor is ambiguous about the inflation model and prefers a portfolio strategy which is robust to model misspecification. Ambiguity about the inflation dynamics is shown to affect the optimal portfolio fundamentally different than ambiguity about the price dynamics of traded assets...
On the stochastic approach to inflation and the initial conditions in the universe
International Nuclear Information System (INIS)
Pollock, M.D.
1986-05-01
By applying stochastic methods to a theory in which a potential V(Φ) causes a period of quasi-expansion of the universe, Starobinsky has derived an expression for the probability distribution P(V) appropriate to chaotic inflation in the classical approximation. We obtain the corresponding expression for a broken-symmetry theory of gravity. For the Coleman-Weinberg potential, it appears most probable that the initial value of Φ is Φ i O , in which case inflation occurs naturally, because V(Φ i )>O
Dark energy properties in DBI theory
International Nuclear Information System (INIS)
Ahn, Changrim; Kim, Chanju; Linder, Eric V.
2009-01-01
The Dirac-Born-Infeld (DBI) action from string theory provides several new classes of dark energy behavior beyond quintessence due to its relativistic kinematics. We constrain parameters of natural potentials and brane tensions with cosmological observations as well as showing how to design these functions for a desired expansion history. We enlarge the attractor solutions, including new ways of obtaining cosmological constant behavior, to the case of generalized DBI theory with multiple branes. An interesting novel signature of DBI attractors is that the sound speed is driven to zero, unlike for quintessence where it is the speed of light.
On the stochastic approach to inflation and the initial conditions in the universe
Pollock, M. D.
1988-03-01
By the application of stochastic methods to a theory in which a potential V(ø) causes a period of quasi-exponential expansion of the universe, an expression for the probability distribution P(V) appropriate for chaotic inflation has recently been derived. The method was developed by Starobinsky and by Linde. Beyond some critical point øc, long-wavelength quantum fluctuations δø ~H/2π cannot be ignored. The effect of these fluctuation in general relativity for values of ø such that V(ø)>V(ø) has been considered by Linde, who concluded that most of the present universe arises as a result of expansion of domains with a domains with a maximum possible value of ø, such that V(ømax ~ mp4. We obtain the corresponding expression for P in a broken-symmetry theory of gravity, in which the newtonian gravitational constant is replaced by G = (8πɛø2)-1, and also for a theory which includes higher-derivative terms R2 = γR2 + βR2 1n(R/μ2), so that the trace anomaly is Tanom ~βR2 , in which an effective inflation field øe can be defined as øe2 = 24γR. Conclusions analogous to those of Linde can be drawn in both these theories. Present address: Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Bombay 400.005, India.
Stochastic and sensitivity analysis of shape error of inflatable antenna reflectors
San, Bingbing; Yang, Qingshan; Yin, Liwei
2017-03-01
Inflatable antennas are promising candidates to realize future satellite communications and space observations since they are lightweight, low-cost and small-packaged-volume. However, due to their high flexibility, inflatable reflectors are difficult to manufacture accurately, which may result in undesirable shape errors, and thus affect their performance negatively. In this paper, the stochastic characteristics of shape errors induced during manufacturing process are investigated using Latin hypercube sampling coupled with manufacture simulations. Four main random error sources are involved, including errors in membrane thickness, errors in elastic modulus of membrane, boundary deviations and pressure variations. Using regression and correlation analysis, a global sensitivity study is conducted to rank the importance of these error sources. This global sensitivity analysis is novel in that it can take into account the random variation and the interaction between error sources. Analyses are parametrically carried out with various focal-length-to-diameter ratios (F/D) and aperture sizes (D) of reflectors to investigate their effects on significance ranking of error sources. The research reveals that RMS (Root Mean Square) of shape error is a random quantity with an exponent probability distribution and features great dispersion; with the increase of F/D and D, both mean value and standard deviation of shape errors are increased; in the proposed range, the significance ranking of error sources is independent of F/D and D; boundary deviation imposes the greatest effect with a much higher weight than the others; pressure variation ranks the second; error in thickness and elastic modulus of membrane ranks the last with very close sensitivities to pressure variation. Finally, suggestions are given for the control of the shape accuracy of reflectors and allowable values of error sources are proposed from the perspective of reliability.
Directory of Open Access Journals (Sweden)
Jingyun Sun
2016-01-01
Full Text Available We consider a portfolio selection problem for a defined contribution (DC pension plan under the mean-variance criteria. We take into account the inflation risk and assume that the salary income process of the pension plan member is stochastic. Furthermore, the financial market consists of a risk-free asset, an inflation-linked bond, and a risky asset with Heston’s stochastic volatility (SV. Under the framework of game theory, we derive two extended Hamilton-Jacobi-Bellman (HJB equations systems and give the corresponding verification theorems in both the periods of accumulation and distribution of the DC pension plan. The explicit expressions of the equilibrium investment strategies, corresponding equilibrium value functions, and the efficient frontiers are also obtained. Finally, some numerical simulations and sensitivity analysis are presented to verify our theoretical results.
EFT Beyond the Horizon: Stochastic Inflation and How Primordial Quantum Fluctuations Go Classical
Burgess, C P; Tasinato, G; Williams, M
2015-01-01
We identify the effective theory describing inflationary super-Hubble scales and show it to be a special case of effective field theories appropriate to open systems. Open systems allow information to be exchanged between the degrees of freedom of interest and those that are integrated out, such as for particles moving through a fluid. Strictly speaking they cannot in general be described by an effective lagrangian; rather the appropriate `low-energy' limit is instead a Lindblad equation describing the evolution of the density matrix of the slow degrees of freedom. We derive the equation relevant to super-Hubble modes of quantum fields in near-de Sitter spacetimes and derive two implications. We show the evolution of the diagonal density-matrix elements quickly approaches the Fokker-Planck equation of Starobinsky's stochastic inflationary picture. This provides an alternative first-principles derivation of this picture's stochastic noise and drift, as well as its leading corrections. (An application computes ...
Stochastic inflation lattice simulations: Ultra-large scale structure of the universe
International Nuclear Information System (INIS)
Salopek, D.S.
1990-11-01
Non-Gaussian fluctuations for structure formation may arise in inflation from the nonlinear interaction of long wavelength gravitational and scalar fields. Long wavelength fields have spatial gradients α -1 triangledown small compared to the Hubble radius, and they are described in terms of classical random fields that are fed by short wavelength quantum noise. Lattice Langevin calculations are given for a ''toy model'' with a scalar field interacting with an exponential potential where one can obtain exact analytic solutions of the Fokker-Planck equation. For single scalar field models that are consistent with current microwave background fluctuations, the fluctuations are Gaussian. However, for scales much larger than our observable Universe, one expects large metric fluctuations that are non-Guassian. This example illuminates non-Gaussian models involving multiple scalar fields which are consistent with current microwave background limits. 21 refs., 3 figs
WMAP constraints on k-inflation
International Nuclear Information System (INIS)
Devi, N. Chandrachani; Sen, Anjan A.; Nautiyal, Akhilesh
2011-01-01
We study the k-inflation models where the inflaton field has a noncanonical kinetic term. In particular, we consider the Dirac-Born-Infeld (DBI) form for the kinetic energy of the inflaton field. We consider quadratic and quartic potentials as well as the potential for the natural inflation. We use a modified version of MODECODE[M. J. Mortonson, H. V. Peiris, and R. Easther, Phys. Rev. D 83, 043505 (2011).] to calculate the power spectrum of the primordial perturbations generated by the inflaton field and subsequently use the WMAP7 results to constrain the models. Interestingly, with the DBI type kinetic term, less gravity waves are produced as one approaches scale invariance. This is true for all the potentials considered. Unlike the canonical case, this feature, in particular, helps the quartic (λφ 4 ) potential with the DBI type kinetic term to be consistent with the WMAP data.
Relations between canonical and non-canonical inflation
Energy Technology Data Exchange (ETDEWEB)
Gwyn, Rhiannon [Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut), Potsdam (Germany); Rummel, Markus [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Westphal, Alexander [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group
2012-12-15
We look for potential observational degeneracies between canonical and non-canonical models of inflation of a single field {phi}. Non-canonical inflationary models are characterized by higher than linear powers of the standard kinetic term X in the effective Lagrangian p(X,{phi}) and arise for instance in the context of the Dirac-Born-Infeld (DBI) action in string theory. An on-shell transformation is introduced that transforms non-canonical inflationary theories to theories with a canonical kinetic term. The 2-point function observables of the original non-canonical theory and its canonical transform are found to match in the case of DBI inflation.
Inflation and quantum cosmology
International Nuclear Information System (INIS)
Linde, A.
1991-01-01
In this article a review of the present status of inflationary cosmology is given. We start with a discussion of the simplest version of the chaotic inflation scenario. Then we discuss some recent develoments in the inflationary cosmology, including the theory of a self-reproducing inflationary universe (eternal chaotic inflation). We do it with the help of stochastic approach to inflation. The results obtained within this approach are compared with the results obtained in the context of Euclidean quantum cosmology. (WL)
Inflation targeting and core inflation
Julie Smith
2005-01-01
This paper examines the interaction of core inflation and inflation targeting as a monetary policy regime. Interest in core inflation has grown because of inflation targeting. Core inflation is defined in numerous ways giving rise to many potential measures; this paper defines core inflation as the best forecaster of inflation. A cross-country study finds before the start of inflation targeting, but not after, core inflation differs between non-inflation targeters and inflation targeters. Thr...
Thermodynamics of DBI Black Holes in Anti-de Sitter Spacetime
International Nuclear Information System (INIS)
Jia Dongyan; Yue Ruihong; Huang Shiming
2011-01-01
Through the gauge field theory, we obtain the solution of the DBI-AdS black hole. In the meantime, according to the relations between the action and the grand partition function, we obtain the grand partition function in the DBI-AdS black hole. The temperature and the potential of the DBI-AdS black hole are gained from differential of the grand partition function. With the thermodynamic relations, other thermodynamics are also obtained. The solution and the thermodynamics of the DBI-AdS black hole are turned out that they can reduce to the case of a charged black hole in four-dimensional spacetimes. (general)
Screening fifth forces in k-essence and DBI models
Energy Technology Data Exchange (ETDEWEB)
Brax, Philippe [Institut de Physique Théorique, CEA, IPhT, CNRS, URA2306, F-91191 Gif-sur-Yvette cédex (France); Burrage, Clare [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Davis, Anne-Christine, E-mail: Philippe.Brax@cea.fr, E-mail: Clare.Burrage@nottingham.ac.uk, E-mail: A.C.Davis@damtp.cam.ac.uk [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, Cambridge CB3 0WA (United Kingdom)
2013-01-01
New fifth forces have not yet been detected in the laboratory or in the solar system, hence it is typically difficult to introduce new light scalar fields that would mediate such forces. In recent years it has been shown that a number of non-linear scalar field theories allow for a dynamical mechanism, such as the Vainshtein and chameleon ones, that suppresses the strength of the scalar fifth force in experimental environments. This is known as screening, however it is unclear how common screening is within non-linear scalar field theories. k-essence models are commonly studied examples of non-linear models, with DBI as the best motivated example, and so we ask whether these non-linearities are able to screen a scalar fifth force. We find that a Vainshtein-like screening mechanism exists for such models although with limited applicability. For instance, we cannot find a screening mechanism for DBI models. On the other hand, we construct a large class of k-essence models which lead to the acceleration of the Universe in the recent past for which the fifth force mediated by the scalar can be screened.
Extended DBI massive gravity with generalized fiducial metric
Chullaphan, Tossaporn; Tannukij, Lunchakorn; Wongjun, Pitayuth
2015-06-01
We consider an extended model of DBI massive gravity by generalizing the fiducial metric to be an induced metric on the brane corresponding to a domain wall moving in five-dimensional Schwarzschild-Anti-de Sitter spacetime. The model admits all solutions of FLRW metric including flat, closed and open geometries while the original one does not. The background solutions can be divided into two branches namely self-accelerating branch and normal branch. For the self-accelerating branch, the graviton mass plays the role of cosmological constant to drive the late-time acceleration of the universe. It is found that the number degrees of freedom of gravitational sector is not correct similar to the original DBI massive gravity. There are only two propagating degrees of freedom from tensor modes. For normal branch, we restrict our attention to a particular class of the solutions which provides an accelerated expansion of the universe. It is found that the number of degrees of freedom in the model is correct. However, at least one of them is ghost degree of freedom which always present at small scale implying that the theory is not stable.
Extended DBI massive gravity with generalized fiducial metric
International Nuclear Information System (INIS)
Chullaphan, Tossaporn; Tannukij, Lunchakorn; Wongjun, Pitayuth
2015-01-01
We consider an extended model of DBI massive gravity by generalizing the fiducial metric to be an induced metric on the brane corresponding to a domain wall moving in five-dimensional Schwarzschild-Anti-de Sitter spacetime. The model admits all solutions of FLRW metric including flat, closed and open geometries while the original one does not. The background solutions can be divided into two branches namely self-accelerating branch and normal branch. For the self-accelerating branch, the graviton mass plays the role of cosmological constant to drive the late-time acceleration of the universe. It is found that the number degrees of freedom of gravitational sector is not correct similar to the original DBI massive gravity. There are only two propagating degrees of freedom from tensor modes. For normal branch, we restrict our attention to a particular class of the solutions which provides an accelerated expansion of the universe. It is found that the number of degrees of freedom in the model is correct. However, at least one of them is ghost degree of freedom which always present at small scale implying that the theory is not stable.
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2012-10-24
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Thermal DBI action for the D3-brane at weak and strong coupling
DEFF Research Database (Denmark)
Grignani, Gianluca; Harmark, Troels; Marini, Andrea
2014-01-01
We study the effective action for finite-temperature D3-branes with an electromagnetic field at weak and strong coupling. We call this action the thermal DBI action. Comparing at low temperature the leading T4 correction for the thermal DBI action at weak and strong coupling we find that the 3/4 ...
Mathematical issues in eternal inflation
Singh Kohli, Ikjyot; Haslam, Michael C.
2015-04-01
In this paper, we consider the problem of the existence and uniqueness of solutions to the Einstein field equations for a spatially flat Friedmann-Lemaître-Robertson-Walker universe in the context of stochastic eternal inflation, where the stochastic mechanism is modelled by adding a stochastic forcing term representing Gaussian white noise to the Klein-Gordon equation. We show that under these considerations, the Klein-Gordon equation actually becomes a stochastic differential equation. Therefore, the existence and uniqueness of solutions to Einstein’s equations depend on whether the coefficients of this stochastic differential equation obey Lipschitz continuity conditions. We show that for any choice of V(φ ), the Einstein field equations are not globally well-posed, hence, any solution found to these equations is not guaranteed to be unique. Instead, the coefficients are at best locally Lipschitz continuous in the physical state space of the dynamical variables, which only exist up to a finite explosion time. We further perform Feller’s explosion test for an arbitrary power-law inflaton potential and prove that all solutions to the Einstein field equations explode in a finite time with probability one. This implies that the mechanism of stochastic inflation thus considered cannot be described to be eternal, since the very concept of eternal inflation implies that the process continues indefinitely. We therefore argue that stochastic inflation based on a stochastic forcing term would not produce an infinite number of universes in some multiverse ensemble. In general, since the Einstein field equations in both situations are not well-posed, we further conclude that the existence of a multiverse via the stochastic eternal inflation mechanism considered in this paper is still very much an open question that will require much deeper investigation.
A note on calm excited states of inflation
International Nuclear Information System (INIS)
Ashoorioon, Amjad; Shiu, Gary
2011-01-01
We identify a two-parameter family of excited states within slow-roll inflation for which either the corrections to the two-point function or the characteristic signatures of excited states in the three-point function — i.e. the enhancement for the flattened momenta configurations– are absent. These excited states may nonetheless violate the adiabaticity condition maximally. We dub these initial states of inflation calm excited states. We show that these two sets do not intersect, i.e., those that leave the power-spectrum invariant can be distinguished from their bispectra, and vice versa. The same set of calm excited states that leave the two-point function invariant for slow-roll inflation, do the same task for DBI inflation. However, at the level of three-point function, the calm excited states whose flattened configuration signature is absent for slow-roll inflation, will lead to an enhancement for DBI inflation generally, although the signature is smaller than what suggested by earlier analysis. This example also illustrates that imposing the Wronskian condition is important for obtaining a correct estimate of the non-Gaussian signatures
INFLATE: INFlate Landing Apparatus Technology
Koryanov, V. V. K.; Da-Poian, V. D. P.
2018-02-01
Our project, named INFLATE (INFlatable Landing Apparatus Technology), aims at reducing space landing risks and constraints and so optimizing space missions (reducing cost, mass, and risk and in the same time improving performance).
Berkin, Andrew L.; Maeda, Kei-Ichi; Yokoyama, Junichi
1990-01-01
The cosmology resulting from two coupled scalar fields was studied, one which is either a new inflation or chaotic type inflation, and the other which has an exponentially decaying potential. Such a potential may appear in the conformally transformed frame of generalized Einstein theories like the Jordan-Brans-Dicke theory. The constraints necessary for successful inflation are examined. Conventional GUT models such as SU(5) were found to be compatible with new inflation, while restrictions on the self-coupling constant are significantly loosened for chaotic inflation.
Maleknejad, A.; Sheikh-Jabbari, M. M.; Soda, J.
2013-07-01
discussion in Section 2.2) cs2≡{P}/{P+2XP}. Finding K-inflation actions P(φ,X) which are well-motivated and consistently embedded in high-energy theories is the main challenge of this class of models [9]. Nonetheless, DBI inflation is a special kind of K-inflation, which is well-motivated from string theory with the action [15] S=∫d4x√{-g}[{R}/{2}-{1}/{f(φ)}((√{D}-1)+V(φI))], where D=1-2f(φ)X. In the presence of another natural cutoff Λ in the model, smallness or largeness of the inflaton field should be compared to Λ; Λ could be sub-Planckian and in general Λ≲M. For a discussion on this see [10,11].
International Nuclear Information System (INIS)
Antusch, S.; King, F.S.; Malinsky, M.; Velasco-Sevilla, L.; Zavala, I.
2008-04-01
We propose an entirely new class of particle physics models of inflation based on the phase transition associated with the spontaneous breaking of family symmetry responsible for the generation of the effective quark and lepton Yukawa couplings. We show that the Higgs fields responsible for the breaking of family symmetry, called flavons, are natural candidates for the inflation field in new inflation, or the waterfall fields in hybrid inflation. This opens up a rich vein of possible inflation models, all linked to the physics of flavour, with interesting cosmological and phenomenological implications. Out of these many possibilities we discuss two examples which realise flavon inflation: a model of new inflation based on the discrete non-Abelian family symmetry group A 4 or Δ 27 , and a model of hybrid inflation embedded in an existing flavour model with a continuous SU(3) family symmetry. With the inflation scale and family symmetry breaking scale below the Grand Unification Theory (GUT) scale, these classes of models are free of the monopole (and similar) problems which are often associated with the GUT phase transition. (author)
Consistency relation for the Lorentz invariant single-field inflation
International Nuclear Information System (INIS)
Huang, Qing-Guo
2010-01-01
In this paper we compute the sizes of equilateral and orthogonal shape bispectrum for the general Lorentz invariant single-field inflation. The stability of field theory implies a non-negative square of sound speed which leads to a consistency relation between the sizes of orthogonal and equilateral shape bispectrum, namely f NL orth. ≤ −0.054f NL equil. . In particular, for the single-field Dirac-Born-Infeld (DBI) inflation, the consistency relation becomes f NL orth. = 0.070f NL equil. ≤ 0. These consistency relations are also valid in the mixed scenario where the quantum fluctuations of some other light scalar fields contribute to a part of total curvature perturbation on the super-horizon scale and may generate a local form bispectrum. A distinguishing prediction of the mixed scenario is τ NL loc. > ((6/5)f NL loc. ) 2 . Comparing these consistency relations to WMAP 7yr data, there is still a big room for the Lorentz invariant inflation, but DBI inflation has been disfavored at more than 68% CL
Energy Technology Data Exchange (ETDEWEB)
Antusch, S. [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, D-80805 Muenchen (Germany); King, S.F.; Malinsky, M. [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Velasco-Sevilla, L. [ICTP, Strada Costiera 11, Trieste 34014 (Italy)], E-mail: lvelasco@ictp.it; Zavala, I. [CPT and IPPP, Durham University, South Road, DH1 3LE, Durham (United Kingdom)
2008-08-14
We propose an entirely new class of particle physics models of inflation based on the phase transition associated with the spontaneous breaking of family symmetry responsible for the generation of the effective quark and lepton Yukawa couplings. We show that the Higgs fields responsible for the breaking of family symmetry, called flavons, are natural candidates for the inflaton field in new inflation, or the waterfall fields in hybrid inflation. This opens up a rich vein of possibilities for inflation, all linked to the physics of flavour, with interesting cosmological and phenomenological implications. Out of these, we discuss two examples which realise flavon inflation: a model of new inflation based on the discrete non-Abelian family symmetry group A{sub 4} or {delta}{sub 27}, and a model of hybrid inflation embedded in an existing flavour model with a continuous SU(3) family symmetry. With the inflation scale and family symmetry breaking scale below the Grand Unification Theory (GUT) scale, these classes of models are free of the monopole (and similar) problems which are often associated with the GUT phase transition.
International Nuclear Information System (INIS)
Antusch, S.; King, S.F.; Malinsky, M.; Velasco-Sevilla, L.; Zavala, I.
2008-01-01
We propose an entirely new class of particle physics models of inflation based on the phase transition associated with the spontaneous breaking of family symmetry responsible for the generation of the effective quark and lepton Yukawa couplings. We show that the Higgs fields responsible for the breaking of family symmetry, called flavons, are natural candidates for the inflaton field in new inflation, or the waterfall fields in hybrid inflation. This opens up a rich vein of possibilities for inflation, all linked to the physics of flavour, with interesting cosmological and phenomenological implications. Out of these, we discuss two examples which realise flavon inflation: a model of new inflation based on the discrete non-Abelian family symmetry group A 4 or Δ 27 , and a model of hybrid inflation embedded in an existing flavour model with a continuous SU(3) family symmetry. With the inflation scale and family symmetry breaking scale below the Grand Unification Theory (GUT) scale, these classes of models are free of the monopole (and similar) problems which are often associated with the GUT phase transition
Inflation and Inflation Uncertainty in Turkey
dogru, bulent
2014-01-01
Abstract: In this study, the relationship between inflation and inflation uncertainty is analyzed using Granger causality tests with annual inflation series covering the time period 1923 to 2012 for Turkish Economy. Inflation uncertainty is measured by Exponential Generalized Autoregressive Conditional Heteroskedastic model. Econometric findings suggest that although in long run the Friedman's hypothesis that high inflation increases inflation ...
International Nuclear Information System (INIS)
Murphy, P.J.
1987-01-01
The Theory of Inflation, namely, that at some point the entropy content of the universe was greatly increased, has much promise. It may solve the puzzles of homogeneity and the creation of structure. However, no particle physics model has yet been found that can successfully drive inflation. The difficulty in satisfying the constraint that the isotropy of the microwave background places on the effective potential of prospective models is immense. In this work we have codified the requirements of such models in a most general form. We have carefully calculated the amounts of inflation the various problems of the Standard Model need for their solution. We have derived a completely model independent upper bond on the inflationary Hubble parameter. We have developed a general notation with which to probe the possibilities of Multiple Inflation. We have shown that only in very unlikely circumstances will any evidence of an earlier inflation, survive the de Sitter period of its successor. In particular, it is demonstrated that it is most unlikely that two bouts of inflation will yield high amplitudes of density perturbations on small scales and low amplitudes on large. We conclude that, while multiple inflation will be of great theoretical interest, it is unlikely to have any observational impact
Energy Technology Data Exchange (ETDEWEB)
Burrage, Clare [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Rham, Claudia de [Univ. de Geneve (Switzerland). Dept. de Physique Theorique; Seery, David [Sussex Univ., Brigthon (United Kingdom). Dept. of Physics and Astronomy; Tolley, Andrew J. [Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Physics
2010-09-15
Galileon inflation is a radiatively stable higher derivative model of inflation. The model is determined by a finite number of relevant operators which are protected by a covariant generalization of the Galileon shift symmetry. We show that the nongaussianity of the primordial density perturbation generated during an epoch of Galileon inflation is a particularly powerful observational probe of these models and that, when the speed of sound is small, f{sub NL} can be larger than the usual result f{sub NL} {proportional_to} C{sup -2}{sub s}. (orig.)
International Nuclear Information System (INIS)
Silk, J.; Turner, M.S.
1986-04-01
The Zel'dovich spectrum of adiabatic density perturbations is a generic prediction of inflation. There is increasing evidence that when the spectrum is normalized by observational data on small scales, there is not enough power on large scales to account for the observed large-scale structure in the Universe. Decoupling the spectrum on large and small scales could solve this problem. As a means of decoupling the large and small scales we propose double inflation (i.e., two episodes of inflation). In this scenario the spectrum on large scales is determined by the first episode of inflation and those on small scales by a second episode of inflation. We present three models for such a scenario. By nearly saturating the large angular-scale cosmic microwave anisotropy bound, we can easily account for the observed large-scale structure. We take the perturbations on small scales to be very large, deltarho/rho approx. = 0.1 to 0.01, which results in the production of primordial black holes (PBHs), early formation of structure, reionization of the Universe, and a rich array of astrophysical events. The Ω-problem is also addressed by our scenario. Allowing the density perturbations produced by the second episode of inflation to be large also lessens the fine-tuning required in the scalar potential and makes reheating much easier. We briefly speculate on the possibility that the second episode of inflation proceeds through the nucleation of bubbles, which today manifest themselves as empty bubbles whose surfaces are covered with galaxies. 37 refs., 1 fig
Planck limits on non-canonical generalizations of large-field inflation models
Energy Technology Data Exchange (ETDEWEB)
Stein, Nina K.; Kinney, William H., E-mail: ninastei@buffalo.edu, E-mail: whkinney@buffalo.edu [Dept. of Physics, University at Buffalo, the State University of New York, Buffalo, NY 14260-1500 (United States)
2017-04-01
In this paper, we consider two case examples of Dirac-Born-Infeld (DBI) generalizations of canonical large-field inflation models, characterized by a reduced sound speed, c {sub S} < 1. The reduced speed of sound lowers the tensor-scalar ratio, improving the fit of the models to the data, but increases the equilateral-mode non-Gaussianity, f {sup equil.}{sub NL}, which the latest results from the Planck satellite constrain by a new upper bound. We examine constraints on these models in light of the most recent Planck and BICEP/Keck results, and find that they have a greatly decreased window of viability. The upper bound on f {sup equil.}{sub NL} corresponds to a lower bound on the sound speed and a corresponding lower bound on the tensor-scalar ratio of r ∼ 0.01, so that near-future Cosmic Microwave Background observations may be capable of ruling out entire classes of DBI inflation models. The result is, however, not universal: infrared-type DBI inflation models, where the speed of sound increases with time, are not subject to the bound.
Hebecker, Arthur; Lust, Dieter; Steinfurt, Stephan; Weigand, Timo
2012-01-01
As a first step towards inflation in genuinely F-theoretic setups, we propose a scenario where the inflaton is the relative position of two 7-branes on holomorphic 4-cycles. Non-supersymmetric gauge flux induces an attractive inter-brane potential. The latter is sufficiently flat in the supergravity regime of large volume moduli. Thus, in contrast to brane-antibrane inflation, fluxbrane inflation does not require warping. We calculate the inflaton potential both in the supergravity approximation and via an open-string one-loop computation on toroidal backgrounds. This leads us to propose a generalisation to genuine Calabi-Yau manifolds. We also comment on competing F-term effects. The end of inflation is marked by the condensation of tachyonic recombination fields between the 7-branes, triggering the formation of a bound state described as a stable extension along the 7-brane divisor. Hence our model fits in the framework of hybrid D-term inflation. We work out the main phenomenological properties of our D-te...
Gravitational waves from inflation
International Nuclear Information System (INIS)
Guzzetti, M.C.; Bartolo, N.; Liguori, M.; Matarrese, S.
2016-01-01
The production of a stochastic background of gravitational waves is a fundamental prediction of any cosmological inflationary model. The features of such a signal encode unique information about the physics of the Early Universe and beyond, thus representing an exciting, powerful window on the origin and evolution of the Universe. We review the main mechanisms of gravitational-wave production, ranging from quantum fluctuations of the gravitational field to other mechanisms that can take place during or after inflation. These include e.g. gravitational waves generated as a consequence of extra particle production during inflation, or during the (p)reheating phase. Gravitational waves produced in inflation scenarios based on modified gravity theories and second-order gravitational waves are also considered. For each analyzed case, the expected power spectrum is given. We discuss the discriminating power among different models, associated with the validity/violation of the standard consistency relation between tensor-to-scalar ratio r and tensor spectral index ηT. In light of the prospects for (directly/indirectly) detecting primordial gravitational waves, we give the expected present-day gravitational radiation spectral energy-density, highlighting the main characteristics imprinted by the cosmic thermal history, and we outline the signatures left by gravitational waves on the Cosmic Microwave Background and some imprints in the Large-Scale Structure of the Universe. Finally, current bounds and prospects of detection for inflationary gravitational waves are summarized.
Inflation and quantum cosmology
International Nuclear Information System (INIS)
Linde, A.
1990-01-01
We investigate an interplay between elementary particle physics, quantum cosmology and inflation. These results obtained within this approach are compared with the results obtained in the context of Euclidean quantum cosmology. In particular, we discuss relations between the stochastic approach to inflationary cosmology and the approaches based on the investigation of the Hartle-Hawking and tunneling wave functions of the universe. We argue that neither of these wave functions can be used for a complete description of the inflationary universe, but in certain cases they can be used for a description of some particular stages of inflation. It is shown that if the present vacuum energy density ρ υ exceeds some extremely small critical value ρ c (ρ c ∼ 10 -107 ) g cm -3 for chaotic inflation in the theory 1/2m 2 φ 2 ), then the lifetime of mankind in the inflationary universe should be finite, even though the universe as a whole will exist without end. A possible way to justify the anthropic principle in the context of the baby universe theory and to apply it to the evaluation of masses of elementary particles, of their coupling constants and of the vacuum energy density is also discussed. (author)
García-Bellido, J
1998-01-01
We propose a new model of inflation based on the soft-breaking of N=2 supersymmetric SU(2) Yang-Mills theory. The advantage of such a model is the fact that we can write an exact expression for the effective scalar potential, including non-perturbative effects, which preserves the analyticity and duality properties of the Seiberg-Witten solution. We find that the scalar condensate that plays the role of the inflaton can drive a long period of cosmological expansion, produce the right amount of temperature anisotropies in the microwave background, and end inflation when the monopole acquires a vacuum expectation value. Duality properties relate the weak coupling Higgs region where inflation takes place with the strong coupling monopole region, where reheating occurs, creating particles corresponding to the light degrees of freedom in the true vacuum.
Winitzki, Sergei
2009-01-01
This volume is the only monograph covering the exciting and dazzling recent developments in quantum cosmology, including the theory of the "multiverse" and eternal inflation pioneered by A Vilenkin, A Linde, S W Hawking, and others. Written by a leading expert in the field known for his depth and clarity of presentation, the volume presents an overview of 20 years of development of the theory of eternal inflation as well as a comprehensive, research-level introduction into the current methods and problems. This volume is invaluable for researchers as a definitive reference in the rapidly devel
Directory of Open Access Journals (Sweden)
Antipov Valerij Ivanovich
2015-10-01
Full Text Available The article gives a modern interpretation of the Fisher formula, the calculated velocity of circulation of money supply M2 in the interval 1995-2013 and forecast of its changes until 2030 when hypotheses about the rate of inflation and GDP. Points to the fallacy of its direct use to control inflation and money supply. For a more detailed understanding of the inflationary process proposes a new frequency formula and the explanation of the situation with the regulation of prices in the economy.
Energy Technology Data Exchange (ETDEWEB)
Green, Daniel; Horn, Bart; /SLAC /Stanford U., Phys. Dept.; Senatore, Leonardo; /Princeton, Inst. Advanced Study /Harvard U., Phys. Dept. /Harvard-Smithsonian Ctr. Astrophys.; Silverstein, Eva; /SLAC /Stanford U., Phys. Dept.
2009-06-19
We analyze a distinctive mechanism for inflation in which particle production slows down a scalar field on a steep potential, and show how it descends from angular moduli in string compactifications. The analysis of density perturbations - taking into account the integrated effect of the produced particles and their quantum fluctuations - requires somewhat new techniques that we develop. We then determine the conditions for this effect to produce sixty e-foldings of inflation with the correct amplitude of density perturbations at the Gaussian level, and show that these requirements can be straightforwardly satisfied. Finally, we estimate the amplitude of the non-Gaussianity in the power spectrum and find a significant equilateral contribution.
Zvi Bodie
1989-01-01
A contract to insure $1 against inflation is equivalent to a European call option on the consumer price index. When there is no deductible this call option is equivalent to a forward contract on the CPI. Its price is the difference between the prices of a zero coupon real bond and a zero coupon nominal bond, both free of default risk. Provided that the risk-free real rate of interest is positive, the price of such an inflation insurance policy first rises and then falls with time to maturity....
D6-branes and axion monodromy inflation
Energy Technology Data Exchange (ETDEWEB)
Escobar, Dagoberto; Landete, Aitor; Marchesano, Fernando [Instituto de Física Teórica UAM-CSIC,Cantoblanco, 28049 Madrid (Spain); Regalado, Diego [Max-Planck-Institut für Physik,Föhringer Ring 6, 80805 Munich (Germany); Institute for Theoretical Physics and Center for Extreme Matter and Emergent Phenomena, Utrecht University,Leuvenlaan 4, 3584 CE Utrecht (Netherlands)
2016-03-16
We develop new scenarios of large field inflation in type IIA string compactifications in which the key ingredient is a D6-brane that creates a potential for a B-field axion. The potential has the multi-branched structure typical of F-term axion monodromy models and, near its supersymmetric minima, it is described by a 4d supergravity model of chaotic inflation with a stabiliser field. The same statement applies to the D6-brane Wilson line, which can also be considered as an inflaton candidate. We analyse both cases in the context of type IIA moduli stabilisation, finding an effective potential for the inflaton system and a simple mechanism to lower the inflaton mass with respect to closed string moduli stabilised by fluxes. Finally, we compute the B-field potential for trans-Planckian field values by means of the DBI action. The effect of Planck suppressed corrections is a flattened potential which, in terms of the compactification parameters, interpolates between linear and quadratic inflation. This renders the cosmological parameters of these models compatible with current experimental bounds, with the tensor-to-scalar ratio ranging as 0.08≲r≲0.12.
International Nuclear Information System (INIS)
Steinhardt, P.J.; Accetta, F.S.
1990-01-01
We present a dynamical mechanism for completing inflationary phase transitions via bubble nucleation which can satisfy all known constraints for a wide spectrum of models and parameters. The approach is a generalization of the recent ''extended inflation'' model which corrects a serious flaw. We find an essentially model-independent bubble-size distribution which may be important for large-scale structure
Enqvist, K
2012-01-01
The very basics of cosmological inflation are discussed. We derive the equations of motion for the inflaton field, introduce the slow-roll parameters, and present the computation of the inflationary perturbations and their connection to the temperature fluctuations of the cosmic microwave background.
Ho, Chiu Man; Kephart, Thomas W.
2010-01-01
We consider a 4+N dimensional Einstein gravity coupled to a non-linear sigma model. This theory admits a solution in which the N extra dimensions contract exponentially while the ordinary space expand exponentially. Physically, the non-linear sigma fields induce the dynamical compactification of the extra dimensions, which in turn drives inflation. No inflatons are required.
Kehagias, Alex
2017-01-01
We investigate the recently proposed clockwork mechanism delivering light degrees of freedom with suppressed interactions and show, with various examples, that it can be efficiently implemented in inflationary scenarios to generate flat inflaton potentials and small density perturbations without fine-tunings. We also study the clockwork graviton in de Sitter and, interestingly, we find that the corresponding clockwork charge is site-dependent. As a consequence, the amount of tensor modes is generically suppressed with respect to the standard cases where the clockwork set-up is not adopted. This point can be made a virtue in resurrecting models of inflation which were supposed to be ruled out because of the excessive amount of tensor modes from inflation.
A state-dependent model for inflation forecasting
Andrea Stella; James H. Stock
2012-01-01
We develop a parsimonious bivariate model of inflation and unemployment that allows for persistent variation in trend inflation and the NAIRU. The model, which consists of five unobserved components (including the trends) with stochastic volatility, implies a time-varying VAR for changes in the rates of inflation and unemployment. The implied backwards-looking Phillips curve has a time-varying slope that is steeper in the 1970s than in the 1990s. Pseudo out-of-sample forecasting experiments i...
Energy Technology Data Exchange (ETDEWEB)
Croon, Djuna; Sanz, Verónica; Setford, Jack [Department of Physics and Astronomy, University of Sussex,Brighton BN1 9QH (United Kingdom)
2015-10-05
Identifying the inflaton with a pseudo-Goldstone boson explains the flatness of its potential. Successful Goldstone Inflation should also be robust against UV corrections, such as from quantum gravity: in the language of the effective field theory this implies that all scales are sub-Planckian. In this paper we present scenarios which realise both requirements by examining the structure of Goldstone potentials arising from Coleman-Weinberg contributions. We focus on single-field models, for which we notice that both bosonic and fermionic contributions are required and that spinorial fermion representations can generate the right potential shape. We then evaluate the constraints on non-Gaussianity from higher-derivative interactions, finding that axiomatic constraints on Goldstone boson scattering prevail over the current CMB measurements. The fit to CMB data can be connected to the UV completions for Goldstone Inflation, finding relations in the spectrum of new resonances. Finally, we show how hybrid inflation can be realised in the same context, where both the inflaton and the waterfall fields share a common origin as Goldstones.
Croon, Djuna; Sanz, Verónica; Setford, Jack
2015-10-01
Identifying the inflaton with a pseudo-Goldstone boson explains the flatness of its potential. Successful Goldstone Inflation should also be robust against UV corrections, such as from quantum gravity: in the language of the effective field theory this implies that all scales are sub-Planckian. In this paper we present scenarios which realise both requirements by examining the structure of Goldstone potentials arising from Coleman-Weinberg contributions. We focus on single-field models, for which we notice that both bosonic and fermionic contributions are required and that spinorial fermion representations can generate the right potential shape. We then evaluate the constraints on non-Gaussianity from higher-derivative interactions, finding that axiomatic constraints on Goldstone boson scattering prevail over the current CMB measurements. The fit to CMB data can be connected to the UV completions for Goldstone Inflation, finding relations in the spectrum of new resonances. Finally, we show how hybrid inflation can be realised in the same context, where both the inflaton and the waterfall fields share a common origin as Goldstones.
International Nuclear Information System (INIS)
Croon, Djuna; Sanz, Verónica; Setford, Jack
2015-01-01
Identifying the inflaton with a pseudo-Goldstone boson explains the flatness of its potential. Successful Goldstone Inflation should also be robust against UV corrections, such as from quantum gravity: in the language of the effective field theory this implies that all scales are sub-Planckian. In this paper we present scenarios which realise both requirements by examining the structure of Goldstone potentials arising from Coleman-Weinberg contributions. We focus on single-field models, for which we notice that both bosonic and fermionic contributions are required and that spinorial fermion representations can generate the right potential shape. We then evaluate the constraints on non-Gaussianity from higher-derivative interactions, finding that axiomatic constraints on Goldstone boson scattering prevail over the current CMB measurements. The fit to CMB data can be connected to the UV completions for Goldstone Inflation, finding relations in the spectrum of new resonances. Finally, we show how hybrid inflation can be realised in the same context, where both the inflaton and the waterfall fields share a common origin as Goldstones.
Dynamical study of DBI-essence in loop quantum cosmology and brane world
Energy Technology Data Exchange (ETDEWEB)
Bhadra, Jhumpa; Debnath, Ujjal [Bengal Engineering and Science University, Department of Mathematics, Howrah (India)
2012-08-15
We have studied homogeneous isotropic FRW model having dynamical dark energy DBI-essence with scalar field. Existence of cosmological scaling solutions restricts the Lagrangian of the scalar field {phi}. Choosing p=Xg(Xe{sup {lambda}{phi}}), where X=-g {sup {mu}{nu}}{partial_derivative}{sub {mu}}{phi}{partial_derivative}{sub {nu}}{phi}/2 with g any function of Xe{sup {lambda}{phi}} and defining some suitable transformations, we have constructed the dynamical system in different models of gravity: (i) Loop Quantum Cosmology (LQC), (ii) DGP brane world and (iii) RS II brane world. We have investigated stability of this dynamical system around the critical point for three gravity models and investigated the scalar-field dominated attractor solution in support of accelerated universe. The roles of the physical parameters have also been shown graphically during the accelerating phase of the universe. (orig.)
Dynamical study of DBI-essence in loop quantum cosmology and brane world
International Nuclear Information System (INIS)
Bhadra, Jhumpa; Debnath, Ujjal
2012-01-01
We have studied homogeneous isotropic FRW model having dynamical dark energy DBI-essence with scalar field. Existence of cosmological scaling solutions restricts the Lagrangian of the scalar field φ. Choosing p=Xg(Xe λφ ), where X=-g μν ∂ μ φ∂ ν φ/2 with g any function of Xe λφ and defining some suitable transformations, we have constructed the dynamical system in different models of gravity: (i) Loop Quantum Cosmology (LQC), (ii) DGP brane world and (iii) RS II brane world. We have investigated stability of this dynamical system around the critical point for three gravity models and investigated the scalar-field dominated attractor solution in support of accelerated universe. The roles of the physical parameters have also been shown graphically during the accelerating phase of the universe. (orig.)
Gersbach, Hans; Hahn, Volker
2012-01-01
We introduce a new type of incentive contract for central bankers: inflation forecast contracts, which make central bankers’ remunerations contingent on the precision of their inflation forecasts. We show that such contracts enable central bankers to influence inflation expectations more effectively, thus facilitating more successful stabilization of current inflation. Inflation forecast contracts improve the accuracy of inflation forecasts, but have adverse consequences for output. On balanc...
Multifield dynamics in Higgs-otic inflation
Energy Technology Data Exchange (ETDEWEB)
Bielleman, S.; Ibáñez, L.E.; Pedro, F.G.; Valenzuela, I. [Departamento de Física Teórica UAM and Instituto de Física Teórica UAM/CSIC,Universidad Autónoma de Madrid,Cantoblanco, 28049 Madrid (Spain)
2016-01-20
In Higgs-otic inflation a complex neutral scalar combination of the h{sup 0} and H{sup 0} MSSM Higgs fields plays the role of inflaton in a chaotic fashion. The potential is protected from large trans-Planckian corrections at large inflaton if the system is embedded in string theory so that the Higgs fields parametrize a D-brane position. The inflaton potential is then given by a DBI+CS D-brane action yielding an approximate linear behaviour at large field. The inflaton scalar potential is a 2-field model with specific non-canonical kinetic terms. Previous computations of the cosmological parameters (i.e. scalar and tensor perturbations) did not take into account the full 2-field character of the model, ignoring in particular the presence of isocurvature perturbations and their coupling to the adiabatic modes. It is well known that for generic 2-field potentials such effects may significantly alter the observational signatures of a given model. We perform a full analysis of adiabatic and isocurvature perturbations in the Higgs-otic 2-field model. We show that the predictivity of the model is increased compared to the adiabatic approximation. Isocurvature perturbations moderately feed back into adiabatic fluctuations. However, the isocurvature component is exponentially damped by the end of inflation. The tensor to scalar ratio varies in a region r=0.08–0.12, consistent with combined Planck/BICEP results.
Inflation Aversion and the Optimal Inflation Tax
Gaowang Wang; Heng-fu Zou
2011-01-01
The optimal inflation tax is reexamined in the framework of dynamic second best economy populated by individuals with inflation aversion. A simple formula for the optimal inflation rate is derived. Different from the literature, it is shown that if the marginal excess burden of other distorting taxes approaches zero, Friedman's rule for optimum quantity of money is not optimal, and the optimal inflation tax is negative; if the marginal excess burden of other taxes is nonzero, the optimal infl...
Energy Technology Data Exchange (ETDEWEB)
Hardwick, Robert J.; Vennin, Vincent; Wands, David [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); Byrnes, Christian T.; Torrado, Jesús, E-mail: robert.hardwick@port.ac.uk, E-mail: vincent.vennin@port.ac.uk, E-mail: c.byrnes@sussex.ac.uk, E-mail: jesus.torrado@sussex.ac.uk, E-mail: david.wands@port.ac.uk [Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom)
2017-10-01
We study the stochastic distribution of spectator fields predicted in different slow-roll inflation backgrounds. Spectator fields have a negligible energy density during inflation but may play an important dynamical role later, even giving rise to primordial density perturbations within our observational horizon today. During de-Sitter expansion there is an equilibrium solution for the spectator field which is often used to estimate the stochastic distribution during slow-roll inflation. However slow roll only requires that the Hubble rate varies slowly compared to the Hubble time, while the time taken for the stochastic distribution to evolve to the de-Sitter equilibrium solution can be much longer than a Hubble time. We study both chaotic (monomial) and plateau inflaton potentials, with quadratic, quartic and axionic spectator fields. We give an adiabaticity condition for the spectator field distribution to relax to the de-Sitter equilibrium, and find that the de-Sitter approximation is never a reliable estimate for the typical distribution at the end of inflation for a quadratic spectator during monomial inflation. The existence of an adiabatic regime at early times can erase the dependence on initial conditions of the final distribution of field values. In these cases, spectator fields acquire sub-Planckian expectation values. Otherwise spectator fields may acquire much larger field displacements than suggested by the de-Sitter equilibrium solution. We quantify the information about initial conditions that can be obtained from the final field distribution. Our results may have important consequences for the viability of spectator models for the origin of structure, such as the simplest curvaton models.
International Nuclear Information System (INIS)
Hardwick, Robert J.; Vennin, Vincent; Wands, David; Byrnes, Christian T.; Torrado, Jesús
2017-01-01
We study the stochastic distribution of spectator fields predicted in different slow-roll inflation backgrounds. Spectator fields have a negligible energy density during inflation but may play an important dynamical role later, even giving rise to primordial density perturbations within our observational horizon today. During de-Sitter expansion there is an equilibrium solution for the spectator field which is often used to estimate the stochastic distribution during slow-roll inflation. However slow roll only requires that the Hubble rate varies slowly compared to the Hubble time, while the time taken for the stochastic distribution to evolve to the de-Sitter equilibrium solution can be much longer than a Hubble time. We study both chaotic (monomial) and plateau inflaton potentials, with quadratic, quartic and axionic spectator fields. We give an adiabaticity condition for the spectator field distribution to relax to the de-Sitter equilibrium, and find that the de-Sitter approximation is never a reliable estimate for the typical distribution at the end of inflation for a quadratic spectator during monomial inflation. The existence of an adiabatic regime at early times can erase the dependence on initial conditions of the final distribution of field values. In these cases, spectator fields acquire sub-Planckian expectation values. Otherwise spectator fields may acquire much larger field displacements than suggested by the de-Sitter equilibrium solution. We quantify the information about initial conditions that can be obtained from the final field distribution. Our results may have important consequences for the viability of spectator models for the origin of structure, such as the simplest curvaton models.
International Nuclear Information System (INIS)
Matsuda, Tomohiro
2010-01-01
We describe new scenarios for generating curvature perturbations when inflaton (curvaton) has significant interactions. We consider a ''spot'', which arises from interactions associated with an enhanced symmetric point (ESP) on the trajectory. Our first example uses the spot to induce a gap in the field equation. We observe that the gap in the field equation may cause generation of curvature perturbation if it does not appear simultaneous in space. The mechanism is similar to the scenario of inhomogeneous phase transition. Then we observe that the spot interactions may initiate warm inflation in the cold Universe. Creation of cosmological perturbation is discussed in relation to the inflaton dynamics and the modulation associated with the spot interactions
Vacua and inflation in string theory and supergravity
International Nuclear Information System (INIS)
Rummel, Markus
2013-07-01
We study the connection between the early and late accelerated expansion of the universe and string theory. In Part I of this thesis, the observational degeneracy between single field models of inflation with canonical kinetic terms and noncanonical kinetic terms, in particular string theory inspired models, is discussed. The 2-point function observables of a given non-canonical theory and its canonical transform that is obtained by matching the inflationary trajectories in phase space are found to match in the case of Dirac-Born-Infeld (DBI) inflation. At the level of the 3-point function observables (non-Gaussianities), we find degeneracy between non-canonical inflation and canonical inflation with a potential that includes a sum of modulated terms. In Part II, we present explicit examples for de Sitter vacua in type IIB string theory. After deriving a sufficient condition for de Sitter vacua in the Kahler uplifting scenario, we show that a globally consistent de Sitter model can be realized on a certain Calabi-Yau manifold. All geometric moduli are stabilized and all known consistency constraints are fulfilled. The complex structure moduli stabilization by fluxes is studied explicitly for a small number of cycles. Extrapolating to a larger number of flux carrying cycles, we verify statistical studies in the literature which show that, in principle, the string landscape can account for a universe with an extremely small cosmological constant.
Vacua and inflation in string theory and supergravity
Energy Technology Data Exchange (ETDEWEB)
Rummel, Markus
2013-07-15
We study the connection between the early and late accelerated expansion of the universe and string theory. In Part I of this thesis, the observational degeneracy between single field models of inflation with canonical kinetic terms and noncanonical kinetic terms, in particular string theory inspired models, is discussed. The 2-point function observables of a given non-canonical theory and its canonical transform that is obtained by matching the inflationary trajectories in phase space are found to match in the case of Dirac-Born-Infeld (DBI) inflation. At the level of the 3-point function observables (non-Gaussianities), we find degeneracy between non-canonical inflation and canonical inflation with a potential that includes a sum of modulated terms. In Part II, we present explicit examples for de Sitter vacua in type IIB string theory. After deriving a sufficient condition for de Sitter vacua in the Kahler uplifting scenario, we show that a globally consistent de Sitter model can be realized on a certain Calabi-Yau manifold. All geometric moduli are stabilized and all known consistency constraints are fulfilled. The complex structure moduli stabilization by fluxes is studied explicitly for a small number of cycles. Extrapolating to a larger number of flux carrying cycles, we verify statistical studies in the literature which show that, in principle, the string landscape can account for a universe with an extremely small cosmological constant.
International Nuclear Information System (INIS)
Green, Dan
2014-01-01
The last few years have yielded remarkable discoveries in physics. In particle physics it appears that a fundamental scalar field exists. The Higgs boson is measured to have a mass of about 126 GeV and to have spin zero and positive parity. The Higgs field is the first fundamental scalar to be discovered in physics. The Cosmic Microwave Background, CMB, is known to have a uniform temperature to parts per 10 5 , but has well measured fluctuations, which are thought to evolve gravitationally to provide the seeds of the current structure of the Universe. In addition, the Universe appears to contain, at present, an unknown ''dark energy'', which is presently the majority energy density of the Universe, larger than either matter or radiation. This may, indeed, be a fundamental scalar field like the Higgs. ''Big Bang'' (BB) cosmology is a very successful ''standard model'' in cosmology. However, it cannot explain the uniformity of the CMB because the CMB consists of many regions not causally connected in the context of the BB model. In addition, the Universe appears to be spatially flat. However, in BB cosmology the present spatial curvature is not stable, so that the initial conditions for BB cosmology would need to be fantastically fine-tuned in order to successfully predict the presently small value of the observed curvature. These issues for BB cosmology have led to the hypothesis of ''inflation'' which postulates an unknown scalar field, not presumably the Higgs field or the dark energy, which causes an exponential expansion of the Universe at very early times. This attractive hypothesis can account for the problems in BB cosmology of flatness and causal CMB connectivity. In addition, the quantum fluctuations of this postulated field provide a natural explanation of the CMB fluctuations which are the seeds of the structure of galaxies. Researchers are now searching for gravitational
International Nuclear Information System (INIS)
Liu, Yang; Piao, Yun-Song; Si, Zong-Guo
2009-01-01
In this paper, we revisit the idea of locked inflation, which does not require a potential satisfying the normal slow-roll condition, but suffers from the problems associated with ''saddle inflation''. We propose a scenario based on locked inflation, however, with an alternative evolution mechanism of the ''waterfall field'' φ. Instead of rolling down along the potential, the φ field will tunnel to end the inflation stage like in old inflation, by which the saddle inflation could be avoided. Further, we study a cascade of old locked inflation, which can be motivated by the string landscape. Our model is based on the consideration of making locked inflation feasible so as to give a working model without slow roll; It also can be seen as an effort to embed the old inflation in string landscape
Energy Technology Data Exchange (ETDEWEB)
Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kobayashi, Tsutomu [Kyoto Univ. (Japan). Hakubi Center; Kyoto Univ. (Japan). Dept. of Physics; Takahashi, Tomo [Saga Univ. (Japan). Dept. of Physics; Yamaguchi, Masahide [Tokyo Institute of Technology (Japan). Dept. of Physics; Yokoyama, Jun' ichi [Tokyo Univ. (JP). Research Center for the Early Universe (RESCEU); Tokyo Univ., Chiba (JP). Inst. for the Physics and Mathematics of the Universe (IPMU)
2012-03-15
We study Higgs inflation in the context of generalized G-inflation, i.e., the most general single-field inflation model with second-order field equations. The four variants of Higgs inflation proposed so far in the literature can be accommodated at one time in our framework. We also propose yet another class of Higgs inflation, the running Einstein inflation model, that can naturally arise from the generalized G-inflation framework. As a result, five Higgs inflation models in all should be discussed on an equal footing. Concise formulas for primordial fluctuations in these generalized Higgs inflation models are provided, which will be helpful to determine which model is favored from the future experiments and observations such as the Large Hadron Collider and the Planck satellite.
International Nuclear Information System (INIS)
Barenboim, Gabriela; Park, Wan-Il; Kinney, William H.
2016-01-01
We consider eternal inflation in hilltop-type inflation models, favored by current data, in which the scalar field in inflation rolls off of a local maximum of the potential. Unlike chaotic or plateau-type inflation models, in hilltop inflation the region of field space which supports eternal inflation is finite, and the expansion rate H EI during eternal inflation is almost exactly the same as the expansion rate H * during slow roll inflation. Therefore, in any given Hubble volume, there is a finite and calculable expectation value for the lifetime of the ''eternal'' inflation phase, during which quantum flucutations dominate over classical field evolution. We show that despite this, inflation in hilltop models is nonetheless eternal in the sense that the volume of the spacetime at any finite time is exponentially dominated by regions which continue to inflate. This is true regardless of the energy scale of inflation, and eternal inflation is supported for inflation at arbitrarily low energy scale.
Detection of gravitational waves from inflation
International Nuclear Information System (INIS)
Kamionkowski, M.; Jaffe, A.H.
2001-01-01
Recent measurements of temperature fluctuations in the cosmic microwave background (CMB) indicate that the Universe is flat and that large-scale structure grew via gravitational infall from primordial adiabatic perturbations. Both of these observations seem to indicate that we are on the right track with inflation. But what is the new physics responsible for inflation? This question can be answered with observations of the polarization of the CMB. Inflation predicts robustly the existence of a stochastic background of cosmological gravitational waves with an amplitude proportional to the square of the energy scale of inflation. This gravitational-wave background induces a unique signature in the polarization of the CMB. If inflation took place at an energy scale much smaller than that of grand unification, then the signal will be too small to be detectable. However, if inflation had something to do with grand unification or Planck-scale physics, then the signal is conceivably detectable in the optimistic case by the Planck satellite, or if not, then by a dedicated post-Planck CMB polarization experiment. Realistic developments in detector technology as well as a proper scan strategy could produce such a post-Planck experiment that would improve on Planck's sensitivity to the gravitational-wave background by several orders of magnitude in a decade timescale. (author)
Inflation persistence in African countries: Does inflation targeting matter?
Phiri, Andrew
2016-01-01
This study investigates inflation persistence in annual CPI inflation collected between 1994 and 2014 for 46 African countries. We group these countries into panels according to whether they are inflation targeters or not and conduct estimations for pre and post inflation targeting periods. Interestingly enough, we find that inflation persistence was much higher for inflation targeters in periods before adopting their inflation targeting regimes and inflation persistence dropped by 40 percent...
Energy Technology Data Exchange (ETDEWEB)
Green, Dan [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2014-03-01
inflation since metrical fluctuations, both scalar and tensor, are also produced in inflationary models. Thus, the time appears to be appropriate for a very basic and simple exposition of the inflationary model written from a particle physics perspective. Only the simplest scalar model will be explored because it is easy to understand and contains all the basic elements of the inflationary model.
International Nuclear Information System (INIS)
Kolb, E.W.
1991-01-01
In the original proposal, inflation occurred in the process of a strongly first-order phase transition. This model was soon demonstrated to be fatally flawed. Subsequent models for inflation involved phase transitions that were second-order, or perhaps weakly first-order; some even involved no phase transition at all. Recently the possibility of inflation during a strongly first-order phase transition has been reviewed. In this talk I will discuss some models for first-order inflation, and emphasize unique signatures that result if inflation is realized in a first-order transition. Before discussing first-order inflation, I will briefly review some of the history of inflation to demonstrate how first-order inflation differs from other models. (orig.)
International Nuclear Information System (INIS)
Kolb, E.W.; Chicago Univ., IL
1990-09-01
In the original proposal, inflation occurred in the process of a strongly first-order phase transition. This model was soon demonstrated to be fatally flawed. Subsequent models for inflation involved phase transitions that were second-order, or perhaps weakly first-order; some even involved no phase transition at all. Recently the possibility of inflation during a strongly first-order phase transition has been revived. In this talk I will discuss some models for first-order inflation, and emphasize unique signatures that result in inflation is realized in a first-order transition. Before discussing first-order inflation, I will briefly review some of the history of inflation to demonstrate how first-order inflation differs from other models. 58 refs., 3 figs
Retrofitting models of inflation
International Nuclear Information System (INIS)
Kain, Ben
2009-01-01
I use the method of retrofitting, developed by Dine, Feng and Silverstein, to generate the scale of inflation dynamically, allowing it to be naturally small. This is a general procedure that may be performed on existing models of supersymmetric inflation. I illustrate this idea on two such models, one an example of F-term inflation and the other an example of D-term inflation.
Inflation Protected Investment Strategies
Directory of Open Access Journals (Sweden)
Mirco Mahlstedt
2016-03-01
Full Text Available In this paper, a dynamic inflation-protected investment strategy is presented, which is based on traditional asset classes and Markov-switching models. Different stock market, as well as inflation regimes are identified, and within those regimes, the inflation hedging potential of stocks, bonds, real estate, commodities and gold are investigated. Within each regime, we determine optimal investment portfolios driven by the investment idea of protection from losses due to changing inflation if inflation is rising or high, but decoupling the performance from inflation if inflation is low. The results clearly indicate that these asset classes behave differently in different stock market and inflation regimes. Whereas in the long-run, we agree with the general opinion in the literature that stocks and bonds are a suitable hedge against inflation, we observe for short time horizons that the hedging potential of each asset class, especially of real estate and commodities, depend strongly on the state of the current market environment. Thus, our approach provides a possible explanation for different statements in the literature regarding the inflation hedging properties of these asset classes. A dynamic inflation-protected investment strategy is developed, which combines inflation protection and upside potential. This strategy outperforms standard buy-and-hold strategies, as well as the well-known 1 N -portfolio.
LIU Jinquan; ZHENG Tingguo; SUI Jianli
2008-01-01
This paper uses the ARFIMA-FIGARCH model to investigate the China¡¯s monthly inflation rate from January 1983 to October 2005. It is found that both first moment and second moment of inflation have remarkable long memory, indicating the existence of long memory properties in both inflation level and inflation uncertainty. By the Granger-causality test on inflation rate and inflation uncertainty, it is shown that the inflation level affects the inflation uncertainty and so supports Friedman hy...
Attractors, universality, and inflation
Downes, Sean; Dutta, Bhaskar; Sinha, Kuver
2012-11-01
Studies of the initial conditions for inflation have conflicting predictions from exponential suppression to inevitability. At the level of phase space, this conflict arises from the competing intuitions of CPT invariance and thermodynamics. After reviewing this conflict, we enlarge the ensemble beyond phase space to include scalar potential data. We show how this leads to an important contribution from inflection point inflation, enhancing the likelihood of inflation to a power law, 1/Ne3. In the process, we emphasize the attractor dynamics of the gravity-scalar system and the existence of universality classes from inflection point inflation. Finally, we comment on the predictivity of inflation in light of these results.
Stochastic volatility and stochastic leverage
DEFF Research Database (Denmark)
Veraart, Almut; Veraart, Luitgard A. M.
This paper proposes the new concept of stochastic leverage in stochastic volatility models. Stochastic leverage refers to a stochastic process which replaces the classical constant correlation parameter between the asset return and the stochastic volatility process. We provide a systematic...... treatment of stochastic leverage and propose to model the stochastic leverage effect explicitly, e.g. by means of a linear transformation of a Jacobi process. Such models are both analytically tractable and allow for a direct economic interpretation. In particular, we propose two new stochastic volatility...... models which allow for a stochastic leverage effect: the generalised Heston model and the generalised Barndorff-Nielsen & Shephard model. We investigate the impact of a stochastic leverage effect in the risk neutral world by focusing on implied volatilities generated by option prices derived from our new...
Non-Gaussianity in multi-sound-speed disformally coupled inflation
Energy Technology Data Exchange (ETDEWEB)
De Bruck, Carsten van; Longden, Chris [Consortium for Fundamental Physics, School of Mathematics and Statistics, University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Koivisto, Tomi, E-mail: C.vandeBruck@sheffield.ac.uk, E-mail: tomi.koivisto@nordita.org, E-mail: cjlongden1@sheffield.ac.uk [Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden)
2017-02-01
Most, if not all, scalar-tensor theories are equivalent to General Relativity with a disformally coupled matter sector. In extra-dimensional theories such a coupling can be understood as a result of induction of the metric on a brane that matter is confined to. This article presents a first look at the non-Gaussianities in disformally coupled inflation, a simple two-field model that features a novel kinetic interaction. Cases with both canonical and Dirac-Born-Infeld (DBI) kinetic terms are taken into account, the latter motivated by the possible extra-dimensional origin of the disformality. The computations are carried out for the equilateral configuration in the slow-roll regime, wherein it is found that the non-Gaussianity is typically rather small and negative. This is despite the fact that the new kinetic interaction causes the perturbation modes to propagate with different sounds speeds, which may both significantly deviate from unity during inflation.
Towards a formal link between inflation perceptions and inflation ...
African Journals Online (AJOL)
This paper reports the finding of a survey of inflation perceptions and inflation expectations in South Africa undertaken in 2014. This survey posed questions on perceptions of past inflation (historic inflation) and expectations of future inflation to the same respondents and determined linkages between historic views and ...
Pseudosmooth tribrid inflation
Energy Technology Data Exchange (ETDEWEB)
Antusch, Stefan; Nolde, David; Rehman, Mansoor Ur, E-mail: stefan.antusch@unibas.ch, E-mail: david.nolde@unibas.ch, E-mail: mansoor-ur.rehman@unibas.ch [Department of Physics, University of Basel, Klingelbergstr. 82, CH-4056 Basel (Switzerland)
2012-08-01
We explore a new class of supersymmetric models of inflation where the inflaton is realised as a combination of a Higgs field and (gauge non-singlet) matter fields, using a ''tribrid'' structure of the superpotential. Inflation is associated with a phase transition around GUT scale energies. The inflationary trajectory already preselects the later vacuum after inflation, which has the advantage of automatically avoiding the production of dangerous topological defects at the end of inflation. While at first sight the models look similar to smooth inflation, they feature a waterfall and are therefore only pseudosmooth. The new class of models offers novel possibilities for realising inflation in close contact with particle physics, for instance with supersymmetric GUTs or with supersymmetric flavour models based on family symmetries.
Pseudosmooth tribrid inflation
Antusch, Stefan; Nolde, David; Rehman, Mansoor Ur
2012-08-01
We explore a new class of supersymmetric models of inflation where the inflaton is realised as a combination of a Higgs field and (gauge non-singlet) matter fields, using a ``tribrid'' structure of the superpotential. Inflation is associated with a phase transition around GUT scale energies. The inflationary trajectory already preselects the later vacuum after inflation, which has the advantage of automatically avoiding the production of dangerous topological defects at the end of inflation. While at first sight the models look similar to smooth inflation, they feature a waterfall and are therefore only pseudosmooth. The new class of models offers novel possibilities for realising inflation in close contact with particle physics, for instance with supersymmetric GUTs or with supersymmetric flavour models based on family symmetries.
Pseudosmooth tribrid inflation
International Nuclear Information System (INIS)
Antusch, Stefan; Nolde, David; Rehman, Mansoor Ur
2012-01-01
We explore a new class of supersymmetric models of inflation where the inflaton is realised as a combination of a Higgs field and (gauge non-singlet) matter fields, using a ''tribrid'' structure of the superpotential. Inflation is associated with a phase transition around GUT scale energies. The inflationary trajectory already preselects the later vacuum after inflation, which has the advantage of automatically avoiding the production of dangerous topological defects at the end of inflation. While at first sight the models look similar to smooth inflation, they feature a waterfall and are therefore only pseudosmooth. The new class of models offers novel possibilities for realising inflation in close contact with particle physics, for instance with supersymmetric GUTs or with supersymmetric flavour models based on family symmetries
International Nuclear Information System (INIS)
Zavala, I.
2008-01-01
A new class of particle physics models of inflation based on the phase transition associated with the spontaneous breaking of family symmetry is proposed. The Higgs fields responsible for the breaking of family symmetry, the flavons, are natural inflaton candidates or waterfall fields in hybrid inflation. This opens up a rich vein of possible inflation models, all linked to the physics of flavour, with several interesting cosmological implications.
Coopersmith, Michael; Gambardella, Pascal J.
2016-01-01
This article is an extension of the work of one of us (Coopersmith, 2011) in deriving the relationship between certain interest rates and the inflation rate of a two component economic system. We use the well-known Fisher relation between the difference of the nominal interest rate and its inflation adjusted value to eliminate the inflation rate and obtain a delay differential equation. We provide computer simulated solutions for this equation over regimes of interest. This paper could be of ...
Kenneth H. Thomas
2000-01-01
Community Reinvestment Act of 1977 (CRA) ratings and performance evaluations are the only bank and thrift exam findings disclosed by financial institution regulators. Inflation of CRA ratings has been alleged by community activists for two decades, but there has been no quantification or empirical investigation of grade inflation. Using a unique grade inflation methodology on actual ratings and evaluation data for 1,407 small banks and thrifts under the revised CRA regulations, this paper con...
Estimating Venezuelas Latent Inflation
Juan Carlos Bencomo; Hugo J. Montesinos; Hugo M. Montesinos; Jose Roberto Rondo
2011-01-01
Percent variation of the consumer price index (CPI) is the inflation indicator most widely used. This indicator, however, has some drawbacks. In addition to measurement errors of the CPI, there is a problem of incongruence between the definition of inflation as a sustained and generalized increase of prices and the traditional measure associated with the CPI. We use data from 1991 to 2005 to estimate a complementary indicator for Venezuela, the highest inflation country in Latin America. Late...
Nonminimally coupled hybrid inflation
International Nuclear Information System (INIS)
Koh, Seoktae; Minamitsuji, Masato
2011-01-01
We discuss the hybrid inflation model where the inflaton field is nonminimally coupled to gravity. In the Jordan frame, the potential contains φ 4 term as well as terms in the original hybrid inflation model. In our model, inflation can be classified into the type (I) and the type (II). In the type (I), inflation is terminated by the tachyonic instability of the waterfall field, while in the type (II) by the violation of slow-roll conditions. In our model, the reheating takes place only at the true minimum and even in the case (II) finally the tachyonic instability occurs after the termination of inflation. For a negative nonminimal coupling, inflation takes place in the vacuum-dominated region, in the large field region, or near the local minimum/maximum. Inflation in the vacuum-dominated region becomes either the type (I) or (II), resulting in a blue or red spectrum of the curvature perturbations, respectively. Inflation around the local maximum can be either the type (I) or the type (II), which results in the red spectrum of the curvature perturbations, while around the local minimum it must be the type (I), which results in the blue spectrum. In the large field region, to terminate inflation, potential in the Einstein frame must be positively tilted, always resulting in the red spectrum. We then numerically solve the equations of motion to investigate the whole dynamics of inflaton and confirm that the spectrum of curvature perturbations changes from red to blue ones as scales become smaller.
International Nuclear Information System (INIS)
Vishniac, E.T.
1987-01-01
We examine the compatibility of inflation with the cosmic string theory for galaxy formation. There is a general conflict between having sufficient string tension to effect galaxy formation, and reheating after inflation to a high enough temperature that strings may form in a thermal phase transition. To escape this conflict, we propose a class of models where the inflation is coupled to the string-producing field. The strings are formed late in inflation as the inflaton rolls towards its zero-temperature value. A large subset of these models have a novel large-scale distribution of galaxies that is fractal, displays biasing without dynamics or feedback mechanisms, and contains voids. (orig.)
Quantum fluctuations and inflation
International Nuclear Information System (INIS)
Bardeen, J.M.; Bublik, G.J.
1986-05-01
We study the effect of quantum fluctuations on the roll-down rate of the inflation field in a semiclassical approximation; this is done by treating the inflation field as a classical random field. The quantum fluctuations are simulated by a noise term in the equation of motion. We consider two different inflationary scenarios (new and chaotic inflation) and find that the roll-down rate of the median value of the inflation field is increased by the quantum fluctuations. Non-linear effects may become important in the later stages of the inflationary regime. 8 refs., 2 figs
Quantum fluctuations and inflation
International Nuclear Information System (INIS)
Bardeen, J.M.; Bublik, G.J.
1987-01-01
The authors study the effect of quantum fluctuations on the roll-down rate of the inflation field in a semiclassical approximation; this is done by treating the inflation field as a classical random field. The quantum fluctuations are simulated by a noise term in the equation of motion. Two different inflationary scenarios (new and chaotic inflation) are considered and it is found that the roll-down rate of the median value of the inflation field is increased by the quantum fluctuations. Non-linear effects may become important in the later stages of the inflationary regime. (author)
Inflation Volatility and the Inflation-Growth Tradeoff in India
Raghbendra Jha; Varsha S. Kulkarni
2012-01-01
This paper amends the New Keynesian Phillips curve model to include inflation volatility and tests the determinants of such volatility for India. It provides results on the determinants of inflation volatility and expected inflation volatility for OLS and ARDL (1,1) models and for change in inflation volatility and change in expected inflation volatility using ECM models. Output gap affects change in expected inflation volatility along (in the ECM model) and not in the other models. Major det...
Analyzing inflation in Nigeria: a fractionally integrated ARFIMA ...
African Journals Online (AJOL)
The study looked into the stochastic properties of CPI-inflation rate for Nigeria from 1995Q1 to 2016Q4. The study employed an autoregressive fractionally integrated moving average and a general autoregressive conditional heteroskedasticity (ARFIMA-GARCH) methodology as well as ADF/KPSS to investigate the ...
International Nuclear Information System (INIS)
Mishra, Hiranmaya; Mohanty, Subhendra; Nautiyal, Akhilesh
2013-01-01
In warm inflation models there is the requirement of generating large dissipative couplings of the inflation with radiation, while at the same Âătime, not de-stabilising the flatness of the inflation potential due to radiative corrections. One way to achieve this without fine tuning unrelated couplings is by supersymmetry. In this talk we will discuss warm inflation with Pseudo-Nambu-Goldstone Bosons (PNGB). In this case inflation and other light fields are PNGB. So, the radiative corrections to the potential are suppressed and the thermal Âăcorrections are small as long as the temperature is below the symmetry breaking scale. In such models it is possible to fulfill the contrary requirements of an inflation potential which is stable under radiative corrections and the generation of a large dissipative coupling of the inflation field with other light fields. This warm inflation model with PNGB gives the observed CMB-anisotropy amplitude and spectral index having the symmetry breaking scale at the GUT scale. (author)
Inflation experiences of retirees
Kalwij, Adriaan; Alessie, Robertus; Gardner, Jonathan; Ali, Ashik Anwar
The inflation experience of people depends on their expenditure patterns and price developments. This paper identifies groups of retirees that have experienced relatively high price inflation over the last few decades and could thus be considered most vulnerable when income decreases, as has been
The DBI action, higher-derivative supergravity, and flattening inflaton potentials
International Nuclear Information System (INIS)
Bielleman, Sjoerd; Ibáñez, Luis E.; Pedro, Francisco G.; Valenzuela, Irene; Wieck, Clemens
2016-01-01
In string theory compactifications it is common to find an effective Lagrangian for the scalar fields with a non-canonical kinetic term. We study the effective action of the scalar position moduli of Type II Dp-branes. In many instances the kinetic terms are in fact modified by a term proportional to the scalar potential itself. This can be linked to the appearance of higher-dimensional supersymmetric operators correcting the Kähler potential. We identify the supersymmetric dimension-eight operators describing the α"′ corrections captured by the D-brane Dirac-Born-Infeld action. Our analysis then allows an embedding of the D-brane moduli effective action into an N=1 supergravity formulation. The effects of the potential-dependent kinetic terms may be very important if one of the scalars is the inflaton, since they lead to a flattening of the scalar potential. We analyze this flattening effect in detail and compute its impact on the CMB observables for single-field inflation with monomial potentials.
Air-Inflated Fabric Structures
National Research Council Canada - National Science Library
Cavallaro, Paul V; Sadegh, Ali M
2006-01-01
.... Examples include air ships, weather balloons, inflatable antennas and radomes, temporary shelters, pneumatic muscles and actuators, inflatable boats, temporary bridging, and energy absorbers such as automotive air bags...
Extended inflation with nonminimally coupled inflation field
International Nuclear Information System (INIS)
Panchapakesan, N.; Sethi, S.K.
1992-01-01
In this paper, an extended inflation model, in which the inflation field is nonminimally coupled to the gravity, is discussed. It is shown that the nucleation rate of bubbles, during a phase transition in the inflaton field, can increase as the transition proceeds for a wide range of parameters of the inflaton potential. The bounce action for three possible cases - the strong gravity regime, the thick-walled Coleman-DeLuccia bubbles and the thin-walled bubbles - is evaluated. The resulting bubble distribution for all the cases is shown to be in conformity with cosmological constraints for ω < 500
The inflation sector of extended inflation
International Nuclear Information System (INIS)
Kolb, E.W.
1990-11-01
In extended inflation the inflationary era is brought to a close by the process of percolation of true vacuum bubbles produced in a first-order phase transition. In this paper I discuss several effects that might obtain if the Universe undergoes an inflationary first-order phase transition. 17 refs
Inflation perceptions and inflation expectation in South Africa: trends ...
African Journals Online (AJOL)
This paper reports the results of a multinomial analysis of inflation perceptions and inflation expectations in South Africa. Inflation perceptions surveys among South African individuals have been undertaken since 2006. The introduction of these surveys followed on domestic inflation expectation surveys conducted in 2000, ...
International Nuclear Information System (INIS)
Desroche, Mariel; Felder, Gary N.; Kratochvil, Jan M.; Linde, Andrei
2005-01-01
During the last ten years a detailed investigation of preheating was performed for chaotic inflation and for hybrid inflation. However, nonperturbative effects during reheating in the new inflation scenario remained practically unexplored. We investigate preheating in new inflation, using a combination of analytical and numerical methods. We find that the decay of the homogeneous component of the inflaton field and the resulting process of spontaneous symmetry breaking in the simplest models of new inflation usually occurs almost instantly: for the new inflation on the GUT scale it takes only about 5 oscillations of the field distribution. The decay of the homogeneous inflaton field is so efficient because of a combined effect of tachyonic preheating and parametric resonance. At that stage, the homogeneous oscillating inflaton field decays into a collection of waves of the inflaton field, with a typical wavelength of the order of the inverse inflaton mass. This stage usually is followed by a long stage of decay of the inflaton field into other particles, which can be described by the perturbative approach to reheating after inflation. The resulting reheating temperature typically is rather low
Inflation, inflation uncertainty and output growth in the USA
Bhar, Ramprasad; Mallik, Girijasankar
2010-12-01
Employing a multivariate EGARCH-M model, this study investigates the effects of inflation uncertainty and growth uncertainty on inflation and output growth in the United States. Our results show that inflation uncertainty has a positive and significant effect on the level of inflation and a negative and significant effect on the output growth. However, output uncertainty has no significant effect on output growth or inflation. The oil price also has a positive and significant effect on inflation. These findings are robust and have been corroborated by use of an impulse response function. These results have important implications for inflation-targeting monetary policy, and the aim of stabilization policy in general.
Phenomenology of stochastic exponential growth
Pirjol, Dan; Jafarpour, Farshid; Iyer-Biswas, Srividya
2017-06-01
Stochastic exponential growth is observed in a variety of contexts, including molecular autocatalysis, nuclear fission, population growth, inflation of the universe, viral social media posts, and financial markets. Yet literature on modeling the phenomenology of these stochastic dynamics has predominantly focused on one model, geometric Brownian motion (GBM), which can be described as the solution of a Langevin equation with linear drift and linear multiplicative noise. Using recent experimental results on stochastic exponential growth of individual bacterial cell sizes, we motivate the need for a more general class of phenomenological models of stochastic exponential growth, which are consistent with the observation that the mean-rescaled distributions are approximately stationary at long times. We show that this behavior is not consistent with GBM, instead it is consistent with power-law multiplicative noise with positive fractional powers. Therefore, we consider this general class of phenomenological models for stochastic exponential growth, provide analytical solutions, and identify the important dimensionless combination of model parameters, which determines the shape of the mean-rescaled distribution. We also provide a prescription for robustly inferring model parameters from experimentally observed stochastic growth trajectories.
International Nuclear Information System (INIS)
Davis, R.L.; Shellard, E.P.S.; Massachusetts Inst. of Tech., Cambridge
1989-01-01
Without inflation the energy density of relic axions in a Robertson-Walker universe arises not from coherent oscillations of a zero-momentum mode but from radiative decay of axion strings. An estimate of the upper bound on the PQ scale coming from these axions is in conflict with the lower bound from SN1987a. We present analytical and numerical evidence supporting this estimate. If true, then the axion needs inflation. With inflation the axion is safe, but the motivation for axion search experiments is weakened. (orig.)
Euro area Inflation as a Predictor of National Inflation Rates
Antonella Cavallo; Antonio Ribba
2013-01-01
The stability of inflation differentials is an important condition for the smooth working of a currency area, such as the European Economic and Monetary Union. In the presence of stability, changes in national inflation rates, while holding Euro-area inflation fixed contemporaneously, should be only transitory. If this is the case, the rate of inflation of the whole area can also be interpreted as a predictor, at least in the long run, of the different national inflation rates. However, in th...
Tribrid Inflation in Supergravity
International Nuclear Information System (INIS)
Antusch, Stefan; Dutta, Koushik; Kostka, Philipp M.
2010-01-01
We propose a novel class of F-term hybrid inflation models in supergravity (SUGRA) where the η-problem is resolved using either a Heisenberg symmetry or a shift symmetry of the Kaehler potential. In addition to the inflaton and the waterfall field, this class (referred to as tribrid inflation) contains a third 'driving' field which contributes the large vacuum energy during inflation by its F-term. In contrast to the 'standard' hybrid scenario, it has several attractive features due to the property of vanishing inflationary superpotential (W inf = 0) during inflation. While the symmetries of the Kaehler potential ensure a flat inflaton potential at tree-level, quantum corrections induced by symmetry breaking terms in the superpotential generate a slope of the potential and lead to a spectral tilt consistent with recent WMAP observations.
Tribrid Inflation in Supergravity
Antusch, Stefan; Dutta, Koushik; Kostka, Philipp M.
We propose a novel class of F-term hybrid inflation models in supergravity (SUGRA) where the η-problem is resolved using either a Heisenberg symmetry or a shift symmetry of the Kähler potential. In addition to the inflaton and the waterfall field, this class (referred to as tribrid inflation) contains a third "driving" field which contributes the large vacuum energy during inflation by its F-term. In contrast to the "standard" hybrid scenario, it has several attractive features due to the property of vanishing inflationary superpotential (Winf = 0) during inflation. Quantum corrections induced by symmetry breaking terms in the superpotential generate a slope of the potential and lead to a spectral tilt consistent with recent WMAP observations.
Coopersmith, Michael
2011-01-01
A relation between interest rates and inflation is presented using a two component economic model and a simple general principle. Preliminary results indicate a remarkable similarity to classical economic theories, in particular that of Wicksell.
Ellis, John; Nanopoulos, Dimitri V.; Olive, Keith A.
2016-01-01
Supersymmetry is the most natural framework for physics above the TeV scale, and the corresponding framework for early-Universe cosmology, including inflation, is supergravity. No-scale supergravity emerges from generic string compactifications and yields a non-negative potential, and is therefore a plausible framework for constructing models of inflation. No-scale inflation yields naturally predictions similar to those of the Starobinsky model based on $R + R^2$ gravity, with a tilted spectrum of scalar perturbations: $n_s \\sim 0.96$, and small values of the tensor-to-scalar perturbation ratio $r < 0.1$, as favoured by Planck and other data on the cosmic microwave background (CMB). Detailed measurements of the CMB may provide insights into the embedding of inflation within string theory as well as its links to collider physics.
Ellis, John; Garcia, Marcos A. G.; Nanopoulos, Dimitri V.; Olive, Keith A.
2016-05-01
Supersymmetry is the most natural framework for physics above the TeV scale, and the corresponding framework for early-Universe cosmology, including inflation, is supergravity. No-scale supergravity emerges from generic string compactifications and yields a non-negative potential, and is therefore a plausible framework for constructing models of inflation. No-scale inflation yields naturally predictions similar to those of the Starobinsky model based on R+{R}2 gravity, with a tilted spectrum of scalar perturbations: {n}s∼ 0.96, and small values of the tensor-to-scalar perturbation ratio r\\lt 0.1, as favoured by Planck and other data on the cosmic microwave background (CMB). Detailed measurements of the CMB may provide insights into the embedding of inflation within string theory as well as its links to collider physics.
Giudice, Gian F
2011-01-01
We consider a simple extension of the Standard Model Higgs inflation with one new real scalar field which preserves unitarity up to the Planck scale. The new scalar field (called sigma) completes in the ultraviolet the theory of Higgs inflation by linearizing the Higgs kinetic term in the Einstein frame, just as the non-linear sigma model is unitarized into its linear version. The unitarity cutoff of the effective theory, obtained by integrating out the sigma field, varies with the background value of the Higgs field. In our setup, both the Higgs field and the sigma field participate in the inflationary dynamics, following the flat direction of the potential. We obtain the same slow-roll parameters and spectral index as in the original Higgs inflation but we find that the Hubble rate during inflation depends not only on the Higgs self-coupling, but also on the unknown couplings of the sigma field.
International Nuclear Information System (INIS)
Giudice, Gian F.; Lee, Hyun Min
2011-01-01
We consider a simple extension of the Standard Model Higgs inflation with one new real scalar field which preserves unitarity up to the Planck scale. The new scalar field (called sigma) completes in the ultraviolet the theory of Higgs inflation by linearizing the Higgs kinetic term in the Einstein frame, just as the non-linear sigma model is unitarized into its linear version. The unitarity cutoff of the effective theory, obtained by integrating out the sigma field, varies with the background value of the Higgs field. In our setup, both the Higgs field and the sigma field participate in the inflationary dynamics, following the flat direction of the potential. We obtain the same slow-roll parameters and spectral index as in the original Higgs inflation but we find that the Hubble rate during inflation depends not only on the Higgs self-coupling, but also on the unknown couplings of the sigma field.
International Nuclear Information System (INIS)
Oh, P.; Chicago Univ., IL
1986-01-01
Cosmological solutions with three exponentially expanding space dimensions in the N=1 supersymmetric Yang-Mills supergravity system are found under the assumption of gluino and ''subgravitino'' condensation. The potential has a long flat region providing sufficient inflation. (orig.)
Racetrack inflation and cosmic strings
Energy Technology Data Exchange (ETDEWEB)
Brax, P. [CEA-Saclay, Gif sur Yvette (France). CEA/DSM/SPhT, Unite de Recherche Associee au CNRS, Service de Physique Theorique; Bruck, C. van de [Sheffield Univ. (United Kingdom). Dept. of Applied Mathematics; Davis, A.C.; Davis, S.C. [Cambridge Univ. (United Kingdom). DAMTP, Centre for Mathematical Sciences; Jeannerot, R. [Instituut-Lorentz for Theoretical Physics, Leiden (Netherlands); Postma, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)]|[Nationaal Inst. voor Kernfysica en Hoge-Energiefysica (NIKHEF), Amsterdam (Netherlands)
2008-05-15
We consider the coupling of racetrack inflation to matter fields as realised in the D3/D7 brane system. In particular, we investigate the possibility of cosmic string formation in this system. We find that string formation before or at the onset of racetrack inflation is possible, but they are then inflated away. Furthermore, string formation at the end of inflation is prevented by the presence of the moduli sector. As a consequence, no strings survive racetrack inflation. (orig.)
Inflation persistence and flexible prices
Robert Dittmar; William T. Gavin; Finn E. Kydland
2004-01-01
If the central bank follows an interest rate rule, then inflation is likely to be persistence, even when prices are fully flexible. Any shock, whether persistent or not, may lead to inflation persistence. In equilibrium, the dynamics of inflation are determined by the evolution of the spread between the real interest rate and the central bank’s target. Inflation persistence in U.S. data can be characterized by a vector autocorrelation function relating inflation and deviations of output from ...
Racetrack inflation and cosmic strings
International Nuclear Information System (INIS)
Brax, P.; Postma, M.
2008-05-01
We consider the coupling of racetrack inflation to matter fields as realised in the D3/D7 brane system. In particular, we investigate the possibility of cosmic string formation in this system. We find that string formation before or at the onset of racetrack inflation is possible, but they are then inflated away. Furthermore, string formation at the end of inflation is prevented by the presence of the moduli sector. As a consequence, no strings survive racetrack inflation. (orig.)
Do inflation-linked bonds contain information about future inflation?
Directory of Open Access Journals (Sweden)
José Valentim Machado Vicente
2013-06-01
Full Text Available There is a widespread belief that inflation-linked bonds are a direct source of information about inflation expectations. In this paper we address this issue by analyzing the relationship between break-even inflation (the difference between nominal and real yields and future inflation. The dataset is extracted from Brazilian Treasury bonds covering the period from April 2005 to April 2011. We find that break-even inflation is an unbiased forecast only of the 3-month and 6-month ahead inflation. For medium horizons (12 and 18 months, break-even inflation has weak explanatory power of future inflation. Over long horizons (24 and 30 months, we report a significant, but counterintuitive, negative relationship between the break-even and realized inflation rates.
Technical Note: Does Core Inflation Help Forecast Total Inflation? Evidence from Colombia
John Thornton
1998-01-01
In Colombia core and total inflation are both (1) series, and core inflation is cointegrated with total inflation. Granger causality tests using error correction methodology indicate that divergence of total inflation from core inflation is quickly revers
García-Bellido, J; Montes, X; Garcia-Bellido, Juan; Garriga, Jaume; Montes, Xavier
1998-01-01
We show that a large class of two-field models of single-bubble open inflation do not lead to infinite open universes, as it was previously thought, but to an ensemble of very large but finite inflating `islands'. The reason is that the quantum tunneling responsible for the nucleation of the bubble does not occur simultaneously along both field directions and equal-time hypersurfaces in the open universe are not synchronized with equal-density or fixed-field hypersurfaces. The most probable tunneling trajectory corresponds to a zero value of the inflaton field; large values, necessary for the second period of inflation inside the bubble, only arise as localized fluctuations. The interior of each nucleated bubble will contain an infinite number of such inflating regions of comoving size of order $\\gamma^{-1}$, where $\\gamma$ depends on the parameters of the model. Each one of these islands will be a quasi-open universe. Since the volume of the hyperboloid is infinite, inflating islands with all possible values...
Mutated hilltop inflation revisited
Pal, Barun Kumar
2018-05-01
In this work we re-investigate pros and cons of mutated hilltop inflation. Applying Hamilton-Jacobi formalism we solve inflationary dynamics and find that inflation goes on along the {W}_{-1} branch of the Lambert function. Depending on the model parameter mutated hilltop model renders two types of inflationary solutions: one corresponds to small inflaton excursion during observable inflation and the other describes large field inflation. The inflationary observables from curvature perturbation are in tune with the current data for a wide range of the model parameter. The small field branch predicts negligible amount of tensor to scalar ratio r˜ O(10^{-4}), while the large field sector is capable of generating high amplitude for tensor perturbations, r˜ O(10^{-1}). Also, the spectral index is almost independent of the model parameter along with a very small negative amount of scalar running. Finally we find that the mutated hilltop inflation closely resembles the α -attractor class of inflationary models in the limit of α φ ≫ 1.
Jaramillo, Jorge A; Jaramillo, Fredy; Kador, Itzjak; Masuoka, David; Tong, Liyue; Ahn, Chul; Komabayashi, Takashi
2013-03-01
The aim of this study was to use the Hiroshima University - Dental Behavioral Inventory (HU-DBI) to compare oral health attitudes and behavior of dental and civil engineering students in Colombia. The HU-DBI's survey consisting of twenty dichotomous responses (agree-disagree) regarding tooth brushing, was completed at University Antonio Narino for the dental students and the University of Cauca for the civil engineering students. The Spanish version of the HU-DBI questionnaire was taken by 182 of 247 dental students and 411 of 762 engineering students. The data was-statistically analyzed by the chi-square test and backward logistic regression. Compared to the engineering students, the dental students were more likely to agree with questions such as "I am bothered by the color of my gums"(OR = 2.2, 95% CI: 1.3-3.7),"I think I can clean my teeth well without using toothpaste" (OR = 3.0, 95% CI: 1.5-5.9), "I have used a dye to see how clean my teeth are" (OR = 2.9, 95% CI: 1.9-4.3), and "I have had my dentist tell me that I brush very well" (OR = 2.0, 95% CI: 1.3-3.1). The dental education curriculum in a dental school compared to a civil engineering school in Colombia indicated that a three-phase curriculum in didactics and clinics increased oral health attitudes and behavior from entry to graduation.
Parzen, Emanuel
1962-01-01
Well-written and accessible, this classic introduction to stochastic processes and related mathematics is appropriate for advanced undergraduate students of mathematics with a knowledge of calculus and continuous probability theory. The treatment offers examples of the wide variety of empirical phenomena for which stochastic processes provide mathematical models, and it develops the methods of probability model-building.Chapter 1 presents precise definitions of the notions of a random variable and a stochastic process and introduces the Wiener and Poisson processes. Subsequent chapters examine
Is Inflation in India an Attractor of Inflation in Nepal?
Edimon Ginting
2007-01-01
The paper attempts to answer some important questions around the inflationary process in Nepal, particularly the transmission of inflation from India. Because the Nepali currency is pegged to the Indian rupee and the two countries share an open border, price developments in Nepal would be expected to mirror to those in India. The results show that inflation in India and inflation in Nepal tend to converge in the long run. Our estimates indicate that the passthrough of inflation from India to ...
International Nuclear Information System (INIS)
Antusch, Stefan
2006-01-01
We review the scenario of sneutrino hybrid inflation, where one of the singlet sneutrinos, the superpartners of the right-handed neutrinos, plays the role of the inflaton. In a minimal model of sneutrino hybrid inflation, the spectral index is given by ns ≅ 1 + 2γ. With γ = 0.025 ± 0.01 constrained by WMAP, a running spectral index vertical bar dns/dlnk vertical bar << vertical barγvertical bar and a tensor-to-scalar ratio r << γ2 are predicted. Small neutrino masses arise from the seesaw mechanism, with heavy masses for the singlet (s)neutrinos generated by the vacuum expectation value of the waterfall field after inflation. The baryon asymmetry of the universe can be explained by non-thermal leptogenesis via sneutrino inflaton decay, with low reheat temperature TRH ≅ 106 GeV
Energy Technology Data Exchange (ETDEWEB)
Ellis, John [Theoretical Particle Physics and Cosmology Group, Department of Physics, King’s College London, Strand, London WC2R 2LS (United Kingdom); Theory Division, CERN, Route de Meyrin 385, 1217 Meyrin (Switzerland); Gonzalo, Tomás E.; Harz, Julia; Huang, Wei-Chih [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)
2015-03-23
We analyse the prospects for constructing hybrid models of inflation that provide a dynamical realisation of the apparent closeness between the supersymmetric GUT scale and the possible scale of cosmological inflation. In the first place, we consider models based on the flipped SU(5)×U(1) gauge group, which has no magnetic monopoles. In one model, the inflaton is identified with a sneutrino field, and in the other model it is a gauge singlet. In both cases we find regions of the model parameter spaces that are compatible with the experimental magnitudes of the scalar perturbations, A{sub s}, and the tilt in the scalar perturbation spectrum, n{sub s}, as well as with an indicative upper limit on the tensor-to-scalar perturbation ratio, r. We also discuss embeddings of these models into SO(10), which is broken at a higher scale so that its monopoles are inflated away.
Energy Technology Data Exchange (ETDEWEB)
Ellis, John [Theoretical Particle Physics and Cosmology Group, Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom); Gonzalo, Tomás E.; Harz, Julia; Huang, Wei-Chih, E-mail: john.ellis@cern.ch, E-mail: tomas.gonzalo.11@ucl.ac.uk, E-mail: j.harz@ucl.ac.uk, E-mail: wei-chih.huang@ucl.ac.uk [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)
2015-03-01
We analyse the prospects for constructing hybrid models of inflation that provide a dynamical realisation of the apparent closeness between the supersymmetric GUT scale and the possible scale of cosmological inflation. In the first place, we consider models based on the flipped SU(5)×U(1) gauge group, which has no magnetic monopoles. In one model, the inflaton is identified with a sneutrino field, and in the other model it is a gauge singlet. In both cases we find regions of the model parameter spaces that are compatible with the experimental magnitudes of the scalar perturbations, A{sub s}, and the tilt in the scalar perturbation spectrum, n{sub s}, as well as with an indicative upper limit on the tensor-to-scalar perturbation ratio, r. We also discuss embeddings of these models into SO(10), which is broken at a higher scale so that its monopoles are inflated away.
Davoudiasl, Hooman; Hooper, Dan; McDermott, Samuel D
2016-01-22
We describe a general scenario, dubbed "inflatable dark matter," in which the density of dark matter particles can be reduced through a short period of late-time inflation in the early Universe. The overproduction of dark matter that is predicted within many, otherwise, well-motivated models of new physics can be elegantly remedied within this context. Thermal relics that would, otherwise, be disfavored can easily be accommodated within this class of scenarios, including dark matter candidates that are very heavy or very light. Furthermore, the nonthermal abundance of grand unified theory or Planck scale axions can be brought to acceptable levels without invoking anthropic tuning of initial conditions. A period of late-time inflation could have occurred over a wide range of scales from ∼MeV to the weak scale or above, and could have been triggered by physics within a hidden sector, with small but not necessarily negligible couplings to the standard model.
Ferrara, Sergio
2017-01-01
Theories with elementary scalar degrees of freedom seem nowadays required for simple descriptions of the Standard Model and of the Early Universe. It is then natural to embed theories of inflation in supergravity, also in view of their possible ultraviolet completion in String Theory. After some general remarks on inflation in supergravity, we describe examples of minimal inflaton dynamics which are compatible with recent observations, including higher-curvature ones inspired by the Starobinsky model. We also discuss different scenarios for supersymmetry breaking during and after inflation, which include a revived role for non-linear realizations. In this spirit, we conclude with a discussion of the link, in four dimensions, between "brane supersymmetry breaking" and the super--Higgs effect in supergravity.
Supersymmetric Majoron inflation
Energy Technology Data Exchange (ETDEWEB)
King, Stephen F.; Ludl, Patrick Otto [School of Physics and Astronomy, University of Southampton,Southampton, SO17 1BJ (United Kingdom)
2017-03-31
We propose supersymmetric Majoron inflation in which the Majoron field Φ responsible for generating right-handed neutrino masses may also be suitable for giving low scale “hilltop” inflation, with a discrete lepton number ℤ{sub N} spontaneously broken at the end of inflation, while avoiding the domain wall problem. In the framework of non-minimal supergravity, we show that a successful spectral index can result with small running together with small tensor modes. We show that a range of heaviest right-handed neutrino masses can be generated, m{sub N}∼10{sup 1}−10{sup 16} GeV, consistent with the constraints from reheating and domain walls.
International Nuclear Information System (INIS)
Chialva, Diego; Danielsson, Ulf H
2008-01-01
This paper represents an in-depth treatment of the chain inflation scenario. We fully determine the evolution of the universe in the model, the conditions necessary in order to have a successful inflationary period, and the matching with the observational results regarding the cosmological perturbations. We study in great detail, and in general, the dynamics of the background, as well as the mechanism of generation of the perturbations. We also find an explicit formula for the spectrum of adiabatic perturbations. Our results prove that chain inflation is a viable model for solving the horizon, entropy and flatness problems of standard cosmology and for generating the right amount of adiabatic cosmological perturbations. The results are radically different from those found in previous works on the subject. Finally, we argue that there is a natural way to embed chain inflation into flux compactified string theory. We discuss the details of the implementation and how to fit observations
Ellis, John; Harz, Julia; Huang, Wei-Chih
2015-01-01
We analyse the prospects for constructing hybrid models of inflation that provide a dynamical realisation of the apparent closeness between the supersymmetric GUT scale and the possible scale of cosmological inflation. In the first place, we consider models based on the flipped SU(5)$\\times$U(1) gauge group, which has no magnetic monopoles. In one model, the inflaton is identified with a sneutrino field, and in the other model it is a gauge singlet. In both cases we find regions of the model parameter spaces that are compatible with the experimental magnitudes of the scalar perturbations, $A_s$, and the tilt in the scalar perturbation spectrum, $n_s$, as well as with an indicative upper limit on the tensor-to-scalar perturbation ratio, $r$. We also discuss embeddings of these models into SO(10), which is broken at a higher scale so that its monopoles are inflated away.
Transdimensional physics and inflation
International Nuclear Information System (INIS)
Giudice, Gian F.; Kolb, Edward W.; Lesgourgues, Julien; Riotto, Antonio
2002-01-01
Within the framework of a five-dimensional brane world with a stabilized radion, we compute the cosmological perturbations generated during inflation and show that the perturbations are a powerful tool to probe the physics of extra dimensions. While we find that the power spectrum of scalar perturbations is unchanged, we show that the existence of the fifth dimension is imprinted on the spectrum of gravitational waves generated during inflation. In particular, we find that the tensor perturbations receive a correction proportional to (HR) 2 , where H is the Hubble expansion rate during inflation and R is the size of the extra dimension. We also generalize our findings to the case of several extra dimensions as well as to warped geometries
Transdimensional physics and inflation
Giudice, Gian Francesco; Lesgourgues, Julien; Riotto, Antonio; Giudice, Gian F.; Kolb, Edward W.; Lesgourgues, Julien; Riotto, Antonio
2002-01-01
Within the framework of a five-dimensional brane world with a stabilized radion, we compute the cosmological perturbations generated during inflation and show that the perturbations are a powerful tool to probe the physics of extra dimensions. While we find that the power spectrum of scalar perturbations is unchanged, we show that the existence of the fifth dimension is imprinted on the spectrum of gravitational waves generated during inflation. In particular, we find that the tensor perturbations receive a correction proportional to (HR)^2, where H is the Hubble expansion rate during inflation and R is the size of the extra dimension. We also generalize our findings to the case of several extra dimensions as well as to warped geometries.
Quintessential inflation: A unified scenario of inflation and dark energy
Directory of Open Access Journals (Sweden)
Hossain Wali
2018-01-01
Full Text Available Quintessential inflation unifies inflation and late time acceleration by a single scalar field. Such a scenario, with canonical and non-canonical scalar fields, has been discussed. The scalar field behaves as an inflaton field during inflation and as a quintessence field during late time. Also the predictions of the models has been compared with the recent Planck data.
Ellis, John; Gonzalo, Tomás E.; Harz, Julia; Huang, Wei-Chih
2015-01-01
We analyse the prospects for constructing hybrid models of inflation that provide a dynamical realisation of the apparent closeness between the supersymmetric GUT scale and the possible scale of cosmological inflation. In the first place, we consider models based on the flipped SU(5)×U(1) gauge group, which has no magnetic monopoles. In one model, the inflaton is identified with a sneutrino field, and in the other model it is a gauge singlet. In both cases we find regions of the model paramet...
DEFF Research Database (Denmark)
Channuie, Phongpichit; Jark Joergensen, Jakob; Sannino, Francesco
2011-01-01
We investigate models in which the inflaton emerges as a composite field of a four dimensional, strongly interacting and nonsupersymmetric gauge theory featuring purely fermionic matter. We show that it is possible to obtain successful inflation via non-minimal coupling to gravity, and that the u......We investigate models in which the inflaton emerges as a composite field of a four dimensional, strongly interacting and nonsupersymmetric gauge theory featuring purely fermionic matter. We show that it is possible to obtain successful inflation via non-minimal coupling to gravity...
International Nuclear Information System (INIS)
Chimento, Luis P.
2002-01-01
We find the group of symmetry transformations under which the Einstein equations for the spatially flat Friedmann-Robertson-Walker universe are form invariant. They relate the energy density and the pressure of the fluid to the expansion rate. We show that inflation can be obtained from nonaccelerated scenarios by a symmetry transformation. We derive the transformation rule for the spectrum and spectral index of the curvature perturbations. Finally, the group is extended to investigate inflation in the anisotropic Bianchi type-I spacetime and the brane-world cosmology
Supersymmetric inflation: Recent progress
International Nuclear Information System (INIS)
Ovrut, B.A.; Steinhardt, P.J.
1986-01-01
The new inflationary universe scenario is, in principle, a simple and powerful approach to resolving a large number of fundamental cosmological problems. However, in order for the scenario to be considered a complete theory, one critical question remains to be answered: What is the physics responsible for the phase transition that triggers the exponential expansion (inflation) of the universe? One possibility that the authors and several other groups have been pursuing is that the physics responsible for the phase transition involves (local) supersymmetry. The goal of this paper is to review the present status of ''Supersymmetric Inflation'', particularly emphasizing some very exciting results that they recently obtained
International Nuclear Information System (INIS)
Klauder, J.R.
1983-01-01
The author provides an introductory survey to stochastic quantization in which he outlines this new approach for scalar fields, gauge fields, fermion fields, and condensed matter problems such as electrons in solids and the statistical mechanics of quantum spins. (Auth.)
Inflation of a Polymeric Menbrane
DEFF Research Database (Denmark)
Kristensen, Susanne B.; Larsen, Johannes R.; Hassager, Ole
1998-01-01
We consider an axisymmetric polymeric membrane inflated by a uniform pressure difference acting across the membrane.......We consider an axisymmetric polymeric membrane inflated by a uniform pressure difference acting across the membrane....
Stochastic Nominal Wage Contacts in a Cash-in-Advance Model
Collard, Fabrice; Ertz, Guy
1996-01-01
We build a simple cash-in-advance model for the German economy, in which we introduce stochastic nominal wage contracts. This allows to weaken the negative effect of the inflation tax such that monetary shocks exert a positive effect on output dynamics. The nominal wage contract model is able to mimic the correlation of inflation and real balances with output. It also lowers the standard deviation of inflation relative to that of output. Further, the variance decomposition analysis indicates ...
Topological defects in extended inflation
International Nuclear Information System (INIS)
Copeland, E.J.; Kolb, E.W.; Chicago Univ., IL; Liddle, A.R.
1990-04-01
We consider the production of topological defects, especially cosmic strings, in extended inflation models. In extended inflation, the Universe passes through a first-order phase transition via bubble percolation, which naturally allows defects to form at the end of inflation. The correlation length, which determines the number density of the defects, is related to the mean size of bubbles when they collide. This mechanism allows a natural combination of inflation and large-scale structure via cosmic strings. 18 refs
Heterogeneous inflation expectations and learning
Madeira, Carlos; Zafar, Basit
2012-01-01
Using the panel component of the Michigan Survey of Consumers, we estimate a learning model of inflation expectations, allowing for heterogeneous use of both private information and lifetime inflation experience. “Life-experience inflation” has a significant impact on individual expectations, but only for one-year-ahead inflation. Public information is substantially more relevant for longer-horizon expectations. Even controlling for life-experience inflation and public information, idiosyncra...
Topological defects in extended inflation
International Nuclear Information System (INIS)
Copeland, E.J.; Kolb, E.W.; Liddle, A.R.
1990-01-01
We consider the production of topological defects, especially cosmic strings, in extended-inflation models. In extended inflation, the Universe passes through a first-order phase transition via bubble percolation, which naturally allows defects to form at the end of inflation. The correlation length, which determines the number density of the defects, is related to the mean size of the bubbles when they collide. This mechanism allows a natural combination of inflation and large-scale structure via cosmic strings
Inflation with a graceful exit in a random landscape
International Nuclear Information System (INIS)
Pedro, F.G.; Westphal, A.
2016-11-01
We develop a stochastic description of small-field inflationary histories with a graceful exit in a random potential whose Hessian is a Gaussian random matrix as a model of the unstructured part of the string landscape. The dynamical evolution in such a random potential from a small-field inflation region towards a viable late-time de Sitter (dS) minimum maps to the dynamics of Dyson Brownian motion describing the relaxation of non-equilibrium eigenvalue spectra in random matrix theory. We analytically compute the relaxation probability in a saddle point approximation of the partition function of the eigenvalue distribution of the Wigner ensemble describing the mass matrices of the critical points. When applied to small-field inflation in the landscape, this leads to an exponentially strong bias against small-field ranges and an upper bound N<<10 on the number of light fields N participating during inflation from the non-observation of negative spatial curvature.
Inflation with a graceful exit in a random landscape
Energy Technology Data Exchange (ETDEWEB)
Pedro, F.G. [Univ. Autonoma de Madrid (Spain). Dept. de Fisica Teorica y Inst. de Fisica Teorica UAM/CSIC; Westphal, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group
2016-11-15
We develop a stochastic description of small-field inflationary histories with a graceful exit in a random potential whose Hessian is a Gaussian random matrix as a model of the unstructured part of the string landscape. The dynamical evolution in such a random potential from a small-field inflation region towards a viable late-time de Sitter (dS) minimum maps to the dynamics of Dyson Brownian motion describing the relaxation of non-equilibrium eigenvalue spectra in random matrix theory. We analytically compute the relaxation probability in a saddle point approximation of the partition function of the eigenvalue distribution of the Wigner ensemble describing the mass matrices of the critical points. When applied to small-field inflation in the landscape, this leads to an exponentially strong bias against small-field ranges and an upper bound N<<10 on the number of light fields N participating during inflation from the non-observation of negative spatial curvature.
Initial conditions for chaotic inflation
International Nuclear Information System (INIS)
Brandenberger, R.; Kung, J.; Feldman, H.
1991-01-01
In contrast to many other inflationary Universe models, chaotic inflation does not depend on fine tuning initial conditions. Within the context of linear perturbation theory, it is shown that chaotic inflation is stable towards both metric and matter perturbations. Neglecting gravitational perturbations, it is shown that chaotic inflation is an attractor in initial condition space. (orig.)
Theory and numerics of gravitational waves from preheating after inflation
International Nuclear Information System (INIS)
Dufaux, Jean-Francois; Kofman, Lev; Bergman, Amanda; Felder, Gary; Uzan, Jean-Philippe
2007-01-01
Preheating after inflation involves large, time-dependent field inhomogeneities, which act as a classical source of gravitational radiation. The resulting spectrum might be probed by direct detection experiments if inflation occurs at a low enough energy scale. In this paper, we develop a theory and algorithm to calculate, analytically and numerically, the spectrum of energy density in gravitational waves produced from an inhomogeneous background of stochastic scalar fields in an expanding universe. We derive some generic analytical results for the emission of gravity waves by stochastic media of random fields, which can test the validity/accuracy of numerical calculations. We contrast our method with other numerical methods in the literature, and then we apply it to preheating after chaotic inflation. In this case, we are able to check analytically our numerical results, which differ significantly from previous works. We discuss how the gravity-wave spectrum builds up with time and find that the amplitude and the frequency of its peak depend in a relatively simple way on the characteristic spatial scale amplified during preheating. We then estimate the peak frequency and amplitude of the spectrum produced in two models of preheating after hybrid inflation, which for some parameters may be relevant for gravity-wave interferometric experiments
STOCHASTIC ASSESSMENT OF NIGERIAN STOCHASTIC ...
African Journals Online (AJOL)
eobe
STOCHASTIC ASSESSMENT OF NIGERIAN WOOD FOR BRIDGE DECKS ... abandoned bridges with defects only in their decks in both rural and urban locations can be effectively .... which can be seen as the detection of rare physical.
Nanopoulos, D. V.; Srednicki, M.
1983-12-01
We show that, before the onset of primordial inflation, there is plenty of time for fields with very flat potentials and very weak couplings (such as the local supersymmetry breaking field and the axion field) to roll to the global minima of their potentials. Thus there is no energy stored in these fields today and hence no constraint (such as faxion USA.
Inflation from higher dimensions
International Nuclear Information System (INIS)
Shafi, Q.
1987-01-01
We argue that an inflationary phase in the very early universe is related to the transition from a higher dimensional to a four-dimensional universe. We present details of a previously considered model which gives sufficient inflation without fine tuning of parameters. (orig.)
International Nuclear Information System (INIS)
Linde, A.D.
1986-05-01
It is shown that the universe evolution in the chaotic inflation scenario has no end and may have no beginning. According to this scenario, the universe consists of exponentially large number of different mini-universes inside which all possible metastable vacuum states and all possible types of compactification are realized. (author)
Inflation from extra dimensions
International Nuclear Information System (INIS)
Barr, S.M.
1984-01-01
Recently there has been growing interest (1) in the possibility that the universe could have more than four dimensions. Aside from any light this may shed on problems in particle physics, if true it would undoubtedly have important implications for early cosmology. A rather speculative but very appealing possibility suggested by D. Sahdev and by E. Alvarez and B. Gavela is that the gravitational collapse of extra spatial dimensions could drive an inflation of ordinary space. This kind of inflationary cosmology would be quite different from the inflationary cosmologies now so intensively studied which are supposed to result from changes in vacuum energy during phase transitions in the early universe. In our work we examine the physics of these Kaluza-Klein inflationary cosmologies and come to three main conclusions. (1) It is desirable to have many extra dimensions, many being of order forty or fifty. (2) For models which give a realistically large inflation almost all of this inflation occurs in a period when quantum gravity is certainly important. This means that Einstein's equations cannot be used to calculate the details of this inflationary period. (3) Under plausible assumptions one may argue from the second law of thermodynamics that given appropriate initial conditions a large inflation will occur even when details of the inflationary phase cannot be calculated classically
International Nuclear Information System (INIS)
Ishihara, Hideki.
1984-05-01
Dynamical evolution of the Kaluza-Klein space-time is studied using higher dimensional Einstein equation with dust matter. The difference of the topology between the usual space and the internal space gives rise to the segregation of these subspaces. Furthermore the contraction of the internal space causes the inflation of the usual space. (author)
Hilltop Supernatural Inflation
Lin, C.
In this talk, I will explain how to reduce the spectral index to be n_s = 0.96 for supernatural inflation. I will also show the constraint to the reheating temperature from Big Bang Nucleosynthesis of both thermal and non-thermal gravitino production.
Aspects of supersymmetric inflation
International Nuclear Information System (INIS)
Lindblom, P.R.
1987-01-01
A new supersymmetric inflationary model is presented and shown to possess the following features: a successful slow rollover produced by quantum corrections; an acceptable pattern of supersymmetry breaking leading to the correct value of the electroweak scale; and a stable slow rollover transition to a minimum with vanishing cosmological constant. It is demonstrated that there is a class of GUT models which are compatible with an inflationary universe scenario in which: (a) the GUT and inflationary phase transitions are distinct (as in supersymmetric inflation); and (b) an observable number of GUT monopoles are created thermally due to reheating of the GUT sector after inflation. This provides one of the few ways of reconciling an observation of GUT monopoles with inflation. New techniques are developed for constructing inflationary models with multiple inflation fields, such as generalizing the one-dimensional slow rollover constraints and estimating the contribution to δρ/ρ from fluctuations transverse to the path of the slow rollover. A new method for ending the slow rollover portion of the inflationary transition is developed
García-Bellido, J
2003-01-01
In this talk I will review the present status of inflationary cosmology and its emergence as the basic paradigm behind the Standard Cosmological Model, with parameters determined today at better than 10% level from CMB and LSS observations. I will also discuss the recent theoretical developments on the process of reheating after inflation and model building based on string theory and D-branes.
International Nuclear Information System (INIS)
Kripfganz, Jochen; Karl-Marx-Universitaet, Leipzig; Ilgenfritz, E.M.
1986-01-01
A numerical analysis of reheating is performed for a classical scalar field with exponentially flat potential. An operational definition of the reheating time is given involving the gradient contribution to the inflation field energy. For the parameter range studied the product of reheating time and Hubble constant H is found to be of order one, being approximately independent of the value of H. (author)
Chuss, David
2010-01-01
The Cosmic Microwave Background (CMB) has provided a wealth of information about the history and physics of the early Universe. Much progress has been made on uncovering the emerging Standard Model of Cosmology by such experiments as COBE and WMAP, and ESA's Planck Surveyor will likely increase our knowledge even more. Despite the success of this model, mysteries remain. Currently understood physics does not offer a compelling explanation for the homogeneity, flatness, and the origin of structure in the Universe. Cosmic Inflation, a brief epoch of exponential expansion, has been posted to explain these observations. If inflation is a reality, it is expected to produce a background spectrum of gravitational waves that will leave a small polarized imprint on the CMB. Discovery of this signal would give the first direct evidence for inflation and provide a window into physics at scales beyond those accessible to terrestrial particle accelerators. I will briefly review aspects of the Standard Model of Cosmology and discuss our current efforts to design and deploy experiments to measure the polarization of the CMB with the precision required to test inflation.
International Nuclear Information System (INIS)
Kripfganz, J.; Ilgenfritz, E.M.
1985-07-01
A numerical analysis of reheating is performed for a classical scalar field with exponentially flat potential. An operational definition of the reheating time is given involving the gradient contribution to the inflation field energy. For the parameter range studied the product of reheating time and Hubble constant H is found to be of order one, being approximately independent of the value of H. (author)
THE ACTUAL IMPLICATIONS OF INFLATION
Directory of Open Access Journals (Sweden)
Murăriţa Ilie
2011-12-01
Full Text Available The authors have started from the idea that inflationary phenomenon is a companion, the cause and the effect of the globalization of poverty in the broader context of world economy globalization. Therefore, starting from a common definition of inflation, the first objective was to identify causal relationships that singularize contemporary inflationary process. After that, attention was focused on the implications of inflation in the current stage, bearing in mind that monetary financial theory and practice are operating with perfectly anticipated inflation or imperfectly anticipated inflation. Inflation has great implications on the long-term contracts and wage contracts.
Science with the space-based interferometer LISA. IV: probing inflation with gravitational waves
International Nuclear Information System (INIS)
Bartolo, Nicola; Guzzetti, Maria Chiara; Liguori, Michele; Matarrese, Sabino
2016-01-01
We investigate the potential for the LISA space-based interferometer to detect the stochastic gravitational wave background produced from different mechanisms during inflation. Focusing on well-motivated scenarios, we study the resulting contributions from particle production during inflation, inflationary spectator fields with varying speed of sound, effective field theories of inflation with specific patterns of symmetry breaking and models leading to the formation of primordial black holes. The projected sensitivities of LISA are used in a model-independent way for various detector designs and configurations. We demonstrate that LISA is able to probe these well-motivated inflationary scenarios beyond the irreducible vacuum tensor modes expected from any inflationary background.
Science with the space-based interferometer LISA. IV: Probing inflation with gravitational waves
Bartolo, Nicola; Domcke, Valerie; Figueroa, Daniel G.; Garcia-Bellido, Juan; Guzzetti, Maria Chiara; Liguori, Michele; Matarrese, Sabino; Peloso, Marco; Petiteau, Antoine; Ricciardone, Angelo; Sakellariadou, Mairi; Sorbo, Lorenzo; Tasinato, Gianmassimo
2016-01-01
We investigate the potential for the LISA space-based interferometer to detect the stochastic gravitational wave background produced from different mechanisms during inflation. Focusing on well-motivated scenarios, we study the resulting contributions from particle production during inflation, inflationary spectator fields with varying speed of sound, effective field theories of inflation with specific patterns of symmetry breaking and models leading to the formation of primordial black holes. The projected sensitivities of LISA are used in a model-independent way for various detector designs and configurations. We demonstrate that LISA is able to probe these well-motivated inflationary scenarios beyond the irreducible vacuum tensor modes expected from any inflationary background.
Kaehler-driven tribrid inflation
International Nuclear Information System (INIS)
Antusch, Stefan; Nolde, David
2012-01-01
We discuss a new class of tribrid inflation models in supergravity, where the shape of the inflaton potential is dominated by effects from the Kaehler potential. Tribrid inflation is a variant of hybrid inflation which is particularly suited for connecting inflation with particle physics, since the inflaton can be a D-flat combination of charged fields from the matter sector. In models of tribrid inflation studied so far, the inflaton potential was dominated by either loop corrections or by mixing effects with the waterfall field (as in 'pseudosmooth' tribrid inflation). Here we investigate the third possibility, namely that tribrid inflation is dominantly driven by effects from higher-dimensional operators of the Kaehler potential. We specify for which superpotential parameters the new regime is realized and show how it can be experimentally distinguished from the other two (loop-driven and p seudosmooth ) regimes
Chang, Mou-Hsiung
2015-01-01
The classical probability theory initiated by Kolmogorov and its quantum counterpart, pioneered by von Neumann, were created at about the same time in the 1930s, but development of the quantum theory has trailed far behind. Although highly appealing, the quantum theory has a steep learning curve, requiring tools from both probability and analysis and a facility for combining the two viewpoints. This book is a systematic, self-contained account of the core of quantum probability and quantum stochastic processes for graduate students and researchers. The only assumed background is knowledge of the basic theory of Hilbert spaces, bounded linear operators, and classical Markov processes. From there, the book introduces additional tools from analysis, and then builds the quantum probability framework needed to support applications to quantum control and quantum information and communication. These include quantum noise, quantum stochastic calculus, stochastic quantum differential equations, quantum Markov semigrou...
Inflation and Inflation Uncertainty Revisited: Evidence from Egypt
Directory of Open Access Journals (Sweden)
Mesbah Fathy Sharaf
2015-07-01
Full Text Available The welfare costs of inflation and inflation uncertainty are well documented in the literature and empirical evidence on the link between the two is sparse in the case of Egypt. This paper investigates the causal relationship between inflation and inflation uncertainty in Egypt using monthly time series data during the period January 1974–April 2015. To endogenously control for any potential structural breaks in the inflation time series, Zivot and Andrews (2002 and Clemente–Montanes–Reyes (1998 unit root tests are used. The inflation–inflation uncertainty relation is modeled by the standard two-step approach as well as simultaneously using various versions of the GARCH-M model to control for any potential feedback effects. The analyses explicitly control for the effect of the Economic Reform and Structural Adjustment Program (ERSAP undertaken by the Egyptian government in the early 1990s, which affected inflation rate and its associated volatility. Results show a high degree of inflation–volatility persistence in the response to inflationary shocks. Granger-causality test along with symmetric and asymmetric GARCH-M models indicate a statistically significant bi-directional positive relationship between inflation and inflation uncertainty, supporting both the Friedman–Ball and the Cukierman–Meltzer hypotheses. The findings are robust to the various estimation methods and model specifications. The findings of this paper support the view of adopting inflation-targeting policy in Egypt, after fulfilling its preconditions, to reduce the welfare cost of inflation and its related uncertainties. Monetary authorities in Egypt should enhance the credibility of monetary policy and attempt to reduce inflation uncertainty, which will help lower inflation rates.
Energy Technology Data Exchange (ETDEWEB)
Maxfield, Travis; Sethi, Savdeep [Enrico Fermi Institute, University of Chicago,Chicago, IL 60637 (United States)
2017-02-22
We study the dynamics of gravitational lumps. By a lump, we mean a metric configuration that asymptotes to a flat space-time. Such lumps emerge in string theory as strong coupling descriptions of D-branes. We provide a physical argument that the broken global symmetries of such a background, generated by certain large diffeomorphisms, constrain the dynamics of localized modes. These modes include the translation zero modes and any localized tensor modes. The constraints we find are gravitational analogues of those found in brane physics. For the example of a Taub-NUT metric in eleven-dimensional supergravity, we argue that a critical value for the electric field arises from standard gravity without higher derivative interactions.
Ross, Graham G.; Germán, Gabriel; Vázquez, J. Alberto
2016-05-01
We construct two simple effective field theory versions of Hybrid Natural Inflation (HNI) that illustrate the range of its phenomenological implications. The resulting inflationary sector potential, V = Δ4(1 + acos( ϕ/f)), arises naturally, with the inflaton field a pseudo-Nambu-Goldstone boson. The end of inflation is triggered by a waterfall field and the conditions for this to happen are determined. Also of interest is the fact that the slow-roll parameter ɛ (and hence the tensor r) is a non-monotonic function of the field with a maximum where observables take universal values that determines the maximum possible tensor to scalar ratio r. In one of the models the inflationary scale can be as low as the electroweak scale. We explore in detail the associated HNI phenomenology, taking account of the constraints from Black Hole production, and perform a detailed fit to the Planck 2015 temperature and polarisation data.
International Nuclear Information System (INIS)
Ross, Graham G.; Germán, Gabriel; Vázquez, J. Alberto
2016-01-01
We construct two simple effective field theory versions of Hybrid Natural Inflation (HNI) that illustrate the range of its phenomenological implications. The resulting inflationary sector potential, V=Δ"4(1+acos (ϕ/f)), arises naturally, with the inflaton field a pseudo-Nambu-Goldstone boson. The end of inflation is triggered by a waterfall field and the conditions for this to happen are determined. Also of interest is the fact that the slow-roll parameter ϵ (and hence the tensor r) is a non-monotonic function of the field with a maximum where observables take universal values that determines the maximum possible tensor to scalar ratio r. In one of the models the inflationary scale can be as low as the electroweak scale. We explore in detail the associated HNI phenomenology, taking account of the constraints from Black Hole production, and perform a detailed fit to the Planck 2015 temperature and polarisation data.
Energy Technology Data Exchange (ETDEWEB)
Herrera, Ramón, E-mail: ramon.herrera@pucv.cl [Instituto de Física, Pontificia Universidad Católica de Valparaíso, Avenida Brasil 2950, Casilla 4059, Valparaíso (Chile)
2017-05-01
A warm inflationary universe in the context of Galileon model or G-model is studied. Under a general formalism we study the inflationary dynamics and the cosmological perturbations considering a coupling of the form G (φ, X )= g (φ) X . As a concrete example, we consider an exponential potential together with the cases in which the dissipation and Galilean coefficients are constants. Also, we study the weak regime given by the condition R <1+3 gH φ-dot , and the strong regime in which 1< R +3 gH φ-dot . Additionally, we obtain constraints on the parameters during the evolution of G-warm inflation, assuming the condition for warm inflation in which the temperature T > H , the conditions or the weak and strong regimes, together with the consistency relation r = r ( n {sub s} ) from Planck data.
Felder, G; Linde, Andrei D; Tkachev, Igor I; Felder, Gary; Kofman, Lev; Linde, Andrei; Tkachev, Igor
2000-01-01
Preheating after inflation may lead to nonthermal phase transitions with symmetry restoration. These phase transitions may occur even if the total energy density of fluctuations produced during reheating is relatively small as compared with the vacuum energy in the state with restored symmetry. As a result, in some inflationary models one encounters a secondary, nonthermal stage of inflation due to symmetry restoration after preheating. We review the theory of nonthermal phase transitions and make a prediction about the expansion factor during the secondary inflationary stage. We then present the results of lattice simulations which verify these predictions, and discuss possible implications of our results for the theory of formation of topological defects during nonthermal phase transitions.
Energy Technology Data Exchange (ETDEWEB)
Bachlechner, Thomas C. [Department of Physics, Columbia University,New York, NY 10027 (United States)
2016-12-30
We argue that moduli stabilization generically restricts the evolution following transitions between weakly coupled de Sitter vacua and can induce a strong selection bias towards inflationary cosmologies. The energy density of domain walls between vacua typically destabilizes Kähler moduli and triggers a runaway towards large volume. This decompactification phase can collapse the new de Sitter region unless a minimum amount of inflation occurs after the transition. A stable vacuum transition is guaranteed only if the inflationary expansion generates overlapping past light cones for all observable modes originating from the reheating surface, which leads to an approximately flat and isotropic universe. High scale inflation is vastly favored. Our results point towards a framework for studying parameter fine-tuning and inflationary initial conditions in flux compactifications.
Herrera, Ramón
2017-05-01
A warm inflationary universe in the context of Galileon model or G-model is studied. Under a general formalism we study the inflationary dynamics and the cosmological perturbations considering a coupling of the form G(phi,X)=g(phi) X. As a concrete example, we consider an exponential potential together with the cases in which the dissipation and Galilean coefficients are constants. Also, we study the weak regime given by the condition RR+3gHdot phi. Additionally, we obtain constraints on the parameters during the evolution of G-warm inflation, assuming the condition for warm inflation in which the temperature T>H, the conditions or the weak and strong regimes, together with the consistency relation r=r(ns) from Planck data.
Fairbairn, Malcolm; Markkanen, Tommi; Rodriguez Roman, David
2018-04-01
We consider the effect of the Gibbons-Hawking radiation on the inflaton in the situation where it is coupled to a large number of spectator fields. We argue that this will lead to two important effects - a thermal contribution to the potential and a gradual change in parameters in the Lagrangian which results from thermodynamic and energy conservation arguments. We present a scenario of hilltop inflation where the field starts trapped at the origin before slowly experiencing a phase transition during which the field extremely slowly moves towards its zero temperature expectation value. We show that it is possible to obtain enough e-folds of expansion as well as the correct spectrum of perturbations without hugely fine-tuned parameters in the potential (albeit with many spectator fields). We also comment on how initial conditions for inflation can arise naturally in this situation.
The Primordial Inflation Explorer
Kogut, Alan J.
2012-01-01
The Primordial Inflation Explorer is an Explorer-class mission to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the linear polarization of the cosmic microwave background. PIXIE uses an innovative optical design to achieve background-limited sensitivity in 400 spectral channels spanning 2.5 decades in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r < 10(exp -3) at 5 standard deviations. The rich PIXIE data set will also constrain physical processes ranging from Big Bang cosmology to the nature of the first stars to physical conditions within the interstellar medium of the Galaxy. I describe the PIXIE instrument and mission architecture needed to detect the inflationary signature using only 4 semiconductor bolometers.
International Nuclear Information System (INIS)
Mishra, Hiranmaya; Mohanty, Subhendra; Nautiyal, Akhilesh
2012-01-01
In warm inflation models there is the requirement of generating large dissipative couplings of the inflaton with radiation, while at the same time, not de-stabilising the flatness of the inflaton potential due to radiative corrections. One way to achieve this without fine tuning unrelated couplings is by supersymmetry. In this Letter we show that if the inflaton and other light fields are pseudo-Nambu-Goldstone bosons then the radiative corrections to the potential are suppressed and the thermal corrections are small as long as the temperature is below the symmetry breaking scale. In such models it is possible to fulfil the contrary requirements of an inflaton potential which is stable under radiative corrections and the generation of a large dissipative coupling of the inflaton field with other light fields. We construct a warm inflation model which gives the observed CMB-anisotropy amplitude and spectral index where the symmetry breaking is at the GUT scale.
International Nuclear Information System (INIS)
Turner, M.S.
1983-01-01
The hot big bang cosmology provides a reliable accounting of the evolution of the Universe from -- 0.01 s after 'the bang' until the present (10-20 Byr after 'the bang'). This is a truly impressive achievement. There are, however, a handful of very fundamental 'cosmological facts' which the model by itself fails to elucidate. They include: the large-scale homogeneity, the isotropy, the small-scale inhomogeneity, the near critical expansion rate, the predominance of matter, the 'monopole problem', and the extremely tiny value of the present cosmological term. Inflation makes the present state of the observable Universe virtually insensitive to the initial state of the Universe. Unfortunately, at present there is no model of new inflation which both resolves the cosmological puzzles and leads to sensible particle physics. A general prescription for the cosmologically-desirable Higgs potential does exist
International Nuclear Information System (INIS)
Turok, N.
1987-11-01
It is argued that, in fundamental string theories, as one traces the universe back in time a point is reached when the expansion rate is so fast that the rate of string creation due to quantum effects balances the dilution of the string density due to the expansion. One is therefore led into a phase of constant string density and an exponentially expanding universe. Fundamental strings therefore seem to lead naturally to inflation. 17 refs., 1 fig
International Nuclear Information System (INIS)
Turok, N.
1988-01-01
It is argued that, in fundamental string theories, as one traces the universe back in time a point is reached when the expansion rate is so fast that the rate of string creation due to quantum effects balances the dilution of the string density due to the expansion. One is therefore led into a phase of constant string density and an exponentially expanding universe. Fundamental strings therefore seem to lead naturally to inflation
International Nuclear Information System (INIS)
Barrow, J.D.; California Univ., Berkeley; Turner, M.S.; Chicago Univ., IL
1981-01-01
The problems of explaining the observed isotropy, homogeneity, flatness and specific entropy of the Universe are discussed in the context of an inflationary Universe which has recently been suggested. It is shown that the isotropy cannot be ignored as a Universe with a large amount of anisotropy will not undergo the inflationary phase. A Universe with only moderate anistropy will undergo inflation and will be rapidly isotropized. (U.K.)
Inflation from supersymmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Antoniadis, I. [UMR CNRS 7589 Sorbonne Universites, UPMC Paris 6, LPTHE, Paris (France); University of Bern, Albert Einstein Center, Institute for Theoretical Physics, Bern (Switzerland); Chatrabhuti, A.; Isono, H.; Knoops, R. [Chulalongkorn University, Department of Physics, Faculty of Science, Pathumwan, Bangkok (Thailand)
2017-11-15
We explore the possibility that inflation is driven by supersymmetry breaking with the superpartner of the goldstino (sgoldstino) playing the role of the inflaton. Moreover, we impose an R-symmetry that allows one to satisfy easily the slow-roll conditions, avoiding the so-called η-problem, and leads to two different classes of small-field inflation models; they are characterised by an inflationary plateau around the maximum of the scalar potential, where R-symmetry is either restored or spontaneously broken, with the inflaton rolling down to a minimum describing the present phase of our Universe. To avoid the Goldstone boson and be left with a single (real) scalar field (the inflaton), R-symmetry is gauged with the corresponding gauge boson becoming massive. This framework generalises a model studied recently by the present authors, with the inflaton identified by the string dilaton and R-symmetry together with supersymmetry restored at weak coupling, at infinity of the dilaton potential. The presence of the D-term allows a tuning of the vacuum energy at the minimum. The proposed models agree with cosmological observations and predict a tensor-to-scalar ratio of primordial perturbations 10{sup -9}
International Nuclear Information System (INIS)
Dimopoulos, Konstantinos; Lyth, David H.; Kohri, Kazunori; Matsuda, Tomohiro
2012-01-01
The primordial curvature perturbation ζ may be generated by some curvaton field σ, which is negligible during inflation and has more or less negligible interactions until it decays. In the current scenario, the curvaton starts to oscillate while its energy density ρσ is negligible. We explore the opposite scenario, in which ρσ drives a few e-folds of inflation before the oscillation begins. In this scenario for generating ζ it is exceptionally easy to solve the η problem; one just has to make the curvaton a string axion, with anomaly-mediated susy breaking which may soon be tested at the LHC. The observed spectral index n can be obtained with a potential V∝φ p for the first inflation; p = 1 or 2 is allowed by the current uncertainty in n but the improvement in accuracy promised by Planck may rule out p = 1. The predictions include (i) running n' ≅ 0.0026 (0.0013) for p = 1 (2) that will probably be observed, (ii) non-gaussianity parameter f NL ; ∼ −1 that may be observed, (iii) tensor fraction r is probably too small to ever observed
Energy Technology Data Exchange (ETDEWEB)
Dvali, Gia
2003-10-03
We propose a new class of inflationary solutions to the standard cosmological problems (horizon, flatness, monopole,...), based on a modification of old inflation. These models do not require a potential which satisfies the normal inflationary slow-roll conditions. Our universe arises from a single tunneling event as the inflaton leaves the false vacuum. Subsequent dynamics (arising from either the oscillations of the inflaton field or thermal effects) keep a second field trapped in a false minimum, resulting in an evanescent period of inflation (with roughly 50 e-foldings) inside the bubble. This easily allows the bubble to grow sufficiently large to contain our present horizon volume. Reheating is accomplished when the inflaton driving the last stage of inflation rolls down to the true vacuum, and adiabatic density perturbations arise from moduli-dependent Yukawa couplings of the inflaton to matter fields. Our scenario has several robust predictions, including virtual absence of gravity waves, a possible absence of tilt in scalar perturbations, and a higher degree of non-Gaussianity than other models. It also naturally incorporates a solution to the cosmological moduli problem.
Remote inflation as hybrid-like sneutrino/MSSM inflation
International Nuclear Information System (INIS)
Matsuda, Tomohiro
2009-01-01
A new scenario of hybrid-like inflation is considered for sneutrino and MSSM fields. Contrary to the usual hybrid inflation model, the direct coupling between a trigger field and the sneutrino/MSSM inflaton field is not necessary for the scenario. The dissipation and the radiation from the sneutrino/MSSM inflaton can be written explicitly by using the Yukawa couplings. Remote inflation does not require the shift symmetry or cancellation in solving the η problem.
International Nuclear Information System (INIS)
Bisognano, J.; Leemann, C.
1982-03-01
Stochastic cooling is the damping of betatron oscillations and momentum spread of a particle beam by a feedback system. In its simplest form, a pickup electrode detects the transverse positions or momenta of particles in a storage ring, and the signal produced is amplified and applied downstream to a kicker. The time delay of the cable and electronics is designed to match the transit time of particles along the arc of the storage ring between the pickup and kicker so that an individual particle receives the amplified version of the signal it produced at the pick-up. If there were only a single particle in the ring, it is obvious that betatron oscillations and momentum offset could be damped. However, in addition to its own signal, a particle receives signals from other beam particles. In the limit of an infinite number of particles, no damping could be achieved; we have Liouville's theorem with constant density of the phase space fluid. For a finite, albeit large number of particles, there remains a residue of the single particle damping which is of practical use in accumulating low phase space density beams of particles such as antiprotons. It was the realization of this fact that led to the invention of stochastic cooling by S. van der Meer in 1968. Since its conception, stochastic cooling has been the subject of much theoretical and experimental work. The earliest experiments were performed at the ISR in 1974, with the subsequent ICE studies firmly establishing the stochastic cooling technique. This work directly led to the design and construction of the Antiproton Accumulator at CERN and the beginnings of p anti p colliding beam physics at the SPS. Experiments in stochastic cooling have been performed at Fermilab in collaboration with LBL, and a design is currently under development for a anti p accumulator for the Tevatron
Accidental inflation from Kaehler uplifting
International Nuclear Information System (INIS)
Ben-Dayan, Ido; Westphal, Alexander; Wieck, Clemens; Jing, Shenglin; Toronto Univ., ON
2013-09-01
We analyze the possibility of realizing inflation with a subsequent dS vacuum in the Kaehler uplifting scenario. The inclusion of several quantum corrections to the 4d effective action evades previous no-go theorems and allows for construction of simple and successful models of string inflation. The predictions of several benchmark models are in accord with current observations, i.e., a red spectral index, negligible non-gaussianity, and spectral distortions similar to the simplest models of inflation. A particularly interesting subclass of models are ''left-rolling'' ones, where the overall volume of the compactified dimensions shrinks during inflation. We call this phenomenon ''inflation by deflation'' (IBD), where deflation refers to the internal manifold. This subclass has the appealing features of being insensitive to initial conditions, avoiding the overshooting problem, and allowing for observable running α -5 . The latter results differ significantly from many string inflation models.
Scale-invariant extended inflation
International Nuclear Information System (INIS)
Holman, R.; Kolb, E.W.; Vadas, S.L.; Wang, Y.
1991-01-01
We propose a model of extended inflation which makes use of the nonlinear realization of scale invariance involving the dilaton coupled to an inflaton field whose potential admits a metastable ground state. The resulting theory resembles the Jordan-Brans-Dicke version of extended inflation. However, quantum effects, in the form of the conformal anomaly, generate a mass for the dilaton, thus allowing our model to evade the problems of the original version of extended inflation. We show that extended inflation can occur for a wide range of inflaton potentials with no fine-tuning of dimensionless parameters required. Furthermore, we also find that it is quite natural for the extended-inflation period to be followed by an epoch of slow-rollover inflation as the dilaton settles down to the minimum of its induced potential
Eichhorn, Ralf; Aurell, Erik
2014-04-01
'Stochastic thermodynamics as a conceptual framework combines the stochastic energetics approach introduced a decade ago by Sekimoto [1] with the idea that entropy can consistently be assigned to a single fluctuating trajectory [2]'. This quote, taken from Udo Seifert's [3] 2008 review, nicely summarizes the basic ideas behind stochastic thermodynamics: for small systems, driven by external forces and in contact with a heat bath at a well-defined temperature, stochastic energetics [4] defines the exchanged work and heat along a single fluctuating trajectory and connects them to changes in the internal (system) energy by an energy balance analogous to the first law of thermodynamics. Additionally, providing a consistent definition of trajectory-wise entropy production gives rise to second-law-like relations and forms the basis for a 'stochastic thermodynamics' along individual fluctuating trajectories. In order to construct meaningful concepts of work, heat and entropy production for single trajectories, their definitions are based on the stochastic equations of motion modeling the physical system of interest. Because of this, they are valid even for systems that are prevented from equilibrating with the thermal environment by external driving forces (or other sources of non-equilibrium). In that way, the central notions of equilibrium thermodynamics, such as heat, work and entropy, are consistently extended to the non-equilibrium realm. In the (non-equilibrium) ensemble, the trajectory-wise quantities acquire distributions. General statements derived within stochastic thermodynamics typically refer to properties of these distributions, and are valid in the non-equilibrium regime even beyond the linear response. The extension of statistical mechanics and of exact thermodynamic statements to the non-equilibrium realm has been discussed from the early days of statistical mechanics more than 100 years ago. This debate culminated in the development of linear response
Inflation, its Volatility and the Inflation-Growth Tradeoff in India
Raghbendra Jha; Varsha S. Kulkarni
2013-01-01
This paper amends the New Keynesian Phillips curve model to include inflation volatility. It provides results on the determinants of inflation volatility and expected inflation volatility for OLS and ARDL(1,1) models and for change in inflation volatility and change in expected inflation volatility using ECM models. Output gap affects change in expected inflation volatility alone (in the ECM model) and not in the other models. Major determinants of inflation volatility and expected inflation ...
Inflation and the Higgs Scalar
Energy Technology Data Exchange (ETDEWEB)
Green, Dan [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
2014-12-05
This note makes a self-contained exposition of the basic facts of big bang cosmology as they relate to inflation. The fundamental problems with that model are then explored. A simple scalar model of inflation is evaluated which provides the solution of those problems and makes predictions which will soon be definitively tested. The possibility that the recently discovered fundamental Higgs scalar field drives inflation is explored.
Dark energy from gravitoelectromagnetic inflation?
International Nuclear Information System (INIS)
Membiela, A.; Bellini, M.
2008-01-01
Gravitoelectromagnetic Inflation (GI) was introduced to describe in a unified manner electromagnetic, gravitatory and inflation fields from a 5D vacuum state. On the other hand, the primordial origin and evolution of dark energy is today unknown. In this letter we show using GI that the zero modes of some redefined vector fields B i = A i /a produced during inflation could be the source of dark energy in the Universe.
Stability of compactification during inflation
International Nuclear Information System (INIS)
Amendola, L.; Litterio, M.; Occhionero, F.; Kolb, E.W.
1990-03-01
The possibility that inflation may trigger an instability in compactification of extra spatial dimensions is considered. In old, new, or extended inflation, the false vacuum energy results in a semiclassical instability in which the scalar field representing the radius of the extra dimensions may tunnel through a potential barrier leading to an expansion of the internal space. In chaotic inflation, if the initial value of the scalar field responsible for inflation is large enough, the internal space becomes classically unstable to ever increasing expansion. Restrictions on inflationary models necessary to keep the extra dimensions small are discussed. 15 refs., 5 figs
A critical review of inflation
Turok, N G
2002-01-01
The theory of cosmic inflation offers an attractive resolution of some of the great paradoxes in cosmology: why the universe is so large, flat and uniform on large scales, and how density variations arose. Inflation has rightly dominated cosmological thinking for the past two decades, helping stimulate the development of high-precision observational programmes. The survival of simple inflationary models in the face of an impressive observational onslaught has been interpreted as convincing evidence of the correctness of the basic idea. In this paper, I review inflation, but highlight its weaknesses, explaining my reasons for believing that a more complete theory may supersede inflation without necessarily incorporating it.
A critical review of inflation
International Nuclear Information System (INIS)
Turok, Neil
2002-01-01
The theory of cosmic inflation offers an attractive resolution of some of the great paradoxes in cosmology: why the universe is so large, flat and uniform on large scales, and how density variations arose. Inflation has rightly dominated cosmological thinking for the past two decades, helping stimulate the development of high-precision observational programmes. The survival of simple inflationary models in the face of an impressive observational onslaught has been interpreted as convincing evidence of the correctness of the basic idea. In this paper, I review inflation, but highlight its weaknesses, explaining my reasons for believing that a more complete theory may supersede inflation without necessarily incorporating it
Kadota, Kenji; Kobayashi, Tatsuo; Saga, Ikumi; Sumita, Keigo
2018-04-01
We propose a new model of single-field D-term inflation in supergravity, where the inflation is driven by a single modulus field which transforms non-linearly under the U(1) gauge symmetry. One of the notable features of our modulus D-term inflation scenario is that the global U(1) remains unbroken in the vacuum and hence our model is not plagued by the cosmic string problem which can exclude most of the conventional D-term inflation models proposed so far due to the CMB observations.
Crisan, Dan
2011-01-01
"Stochastic Analysis" aims to provide mathematical tools to describe and model high dimensional random systems. Such tools arise in the study of Stochastic Differential Equations and Stochastic Partial Differential Equations, Infinite Dimensional Stochastic Geometry, Random Media and Interacting Particle Systems, Super-processes, Stochastic Filtering, Mathematical Finance, etc. Stochastic Analysis has emerged as a core area of late 20th century Mathematics and is currently undergoing a rapid scientific development. The special volume "Stochastic Analysis 2010" provides a sa
Borodin, Andrei N
2017-01-01
This book provides a rigorous yet accessible introduction to the theory of stochastic processes. A significant part of the book is devoted to the classic theory of stochastic processes. In turn, it also presents proofs of well-known results, sometimes together with new approaches. Moreover, the book explores topics not previously covered elsewhere, such as distributions of functionals of diffusions stopped at different random times, the Brownian local time, diffusions with jumps, and an invariance principle for random walks and local times. Supported by carefully selected material, the book showcases a wealth of examples that demonstrate how to solve concrete problems by applying theoretical results. It addresses a broad range of applications, focusing on concrete computational techniques rather than on abstract theory. The content presented here is largely self-contained, making it suitable for researchers and graduate students alike.
Magnetogenesis from axion inflation
Energy Technology Data Exchange (ETDEWEB)
Adshead, Peter; Scully, Timothy R.; Sfakianakis, Evangelos I. [Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801 (United States); Giblin, John T., E-mail: adshead@illinois.edu, E-mail: giblinj@kenyon.edu, E-mail: tscully2@illinois.edu, E-mail: esfaki@illinois.edu [Department of Physics, Kenyon College, 201 North College Rd, Gambier, Ohio 43022 (United States)
2016-10-01
In this work we compute the production of magnetic fields in models of axion inflation coupled to the hypercharge sector of the Standard Model through a Chern-Simons interaction term. We make the simplest choice of a quadratic inflationary potential and use lattice simulations to calculate the magnetic field strength, helicity and correlation length at the end of inflation. For small values of the axion-gauge field coupling strength the results agree with no-backreaction calculations and estimates found in the literature. For larger couplings the helicity of the magnetic field differs from the no-backreaction estimate and depends strongly on the comoving wavenumber. We estimate the post-inflationary evolution of the magnetic field based on known results for the evolution of helical and non-helical magnetic fields. The magnetic fields produced by axion inflation with large couplings to U(1) {sub Y} can reach B {sub eff} ∼> 10{sup −16} G, exhibiting a field strength B {sub phys} ≈ 10{sup −13} G and a correlation length λ{sub phys} ≈10 pc. This result is insensitive to the exact value of the coupling, as long as the coupling is large enough to allow for instantaneous preheating. Depending on the assumptions for the physical processes that determine blazar properties, these fields can be found consistent with blazar observations based on the value of B {sub eff}. Finally, the intensity of the magnetic field for large coupling can be enough to satisfy the requirements for a recently proposed baryogenesis mechanism, which utilizes the chiral anomaly of the Standard Model.
Inflation targeting and inflation performance : a comparative analysis
Samarina, Anna; De Haan, Jakob; Terpstra, M.
2014-01-01
This article examines how the impact of inflation targeting on inflation performance depends on the choice of country samples, adoption dates, time periods and methodological approaches. We apply two different estimation methods - difference-in-differences and propensity score matching - for our
News on Inflation and the Epidemiology of Inflation Expectations
Pfajfar, D.; Santoro, E.
2012-01-01
Abstract: This paper examines the nexus between news coverage on inflation and households' inflation expectations. In doing so, we test the epidemiological foundations of the sticky information model (Carroll, 2003, 2006). We use both aggregate and household-level data from the Survey Research
News on inflation and the epidemiology of inflation expectations
Pfajfar, D.; Santoro, E.
2013-01-01
This paper examines the nexus between news coverage on inflation and households’ inflation expectations. In doing so, we test the epidemiological foundations of the sticky information model (Carroll 2003, 2006). We use both aggregate and household-level data from the Survey Research Center at the
Assessing inflation persistence: micro evidence on an inflation targeting economy
Czech Academy of Sciences Publication Activity Database
Babecký, Jan; Coricelli, F.; Horváth, R.
-, č. 353 (2008), s. 1-37 ISSN 1211-3298 Institutional research plan: CEZ:AV0Z70850503 Keywords : inflation dynamics * persistence * inflation targeting Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp353.pdf
International Nuclear Information System (INIS)
Li Sheng; Piao Yunsong; Liu Yang
2009-01-01
In a given path with multiple branches, in principle, it can be expected that there are some fork points, where one branch is bifurcated into different branches, or various branches converge into one or several branches. In this paper, it is shown that if there is a web formed by such branches in a given field space, in which each branch can be responsible for a period of slow roll inflation, a multiverse separated by a domain wall network will come into being, some of which might correspond to our observable universe. We discuss this scenario and show possible observations of a given observer at late time.
International Nuclear Information System (INIS)
Brandenberger, R.H.
1986-01-01
Cosmological phase transitions are examined using a new approach based on the dynamical analysis of the equations of motion of quantum fields rather than on static effective potential considerations. In many models the universe enters a period of exponential expansion required for an inflationary cosmology. Analytical methods show that this will be the case if the interaction rate due to quantum field nonlinearities is small compared to the expansion rate of the universe. They derive a heuristic criterion for the maximal value of the coupling constant for which they expect inflation. The prediction is in good agreement with numerical results
International Nuclear Information System (INIS)
Binetruy, P.
1985-08-01
The reasons that led to study supersymmetric models in the context of inflation are reviewed by setting up the constraints that candidates to an inflationary scenario must satisfy. The question is raised whether the groundstate of the new scalar field introduced, the inflaton, breaks supersymmetry. This is discussed in connection with the so-called thermal constraint. Some problems about the study of thermal fluctuations are discussed. The different models available are reviewed and the way they address those issues. A discussion of baryon number generation and of the gravitino problem follows. 67 refs., 4 figs
International Nuclear Information System (INIS)
Ellis, John; Mavromatos, Nikolaos; Nanopoulos, Dimitri; Sakharov, Alexander
2004-01-01
We present a specific model for cosmological inflation driven by the Liouville field in a non-critical supersymmetric string framework, in which the departure from criticality is due to open strings stretched between two moving Type-II 5-branes. We use WMAP and other data on fluctuations in the cosmic microwave background to fix the parameters of the model, such as the relative separation and velocity of the 5-branes, respecting also the constraints imposed by data on light propagation from distant gamma-ray bursters. The model also suggests a small, relaxing component in the present vacuum energy that may accommodate the breaking of supersymmetry
International Nuclear Information System (INIS)
Albrecht, A.; Brandenberger, R.H.
1985-01-01
We examine cosmological phase transitions using a new approach and argue that there are many models in which the universe enters a period of exponential expansion required for an inflationary cosmology. A sufficient condition is that the interaction rates due to quantum field nonlinearities be sufficiently small compared to the expansion rate of the universe. In Coleman-Weinberg-type models this requires tuning the gauge coupling constant to a low value. In pure scalar field theories, the conditions for inflation are satisfied if the scale of symmetry breaking is of the order of the Planck scale
Stochastic modelling inflation in Nigeria | Iwueze | Global Journal of ...
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Stochastic modelling inflation in Nigeria | Iwueze | Global Journal of ...
African Journals Online (AJOL)
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Baryon asymmetry and gravitational waves from pseudoscalar inflation
Jiménez, Daniel; Kamada, Kohei; Schmitz, Kai; Xu, Xun-Jie
2017-12-01
In models of inflation driven by an axion-like pseudoscalar field, the inflaton, a, may couple to the standard model hypercharge via a Chern-Simons-type interaction, Script L ⊃ a/(4Λ) Ftilde F. This coupling results in explosive gauge field production during inflation, especially at its last stage, which has interesting phenomenological consequences: For one thing, the primordial hypermagnetic field is maximally helical. It is thus capable of sourcing the generation of nonzero baryon number, via the standard model chiral anomaly, around the time of electroweak symmetry breaking. For another thing, the gauge field production during inflation feeds back into the primordial tensor power spectrum, leaving an imprint in the stochastic background of gravitational waves (GWs). In this paper, we focus on the correlation between these two phenomena. Working in the approximation of instant reheating, we (1) update the investigation of baryogenesis via hypermagnetic fields from pseudoscalar inflation and (2) examine the corresponding implications for the GW spectrum. We find that successful baryogenesis requires a suppression scale Λ of around Λ ~ 3 × 1017 GeV, which corresponds to a relatively weakly coupled axion. The gauge field production at the end of inflation is then typically accompanied by a peak in the GW spectrum at frequencies in the MHz range or above. The detection of such a peak is out of reach of present-day technology; but in the future, it may serve as a smoking-gun signal for baryogenesis from pseudoscalar inflation. Conversely, models that do yield an observable GW signal suffer from the overproduction of baryon number, unless the reheating temperature is lower than the electroweak scale.
Strings, texture, and inflation
International Nuclear Information System (INIS)
Hodges, H.M.; Primack, J.R.
1991-01-01
We examine mechanisms, several of which are proposed here, to generate structure formation, or to just add large-scale features, through either gauged or global cosmic strings or global texture, within the framework of inflation. We first explore the possibility that strings or texture form if there is no coupling between the topological theory and the inflaton or spacetime curvature, via (1) quantum creation, and (2) a sufficiently high reheat temperature. In addition, we examine the prospects for the inflaton field itself to generate strings or texture. Then, models with the string/texture field coupled to the curvature, and an equivalent model with coupling to the inflaton field, are considered in detail. The requirement that inflationary density fluctuations are not so large as to conflict with observations leads to a number of constraints on model parameters. We find that strings of relevance for structure formation can form in the absence of coupling to the inflaton or curvature through the process of quantum creation, but only if the strings are strongly type I, or if they are global strings. If formed after reheating, naturalness suggests that gauged cosmic strings correspond to a type-I superconductor. Similarly, gauged strings formed during inflation via conformal coupling ξ=1/6 to the spacetime curvature (in a model suggested by Yokoyama in order to evade the millisecond pulsar constraint on cosmic strings) are expected to be strongly type I
Holography of Little Inflation
Directory of Open Access Journals (Sweden)
Brett McInnes
2015-05-01
Full Text Available For several crucial microseconds of its early history, the Universe consisted of a Quark–Gluon Plasma. As it cooled during this era, it traced out a trajectory in the quark matter phase diagram. The form taken by this trajectory is not known with certainty, but is of great importance: it determines, for example, whether the cosmic plasma passed through a first-order phase change during the transition to the hadron era, as has recently been suggested by advocates of the “Little Inflation” model. Just before this transition, the plasma was strongly coupled and therefore can be studied by holographic techniques. We show that holography imposes a strong constraint (taking the form of a bound on the baryonic chemical potential relative to the temperature on the domain through which the cosmic plasma could pass as it cooled, with important consequences for Little Inflation. In fact, we find that holography applied to Little Inflation implies that the cosmic plasma must have passed quite close to the quark matter critical point, and might therefore have been affected by the associated fluctuation phenomena.
Notari, Alessio
2016-12-22
We analyze in detail the background cosmological evolution of a scalar field coupled to a massless abelian gauge field through an axial term $\\frac{\\phi}{f_\\gamma} F \\tilde{F}$, such as in the case of an axion. Gauge fields in this case are known to experience tachyonic growth and therefore can backreact on the background as an effective dissipation into radiation energy density $\\rho_R$, which which can lead to inflation without the need of a flat potential. We analyze the system, for momenta $k$ smaller than the cutoff $f_\\gamma$, including numerically the backreaction. We consider the evolution from a given static initial condition and explicitly show that, if $f_\\gamma$ is smaller than the field excursion $\\phi_0$ by about a factor of at least ${\\cal O} (20)$, there is a friction effect which turns on before that the field can fall down and which can then lead to a very long stage of inflation with a generic potential. In addition we find superimposed oscillations, which would get imprinted on any kind of...
Anisotropic constant-roll inflation
Energy Technology Data Exchange (ETDEWEB)
Ito, Asuka; Soda, Jiro [Kobe University, Department of Physics, Kobe (Japan)
2018-01-15
We study constant-roll inflation in the presence of a gauge field coupled to an inflaton. By imposing the constant anisotropy condition, we find new exact anisotropic constant-roll inflationary solutions which include anisotropic power-law inflation as a special case. We also numerically show that the new anisotropic solutions are attractors in the phase space. (orig.)
Regional Inflation and Financial Dollarization
Brown, M.; de Haas, R.; Sokolov, V.
2013-01-01
Abstract: We exploit variation in consumer price inflation across 71 Russian regions to examine the relationship between the perceived stability of the local currency and financial dollarization. Our results show that regions with higher inflation experience an increase in the dollarization of
Forecasting Interest Rates and Inflation
DEFF Research Database (Denmark)
Chun, Albert Lee
the best overall for short horizon forecasts of short to medium term yields and inflation. Econometric models with shrinkage perform the best over longer horizons and maturities. Aggregating over a larger set of analysts improves inflation surveys while generally degrading interest rates surveys. We...
Inflation differentials among Czech households
Czech Academy of Sciences Publication Activity Database
Janský, Petr; Hait, Pavel
2016-01-01
Roč. 25, č. 1 (2016), s. 71-84 ISSN 1210-0455 R&D Projects: GA TA ČR(CZ) TD020188 Institutional support: RVO:67985998 Keywords : households * inflation * inflation differentials Subject RIV: AH - Economics Impact factor: 0.710, year: 2016
Assisted inflation from geometric tachyon
International Nuclear Information System (INIS)
Panigrahi, Kamal L.; Singh, Harvendra
2007-01-01
We study the effect of rolling of N D3-branes in the vicinity of NS5-branes. We find out that this system coupled with the four dimensional gravity gives the slow roll assisted inflation of the scalar field theory. Once again this expectation is exactly similar to that of N-tachyon assisted inflation on unstable D-branes
Covariant second-order perturbations in generalized two-field inflation
International Nuclear Information System (INIS)
Tzavara, Eleftheria; Tent, Bartjan van; Mizuno, Shuntaro
2014-01-01
We examine the covariant properties of generalized models of two-field inflation, with non-canonical kinetic terms and a possibly non-trivial field metric. We demonstrate that kinetic-term derivatives and covariant field derivatives do commute in a proper covariant framework, which was not realized before in the literature. We also define a set of generalized slow-roll parameters, using a unified notation. Within this framework, we study the most general class of models that allows for well-defined adiabatic and entropic sound speeds, which we identify as the models with parallel momentum and field velocity vectors. For these models we write the exact cubic action in terms of the adiabatic and isocurvature perturbations. We thus provide the tool to calculate the exact non-Gaussianity beyond slow-roll and at any scale for these generalized models. We illustrate our general results by considering their long-wavelength limit, as well as with the example of two-field DBI inflation
Stochastic samples versus vacuum expectation values in cosmology
International Nuclear Information System (INIS)
Tsamis, N.C.; Tzetzias, Aggelos; Woodard, R.P.
2010-01-01
Particle theorists typically use expectation values to study the quantum back-reaction on inflation, whereas many cosmologists stress the stochastic nature of the process. While expectation values certainly give misleading results for some things, such as the stress tensor, we argue that operators exist for which there is no essential problem. We quantify this by examining the stochastic properties of a noninteracting, massless, minimally coupled scalar on a locally de Sitter background. The square of the stochastic realization of this field seems to provide an example of great relevance for which expectation values are not misleading. We also examine the frequently expressed concern that significant back-reaction from expectation values necessarily implies large stochastic fluctuations between nearby spatial points. Rather than viewing the stochastic formalism in opposition to expectation values, we argue that it provides a marvelously simple way of capturing the leading infrared logarithm corrections to the latter, as advocated by Starobinsky
The Higgs boson can delay reheating after inflation
Freese, Katherine; Sfakianakis, Evangelos I.; Stengel, Patrick; Visinelli, Luca
2018-05-01
The Standard Model Higgs boson, which has previously been shown to develop an effective vacuum expectation value during inflation, can give rise to large particle masses during inflation and reheating, leading to temporary blocking of the reheating process and a lower reheat temperature after inflation. We study the effects on the multiple stages of reheating: resonant particle production (preheating) as well as perturbative decays from coherent oscillations of the inflaton field. Specifically, we study both the cases of the inflaton coupling to Standard Model fermions through Yukawa interactions as well as to Abelian gauge fields through a Chern-Simons term. We find that, in the case of perturbative inflaton decay to SM fermions, reheating can be delayed due to Higgs blocking and the reheat temperature can decrease by up to an order of magnitude. In the case of gauge-reheating, Higgs-generated masses of the gauge fields can suppress preheating even for large inflaton-gauge couplings. In extreme cases, preheating can be shut down completely and must be substituted by perturbative decay as the dominant reheating channel. Finally, we discuss the distribution of reheat temperatures in different Hubble patches, arising from the stochastic nature of the Higgs VEV during inflation and its implications for the generation of both adiabatic and isocurvature fluctuations.
International Nuclear Information System (INIS)
Colombino, A.; Mosiello, R.; Norelli, F.; Jorio, V.M.; Pacilio, N.
1975-01-01
A nuclear system kinetics is formulated according to a stochastic approach. The detailed probability balance equations are written for the probability of finding the mixed population of neutrons and detected neutrons, i.e. detectrons, at a given level for a given instant of time. Equations are integrated in search of a probability profile: a series of cases is analyzed through a progressive criterium. It tends to take into account an increasing number of physical processes within the chosen model. The most important contribution is that solutions interpret analytically experimental conditions of equilibrium (moise analysis) and non equilibrium (pulsed neutron measurements, source drop technique, start up procedures)
Directory of Open Access Journals (Sweden)
Romanu Ekaterini
2006-01-01
Full Text Available This article shows the similarities between Claude Debussy’s and Iannis Xenakis’ philosophy of music and work, in particular the formers Jeux and the latter’s Metastasis and the stochastic works succeeding it, which seem to proceed parallel (with no personal contact to what is perceived as the evolution of 20th century Western music. Those two composers observed the dominant (German tradition as outsiders, and negated some of its elements considered as constant or natural by "traditional" innovators (i.e. serialists: the linearity of musical texture, its form and rhythm.
The productivity-inflation nexus: the case of the Australian mining sector
International Nuclear Information System (INIS)
Mahadevan, R.; Asafu Adjaye, J.
2005-01-01
This paper examines the causal links between productivity growth and two price series given by domestic inflation and the price of mineral products in Australia's mining sector for the period 1968/1969 to 1997/1998. The study also uses a stochastic translog cost frontier to generate improved estimates of total factor productivity (TFP) growth. The results indicate negative unidirectional causality running from both price series to mining productivity growth. Regression analysis further shows that domestic inflation has a small but adverse effect on mining productivity growth, thus providing some empirical support for Australia's 'inflation first' monetary policy, at least with respect to the mining sector. Inflation in mineral price, on the other hand, has a greater negative effect on mining productivity growth via mineral export growth. (author)
Can massive primordial black holes be produced in mild waterfall hybrid inflation?
International Nuclear Information System (INIS)
Kawasaki, Masahiro; Tada, Yuichiro
2016-01-01
We studied the possibility whether the massive primordial black holes (PBHs) surviving today can be produced in hybrid inflation. Though it is of great interest since such PBHs can be the candidate for dark matter or seeds of the supermassive black holes in galaxies, there have not been quantitatively complete works yet because of the non-perturbative behavior around the critical point of hybrid inflation. Therefore, combining the stochastic and δ N formalism, we numerically calculated the curvature perturbations in a non-perturbative way and found, without any specific assumption of the types of hybrid inflation, PBHs are rather overproduced when the waterfall phase of hybrid inflation continues so long that the PBH scale is well enlarged and the corresponding PBH mass becomes sizable enough.
International Nuclear Information System (INIS)
Halter, Sebastian
2012-01-01
This thesis is concerned with aspects of inflation both from a field theory and a string theory perspective. It aims at exploring new approaches to address the problem of moduli destabilization and the η-problem and to realize inflation in the matter sector. The first part is devoted to studying models of inflation in the framework of four-dimensional N=1 supergravity. We begin with investigating a new proposal to solve the problem of moduli destabilization, which seems to force us to choose between low-energy supersymmetry and high-scale inflation. This new approach is based on a particular way to couple the modulus to the F-term driving inflation. Using chaotic inflation with a shift symmetry as an example, we show that we can successfully combine low-energy supersymmetry and high-scale inflation. We construct a class of inflation models in N=1 supergravity where the inflaton resides in gauge non-singlet matter fields. These are extensions of a special class of hybrid inflation models, so-called tribrid inflation, where the η-problem can be solved by a Heisenberg symmetry. Compared to previously studied models, we have generalized our models with some inspiration from string theory. We investigate moduli stabilization during inflation and identify situations in which the inflaton slope is dominated by radiative corrections. We outline under which conditions this class of matter inflation models could be embedded into heterotic orbifold compactifications. In doing so, we suggest a new mechanism to stabilize some Kaehler moduli by F-terms for matter fields. In the second part, we consider models of warped D-brane inflation on a family of ten-dimensional supergravity backgrounds. We consider inflation along the radial direction near the tip of the warped throat and show that generically an inflection point arises for the inflaton potential, which is related to an inflection point of the dilaton profile. A universal scaling behaviour with the parameters of the
Energy Technology Data Exchange (ETDEWEB)
Halter, Sebastian
2012-07-09
This thesis is concerned with aspects of inflation both from a field theory and a string theory perspective. It aims at exploring new approaches to address the problem of moduli destabilization and the η-problem and to realize inflation in the matter sector. The first part is devoted to studying models of inflation in the framework of four-dimensional N=1 supergravity. We begin with investigating a new proposal to solve the problem of moduli destabilization, which seems to force us to choose between low-energy supersymmetry and high-scale inflation. This new approach is based on a particular way to couple the modulus to the F-term driving inflation. Using chaotic inflation with a shift symmetry as an example, we show that we can successfully combine low-energy supersymmetry and high-scale inflation. We construct a class of inflation models in N=1 supergravity where the inflaton resides in gauge non-singlet matter fields. These are extensions of a special class of hybrid inflation models, so-called tribrid inflation, where the η-problem can be solved by a Heisenberg symmetry. Compared to previously studied models, we have generalized our models with some inspiration from string theory. We investigate moduli stabilization during inflation and identify situations in which the inflaton slope is dominated by radiative corrections. We outline under which conditions this class of matter inflation models could be embedded into heterotic orbifold compactifications. In doing so, we suggest a new mechanism to stabilize some Kaehler moduli by F-terms for matter fields. In the second part, we consider models of warped D-brane inflation on a family of ten-dimensional supergravity backgrounds. We consider inflation along the radial direction near the tip of the warped throat and show that generically an inflection point arises for the inflaton potential, which is related to an inflection point of the dilaton profile. A universal scaling behaviour with the parameters of the
The condition for classical slow rolling in new inflation
International Nuclear Information System (INIS)
Sasaki, Misao; Nambu, Yasusada; Nakao, Ken-ichi.
1988-02-01
By means of the stochastic description of inflation, we investigate the dynamics of a fixed comoving domain in a continuously inflating universe on the global scale, both analytically and numerically. A particular attention is paid to the condition for a domain to enter the classical slow rolling phase. New inflationary universe models with the potential form, V(φ) ∼ V 0 - cφ 2n at φ ∼ 0 are considered. The critical value of the scalar field beyond which the field slowly rolls down the potential hill is estimated. We find, for all models under consideration, the condition for classical slow rolling is a sufficient condition for the expected amplitude of density perturbations to be smaller than unity. In other words, the density perturbation amplitude at the later Friedmann stage is always smaller than unity if the universe experienced the classical slow roll-over phase. (author)
The condition for classical slow rolling in new inflation
International Nuclear Information System (INIS)
Sasaki, Misao; Nambu, Yasusada; Nakao, Ken-ichi
1988-01-01
By means of the stochastic description of inflation we investigate the dynamics of a fixed comoving domain in a continuously inflating universe on a global scale, both analytically and numerically. Particular attention is paid to the condition for a domain to enter the classical slow rolling phase. New inflationary universe models with the potential form V(φ) ≅ V 0 -cφ 2n at φ ≅ 0 are considered. The critical value of the scalar field beyond which the field slowly rolls down the potential hill is estimated. We find that for all models under consideration, the condition for classical slow rolling is a sufficient condition for the expected amplitude of density perturbations to be smaller than unity. In other words, the density perturbation amplitude at the later Friedmann stage is always smaller than unity if the universe experienced the classical slow roll-over phase. (orig.)
News on Inflation and the Epidemiology of Inflation Expectations
DEFF Research Database (Denmark)
Pfajfar, Damjan; Santoro, Emiliano
2013-01-01
This paper examines the nexus between news coverage on inflation and households’ inflation expectations. In doing so, we test the epidemiological foundations of the sticky information model (Carroll ). We use both aggregate and household-level data from the Survey Research Center at the University...... of Michigan. We highlight a fundamental disconnection among news on inflation, consumers’ frequency of expectation updating, and the accuracy of their expectations. Our evidence provides at best weak support to the epidemiological framework, as most of the consumers who update their expectations do not revise...
Herrera, Ramón
2018-03-01
The reconstruction of a warm inflationary universe model from the scalar spectral index n_S(N) and the tensor to scalar ratio r( N) as a function of the number of e-folds N is studied. Under a general formalism we find the effective potential and the dissipative coefficient in terms of the cosmological parameters n_S and r considering the weak and strong dissipative stages under the slow roll approximation. As a specific example, we study the attractors for the index n_S given by nS-1∝ N^{-1} and for the ratio r∝ N^{-2}, in order to reconstruct the model of warm inflation. Here, expressions for the effective potential V(φ ) and the dissipation coefficient Γ (φ ) are obtained.
Inflation from Minkowski space
International Nuclear Information System (INIS)
Pirtskhalava, David; Santoni, Luca; Trincherini, Enrico; Uttayarat, Patipan
2014-01-01
We propose a class of scalar models that, once coupled to gravity, lead to cosmologies that smoothly and stably connect an inflationary quasi-de Sitter universe to a low, or even zero-curvature, maximally symmetric spacetime in the asymptotic past, strongly violating the null energy condition ( H-dot ≫H"2) at intermediate times. The models are deformations of the conformal galileon lagrangian and are therefore based on symmetries, both exact and approximate, that ensure the quantum robustness of the whole picture. The resulting cosmological backgrounds can be viewed as regularized extensions of the galilean genesis scenario, or, equivalently, as ‘early-time-complete’ realizations of inflation. The late-time inflationary dynamics possesses phenomenologically interesting properties: it can produce a large tensor-to-scalar ratio within the regime of validity of the effective field theory and can lead to sizeable equilateral nongaussianities.
Constraining monodromy inflation
International Nuclear Information System (INIS)
Peiris, Hiranya V.; Easther, Richard; Flauger, Raphael
2013-01-01
We use cosmic microwave background (CMB) data from the 9-year WMAP release to derive constraints on monodromy inflation, which is characterized by a linear inflaton potential with a periodic modulation. We identify two possible periodic modulations that significantly improve the fit, lowering χ 2 by approximately 10 and 20. However, standard Bayesian model selection criteria assign roughly equal odds to the modulated potential and the unmodulated case. A modulated inflationary potential can generate substantial primordial non-Gaussianity with a specific and characteristic form. For the best-fit parameters to the WMAP angular power spectrum, the corresponding non-Gaussianity might be detectable in upcoming CMB data, allowing nontrivial consistency checks on the predictions of a modulated inflationary potential
Ellis, John; Sueiro, Maria
2014-01-01
Inflationary models based on a single scalar field $\\phi$ with a quadratic potential $V = \\frac{1}{2} m^2 \\phi^2$ are disfavoured by the recent Planck constraints on the scalar index, $n_s$, and the tensor-to-scalar ratio for cosmological density perturbations, $r_T$. In this paper we study how such a quadratic inflationary model can be rescued by postulating additional fields with quadratic potentials, such as might occur in sneutrino models, which might serve as either curvatons or supplementary inflatons. Introducing a second scalar field reduces but does not remove the pressure on quadratic inflation, but we find a sample of three-field models that are highly compatible with the Planck data on $n_s$ and $r_T$. We exhibit a specific three-sneutrino example that is also compatible with the data on neutrino mass difference and mixing angles.
Cosmology, inflation, and supersymmetry
International Nuclear Information System (INIS)
Albrecht, A.; Dimopoulos, S.; Fischler, W.; Kolb, E.W.; Raby, S.; Steinhardt, P.J.
1982-01-01
Cosmological consequences of supersymmetric grand unified models based on the Witten-O'Raifeartaigh potential are discussed. In particular we study the development of the phase transition in the spontaneous breaking of supersymmetry. We find that in realistic models where light fields feel supersymmetry breaking only through coupling to massive fields, e.g., the Geometric Hierarchy model, the universe does not inflate or reheat. Thus, the standard cosmological flatness, monopole, and horizon problems remain. In addition, we find that the transition is never completed, in the sense that the universe remains dominated by coherent Higgs field energy, resulting in an apparent matter dominated universe with Ω greater than or equal to 10 30
Extended inflation with induced gravity
International Nuclear Information System (INIS)
Accetta, F.S.; Trester, J.J.; Department of Physics, Yale University, New Haven, Connecticut 06520)
1989-01-01
We consider a recently proposed extended model of inflation which improves upon the original old inflation scenario by achieving a graceful exit from the false-vacuum phase. In this paper extended inflation is generalized to include a potential V(phi) for the Brans-Dicke-type field phi. We find that whereas a graceful exit can still be had, the inclusion of a potential places constraints on the percolation time scale for exiting the inflationary phase. Additional constraints on V(phi) and the false-vacuum energy density rho /sub F/ from density and gravitational-wave perturbations are discussed. For initially small values of phi the false vacuum undergoes power-law inflation, while for initially large values of phi the expansion is exponential. Within true-vacuum regions slow-rolling inflation can occur. As a result, this model generically leads to multiple episodes of inflation. We discuss the significance these multiple episodes of inflation may have on the formation of large-scale structure and the production of voids
Inflation Rate Modelling in Indonesia
Directory of Open Access Journals (Sweden)
Rezzy Eko Caraka
2016-10-01
Full Text Available The purposes of this research were to analyse: (i Modelling the inflation rate in Indonesia with parametric regression. (ii Modelling the inflation rate in Indonesia using non-parametric regression spline multivariable (iii Determining the best model the inflation rate in Indonesia (iv Explaining the relationship inflation model parametric and non-parametric regression spline multivariable. Based on the analysis using the two methods mentioned the coefficient of determination (R2 in parametric regression of 65.1% while non-parametric amounted to 99.39%. To begin with, the factor of money supply or money stock, crude oil prices and the rupiah exchange rate against the dollar is significant on the rate of inflation. The stability of inflation is essential to support sustainable economic development and improve people's welfare. In conclusion, unstable inflation will complicate business planning business activities, both in production and investment activities as well as in the pricing of goods and services produced.DOI: 10.15408/etk.v15i2.3260
Inflation perceptions and inflation expectation in South Africa: trends ...
African Journals Online (AJOL)
Inflation expectations are related to expected future changes .... had to choose from a menu of options with a further response in one instance, while .... 1The marginal effect or partial derivatives depend on the value of x, and the marginal.
Natural inflation and quantum gravity.
de la Fuente, Anton; Saraswat, Prashant; Sundrum, Raman
2015-04-17
Cosmic inflation provides an attractive framework for understanding the early Universe and the cosmic microwave background. It can readily involve energies close to the scale at which quantum gravity effects become important. General considerations of black hole quantum mechanics suggest nontrivial constraints on any effective field theory model of inflation that emerges as a low-energy limit of quantum gravity, in particular, the constraint of the weak gravity conjecture. We show that higher-dimensional gauge and gravitational dynamics can elegantly satisfy these constraints and lead to a viable, theoretically controlled and predictive class of natural inflation models.
Bianchi models and new inflation
International Nuclear Information System (INIS)
Turner, M.S.; Widrow, L.
1986-03-01
The promise of the inflationary Universe scenario is to free the present state of the Universe from extreme dependence on initial data. Paradoxically, inflation is usually analyzed in the context of the homogeneous and isotropic Robertson-Walker (RW) cosmological models. We show that all but a small subset of the homogeneous models (the Bianchi models) undergo inflation. Any initial anisotropy is so strongly damped that if sufficient inflation occurs to solve the flatness/horizon problems the Universe today would still be very isotropic. Some of the Bianchi models will eventually (in the exponentially distant future) become very anisotropic again. 15 refs
CERN. Geneva
2015-01-01
After reviewing the nice properties of Higgs inflation and some of its problems, I will discuss a simple unitarization of the scenario that is genuinely weakly coupled up to Planckian energies. A large non-minimal coupling between the Higgs and the Ricci curvature is induced dynamically at intermediate energies, as a simple ratio of mass scales. Inflationary dynamics is not dominated by the Higgs field, but 'Higgs inflation' arises as an approximate 'mirage' picture of the true dynamics. I will speculate on the generality of this phenomenon and show that, if Higgs-inflation arises as an effective description, the details of the UV completion are necessary to extract robust quantitative predictions.
Assessing inflation persistence: micro evidence on an inflation targeting economy
Czech Academy of Sciences Publication Activity Database
Babecký, Jan; Coricelli, F.; Horváth, R.
2009-01-01
Roč. 59, č. 2 (2009), s. 102-127 ISSN 0015-1920 Grant - others:Česká národní banka(CZ) E5/05 Institutional research plan: CEZ:AV0Z70850503 Keywords : inflation dynamics * persistence * inflation targeting Subject RIV: AH - Economics Impact factor: 0.264, year: 2009 http://journal.fsv.cuni.cz/storage/1153_babeck%C3%BD_horv%C3%A1th_coricelli.pdf
12 CFR 19.240 - Inflation adjustments.
2010-01-01
... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Inflation adjustments. 19.240 Section 19.240... PROCEDURE Civil Money Penalty Inflation Adjustments § 19.240 Inflation adjustments. (a) The maximum amount... Civil Penalties Inflation Adjustment Act of 1990 (28 U.S.C. 2461 note) as follows: ER10NO08.001 (b) The...
Gravity waves from tachyonic preheating after hybrid inflation
Energy Technology Data Exchange (ETDEWEB)
Dufaux, Jean-Francois [Instituto de Fisica Teorica UAM/CSIC, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Felder, Gary [Department of Physics, Clark Science Center, Smith College, Northampton, MA 01063 (United States); Kofman, Lev [CITA, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Navros, Olga, E-mail: jeff.dufaux@uam.es, E-mail: gfelder@email.smith.edu, E-mail: kofman@cita.utoronto.ca, E-mail: navros@email.unc.edu [Department of Mathematics, University of North Carolina Chapel Hill, CB3250 Philips Hall, Chapel Hill, NC 27599 (United States)
2009-03-15
We study the stochastic background of gravitational waves produced from preheating in hybrid inflation models. We investigate different dynamical regimes of preheating in these models and we compute the resulting gravity wave spectra using analytical estimates and numerical simulations. We discuss the dependence of the gravity wave frequencies and amplitudes on the various potential parameters. We find that large regions of the parameter space leads to gravity waves that may be observable in upcoming interferometric experiments, including Advanced LIGO, but this generally requires very small coupling constants.
Lanchier, Nicolas
2017-01-01
Three coherent parts form the material covered in this text, portions of which have not been widely covered in traditional textbooks. In this coverage the reader is quickly introduced to several different topics enriched with 175 exercises which focus on real-world problems. Exercises range from the classics of probability theory to more exotic research-oriented problems based on numerical simulations. Intended for graduate students in mathematics and applied sciences, the text provides the tools and training needed to write and use programs for research purposes. The first part of the text begins with a brief review of measure theory and revisits the main concepts of probability theory, from random variables to the standard limit theorems. The second part covers traditional material on stochastic processes, including martingales, discrete-time Markov chains, Poisson processes, and continuous-time Markov chains. The theory developed is illustrated by a variety of examples surrounding applications such as the ...
Consumer's inflation expectations in Brazil
Directory of Open Access Journals (Sweden)
Fernando Ormonde Teixeira
Full Text Available Abstract This paper investigates what are the main components of consumer's inflation expectations. We combine the FGV's Consumer Survey with the indices of inflation (IPCA and government regulated prices, professional forecasts disclosed in the Focus report, and media data which we crawl from one of the biggest and most important Brazilian newspapers, Folha de São Paulo, to determine what factors are responsible for and improve consumer's forecast accuracy. We found gender, age and city of residence as major elements when analyzing micro-data. Aggregate data shows the past inflation as an important trigger in the formation of consumers' expectations and professional forecasts as negligible. Moreover, the media plays a significant role, accounting not only for the expectations' formation but for a better understanding of actual inflation as well.
Symmetry breaking patterns for inflation
Klein, Remko; Roest, Diederik; Stefanyszyn, David
2018-06-01
We study inflationary models where the kinetic sector of the theory has a non-linearly realised symmetry which is broken by the inflationary potential. We distinguish between kinetic symmetries which non-linearly realise an internal or space-time group, and which yield a flat or curved scalar manifold. This classification leads to well-known inflationary models such as monomial inflation and α-attractors, as well as a new model based on fixed couplings between a dilaton and many axions which non-linearly realises higher-dimensional conformal symmetries. In this model, inflation can be realised along the dilatonic direction, leading to a tensor-to-scalar ratio r ˜ 0 .01 and a spectral index n s ˜ 0 .975. We refer to the new model as ambient inflation since inflation proceeds along an isometry of an anti-de Sitter ambient space-time, which fully determines the kinetic sector.
Hypersonic Inflatable Aerodynamic Decelerator (HIAD)
National Aeronautics and Space Administration — Develop an entry and descent technology to enhance and enable robotic and scientific missions to destinations with atmospheres.The Hypersonic Inflatable Aerodynamic...
Linear inflation from quartic potential
Energy Technology Data Exchange (ETDEWEB)
Kannike, Kristjan; Racioppi, Antonio [National Institute of Chemical Physics and Biophysics,Rävala 10, 10143 Tallinn (Estonia); Raidal, Martti [National Institute of Chemical Physics and Biophysics,Rävala 10, 10143 Tallinn (Estonia); Institute of Physics, University of Tartu,Tartu (Estonia)
2016-01-07
We show that if the inflaton has a non-minimal coupling to gravity and the Planck scale is dynamically generated, the results of Coleman-Weinberg inflation are confined in between two attractor solutions: quadratic inflation, which is ruled out by the recent measurements, and linear inflation which, instead, is in the experimental allowed region. The minimal scenario has only one free parameter — the inflaton’s non-minimal coupling to gravity — that determines all physical parameters such as the tensor-to-scalar ratio and the reheating temperature of the Universe. Should the more precise future measurements of inflationary parameters point towards linear inflation, further interest in scale-invariant scenarios would be motivated.
Energy Technology Data Exchange (ETDEWEB)
Notari, Alessio [Departament de Física Fondamental i Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès 1, Barcelona, 08028 Spain (Spain); Tywoniuk, Konrad, E-mail: notari@ffn.ub.es, E-mail: konrad.tywoniuk@cern.ch [Theoretical Physics Department, CERN, Geneva (Switzerland)
2016-12-01
We analyze in detail the background cosmological evolution of a scalar field coupled to a massless abelian gauge field through an axial term φ/ f {sub γ} F ∼ F , such as in the case of an axion. Gauge fields in this case are known to experience tachyonic growth and therefore can backreact on the background as an effective dissipation into radiation energy density ρ{sub R}, which can lead to inflation without the need of a flat potential. We analyze the system, for momenta k smaller than the cutoff f {sub γ}, including the backreaction numerically. We consider the evolution from a given static initial condition and explicitly show that, if f {sub γ} is smaller than the field excursion φ{sub 0} by about a factor of at least O (20), there is a friction effect which turns on before the field can fall down and which can then lead to a very long stage of inflation with a generic potential. In addition we find superimposed oscillations, which would get imprinted on any kind of perturbations, scalars and tensors. Such oscillations have a period of 4–5 efolds and an amplitude which is typically less than a few percent and decreases linearly with f {sub γ}. We also stress that the curvature perturbation on uniform density slices should be sensitive to slow-roll parameters related to ρ{sub R} rather than φ-dot {sup 2}/2 and we discuss the existence of friction terms acting on the perturbations, although we postpone a calculation of the power spectrum and of non-gaussianity to future work and we simply define and compute suitable slow roll parameters. Finally we stress that this scenario may be realized in the axion case, if the coupling 1/ f {sub γ} to U(1) (photons) is much larger than the coupling 1/ f {sub G} to non-abelian gauge fields (gluons), since the latter sets the range of the potential and therefore the maximal allowed φ{sub 0∼} f {sub G}.
How useful are leading indicators of inflation?
C. Alan Garner
1995-01-01
Many economists expect inflation to rise in 1995. These expectations are based on various approaches to forecasting inflation. One approach is based on the standard economic theory that inflation rises when slack is eliminated from the economy and production exceeds capacity constraints. According to this view, measures of economic slack such as unemployment and capacity utilization provide useful information about the inflation outlook. But the relationship between slack and inflation is com...
Complex Hybrid Inflation and Baryogenesis
Delepine, David; Martinez, Carlos; Urena-Lopez, L. Arturo
2006-01-01
We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vev of the waterfall field, which is well constrained by diverse cosmological observations.
Complex Hybrid Inflation and Baryogenesis
International Nuclear Information System (INIS)
Delepine, David; Martinez, Carlos; Urena-Lopez, L. Arturo
2007-01-01
We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated with the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vacuum expectation value of the waterfall field, which is well constrained by diverse cosmological observations
Theoretical aspects of inflation targeting
Directory of Open Access Journals (Sweden)
Obradović Jelena
2014-01-01
Full Text Available Inflation targeting is one of the possible strategies used by central banks during conducting monetary policy. The basic characteristics, advantages and disadvantages of inflation targeting will be presented in this paper. The focus is on the the presentation and interpretation of the understanding of this strategy from the perspective of monetarist and Keynesian theory, the theory of rational expectations, and methodological analysis of the strategy in light of the game theory using payoff matrix.
Complex hybrid inflation and baryogenesis.
Delepine, David; Martínez, Carlos; Ureña-López, L Arturo
2007-04-20
We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated with the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vacuum expectation value of the waterfall field, which is well constrained by diverse cosmological observations.
Dark energy from gravitoelectromagnetic inflation?
Membiela, F. A.; Bellini, M.
2008-02-01
Gravitoectromagnetic Inflation (GI) was introduced to describe in an unified manner, electromagnetic, gravitatory and inflaton fields from a 5D vacuum state. On the other hand, the primordial origin and evolution of dark energy is today unknown. In this letter we show using GI that the zero modes of some redefined vector fields $B_i=A_i/a$ produced during inflation, could be the source of dark energy in the universe.
Some problems with extended inflation
International Nuclear Information System (INIS)
Weinberg, E.J.
1989-01-01
The recently proposed extended inflation scenario is examined. Upper bounds on the Brans-Dicke parameter ω are obtained by requiring that the recovery from the supercooled regime be such that the presently observed Universe could have emerged. These bounds are well below the present-day experimental limits, implying that one must use models which have a potential to fix the present value of the Brans-Dicke-like scalar field. The implications for extended inflation in such models are discussed
Dark Energy and Inflation from Gravitational Waves
Directory of Open Access Journals (Sweden)
Leonid Marochnik
2017-10-01
Full Text Available In this seven-part paper, we show that gravitational waves (classical and quantum produce the accelerated de Sitter expansion at the start and at the end of the cosmological evolution of the Universe. In these periods, the Universe contains no matter fields but contains classical and quantum metric fluctuations, i.e., it is filled with classical and quantum gravitational waves. In such evolution of the Universe, dominated by gravitational waves, the de Sitter state is the exact solution to the self-consistent equations for classical and quantum gravitational waves and background geometry for the empty space-time with FLRW metric. In both classical and quantum cases, this solution is of the instanton origin since it is obtained in the Euclidean space of imaginary time with the subsequent analytic continuation to real time. The cosmological acceleration from gravitational waves provides a transparent physical explanation to the coincidence, threshold and “old cosmological constant” paradoxes of dark energy avoiding recourse to the anthropic principle. The cosmological acceleration from virtual gravitons at the start of the Universe evolution produces inflation, which is consistent with the observational data on CMB anisotropy. Section 1 is devoted to cosmological acceleration from classical gravitational waves. Section 2 is devoted to the theory of virtual gravitons in the Universe. Section 3 is devoted to cosmological acceleration from virtual gravitons. Section 4 discusses the consistency of the theory with observational data on dark energy and inflation. The discussion of mechanism of acceleration and cosmological scenario are contained in Sections 5 and 6. Appendix contains the theory of stochastic nonlinear gravitational waves of arbitrary wavelength and amplitude in an isotropic Universe.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
In this paper, the stochastic flow of mappings generated by a Feller convolution semigroup on a compact metric space is studied. This kind of flow is the generalization of superprocesses of stochastic flows and stochastic diffeomorphism induced by the strong solutions of stochastic differential equations.
Stochastic Averaging and Stochastic Extremum Seeking
Liu, Shu-Jun
2012-01-01
Stochastic Averaging and Stochastic Extremum Seeking develops methods of mathematical analysis inspired by the interest in reverse engineering and analysis of bacterial convergence by chemotaxis and to apply similar stochastic optimization techniques in other environments. The first half of the text presents significant advances in stochastic averaging theory, necessitated by the fact that existing theorems are restricted to systems with linear growth, globally exponentially stable average models, vanishing stochastic perturbations, and prevent analysis over infinite time horizon. The second half of the text introduces stochastic extremum seeking algorithms for model-free optimization of systems in real time using stochastic perturbations for estimation of their gradients. Both gradient- and Newton-based algorithms are presented, offering the user the choice between the simplicity of implementation (gradient) and the ability to achieve a known, arbitrary convergence rate (Newton). The design of algorithms...
Accidental inflation from Kaehler uplifting
Energy Technology Data Exchange (ETDEWEB)
Ben-Dayan, Ido; Westphal, Alexander; Wieck, Clemens [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany). Theory Group; Jing, Shenglin [Toronto Univ., ON (Canada). Canadian Inst. for Theoretical Astrophysics; Toronto Univ., ON (Canada). Dept. of Astronomy and Astrophysics
2013-09-15
We analyze the possibility of realizing inflation with a subsequent dS vacuum in the Kaehler uplifting scenario. The inclusion of several quantum corrections to the 4d effective action evades previous no-go theorems and allows for construction of simple and successful models of string inflation. The predictions of several benchmark models are in accord with current observations, i.e., a red spectral index, negligible non-gaussianity, and spectral distortions similar to the simplest models of inflation. A particularly interesting subclass of models are ''left-rolling'' ones, where the overall volume of the compactified dimensions shrinks during inflation. We call this phenomenon ''inflation by deflation'' (IBD), where deflation refers to the internal manifold. This subclass has the appealing features of being insensitive to initial conditions, avoiding the overshooting problem, and allowing for observable running {alpha}<{proportional_to}0.012 and enhanced tensor-to-scalar ratio r{proportional_to}10{sup -5}. The latter results differ significantly from many string inflation models.
Staggered multi-field inflation
International Nuclear Information System (INIS)
Battefeld, Diana; Battefeld, Thorsten; Davis, Anne-Christine
2008-01-01
We investigate multi-field inflationary scenarios with fields that drop out of the model in a staggered fashion. This feature is natural in certain multi-field inflationary setups within string theory; for instance, it can manifest itself when fields are related to tachyons that condense, or inter-brane distances that become meaningless when branes annihilate. Considering a separable potential, and promoting the number of fields to a smooth time dependent function, we derive the formalism to deal with these models at the background and perturbed level, providing general expressions for the scalar spectral index and the running. We recover known results of e.g. a dynamically relaxing cosmological constant in the appropriate limits. We further show that isocurvature perturbations are suppressed during inflation, and so perturbations are adiabatic and nearly Gaussian. The resulting setup might be interpreted as a novel type of warm inflation, readily implemented within string theory and without many of the shortcomings associated with warm inflation. To exemplify the applicability of the formalism we consider three concrete models: assisted inflation with exponential potentials as a simple toy model (a graceful exit becomes possible), inflation from multiple tachyons (a constant decay rate of the number of fields and negligible slow roll contributions turns out to be in good agreement with observations) and inflation from multiple M5-branes within M-theory (a narrow stacking of branes yields a consistent scenario)
Inflated Grades, Enrollments & Budgets
Directory of Open Access Journals (Sweden)
J. E. Stone
1995-06-01
Full Text Available Reports of the past 13 years that call attention to deficient academic standards in American higher education are enumerated. Particular attention is given the Wingspread Group's recent An American Imperative: Higher Expectations for Higher Education. Low academic standards, grade inflation, and budgetary incentives for increased enrollment are analyzed and a call is made for research at the state level. Reported trends in achievement and GPAs are extrapolated to Tennessee and combined with local data to support the inference that 15% of the state's present day college graduates would not have earned a diploma by mid 1960s standards. A conspicuous lack of interest by public oversight bodies is noted despite a growing public awareness of low academic expectations and lenient grading and an implicit budgetary impact of over $100 million. Various academic policies and the dynamics of bureaucratic control are discussed in relationship to the maintenance of academic standards. The disincentives for challenging course requirements and responsible grading are examined, and the growing movement to address academic quality issues through better training and supervision of faculty are critiqued. Recommendations that would encourage renewed academic integrity and make learning outcomes visible to students, parents, employers, and the taxpaying public are offered and briefly discussed.
Energy Technology Data Exchange (ETDEWEB)
Hinterbichler, Kurt [CERCA, Department of Physics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106 (United States); Joyce, Austin [Center for Theoretical Physics, Department of Physics, Columbia University, New York, NY 10027 (United States); Khoury, Justin, E-mail: kurt.hinterbichler@case.edu, E-mail: austin.joyce@columbia.edu, E-mail: jkhoury@sas.upenn.edu [Center for Particle Cosmology, Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States)
2017-01-01
We investigate the symmetry structure of inflation in 2+1 dimensions. In particular, we show that the asymptotic symmetries of three-dimensional de Sitter space are in one-to-one correspondence with cosmological adiabatic modes for the curvature perturbation. In 2+1 dimensions, the asymptotic symmetry algebra is infinite-dimensional, given by two copies of the Virasoro algebra, and can be traced to the conformal symmetries of the two-dimensional spatial slices of de Sitter. We study the consequences of this infinite-dimensional symmetry for inflationary correlation functions, finding new soft theorems that hold only in 2+1 dimensions. Expanding the correlation functions as a power series in the soft momentum q , these relations constrain the traceless part of the tensorial coefficient at each order in q in terms of a lower-point function. As a check, we verify that the O( q {sup 2}) identity is satisfied by inflationary correlation functions in the limit of small sound speed.
Core inflation indicators for Saudi Arabia
Directory of Open Access Journals (Sweden)
Alkhareif Ryadh M.
2015-01-01
Full Text Available This paper constructs and analyzes core inflation indicators for Saudi Arabia for the period of March 2012 to May 2014 using two alternative approaches: the exclusion method (ex food and housing/rent and the statistical method. The findings of the analysis suggest that the ex food and housing/ rent inflation is more volatile than the overall CPI inflation over the sample period. In contrast, the statistical core inflation is relatively more stable and less volatile. Moreover, the ex food and housing/rent inflation is only weakly correlated with headline inflation, whereas the statistical core inflation exhibits a stronger correlation. This combination of lower volatility and higher correlation with headline inflation makes the statistical method a much better choice for policymakers. From a monetary policy standpoint, using a bundle of core inflation measures, including both properly constructed exclusion and statistical methods, is more desirable, especially when variation across measures is widespread, as is the case in Saudi Arabia.
Energy Technology Data Exchange (ETDEWEB)
Ferreira, Ricardo Z.; Notari, Alessio, E-mail: rferreira@icc.ub.edu, E-mail: notari@ub.edu [Departament de Física Quàntica i Astrofísica i Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona, Martí i Franquès, 1, E-08028, Barcelona (Spain)
2017-09-01
We analyze the dynamics of inflationary models with a coupling of the inflaton φ to gauge fields of the form φ F F-tilde / f , as in the case of axions. It is known that this leads to an instability, with exponential amplification of gauge fields, controlled by the parameter ξ= φ-dot /(2 fH ), which can strongly affect the generation of cosmological perturbations and even the background. We show that scattering rates involving gauge fields can become larger than the expansion rate H , due to the very large occupation numbers, and create a thermal bath of particles of temperature T during inflation. In the thermal regime, energy is transferred to smaller scales, radically modifying the predictions of this scenario. We thus argue that previous constraints on ξ are alleviated. If the gauge fields have Standard Model interactions, which naturally provides reheating, they thermalize already at ξ∼>2.9, before perturbativity constraints and also before backreaction takes place. In absence of SM interactions (i.e. for a dark photon), we find that gauge fields and inflaton perturbations thermalize if ξ∼>3.4; however, observations require ξ∼>6, which is above the perturbativity and backreaction bounds and so a dedicated study is required. After thermalization, though, the system should evolve non-trivially due to the competition between the instability and the gauge field thermal mass. If the thermal mass and the instabilities equilibrate, we expect an equilibrium temperature of T {sub eq} ≅ ξ H / g-bar where g-bar is the effective gauge coupling. Finally, we estimate the spectrum of perturbations if φ is thermal and find that the tensor to scalar ratio is suppressed by H /(2 T ), if tensors do not thermalize.
Upgrading inflatable door seals
International Nuclear Information System (INIS)
Sykes, T.M.; Metcalfe, R.; Welch, L.A.; Josefowich, J.M.
1997-01-01
Inflatable door seals are used for airlocks in CANDU stations. They have been a significant source of unreliability and maintenance cost. A program is underway to improve their performance and reliability, backed by environmental qualification testing. Only commercial products and suppliers existed in 1993. For historical reasons, these 'existing products' did not use the most durable material then available. In hindsight, neither had they been adapted nor optimized to combat conditions often experienced in the plants-sagging doors, damaged sealing surfaces, and many thousands of openings and closings per year. Initial attempts to involve the two existing suppliers in efforts to upgrade these seals were unsuccessful. Another suitable supplier had therefore to be found, and a 'new,' COG-owned seal developed; this was completed in 1997. This paper summarizes its testing, along with that of the two existing products. Resistance to aging has been improved significantly. Testing has shown that an accident can be safely withstood after 10 years of service or 40,000 openings-closings, whichever comes first. AECL's Fluid Sealing Technology Unit (FSTU) has invested in the special moulds, test fixtures and other necessary tooling and documentation required to begin commercial manufacture of this new quality product. Accordingly, as with FSTU's other nuclear products such as pump seals, the long-term supply of door seals to CANDU plants is now protected from many external uncertainties-e.g., commercial products being discontinued, materials being changed, companies going out of business. Manufacturing to AECL's detailed specifications is being subcontracted to the new supplier. FSTU is performing the quality surveillance, inspection, testing, and customer service activities concomitant with direct responsibility for supply to the plants. (author)
Ferreira, Ricardo Z.; Notari, Alessio
2017-09-01
We analyze the dynamics of inflationary models with a coupling of the inflaton phi to gauge fields of the form phi F tilde F/f, as in the case of axions. It is known that this leads to an instability, with exponential amplification of gauge fields, controlled by the parameter ξ= dot phi/(2fH), which can strongly affect the generation of cosmological perturbations and even the background. We show that scattering rates involving gauge fields can become larger than the expansion rate H, due to the very large occupation numbers, and create a thermal bath of particles of temperature T during inflation. In the thermal regime, energy is transferred to smaller scales, radically modifying the predictions of this scenario. We thus argue that previous constraints on ξ are alleviated. If the gauge fields have Standard Model interactions, which naturally provides reheating, they thermalize already at ξgtrsim2.9, before perturbativity constraints and also before backreaction takes place. In absence of SM interactions (i.e. for a dark photon), we find that gauge fields and inflaton perturbations thermalize if ξgtrsim3.4 however, observations require ξgtrsim6, which is above the perturbativity and backreaction bounds and so a dedicated study is required. After thermalization, though, the system should evolve non-trivially due to the competition between the instability and the gauge field thermal mass. If the thermal mass and the instabilities equilibrate, we expect an equilibrium temperature of Teq simeq ξ H/bar g where bar g is the effective gauge coupling. Finally, we estimate the spectrum of perturbations if phi is thermal and find that the tensor to scalar ratio is suppressed by H/(2T), if tensors do not thermalize.
Alchemical inflation: inflaton turns into Higgs
Nakayama, Kazunori; Takahashi, Fuminobu
2012-11-01
We propose a new inflation model in which a gauge singlet inflaton turns into the Higgs condensate after inflation. The inflationary path is characterized by a moduli space of supersymmetric vacua spanned by the inflaton and Higgs field. The inflation energy scale is related to the soft supersymmetry breaking, and the Hubble parameter during inflation is smaller than the gravitino mass. The initial condition for the successful inflation is naturally realized by the pre-inflation in which the Higgs plays a role of the waterfall field.
Alchemical inflation: inflaton turns into Higgs
International Nuclear Information System (INIS)
Nakayama, Kazunori; Takahashi, Fuminobu
2012-01-01
We propose a new inflation model in which a gauge singlet inflaton turns into the Higgs condensate after inflation. The inflationary path is characterized by a moduli space of supersymmetric vacua spanned by the inflaton and Higgs field. The inflation energy scale is related to the soft supersymmetry breaking, and the Hubble parameter during inflation is smaller than the gravitino mass. The initial condition for the successful inflation is naturally realized by the pre-inflation in which the Higgs plays a role of the waterfall field
The scale of inflation in the landscape
International Nuclear Information System (INIS)
Pedro, F.G.; Westphal, A.
2013-03-01
We determine the frequency of regions of small-field inflation in the Wigner landscape as an approximation to random supergravities/type IIB flux compactifications. We show that small-field inflation occurs exponentially more often than large-field inflation The power of primordial gravitational waves from inflation is generically tied to the scale of inflation. For small-field models this is below observational reach. However, we find small-field inflation to be dominated by the highest inflationary energy scales compatible with a sub-Planckian field range. Hence, we expect a typical tensor-to-scalar ratio r∝O(10 -3 ) currently undetectable in upcoming CMB measurements.
Project Evaluation under Inflation Condition
International Nuclear Information System (INIS)
Hindy, M.; El Missiry, P.
2004-01-01
This paper analyzes the role of inflation in capital budgeting and attempts to introduce solutions to such implication in order to make the appropriate decision for the firm' stockholders under these circumstances. Inflation leads to biasness in evaluating the investment projects, due to its impact on the cash flow, the discount rate, the initial investment cost, and the depreciation. This paper has shown that the capital budgeting process is not neutral with respect to inflation, as the output prices will raise as well as the operating and capital expenditures will also be adjusted due to inflation. In addition, it has shown that it is reasonable to expect that the cost of capital will increase as a result of an increase in the real interest rate, the inflation premium, and the cost of equity. Of critical importance is the basis used in calculating the annual depreciation which may lead to the transfer of wealth from the investment projects to the government and will result in underestimating the net present value of the investment projects, if these depreciation charges is calculated based upon the historical values and not on the replacement cost of the fixed assets
Inflation in a closed universe
Ratra, Bharat
2017-11-01
To derive a power spectrum for energy density inhomogeneities in a closed universe, we study a spatially-closed inflation-modified hot big bang model whose evolutionary history is divided into three epochs: an early slowly-rolling scalar field inflation epoch and the usual radiation and nonrelativistic matter epochs. (For our purposes it is not necessary to consider a final dark energy dominated epoch.) We derive general solutions of the relativistic linear perturbation equations in each epoch. The constants of integration in the inflation epoch solutions are determined from de Sitter invariant quantum-mechanical initial conditions in the Lorentzian section of the inflating closed de Sitter space derived from Hawking's prescription that the quantum state of the universe only include field configurations that are regular on the Euclidean (de Sitter) sphere section. The constants of integration in the radiation and matter epoch solutions are determined from joining conditions derived by requiring that the linear perturbation equations remain nonsingular at the transitions between epochs. The matter epoch power spectrum of gauge-invariant energy density inhomogeneities is not a power law, and depends on spatial wave number in the way expected for a generalization to the closed model of the standard flat-space scale-invariant power spectrum. The power spectrum we derive appears to differ from a number of other closed inflation model power spectra derived assuming different (presumably non de Sitter invariant) initial conditions.
International Nuclear Information System (INIS)
Wellens, Thomas; Shatokhin, Vyacheslav; Buchleitner, Andreas
2004-01-01
We are taught by conventional wisdom that the transmission and detection of signals is hindered by noise. However, during the last two decades, the paradigm of stochastic resonance (SR) proved this assertion wrong: indeed, addition of the appropriate amount of noise can boost a signal and hence facilitate its detection in a noisy environment. Due to its simplicity and robustness, SR has been implemented by mother nature on almost every scale, thus attracting interdisciplinary interest from physicists, geologists, engineers, biologists and medical doctors, who nowadays use it as an instrument for their specific purposes. At the present time, there exist a lot of diversified models of SR. Taking into account the progress achieved in both theoretical understanding and practical application of this phenomenon, we put the focus of the present review not on discussing in depth technical details of different models and approaches but rather on presenting a general and clear physical picture of SR on a pedagogical level. Particular emphasis will be given to the implementation of SR in generic quantum systems-an issue that has received limited attention in earlier review papers on the topic. The major part of our presentation relies on the two-state model of SR (or on simple variants thereof), which is general enough to exhibit the main features of SR and, in fact, covers many (if not most) of the examples of SR published so far. In order to highlight the diversity of the two-state model, we shall discuss several examples from such different fields as condensed matter, nonlinear and quantum optics and biophysics. Finally, we also discuss some situations that go beyond the generic SR scenario but are still characterized by a constructive role of noise
Gravitational wave background from reheating after hybrid inflation
International Nuclear Information System (INIS)
Garcia-Bellido, Juan; Figueroa, Daniel G.; Sastre, Alfonso
2008-01-01
The reheating of the Universe after hybrid inflation proceeds through the nucleation and subsequent collision of large concentrations of energy density in the form of bubblelike structures moving at relativistic speeds. This generates a significant fraction of energy in the form of a stochastic background of gravitational waves, whose time evolution is determined by the successive stages of reheating: First, tachyonic preheating makes the amplitude of gravity waves grow exponentially fast. Second, bubble collisions add a new burst of gravitational radiation. Third, turbulent motions finally sets the end of gravitational waves production. From then on, these waves propagate unimpeded to us. We find that the fraction of energy density today in these primordial gravitational waves could be significant for grand unified theory (GUT)-scale models of inflation, although well beyond the frequency range sensitivity of gravitational wave observatories like LIGO, LISA, or BBO. However, low-scale models could still produce a detectable signal at frequencies accessible to BBO or DECIGO. For comparison, we have also computed the analogous gravitational wave background from some chaotic inflation models and obtained results similar to those found by other groups. The discovery of such a background would open a new observational window into the very early universe, where the details of the process of reheating, i.e. the big bang, could be explored. Moreover, it could also serve in the future as a new experimental tool for testing the inflationary paradigm
Inflation with a graceful exit in a random landscape
Energy Technology Data Exchange (ETDEWEB)
Pedro, F.G. [Departamento de Física Teórica and Instituto de Física Teórica UAM/CSIC,Universidad Autónoma de Madrid,Cantoblanco, 28049 Madrid (Spain); Westphal, A. [Deutsches Elektronen-Synchrotron DESY, Theory Group,D-22603 Hamburg (Germany)
2017-03-30
We develop a stochastic description of small-field inflationary histories with a graceful exit in a random potential whose Hessian is a Gaussian random matrix as a model of the unstructured part of the string landscape. The dynamical evolution in such a random potential from a small-field inflation region towards a viable late-time de Sitter (dS) minimum maps to the dynamics of Dyson Brownian motion describing the relaxation of non-equilibrium eigenvalue spectra in random matrix theory. We analytically compute the relaxation probability in a saddle point approximation of the partition function of the eigenvalue distribution of the Wigner ensemble describing the mass matrices of the critical points. When applied to small-field inflation in the landscape, this leads to an exponentially strong bias against small-field ranges and an upper bound N≪10 on the number of light fields N participating during inflation from the non-observation of negative spatial curvature.
Dark energy in hybrid inflation
International Nuclear Information System (INIS)
Gong, Jinn-Ouk; Kim, Seongcheol
2007-01-01
The situation that a scalar field provides the source of the accelerated expansion of the Universe while rolling down its potential is common in both the simple models of the primordial inflation and the quintessence-based dark energy models. Motivated by this point, we address the possibility of causing the current acceleration via the primordial inflation using a simple model based on hybrid inflation. We trigger the onset of the motion of the quintessence field via the waterfall field, and find that the fate of the Universe depends on the true vacuum energy determined by choosing the parameters. We also briefly discuss the variation of the equation of state and the possible implementation of our scenario in supersymmetric theories
Chameleon field dynamics during inflation
Saba, Nasim; Farhoudi, Mehrdad
By studying the chameleon model during inflation, we investigate whether it can be a successful inflationary model, wherein we employ the common typical potential usually used in the literature. Thus, in the context of the slow-roll approximations, we obtain the e-folding number for the model to verify the ability of resolving the problems of standard big bang cosmology. Meanwhile, we apply the constraints on the form of the chosen potential and also on the equation of state parameter coupled to the scalar field. However, the results of the present analysis show that there is not much chance of having the chameleonic inflation. Hence, we suggest that if through some mechanism the chameleon model can be reduced to the standard inflationary model, then it may cover the whole era of the universe from the inflation up to the late time.
Energy Technology Data Exchange (ETDEWEB)
Barbón, J.L.F.; Casas, J.A. [IFT-UAM/CSIC, Universidad Autónoma de Madrid,C/Nicolás Cabrera 13, 28049 Madrid (Spain); Elias-Miró, J. [Departament de Física/IFAE, Universitat Autònoma de Barcelona,Edifici Cn, 08193 Bellaterra, Barcelona (Spain); Espinosa, J.R. [ICREA/IFAE, Universitat Autònoma de Barcelona,Edifici Cn, 08193 Bellaterra, Barcelona (Spain)
2015-09-04
We discuss a simple unitarization of Higgs inflation that is genuinely weakly coupled up to Planckian energies. A large non-minimal coupling between the Higgs and the Ricci curvature is induced dynamically at intermediate energies, as a simple ratio of mass scales. Despite not being dominated by the Higgs field, inflationary dynamics simulates the ‘Higgs inflation’ one would get by blind extrapolation of the low-energy effective Lagrangian, at least qualitatively. Hence, Higgs inflation arises as an approximate ‘mirage’ picture of the true dynamics. We further speculate on the generality of this phenomenon and show that, if Higgs-inflation arises as an effective description, the details of the UV completion are necessary to extract robust quantitative predictions.
Inflation in random Gaussian landscapes
Energy Technology Data Exchange (ETDEWEB)
Masoumi, Ali; Vilenkin, Alexander; Yamada, Masaki, E-mail: ali@cosmos.phy.tufts.edu, E-mail: vilenkin@cosmos.phy.tufts.edu, E-mail: Masaki.Yamada@tufts.edu [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States)
2017-05-01
We develop analytic and numerical techniques for studying the statistics of slow-roll inflation in random Gaussian landscapes. As an illustration of these techniques, we analyze small-field inflation in a one-dimensional landscape. We calculate the probability distributions for the maximal number of e-folds and for the spectral index of density fluctuations n {sub s} and its running α {sub s} . These distributions have a universal form, insensitive to the correlation function of the Gaussian ensemble. We outline possible extensions of our methods to a large number of fields and to models of large-field inflation. These methods do not suffer from potential inconsistencies inherent in the Brownian motion technique, which has been used in most of the earlier treatments.
Individual differences in imagination inflation.
Heaps, C; Nash, M
1999-06-01
Garry, Manning, Loftus, and Sherman (1996) found that when adult subjects imagined childhood events, these events were subsequentlyjudged as more likely to have occurred than were not-imagined events. The authors termed this effect imagination inflation. We replicated the effect, using a novel set of Life Events Inventory events. Further, we tested whether the effect is related to four subject characteristics possibly associated with false memory creation. The extent to which subjects inflated judged likelihood following imagined events was associated with indices of hypnotic suggestibility and dissociativity, but not with vividness of imagery or interrogative suggestibility. Results suggest that imagination plays a role in subsequent likelihood judgments regarding childhood events, and that some individuals are more likely than others to experience imagination inflation.
Lin, Chia-Min; Cheung, Kingman
Following Ref. 10, we explore the parameter space of the case when the supersymmetry (SUSY) breaking scale is lower, for example, in gauge mediated SUSY breaking model. During inflation, the form of the potential is V0 plus MSSM (or A-term) inflation. We show that the model works for a wide range of the potential V0 with the soft SUSY breaking mass m O(1) TeV. The implication to MSSM (or A-term) inflation is that the flat directions which is lifted by the non-renormalizable terms described by the superpotential W=λ p φ p-1/Mp-3 P with p = 4 and p = 5 are also suitable to be an inflaton field for λp = O(1) provided there is an additional false vacuum term V0 with appropriate magnitude. The flat directions correspond to p = 6 also works for 0 < ˜ V0/M_ P4 < ˜ 10-40.
Partially massless fields during inflation
Baumann, Daniel; Goon, Garrett; Lee, Hayden; Pimentel, Guilherme L.
2018-04-01
The representation theory of de Sitter space allows for a category of partially massless particles which have no flat space analog, but could have existed during inflation. We study the couplings of these exotic particles to inflationary perturbations and determine the resulting signatures in cosmological correlators. When inflationary perturbations interact through the exchange of these fields, their correlation functions inherit scalings that cannot be mimicked by extra massive fields. We discuss in detail the squeezed limit of the tensor-scalar-scalar bispectrum, and show that certain partially massless fields can violate the tensor consistency relation of single-field inflation. We also consider the collapsed limit of the scalar trispectrum, and find that the exchange of partially massless fields enhances its magnitude, while giving no contribution to the scalar bispectrum. These characteristic signatures provide clean detection channels for partially massless fields during inflation.
Inflatable Antennas Support Emergency Communication
2010-01-01
Glenn Research Center awarded Small Business Innovation Research (SBIR) contracts to ManTech SRS Technologies, of Newport Beach, California, to develop thin film inflatable antennas for space communication. With additional funding, SRS modified the concepts for ground-based inflatable antennas. GATR (Ground Antenna Transmit and Receive) Technologies, of Huntsville, Alabama, licensed the technology and refined it to become the world s first inflatable antenna certified by the Federal Communications Commission. Capable of providing Internet access, voice over Internet protocol, e-mail, video teleconferencing, broadcast television, and other high-bandwidth communications, the systems have provided communication during the wildfires in California, after Hurricane Katrina in Mississippi, and following the 2010 Haiti earthquake.
International Nuclear Information System (INIS)
Barbón, J.L.F.; Casas, J.A.; Elias-Miró, J.; Espinosa, J.R.
2015-01-01
We discuss a simple unitarization of Higgs inflation that is genuinely weakly coupled up to Planckian energies. A large non-minimal coupling between the Higgs and the Ricci curvature is induced dynamically at intermediate energies, as a simple ratio of mass scales. Despite not being dominated by the Higgs field, inflationary dynamics simulates the ‘Higgs inflation’ one would get by blind extrapolation of the low-energy effective Lagrangian, at least qualitatively. Hence, Higgs inflation arises as an approximate ‘mirage’ picture of the true dynamics. We further speculate on the generality of this phenomenon and show that, if Higgs-inflation arises as an effective description, the details of the UV completion are necessary to extract robust quantitative predictions.
INFLATION TARGETING IN EASTERN EUROPE
Directory of Open Access Journals (Sweden)
Laurian Lungu
2006-05-01
Full Text Available This paper addresses the inflation targeting approach in three transition economies, namely Hungary, Poland and the Czech Republic with the use of Taylor rules as benchmarks. The three economies considered have been successful at achieving disinflation, but deviations of inflation from its target have been persistent in all cases. Except for the Czech Republic, deviations from the Taylor rule are large and persistent, with Hungary displaying the largest fluctuations. Polish interest rates have consistently exceeded those suggested by the Taylor rule and given the prevalence of high unemployment, these undershootings do not augur well for the stability of monetary policy. Finally, the behaviour of Czech interest rates can be remarkably captured by the simple Taylor rule proposed in this paper, suggesting that the Czech National Bank has been the most successful at stabilising inflation and output around their target levels.
Scalar-tensor linear inflation
Energy Technology Data Exchange (ETDEWEB)
Artymowski, Michał [Institute of Physics, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków (Poland); Racioppi, Antonio, E-mail: Michal.Artymowski@uj.edu.pl, E-mail: Antonio.Racioppi@kbfi.ee [National Institute of Chemical Physics and Biophysics, Rävala 10, 10143 Tallinn (Estonia)
2017-04-01
We investigate two approaches to non-minimally coupled gravity theories which present linear inflation as attractor solution: a) the scalar-tensor theory approach, where we look for a scalar-tensor theory that would restore results of linear inflation in the strong coupling limit for a non-minimal coupling to gravity of the form of f (φ) R /2; b) the particle physics approach, where we motivate the form of the Jordan frame potential by loop corrections to the inflaton field. In both cases the Jordan frame potentials are modifications of the induced gravity inflationary scenario, but instead of the Starobinsky attractor they lead to linear inflation in the strong coupling limit.
Simple types of anisotropic inflation
International Nuclear Information System (INIS)
Barrow, John D.; Hervik, Sigbjoern
2010-01-01
We display some simple cosmological solutions of gravity theories with quadratic Ricci curvature terms added to the Einstein-Hilbert Lagrangian which exhibit anisotropic inflation. The Hubble expansion rates are constant and unequal in three orthogonal directions. We describe the evolution of the simplest of these homogeneous and anisotropic cosmological models from its natural initial state and evaluate the deviations they will create from statistical isotropy in the fluctuations produced during a period of anisotropic inflation. The anisotropic inflation is not a late-time attractor in these models but the rate of approach to a final isotropic de Sitter state is slow and is conducive to the creation of observable anisotropic statistical effects in the microwave background. The statistical anisotropy would not be scale invariant and the level of statistical anisotropy will grow with scale.
Stochastic background of gravitational waves from hybrid preheating.
García-Bellido, Juan; Figueroa, Daniel G
2007-02-09
The process of reheating the Universe after hybrid inflation is extremely violent. It proceeds through the nucleation and subsequent collision of large concentrations of energy density in bubblelike structures, which generate a significant fraction of energy in the form of gravitational waves. We study the power spectrum of the stochastic background of gravitational waves produced at reheating after hybrid inflation. We find that the amplitude could be significant for high-scale models, although the typical frequencies are well beyond what could be reached by planned gravitational wave observatories. On the other hand, low-scale models could still produce a detectable stochastic background at frequencies accessible to those detectors. The discovery of such a background would open a new window into the very early Universe.
Inflation with light Weyl ghost
Directory of Open Access Journals (Sweden)
Tokareva Anna
2016-01-01
Full Text Available Inflationary perturbations are considered in a renormalizable but non-unitary theory of gravity with the additional Weyl term. We obtained that ghost degrees of freedom do not spoil the inflation and the scalar perturbation amplitude at the linear level even in a case of the ghost with mass smaller than Hubble parameter at inflation. The ghost impact to the observables is also estimated to be negligible for the range of masses allowed by the experiment. The non-linear level of the theory and its possible application are also discussed.
International Nuclear Information System (INIS)
Ellis, J.; Enqvist, K.; Nanopoulos, D.V.; Olive, K.A.; Srednicki, M.
1985-01-01
We present a simple model for primordial inflation in the context of SU(N, 1) no-scale n=1 supergravity. Because the model at zero temperature very closely resembles global supersymmetry, minima with negative cosmological constants do not exist, and it is easy to have a long inflationary epoch while keeping density perturbations of the right magnitude and satisfying other cosmological constraints. We pay specific attention to satisfying the thermal constraint for inflation, i.e. the existence of a high temperature minimum at the origin. (orig.)
QED vacuum loops and inflation
Energy Technology Data Exchange (ETDEWEB)
Fried, H.M. [Brown University, Department of Physics, Providence, RI (United States); Gabellini, Y. [UMR 6618 CNRS, Institut Non Lineaire de Nice, Valbonne (France)
2015-03-01
A QED-based model of a new version of vacuum energy has recently been suggested, which leads to a simple, finite, one parameter representation of dark energy. An elementary, obvious, but perhaps radical generalization is then able to describe both dark energy and inflation in the same framework of vacuum energy. One further, obvious generalization then leads to a relation between inflation and the big bang, to the automatic inclusion of dark matter, and to a possible understanding of the birth (and death) of a universe. (orig.)
QED vacuum loops and inflation
International Nuclear Information System (INIS)
Fried, H.M.; Gabellini, Y.
2015-01-01
A QED-based model of a new version of vacuum energy has recently been suggested, which leads to a simple, finite, one parameter representation of dark energy. An elementary, obvious, but perhaps radical generalization is then able to describe both dark energy and inflation in the same framework of vacuum energy. One further, obvious generalization then leads to a relation between inflation and the big bang, to the automatic inclusion of dark matter, and to a possible understanding of the birth (and death) of a universe. (orig.)
Hinson, W. F.; Keafer, L. S.
1984-01-01
It is proposed that for inflatable antenna systems, technology feasibility can be demonstrated and parametric design and scalability (scale factor 10 to 20) can be validated with an experiment using a 16-m-diameter antenna attached to the Shuttle. The antenna configuration consists of a thin film cone and paraboloid held to proper shape by internal pressure and a self-rigidizing torus. The cone and paraboloid would be made using pie-shaped gores with the paraboloid being coated with aluminum to provide reflectivity. The torus would be constructed using an aluminum polyester composite that when inflated would erect to a smooth shell that can withstand loads without internal pressure.
Eternal inflation and a thermodynamic treatment of Einstein's equations
Energy Technology Data Exchange (ETDEWEB)
Ghersi, José Tomás Gálvez [Facultad de Ciencias, Universidad Nacional de Ingeniería, Lima, Perú (Peru); Geshnizjani, Ghazal; Shandera, Sarah [Perimeter Institute for Theoretical Physics, Waterloo, Ontario (Canada); Piazza, Federico, E-mail: jotogalgher@gmail.com, E-mail: ggeshnizjani@perimeterinstitute.ca, E-mail: fpiazza@apc.univ-paris7.fr, E-mail: sshandera@perimeterinstitute.ca [PCCP and APC, CNRS (UMR7164), Université Denis Diderot Paris 7, Batiment Condorcet, 10 rue Alice Domon et Léonie Duquet, 75205 Paris (France)
2011-06-01
In pursuing the intriguing resemblance of the Einstein equations to thermodynamic equations, most sharply seen in systems possessing horizons, we suggest that eternal inflation of the stochastic type may be a fruitful phenomenon to explore. We develop a thermodynamic first law for quasi-de Sitter space, valid on the horizon of a single observer's Hubble patch and explore consistancy with previous proposals for horizons of various types in dynamic and static situations. We use this framework to demonstrate that for the local observer fluctuations of the type necessary for stochastic eternal inflation fall within the regime where the thermodynamic approach is believed to apply. This scenario is interesting because of suggestive parallels with black hole evaporation.
Anisotropic inflation from charged scalar fields
International Nuclear Information System (INIS)
Emami, Razieh; Firouzjahi, Hassan; Movahed, S.M. Sadegh; Zarei, Moslem
2011-01-01
We consider models of inflation with U(1) gauge fields and charged scalar fields including symmetry breaking potential, chaotic inflation and hybrid inflation. We show that there exist attractor solutions where the anisotropies produced during inflation becomes comparable to the slow-roll parameters. In the models where the inflaton field is a charged scalar field the gauge field becomes highly oscillatory at the end of inflation ending inflation quickly. Furthermore, in charged hybrid inflation the onset of waterfall phase transition at the end of inflation is affected significantly by the evolution of the background gauge field. Rapid oscillations of the gauge field and its coupling to inflaton can have interesting effects on preheating and non-Gaussianities
Ten years of inflation targeting in Serbia
Directory of Open Access Journals (Sweden)
Bungin Sanja
2017-01-01
Full Text Available Monetary strategy of inflation targeting in Serbia was unofficially introduced in September 2006. The National Bank of Serbia has faced the numerous challenges that are typical for transition countries which apply the same strategy. At the start of inflation targeting, inflation was reduced to a single-digit number, which characterises most other countries. However, the volatility of inflation during the implementation of the strategy has been extremely high, mainly caused by the changes of processed and unprocessed food prices. Moreover, for a country with a high degree of euroisation, such as Serbia, the exchange rate plays an important role in the movement of inflation. Controlling the trends of the exchange rate in order to maintain the stability of inflation is contrary to the assumptions of inflation targeting. However, it can be concluded that despite all the obstacles faced by the NBS, inflation targeting is the optimal choice of a monetary strategy.
Inflation and the theory of cosmological perturbations
International Nuclear Information System (INIS)
Riotto, A.
2003-01-01
These lectures provide a pedagogical introduction to inflation and the theory of cosmological perturbations generated during inflation which are thought to be the origin of structure in the universe. (author)
Air Tight: Building Inflatables/Inflatable Construction: Planning and Details
Kennedy, Kriss J.
2016-01-01
A design-build seminar consisting of students from Physics, Mechanical and Civil Engineering, Robotic, Material Science, Art, and Architecture who will work together on a deployable "closed-loop" inflatable greenhouse for Mars in theory, and an Earth analogue physical mockup on campus.
What is the Globalisation of Inflation?
Altansukh, Gantungalag; Becker, Ralf; Bratsiotis, George J.; Osborn, Denise R.
2017-01-01
This paper studies the globalisation of CPI inflation by analysing core, energy and food components, testing for structural breaks in the relationships between domestic inflation and a corresponding country-specific foreign inflation series at the monthly frequency for OECD countries.The iterative methodology employed separates coefficient and variance breaks, while also taking account of outliers. We find that the overall pattern of globalisation in aggregate inflation is largely driven by c...
Optimal Investment-Consumption Strategy under Inflation in a Markovian Regime-Switching Market
Directory of Open Access Journals (Sweden)
Huiling Wu
2016-01-01
Full Text Available This paper studies an investment-consumption problem under inflation. The consumption price level, the prices of the available assets, and the coefficient of the power utility are assumed to be sensitive to the states of underlying economy modulated by a continuous-time Markovian chain. The definition of admissible strategies and the verification theory corresponding to this stochastic control problem are presented. The analytical expression of the optimal investment strategy is derived. The existence, boundedness, and feasibility of the optimal consumption are proven. Finally, we analyze in detail by mathematical and numerical analysis how the risk aversion, the correlation coefficient between the inflation and the stock price, the inflation parameters, and the coefficient of utility affect the optimal investment and consumption strategy.
Stochastic tools in turbulence
Lumey, John L
2012-01-01
Stochastic Tools in Turbulence discusses the available mathematical tools to describe stochastic vector fields to solve problems related to these fields. The book deals with the needs of turbulence in relation to stochastic vector fields, particularly, on three-dimensional aspects, linear problems, and stochastic model building. The text describes probability distributions and densities, including Lebesgue integration, conditional probabilities, conditional expectations, statistical independence, lack of correlation. The book also explains the significance of the moments, the properties of the
Inflation and Failure of Polymeric Membranes
DEFF Research Database (Denmark)
Hassager, Ole; Neergaard, Jesper
2000-01-01
We consider the inflation of an axisymmetric polymeric membrane.Some membranes composed of viscoelastic materialsdescribed by a Mooney-Rivlin model show a monotone increasingpressure during inflation. These materialsdevelop a homogeneous membrane thickness in agreement with the Considere...... is found to stabilize the inflated polymer membrane....
12 CFR 1780.80 - Inflation adjustments.
2010-01-01
... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Inflation adjustments. 1780.80 Section 1780.80... DEVELOPMENT RULES OF PRACTICE AND PROCEDURE RULES OF PRACTICE AND PROCEDURE Civil Money Penalty Inflation Adjustments § 1780.80 Inflation adjustments. The maximum amount of each civil money penalty within OFHEO's...
Does Education Corrupt? Theories of Grade Inflation
Oleinik, Anton
2009-01-01
Several theories of grade inflation are discussed in this review article. It is argued that grade inflation results from the substitution of criteria specific to the search for truth by criteria of quality control generated outside of academia. Particular mechanisms of the grade inflation that occurs when a university is transformed into a…
Inflation or unemployment? Who cares?
Van Lelyveld, Iman
In the last two decades a large number of game-theoretic models describing monetary policy have been used to examine the characteristics of policies over a wide range of 'rules of the game'. Regardless of the specification of the model, the degree of inflation aversion - relative to unemployment -
Inflation as de Sitter instability
Energy Technology Data Exchange (ETDEWEB)
Cadoni, Mariano; Franzin, Edgardo [Universita di Cagliari, Cittadella Universitaria, Dipartimento di Fisica, Monserrato (Italy); INFN, Sezione di Cagliari, Monserrato (Italy); Mignemi, Salvatore [INFN, Sezione di Cagliari, Monserrato (Italy); Universita di Cagliari, Dipartimento di Matematica e Informatica, Cagliari (Italy)
2016-09-15
We consider cosmological inflation generated by a scalar field slowly rolling off from a de Sitter maximum of its potential. The models belong to the class of hilltop models and represent the most general model of this kind in which the scalar potential can be written as the sum of two exponentials. The minimally coupled Einstein-scalar gravity theory obtained in this way is the cosmological version of a two-scale generalization of known holographic models, allowing for solitonic solutions interpolating between an AdS spacetime in the infrared and scaling solutions in the ultraviolet. We then investigate cosmological inflation in the slow-roll approximation. Our model reproduces correctly, for a wide range of its parameters, the most recent experimental data for the power spectrum of primordial perturbations. Moreover, it predicts inflation at energy scales of four to five orders of magnitude below the Planck scale. At the onset of inflation, the mass of the tachyonic excitation, i.e. of the inflaton, turns out to be seven to eight orders of magnitude smaller than the Planck mass. (orig.)
Davis Meeting on Cosmic Inflation
Kaloper, N; Knox, L; Cosmic Inflation
2003-01-01
The Davis Meeting on Cosmic Inflation marked an exciting milestone on the road to precision cosmology. This is the index page for the proceedings of the conference. Individual proceedings contributions, when they appear on this archive, are linked from this page.
How are inflation targets set?
Czech Academy of Sciences Publication Activity Database
Horváth, R.; Matějů, Jakub
-, č. 426 (2010), s. 1-35 ISSN 1211-3298 Grant - others:MŠk(CZ) SVV-2010-261801 Institutional research plan: CEZ:MSM0021620846 Keywords : inflation targeting * central bank * credibility Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp426.pdf
Inflation,Inflation Variability, and Output Performance. Venezuela 1951-2002
Olivo, Victor
2014-01-01
This paper explores the relationship between the level of inflation, inflation variability, and output performance in the Venezuelan economy for the period 1951-2002. The paper examines the mechanism through which higher inflation translates into lower non-oil real GDP growth. We find empirical evidence that supports Friedman's (1977) contention that higher inflation produces more inflation volatility /uncertainty that leads to relative price variability that in turn, is harmful for the prope...
Estimating core inflation : the role of oil price shocks and imported inflation
Bjørnland, Hilde Christiane
1997-01-01
This paper calculates core inflation, by imposing long run restrictions on a structural vector autoregression (VAR) model containing the growth rate of output, inflation and oil prices. Core inflation is identified as that component in inflation that has no long run effect on output. No restrictions are placed on the response of output and inflation to the oil price shocks. The analysis is applied to Norway and the United Kingdom, both oil producing OECD countries. A model that ...
Recent Inflation of Kilauea Volcano
Miklius, A.; Poland, M.; Desmarais, E.; Sutton, A.; Orr, T.; Okubo, P.
2006-12-01
Over the last three years, geodetic monitoring networks and satellite radar interferometry have recorded substantial inflation of Kilauea's magma system, while the Pu`u `O`o eruption on the east rift zone has continued unabated. Combined with the approximate doubling of carbon dioxide emission rates at the summit during this period, these observations indicate that the magma supply rate to the volcano has increased. Since late 2003, the summit area has risen over 20 cm, and a 2.5 km-long GPS baseline across the summit area has extended almost half a meter. The center of inflation has been variable, with maximum uplift shifting from an area near the center of the caldera to the southeastern part of the caldera in 2004-2005. In 2006, the locus of inflation shifted again, to the location of the long-term magma reservoir in the southern part of the caldera - the same area that had subsided more than 1.5 meters during the last 23 years of the ongoing eruption. In addition, the southwest rift zone reversed its long-term trend of subsidence and began uplifting in early 2006. The east rift zone has shown slightly accelerated rates of extension, but with a year-long hiatus following the January 2005 south flank aseismic slip event. Inflation rates have varied greatly. Accelerated rates of extension and uplift in early 2005 and 2006 were also associated with increased seismicity. Seismicity occurred not only at inflation centers, but was also triggered on the normal faulting area northwest of the caldera and the strike-slip faulting area in the upper east rift zone. In early 2006, at about the time that we started recording uplift on the southwest rift zone, the rate of earthquakes extending from the summit into the southwest rift zone at least quadrupled. The most recent previous episode of inflation at Kilauea, in 2002, may have resulted from reduced lava- transport capacity, as it was associated with decreased outflow at the eruption site. In contrast, eruption volumes
Directory of Open Access Journals (Sweden)
Milošević M.
2016-01-01
Full Text Available The role tachyon fields may play in evolution of early universe is discussed in this paper. We consider the evolution of a flat and homogeneous universe governed by a tachyon scalar field with the DBI-type action and calculate the slow-roll parameters of inflation, scalar spectral index (n, and tensor-scalar ratio (r for the given potentials. We pay special attention to the inverse power potential, first of all to V (x ~ x−4, and compare the available results obtained by analytical and numerical methods with those obtained by observation. It is shown that the computed values of the observational parameters and the observed ones are in a good agreement for the high values of the constant X0. The possibility that influence of the radion field can extend a range of the acceptable values of the constant X0 to the string theory motivated sector of its values is briefly considered. [Projekat Ministarstva nauke Republike Srbije, br. 176021, br. 174020 i br. 43011
Curvaton and the inhomogeneous end of inflation
International Nuclear Information System (INIS)
Assadullahi, Hooshyar; Wands, David; Firouzjahi, Hassan; Namjoo, Mohammad Hossein
2012-01-01
We study the primordial density perturbations and non-Gaussianities generated from the combined effects of an inhomogeneous end of inflation and curvaton decay in hybrid inflation. This dual role is played by a single isocurvature field which is massless during inflation but acquire a mass at the end of inflation via the waterfall phase transition. We calculate the resulting primordial non-Gaussianity characterized by the non-linearity parameter, f NL , recovering the usual end-of-inflation result when the field decays promptly and the usual curvaton result if the field decays sufficiently late
A smooth exit from eternal inflation?
Hawking, S. W.; Hertog, Thomas
2018-04-01
The usual theory of inflation breaks down in eternal inflation. We derive a dual description of eternal inflation in terms of a deformed Euclidean CFT located at the threshold of eternal inflation. The partition function gives the amplitude of different geometries of the threshold surface in the no-boundary state. Its local and global behavior in dual toy models shows that the amplitude is low for surfaces which are not nearly conformal to the round three-sphere and essentially zero for surfaces with negative curvature. Based on this we conjecture that the exit from eternal inflation does not produce an infinite fractal-like multiverse, but is finite and reasonably smooth.
Pre-inflation physics and scalar perturbations
International Nuclear Information System (INIS)
Hirai, Shiro
2005-01-01
The effect of pre-inflation physics on the power spectrum of scalar perturbations is investigated. Considering various pre-inflation models with radiation-dominated or matter-dominated periods before inflation, the power spectra of curvature perturbations for large scales are calculated, and the spectral index and running spectral index are derived. It is shown that pre-inflation models in which the length of inflation is near 60 e-folds may reproduce some key properties implied by the Wilkinson microwave anisotropy probe data
Ogawa, Shigeyoshi
2017-01-01
This book presents an elementary introduction to the theory of noncausal stochastic calculus that arises as a natural alternative to the standard theory of stochastic calculus founded in 1944 by Professor Kiyoshi Itô. As is generally known, Itô Calculus is essentially based on the "hypothesis of causality", asking random functions to be adapted to a natural filtration generated by Brownian motion or more generally by square integrable martingale. The intention in this book is to establish a stochastic calculus that is free from this "hypothesis of causality". To be more precise, a noncausal theory of stochastic calculus is developed in this book, based on the noncausal integral introduced by the author in 1979. After studying basic properties of the noncausal stochastic integral, various concrete problems of noncausal nature are considered, mostly concerning stochastic functional equations such as SDE, SIE, SPDE, and others, to show not only the necessity of such theory of noncausal stochastic calculus but ...
Kähler-driven tribrid inflation
Antusch, Stefan; Nolde, David
2012-11-01
We discuss a new class of tribrid inflation models in supergravity, where the shape of the inflaton potential is dominated by effects from the Kähler potential. Tribrid inflation is a variant of hybrid inflation which is particularly suited for connecting inflation with particle physics, since the inflaton can be a D-flat combination of charged fields from the matter sector. In models of tribrid inflation studied so far, the inflaton potential was dominated by either loop corrections or by mixing effects with the waterfall field (as in "pseudosmooth" tribrid inflation). Here we investigate the third possibility, namely that tribrid inflation is dominantly driven by effects from higher-dimensional operators of the Kähler potential. We specify for which superpotential parameters the new regime is realized and show how it can be experimentally distinguished from the other two (loop-driven and "pseudosmooth") regimes.
Inflation, Reionization, and All That: The Primordial Inflation Explorer
Kogut, Alan J.
2012-01-01
The Primordial Inflation Explorer is an Explorer-class mission to measure the gravity-wave signature of primordial inflation through its distinctive imprint on the linear polarization of the cosmic microwave background. PIXIE uses an innovative optical design to achieve background-limited sensitivity in 400 spectral channels spanning 2.5 decades in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r < 10(exp -3) at 5 standard deviations. The rich PIXIE data set will also constrain physical processes ranging from Big Bang cosmology to the nature of the first stars to physical conditions within the interstellar medium of the Galaxy. I describe the PIXIE instrument and mission architecture needed to detect the inflationary signature using only 4 semiconductor bolometers.
Estimating the Threshold Level of Inflation for Thailand
Jiranyakul, Komain
2017-01-01
Abstract. This paper analyzes the relationship between inflation and economic growth in Thailand using annual dataset during 1990 and 2015. The threshold model is estimated for different levels of threshold inflation rate. The results suggest that the threshold level of inflation above which inflation significantly slow growth is estimated at 3 percent. The negative relationship between inflation and growth is apparent above this threshold level of inflation. In other words, the inflation rat...
Permutation on hybrid natural inflation
Carone, Christopher D.; Erlich, Joshua; Ramos, Raymundo; Sher, Marc
2014-09-01
We analyze a model of hybrid natural inflation based on the smallest non-Abelian discrete group S3. Leading invariant terms in the scalar potential have an accidental global symmetry that is spontaneously broken, providing a pseudo-Goldstone boson that is identified as the inflaton. The S3 symmetry restricts both the form of the inflaton potential and the couplings of the inflaton field to the waterfall fields responsible for the end of inflation. We identify viable points in the model parameter space. Although the power in tensor modes is small in most of the parameter space of the model, we identify parameter choices that yield potentially observable values of r without super-Planckian initial values of the inflaton field.
Hybrid inflation along waterfall trajectories
International Nuclear Information System (INIS)
Clesse, Sebastien
2011-01-01
We identify a new inflationary regime for which more than 60 e-folds are generated classically during the waterfall phase occurring after the usual hybrid inflation. By performing a Bayesian Monte-Carlo-Markov-Chain analysis, this scenario is shown to take place in a large part of the parameter space of the model. When this occurs, the observable perturbation modes leave the Hubble radius during waterfall inflation. The power spectrum of adiabatic perturbations is red, possibly in agreement with CMB constraints. Particular attention has been given to study only the regions for which quantum backreactions do not affect the classical dynamics. Implications concerning the preheating and the absence of topological defects in our Universe are discussed.
Ivanov, Mikhail M
2014-01-01
We present a setup that provides a partial UV-completion of the ghost inflation model up to a scale which can be almost as high as the Planck mass. This is achieved by coupling the inflaton to the Lorentz-violating sector described by the Einstein-aether theory or its khronometric version. Compared to previous works on ghost inflation our setup allows to go beyond the study of small perturbations and include the background dynamics in a unified framework. In the specific regime when the expansion of the Universe is dominated by the kinetic energy of the inflaton we find that the model predicts rather high tensor-to-scalar ratio r ~ 0.02 $\\div$ 0.2 and non-Gaussianity of equilateral type with f_NL in the range from -50 to -5.
Cybersecurity Risks: Are They Inflated?
Directory of Open Access Journals (Sweden)
Petr Chrapavy
2016-05-01
Full Text Available With various views being posed on cybersecurity, this paper examines the proposition that cybersecurity risks are inflated. Due to the complexity of the cybersecurity environment, the risks will be dichotomised into two distinct categories—those posed by cybercrime, and those classified as cyber-warfare. In relation to cyber-crime, the paper examines the rise of cyber-crime, its costs, and the views of these factors by “alarmists” and “sceptics.” In relation to cyber-war, the paper sets aside the emotive issue of the consequences and focuses on the likelihood of a catastrophic attack. The paper concludes that the risk of cyber-crime is real, but the sometimes mooted existential threat poses by cyber-war is inflated. The paper argues that it is important for cyber defences to improve in line with the risks, and to do this, researchers need to work across both categories of cybersecurity.
Inflation from periodic extra dimensions
Energy Technology Data Exchange (ETDEWEB)
Higaki, Tetsutaro [Department of Physics, Keio University, Kanagawa 223-8522 (Japan); Tatsuta, Yoshiyuki, E-mail: thigaki@rk.phys.keio.ac.jp, E-mail: y_tatsuta@akane.waseda.jp [Department of Physics, Waseda University, Tokyo 169-8555 (Japan)
2017-07-01
We discuss a realization of a small field inflation based on string inspired supergravities. In theories accompanying extra dimensions, compactification of them with small radii is required for realistic situations. Since the extra dimension can have a periodicity, there will appear (quasi-)periodic functions under transformations of moduli of the extra dimensions in low energy scales. Such a periodic property can lead to a UV completion of so-called multi-natural inflation model where inflaton potential consists of a sum of multiple sinusoidal functions with a decay constant smaller than the Planck scale. As an illustration, we construct a SUSY breaking model, and then show that such an inflaton potential can be generated by a sum of world sheet instantons in intersecting brane models on extra dimensions containing orbifold. We show also predictions of cosmic observables by numerical analyzes.
Inflation with generalized initial conditions
International Nuclear Information System (INIS)
Albrecht, A.; Brandenberger, R.; Matzner, R.
1987-01-01
In many current models of the early Universe a scalar field phi which is only very weakly coupled to other quantum fields is used to generate inflation. In such models there are no forces which could thermalize the scalar field, and previous assumptions about its preinflation ''initial'' conditions must be abandoned. In this paper the onset of inflation is studied classically for more general initial conditions of the scalar field configuration. In particular, initial conditions with a nonvanishing spatial average of phi, with phi chosen at random in each initial horizon volume, and with random initial momenta are considered. We identify and discuss several mechanisms that can drive these more general initial conditions toward an inflationary state. The analysis is done in one spatial dimension
Hybrid inflation exit through tunneling
International Nuclear Information System (INIS)
Garbrecht, Bjoern; Konstandin, Thomas
2007-01-01
For hybrid inflationary potentials, we derive the tunneling rate from field configurations along the flat direction towards the waterfall regime. This process competes with the classically rolling evolution of the scalar fields and needs to be strongly subdominant for phenomenologically viable models. Tunneling may exclude models with a mass scale below 10 12 GeV, but can be suppressed by small values of the coupling constants. We find that tunneling is negligible for those models, which do not require fine tuning in order to cancel radiative corrections, in particular for GUT-scale SUSY inflation. In contrast, electroweak scale hybrid inflation is not viable, unless the inflaton-waterfall field coupling is smaller than approximately 10 -11
Higgsed Chromo-Natural Inflation
Energy Technology Data Exchange (ETDEWEB)
Adshead, Peter [Department of Physics, University of Illinois at Urbana-Champaign,1110 West Green Street, Urbana, IL 61801 (United States); Martinec, Emil [Enrico Fermi Institute, University of Chicago,5640 S. Ellis Ave., Chicago, IL 60637-1433 (United States); Department of Physics, University of Chicago,5640 S. Ellis Ave., Chicago, IL 60637-1433 (United States); Sfakianakis, Evangelos I. [Department of Physics, University of Illinois at Urbana-Champaign,1110 West Green Street, Urbana, IL 61801 (United States); Wyman, Mark [PDT Partners,1745 Broadway, 25th Floor, New York, NY 10019 (United States)
2016-12-27
We demonstrate that Chromo-Natural Inflation can be made consistent with observational data if the SU(2) gauge symmetry is spontaneously broken. Working in the Stueckelberg limit, we show that isocurvature is negligible, and the resulting adiabatic fluctuations can match current observational constraints. Observable levels of chirally-polarized gravitational radiation (r∼10{sup −3}) can be produced while the evolution of all background fields is sub-Planckian. The gravitational wave spectrum is amplified via linear mixing with the gauge field fluctuations, and its amplitude is not simply set by the Hubble rate during inflation. This allows observable gravitational waves to be produced for an inflationary energy scale below the GUT scale. The tilt of the resulting gravitational wave spectrum can be either blue or red.
Planck constraints on monodromy inflation
International Nuclear Information System (INIS)
Easther, Richard; Flauger, Raphael
2014-01-01
We use data from the nominal Planck mission to constrain modulations in the primordial power spectrum associated with monodromy inflation. The largest improvement in fit relative to the unmodulated model has Δχ 2 ≈ 10 and we find no evidence for a primordial signal, in contrast to a previous analysis of the WMAP9 dataset, for which Δχ 2 ≈ 20. The Planck and WMAP9 results are broadly consistent on angular scales where they are expected to agree as far as best-fit values are concerned. However, even on these scales the significance of the signal is reduced in Planck relative to WMAP, and is consistent with a fit to the ''noise'' associated with cosmic variance. Our results motivate both a detailed comparison between the two experiments and a more careful study of the theoretical predictions of monodromy inflation
Higgsed Chromo-Natural Inflation
International Nuclear Information System (INIS)
Adshead, Peter; Martinec, Emil; Sfakianakis, Evangelos I.; Wyman, Mark
2016-01-01
We demonstrate that Chromo-Natural Inflation can be made consistent with observational data if the SU(2) gauge symmetry is spontaneously broken. Working in the Stueckelberg limit, we show that isocurvature is negligible, and the resulting adiabatic fluctuations can match current observational constraints. Observable levels of chirally-polarized gravitational radiation (r∼10 −3 ) can be produced while the evolution of all background fields is sub-Planckian. The gravitational wave spectrum is amplified via linear mixing with the gauge field fluctuations, and its amplitude is not simply set by the Hubble rate during inflation. This allows observable gravitational waves to be produced for an inflationary energy scale below the GUT scale. The tilt of the resulting gravitational wave spectrum can be either blue or red.
Directory of Open Access Journals (Sweden)
Raphael T Mpofu
2017-03-01
Full Text Available The paper analyses the association between certain macroeconomic variables and food price inflation, non-food price inflation and overall inflation in Zimbabwe, and also seeks to determine the level of association between these variables, given food security implications and overall well-being of its citizens. The study reveals that during the 2010 to 2016 period, Zimbabwe experienced stable food prices—annual food price inflation for food and non-alcoholic beverages averaged a relatively low growth rate of 0.12% monthly, while non-food inflation monthly growth rate was 0.09% and overall inflation growth rate was 0.11%. Although inflation from 2010 had been declining, of late, the increase in annual inflation has been underpinned by a rise in non-food inflation. Zimbabwe’s annual inflation remains lower than inflation rates in other countries in the region. Despite the increases lately in overall inflation, it remained below zero in January 2016, mostly driven by the depreciation of the South African rand and declining international oil prices. It should also be noted that domestic demand continued to decline in 2015, leading to the observed decline in both food and non-food prices. While food inflation has remained relatively low, it should be noted that non-food expenditures is significant component of the household budget and the rising prices result often lead to declining purchasing power and force households to make difficult choices in terms of their purchases. The findings of the study are food inflation has a low association with the independent variables under study; Zimbabwe broad money supply, rand-dollar exchange rates and the South Africa food inflation. There is, however, a very strong association between non-food inflation and these independent variables, as well as between overall inflation and the independent variables. Given the mostly rural population and the high level of unemployment in Zimbabwe, it can be surmised that
Inflation from Asymptotically Safe Theories
DEFF Research Database (Denmark)
Nielsen, Niklas Grønlund; Sannino, Francesco; Svendsen, Ole
2015-01-01
for inflation. In the minimal coupling case the theory requires large non-perturbative quantum corrections to the quantum potential for the theory to agree with data, while in the non- minimal coupling case the perturbative regime in the couplings of the theory is preferred. Requiring the theory to reproduce...... the observed amplitude of density perturbations constrain the geometric data of the theory such as the number of colors and flavors for generic values of the non-minimal coupling....
An introduction to cosmological inflation
International Nuclear Information System (INIS)
Liddle, A.R.
1999-01-01
An introductory account is given of the inflationary cosmology, which postulates a period of accelerated expansion during the Universe's earliest stages. The historical motivation is briefly outlined, and the modelling of the inflationary epoch explained. The most important aspect of inflation is that it provides a possible model for the origin of structure in the Universe, and key results are reviewed, along with a discussion of the current observational situation and outlook. (author)
Reheating for closed string inflation
Energy Technology Data Exchange (ETDEWEB)
Cicoli, Michele [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Mazumdar, Anupam [Lancaster Univ. (United Kingdom). Physics Dept.; Copenhagen Univ. (Denmark). Niels Bohr Institute
2010-05-15
We point out some of the outstanding challenges for embedding inflationary cosmology within string theory studying the process of reheating for models where the inflaton is a closed string mode parameterising the size of an internal cycle of the compactification manifold. A realistic model of inflation must explain the tiny perturbations in the cosmic microwave background radiation and also how to excite the ordinary matter degrees of freedom after inflation, required for the success of Big Bang Nucleosynthesis. We study these issues focusing on two promising inflationary models embedded in LARGE volume type IIB flux compactifications. We show that phenomenological requirements and consistency of the effective field theory treatment imply the presence at low energies of a hidden sector together with a visible sector, where the Minimal Supersymmetric Standard Model fields are residing. A detailed calculation of the inflaton coupling to the fields of the hidden sector, visible sector, and moduli sector, reveals that the inflaton fails to excite primarily the visible sector fields, instead hidden sector fields are excited copiously after the end of inflation. This sets severe constraints on hidden sector model building where the most promising scenario emerges as a pure N=1 SYM theory, forbidding the kinematical decay of the inflaton to the hidden sector. In this case it is possible to reheat the Universe with the visible degrees of freedom even though in some cases we discover a new tension between TeV scale SUSY and reheating on top of the well-known tension between TeV scale SUSY and inflation. (orig.)
Black holes from extended inflation
International Nuclear Information System (INIS)
Hsu, S.D.H.; Lawrence Berkeley Lab., CA
1990-01-01
It is argued that models of extended inflation, in which modified Einstein gravity allows a graceful exit from the false vacuum, lead to copious production of black holes. The critical temperature of the inflationary phase transition must be >10 8 GeV in order to avoid severe cosmological problems in a universe dominated by black holes. We speculate on the possibility that the interiors of false vacuum regions evolve into baby universes. (orig.)
The Implications of Grade Inflation
DEFF Research Database (Denmark)
Smith, David E.; Fleisher, Steven
2011-01-01
The authors review current and past practices of the grade inflation controversy and present ways to return to each institution’s established grading guidelines. Students are graded based on knowledge gathered. Certain faculty members use thorough evaluative methods, such as written and oral pres...... have been profiled in the news. The model is provided to ensure that degree candidates are academic experts in their field, having earned the credential through rigorous study....
Ferrara, Sergio
2016-10-24
We prove that all inflationary models, including those with dark energy after the end of inflation, can be embedded in minimal supergravity with a single chiral superfield. Moreover, the amount of supersymmetry breaking is independently tunable due to a degeneracy in the choice for the superpotential. The inflaton is a scalar partner of the Goldstino in this set-up. We illustrate our general procedure with two examples that are favoured by the Planck data.
Universe: inflation out of chaos
Energy Technology Data Exchange (ETDEWEB)
Linde, A
1985-03-07
The paper reviews the big bang theories of the earliest stages of the evolution of the Universe. The standard model and its associated problems; grand unified theories; scalar fields; and the inflationary Universe scenario; are all described. The newest model - Chaotic inflation, is a variation on the inflationary theme, and is outlined. Applications of this model to some of the standard model problems are discussed.
Energy Technology Data Exchange (ETDEWEB)
Ferrara, Sergio [Theoretical Physics Department, CERN,CH-1211 Geneva 23 (Switzerland); INFN - Laboratori Nazionali di Frascati,Via Enrico Fermi 40, 00044 Frascati (Italy); Department of Physics and Astronomy andMani L. Bhaumik Institute for Theoretical Physics, UCLA,470 Portola Plaza, Los Angeles, CA 90095-1547 (United States); Roest, Diederik [Theoretical Physics Department, CERN,CH-1211 Geneva 23 (Switzerland); Van Swinderen Institute for Particle Physics and Gravity, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands)
2016-10-24
We prove that all inflationary models, including those with dark energy after the end of inflation, can be embedded in minimal supergravity with a single chiral superfield. Moreover, the amount of supersymmetry breaking is independently tunable due to a degeneracy in the choice for the superpotential. The inflaton is a scalar partner of the Goldstino in this set-up. We illustrate our general procedure with two examples that are favoured by the Planck data.
Reheating for closed string inflation
International Nuclear Information System (INIS)
Cicoli, Michele; Mazumdar, Anupam; Copenhagen Univ.
2010-05-01
We point out some of the outstanding challenges for embedding inflationary cosmology within string theory studying the process of reheating for models where the inflaton is a closed string mode parameterising the size of an internal cycle of the compactification manifold. A realistic model of inflation must explain the tiny perturbations in the cosmic microwave background radiation and also how to excite the ordinary matter degrees of freedom after inflation, required for the success of Big Bang Nucleosynthesis. We study these issues focusing on two promising inflationary models embedded in LARGE volume type IIB flux compactifications. We show that phenomenological requirements and consistency of the effective field theory treatment imply the presence at low energies of a hidden sector together with a visible sector, where the Minimal Supersymmetric Standard Model fields are residing. A detailed calculation of the inflaton coupling to the fields of the hidden sector, visible sector, and moduli sector, reveals that the inflaton fails to excite primarily the visible sector fields, instead hidden sector fields are excited copiously after the end of inflation. This sets severe constraints on hidden sector model building where the most promising scenario emerges as a pure N=1 SYM theory, forbidding the kinematical decay of the inflaton to the hidden sector. In this case it is possible to reheat the Universe with the visible degrees of freedom even though in some cases we discover a new tension between TeV scale SUSY and reheating on top of the well-known tension between TeV scale SUSY and inflation. (orig.)
Primordial Kaluza-Klein inflation
International Nuclear Information System (INIS)
Gonzalez-Diaz, P.F.
1986-01-01
In a higher-dimensional version of the gravitational action with higher-derivative terms and logarithmic dependence on the curvature scalar, in addition to the four-dimensional gravitational action integral, the non-gravitational Coleman-Weinberg effective potential that governs primordial inflation is obtained. Also, it is obtained that the length scale for the internal space decreases monotonously during the inflationary era, at a similar rate as the three spacelike dimensions grow. (orig.)
The Primordial Inflation Explorer (PIXIE)
Kogut, Alan; Chluba, Jens; Fixsen, Dale J.; Meyer, Stephan; Spergel, David
2016-01-01
The Primordial Inflation Explorer is an Explorer-class mission to open new windows on the early universe through measurements of the polarization and absolute frequency spectrum of the cosmic microwave background. PIXIE will measure the gravitational-wave signature of primordial inflation through its distinctive imprint in linear polarization, and characterize the thermal history of the universe through precision measurements of distortions in the blackbody spectrum. PIXIE uses an innovative optical design to achieve background-limited sensitivity in 400 spectral channels spanning over 7 octaves in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). Multi-moded non-imaging optics feed a polarizing Fourier Transform Spectrometer to produce a set of interference fringes, proportional to the difference spectrum between orthogonal linear polarizations from the two input beams. Multiple levels of symmetry and signal modulation combine to reduce systematic errors to negligible levels. PIXIE will map the full sky in Stokes I, Q, and U parameters with angular resolution 2.6 degrees and sensitivity 70 nK per 1degree square pixel. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r inflation to the nature of the first stars and the physical conditions within the interstellar medium of the Galaxy. We describe the PIXIE instrument and mission architecture required to measure the CMB to the limits imposed by astrophysical foregrounds.
Elitism and Stochastic Dominance
Bazen, Stephen; Moyes, Patrick
2011-01-01
Stochastic dominance has typically been used with a special emphasis on risk and inequality reduction something captured by the concavity of the utility function in the expected utility model. We claim that the applicability of the stochastic dominance approach goes far beyond risk and inequality measurement provided suitable adpations be made. We apply in the paper the stochastic dominance approach to the measurment of elitism which may be considered the opposite of egalitarianism. While the...
Singular stochastic differential equations
Cherny, Alexander S
2005-01-01
The authors introduce, in this research monograph on stochastic differential equations, a class of points termed isolated singular points. Stochastic differential equations possessing such points (called singular stochastic differential equations here) arise often in theory and in applications. However, known conditions for the existence and uniqueness of a solution typically fail for such equations. The book concentrates on the study of the existence, the uniqueness, and, what is most important, on the qualitative behaviour of solutions of singular stochastic differential equations. This is done by providing a qualitative classification of isolated singular points, into 48 possible types.
On inflation in the heterotic superstring model
International Nuclear Information System (INIS)
Maeda, K.; Pollock, M.D.
1985-11-01
We consider the possibility of achieving inflation in the field-theory limit of the E 8 xE 8 superstring model. We show that neither type I inflation nor inflation due to a SUSY-breaking gaugino-condensation potential, is possible, essentially because of the absence of free dimensionless parameters. Kaluza-Klein type inflation is ruled out because the internal space is Ricci flat. The occurrence of type II inflation (due to some gauge singlet 'inflaton' field phi) depends upon the form of the superpotential F and of the Kaehler potential G, but this also seems not to be possible, unless the SU(n,1) symmetry can be broken in a particular way. Hence, some new type of compactification scheme may be called for, or a different type of inflation
Microwave background anisotropies in quasiopen inflation
García-Bellido, Juan; Garriga, Jaume; Montes, Xavier
1999-10-01
Quasiopenness seems to be generic to multifield models of single-bubble open inflation. Instead of producing infinite open universes, these models actually produce an ensemble of very large but finite inflating islands. In this paper we study the possible constraints from CMB anisotropies on existing models of open inflation. The effect of supercurvature anisotropies combined with the quasiopenness of the inflating regions make some models incompatible with observations, and severely reduces the parameter space of others. Supernatural open inflation and the uncoupled two-field model seem to be ruled out due to these constraints for values of Ω0<~0.98. Others, such as the open hybrid inflation model with suitable parameters for the slow roll potential can be made compatible with observations.
The scale of inflation in the landscape
Energy Technology Data Exchange (ETDEWEB)
Pedro, F.G.; Westphal, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group
2013-03-15
We determine the frequency of regions of small-field inflation in the Wigner landscape as an approximation to random supergravities/type IIB flux compactifications. We show that small-field inflation occurs exponentially more often than large-field inflation The power of primordial gravitational waves from inflation is generically tied to the scale of inflation. For small-field models this is below observational reach. However, we find small-field inflation to be dominated by the highest inflationary energy scales compatible with a sub-Planckian field range. Hence, we expect a typical tensor-to-scalar ratio r{proportional_to}O(10{sup -3}) currently undetectable in upcoming CMB measurements.
Cointegration Approach to Analysing Inflation in Croatia
Directory of Open Access Journals (Sweden)
Lena Malešević-Perović
2009-06-01
Full Text Available The aim of this paper is to analyse the determinants of inflation in Croatia in the period 1994:6-2006:6. We use a cointegration approach and find that increases in wages positively influence inflation in the long-run. Furthermore, in the period from June 1994 onward, the depreciation of the currency also contributed to inflation. Money does not explain Croatian inflation. This irrelevance of the money supply is consistent with its endogeneity to exchange rate targeting, whereby the money supply is determined by developments in the foreign exchange market. The value of inflation in the previous period is also found to be significant, thus indicating some inflation inertia.
Graceful exit from Higgs G-inflation
Energy Technology Data Exchange (ETDEWEB)
Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kobayashi, Tsutomu [Rikkyo Univ., Tokyo (Japan). Dept. of Physics; Kunimitsu, Taro [Tokyo Univ. (Japan). Dept. of Physics; Tokyo Univ. (Japan). Research Center for the Early Universe (RESCEU); Yamaguchi, Masahide [Tokyo Institute of Technology (Japan). Dept. of Physics; Yokoyama, Jun' ichi [Tokyo Univ. (Japan). Research Center for the Early Universe (RESCEU); Tokyo Univ., Chiba (Japan). Kavli Inst. for the Physics and Mathematics of the Universe (Kavli IPMU)
2013-09-15
Higgs G-inflation is a Higgs inflation model with a generalized Galileon term added to the standard model Higgs field, which realizes inflation compatible with observations. Recently, it was claimed that the generalized Galileon term induces instabilities during the oscillation phase, and that the simplest Higgs G-inflation model inevitably suffers from this problem. In this paper, we extend the original Higgs G-inflation Lagrangian to a more general form, namely introducing a higher-order kinetic term and generalizing the form of the Galileon term, so that the Higgs field can oscillate after inflation without encountering instabilities. Moreover, it accommodates a large region of the n{sub s}-r plane, most of which is consistent with current observations, leading us to expect the detection of B-mode polarization in the cosmic microwave background in the near future.
Inflation of Unreefed and Reefed Extraction Parachutes
Ray, Eric S.; Varela, Jose G.
2015-01-01
Data from the Orion and several other test programs have been used to reconstruct inflation parameters for 28 ft Do extraction parachutes as well as the parent aircraft pitch response during extraction. The inflation force generated by extraction parachutes is recorded directly during tow tests but is usually inferred from the payload accelerometer during Low Velocity Airdrop Delivery (LVAD) flight test extractions. Inflation parameters are dependent on the type of parent aircraft, number of canopies, and standard vs. high altitude extraction conditions. For standard altitudes, single canopy inflations are modeled as infinite mass, but the non-symmetric inflations in a cluster are modeled as finite mass. High altitude extractions have necessitated reefing the extraction parachutes, which are best modeled as infinite mass for those conditions. Distributions of aircraft pitch profiles and inflation parameters have been generated for use in Monte Carlo simulations of payload extractions.
2010-10-01
... Inspections § 169.849 Posting placards containing instructions for launching and inflating inflatable... accessible to the ship's company and guests approved placards containing instructions for launching and... determined by the Officer in Charge, Marine Inspection. ...
Directory of Open Access Journals (Sweden)
Jannie Rossouw
2011-08-01
Full Text Available This paper reports a comparison of South African household inflation expectations and inflation credibility surveys undertaken in 2006 and 2008. It tests for possible feed-through between inflation credibility and inflation expectations. It supplements earlier research that focused only on the 2006 survey results. The comparison shows that inflation expectations differed between different income groups in both 2006 and 2008. Inflation credibility differed between male and female respondents, but this difference did not feed through to inflation expectations. More periodic survey data will be required for developing final conclusions on the possibility of feed-through effects. To this end the structure of credibility surveys should be reconsidered, as a large percentage of respondents indicated that they ‘don’t know’ whether the historic rate of inflation is an accurate indication of price increases.
Oil price pass-through into inflation
International Nuclear Information System (INIS)
Chen, Shiu-Sheng
2009-01-01
This paper uses data from 19 industrialized countries to investigate oil price pass-through into inflation across countries and over time. A time-varying pass-through coefficient is estimated and the determinants of the recent declining effects of oil shocks on inflation are investigated. The appreciation of the domestic currency, a more active monetary policy in response to inflation, and a higher degree of trade openness are found to explain the decline in oil price pass-through. (author)
Primordial perturbations in multi-scalar inflation
Energy Technology Data Exchange (ETDEWEB)
Abedi, Habib; Abbassi, Amir M., E-mail: h.abedi@ut.ac.ir, E-mail: amabasi@khayam.ut.ac.ir [Department of Physics, University of Tehran, North Kargar Ave, Tehran (Iran, Islamic Republic of)
2017-07-01
Multiple field models of inflation exhibit new features than single field models. In this work, we study the hierarchy of parameters based on Hubble expansion rate in curved field space and derive the system of flow equations that describe their evolutions. Then we focus on obtaining derivatives of number of e-folds with respect to scalar fields during inflation and at hypersurface of the end of inflation.
Primordial inflation and the monopole problem
International Nuclear Information System (INIS)
Olive, K.A.; Seckel, D.
1984-01-01
This chapter discusses the cosmological abundance of magnetic monopoles in locally supersymmetry grand unified theories (GUTs) and primordial inflation. It is shown how the magnetic monopole problem can be solved in variants of broken N=1 supergravity primordial inflation. The monopole problem and its solution in inflationary models is reviewed. It is demonstrated that the monopole problem can be solved by coupling primordial inflation to supersymmetric SU(5) breaking
Inflation and Stock Prices: No Illusion
Chao Wei
2007-01-01
Campbell and Vuolteenaho (2004) use VAR results to advocate inflation illusion as the explanation for the positive association between inflation and the dividend yield. Contrary to their results, we find that a fully rational dynamic general equilibrium model can generate a positive correlation between the dividend yield and inflation of comparable size to its data counterpart. The model results support a proxy hypothesis, according to which, a third factor, which in our model represents tech...
Heterogeneous inflation expectations, learning, and market outcomes
Madeira, Carlos; Zafar, Basit
2012-01-01
Using the panel component of the Michigan Survey of Consumers, we show that individuals, in particular women and ethnic minorities, are highly heterogeneous in their expectations of inflation. We estimate a model of inflation expectations based on learning from experience that also allows for heterogeneity in both private information and updating. Our model vastly outperforms existing models of inflation expectations in explaining the heterogeneity in the data. We find that women, ethnic mino...
Heterogeneus Inflation Expectations Learning and Market Outcomes
Carlos Madeira; Basit Zafar
2012-01-01
Using the panel component of the Michigan Survey of Consumers we estimate a learning model of inflation expectations, allowing for heterogeneous use of both private information and lifetime inflation experience. We find that women, ethnic minorities, and less educated agents have a higher degree of heterogeneity in their private information, and are slower to update their expectations. During the 2000s, consumers believe inflation to be more persistent in the short term, but temporary fluctua...
Inflation Dynamics in India: An Analysis
Nair, Manju S
2014-01-01
India has exhibited high variability in inflation during the last eight years owing to both internal and external factors. The Global Financial Meltdown, recurrent increase in global oil prices, wage employment programmes, widening current account deficits etc resulted in fluctuations in inflation. These factors have a direct influence on variables like output, money supply, exchange rate which in turn affect inflation. In this context, the study employs a Cointegrated Vector Auto Regressi...
Towards natural inflation in string theory
International Nuclear Information System (INIS)
Ben-Dayan, Ido; Pedro, Francisco G.; Westphal, Alexander
2014-07-01
We provide type IIB string embeddings of two axion variants of natural inflation. We use a combination of RR 2 form axions as the inflaton field and have its potential generated by non perturbative effects in the superpotential. Besides giving rise to inflation, the models developed take into account the stabilization of the compact space, both in the KKLT and large volume scenario regimes, an essential condition for any semi-realistic model of string inflation.
Does a Threshold Inflation Rate Exist? Quantile Inferences for Inflation and Its Variability
WenShwo Fang; Stephen M. Miller; Chih-Chuan Yeh
2009-01-01
Using quantile regressions and cross-sectional data from 152 countries, we examine the relationship between inflation and its variability. We consider two measures of inflation – the mean and median – and three different measures of inflation variability – the standard deviation, relative variation, and median deviation. All results from the mean and standard deviation, the mean and relative variation, or the median and the median deviation support both the hypothesis that higher inflation cr...
Optimal inflation for the U.S.
Roberto M. Billi
2007-01-01
What is the correctly measured inflation rate that monetary policy should aim for in the long-run? This paper characterizes the optimal inflation rate for the U.S. economy in a New Keynesian sticky-price model with an occasionally binding zero lower bound on the nominal interest rate. Real-rate and mark-up shocks jointly determine the optimal inflation rate to be positive but not large. Even allowing for the possibility of extreme model misspecification, the optimal inflation rate is robustly...
Inflatable Rigidizable Solar Array for Small Satellites
National Research Council Canada - National Science Library
Lichodziejewski, David; Veal, Gordon; Helms, Richard; Freeland, Robert; Kruer, Mark
2002-01-01
.... Utilizing L Garde s next-generation stretched aluminum inflatable rigidizable tube technology, and Northrop Grumman s new polymer coverglass photovoltaic cell technology, power densities as high...
Chaotic inflation in models with flat directions
International Nuclear Information System (INIS)
Graziani, F.; Olive, K.
1989-01-01
We consider the chaotic inflationary scenario in models with flat directions. We find that unless the scalars along the flat directions have vacuum expectation values p or 10 14 M p 15 M p depending on the expectation values of the chaotic inflator, Ψ, one or two or more periods of inflation occur but with a resulting energy density perturbation δρ/ρ ≅ 10 -16 , far too small to be of any consequence for galaxy formation. Even with p only limited initial values of ≅ (3-200) M p result in inflation with reasonable density perturbations. Thus chaotic inflation in models with flat directions require rather special initial conditions. (orig.)
Is non-minimal inflation eternal?
International Nuclear Information System (INIS)
Feng, Chao-Jun; Li, Xin-Zhou
2010-01-01
The possibility that the non-minimal coupling inflation could be eternal is investigated. We calculate the quantum fluctuation of the inflaton in a Hubble time and find that it has the same value as that in the minimal case in the slow-roll limit. Armed with this result, we have studied some concrete non-minimal inflationary models including the chaotic inflation and the natural inflation, in which the inflaton is non-minimally coupled to the gravity. We find that the non-minimal coupling inflation could be eternal in some parameter spaces.
Inflation expectations and inflation uncertainty in the eurozone : Evidence from survey data
Arnold, I.J.M.; Lemmen, J.J.G.
2008-01-01
This paper uses the European Commission’s Consumer Survey to assess whether inflation expectations have converged and whether inflation uncertainty has diminished following the introduction of the euro in Europe. Consumers’ responses to the survey suggest that inflation expectations depend more on
Inflation expectations and inflation uncertainty in the Eurozone : Evidence from survey data
Arnold, I.J.M.; Lemmen, J.J.G.
2006-01-01
This paper uses the European Commission's Consumer Survey to assess whether inflation expectations have converged and whether inflation uncertainty has diminished following the introduction of the Euro in Europe. Consumers' responses to the survey suggest that inflation expectations depend more on
Stochastic analytic regularization
International Nuclear Information System (INIS)
Alfaro, J.
1984-07-01
Stochastic regularization is reexamined, pointing out a restriction on its use due to a new type of divergence which is not present in the unregulated theory. Furthermore, we introduce a new form of stochastic regularization which permits the use of a minimal subtraction scheme to define the renormalized Green functions. (author)
Instantaneous stochastic perturbation theory
International Nuclear Information System (INIS)
Lüscher, Martin
2015-01-01
A form of stochastic perturbation theory is described, where the representative stochastic fields are generated instantaneously rather than through a Markov process. The correctness of the procedure is established to all orders of the expansion and for a wide class of field theories that includes all common formulations of lattice QCD.
Gottwald, G.A.; Crommelin, D.T.; Franzke, C.L.E.; Franzke, C.L.E.; O'Kane, T.J.
2017-01-01
In this chapter we review stochastic modelling methods in climate science. First we provide a conceptual framework for stochastic modelling of deterministic dynamical systems based on the Mori-Zwanzig formalism. The Mori-Zwanzig equations contain a Markov term, a memory term and a term suggestive of
Meyer, Joerg M.
2018-01-01
The contrary of stochastic independence splits up into two cases: pairs of events being favourable or being unfavourable. Examples show that both notions have quite unexpected properties, some of them being opposite to intuition. For example, transitivity does not hold. Stochastic dependence is also useful to explain cases of Simpson's paradox.
Cybersecurity Risks: Are They Inflated?
Petr Chrapavy
2016-01-01
With various views being posed on cybersecurity, this paper examines the proposition that cybersecurity risks are inflated. Due to the complexity of the cybersecurity environment, the risks will be dichotomised into two distinct categories—those posed by cybercrime, and those classified as cyber-warfare. In relation to cyber-crime, the paper examines the rise of cyber-crime, its costs, and the views of these factors by “alarmists” and “sceptics.” In relation to cyber-war, the paper sets aside...
Non-minimal inflation revisited
International Nuclear Information System (INIS)
Nozari, Kourosh; Shafizadeh, Somayeh
2010-01-01
We reconsider an inflationary model that inflaton field is non-minimally coupled to gravity. We study the parameter space of the model up to the second (and in some cases third) order of the slow-roll parameters. We calculate inflation parameters in both Jordan and Einstein frames, and the results are compared in these two frames and also with observations. Using the recent observational data from combined WMAP5+SDSS+SNIa datasets, we study constraints imposed on our model parameters, especially the non-minimal coupling ξ.
Foam rigidized inflatable structural assemblies
Tinker, Michael L. (Inventor); Schnell, Andrew R. (Inventor)
2010-01-01
An inflatable and rigidizable structure for use as a habitat or a load bearing structure is disclosed. The structure consists of an outer wall and an inner wall defining a containment member and a bladder. The bladder is pressurized to erect the structure from an initially collapsed state. The containment member is subsequently injected with rigidizable fluid through an arrangement of injection ports. Exhaust gases from the curing rigidizable fluid are vented through an arrangement of exhaust ports. The rate of erection can be controlled by frictional engagement with a container or by using a tether. A method for fabricating a tubular structure is disclosed.
Stochastic quantization and gravity
International Nuclear Information System (INIS)
Rumpf, H.
1984-01-01
We give a preliminary account of the application of stochastic quantization to the gravitational field. We start in Section I from Nelson's formulation of quantum mechanics as Newtonian stochastic mechanics and only then introduce the Parisi-Wu stochastic quantization scheme on which all the later discussion will be based. In Section II we present a generalization of the scheme that is applicable to fields in physical (i.e. Lorentzian) space-time and treat the free linearized gravitational field in this manner. The most remarkable result of this is the noncausal propagation of conformal gravitons. Moreover the concept of stochastic gauge-fixing is introduced and a complete discussion of all the covariant gauges is given. A special symmetry relating two classes of covariant gauges is exhibited. Finally Section III contains some preliminary remarks on full nonlinear gravity. In particular we argue that in contrast to gauge fields the stochastic gravitational field cannot be transformed to a Gaussian process. (Author)
Greenwood, Priscilla E
2016-01-01
This book describes a large number of open problems in the theory of stochastic neural systems, with the aim of enticing probabilists to work on them. This includes problems arising from stochastic models of individual neurons as well as those arising from stochastic models of the activities of small and large networks of interconnected neurons. The necessary neuroscience background to these problems is outlined within the text, so readers can grasp the context in which they arise. This book will be useful for graduate students and instructors providing material and references for applying probability to stochastic neuron modeling. Methods and results are presented, but the emphasis is on questions where additional stochastic analysis may contribute neuroscience insight. An extensive bibliography is included. Dr. Priscilla E. Greenwood is a Professor Emerita in the Department of Mathematics at the University of British Columbia. Dr. Lawrence M. Ward is a Professor in the Department of Psychology and the Brain...
When Parents’ Praise Inflates, Children's Self-Esteem Deflates
Brummelman, Eddie; Nelemans, Stefanie A.; Thomaes, Sander; Orobio De Castro, Bram
2017-01-01
Western parents often give children overly positive, inflated praise. One perspective holds that inflated praise sets unattainable standards for children, eventually lowering children's self-esteem (self-deflation hypothesis). Another perspective holds that children internalize inflated praise to
Stochastic dark energy from inflationary quantum fluctuations
Glavan, Dražen; Prokopec, Tomislav; Starobinsky, Alexei A.
2018-05-01
We study the quantum backreaction from inflationary fluctuations of a very light, non-minimally coupled spectator scalar and show that it is a viable candidate for dark energy. The problem is solved by suitably adapting the formalism of stochastic inflation. This allows us to self-consistently account for the backreaction on the background expansion rate of the Universe where its effects are large. This framework is equivalent to that of semiclassical gravity in which matter vacuum fluctuations are included at the one loop level, but purely quantum gravitational fluctuations are neglected. Our results show that dark energy in our model can be characterized by a distinct effective equation of state parameter (as a function of redshift) which allows for testing of the model at the level of the background.
Towards inflation targeting in Egypt: the relationship between exchange rate and inflation
Directory of Open Access Journals (Sweden)
Aliaa Khodeir
2012-08-01
Full Text Available Since the Egyptian economy has recently moved towards inflation targeting, it became very important to know whether exchange rate movements have serious inflationary implications or not. To investigate this subject, the study aims to analyse the relevance of inflation with the exchange rate by using the Granger-causality test. Two indicators of inflation will be used, the consumer price index (CPI and wholesale price index (WPI. In general, the results show a strong relationship between the two variables in a way that may give support to the application of ‘flexible inflation targeting regime instead of strict inflation targeting regime’.
Quantum diffusion during inflation and primordial black holes
Energy Technology Data Exchange (ETDEWEB)
Pattison, Chris; Assadullahi, Hooshyar; Wands, David [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); Vennin, Vincent, E-mail: hooshyar.assadullahi@port.ac.uk, E-mail: christopher.pattison@port.ac.uk, E-mail: vincent.vennin@port.ac.uk, E-mail: david.wands@port.ac.uk [Laboratoire Astroparticule et Cosmologie, Université Denis Diderot Paris 7, 75013 Paris (France)
2017-10-01
We calculate the full probability density function (PDF) of inflationary curvature perturbations, even in the presence of large quantum backreaction. Making use of the stochastic-δ N formalism, two complementary methods are developed, one based on solving an ordinary differential equation for the characteristic function of the PDF, and the other based on solving a heat equation for the PDF directly. In the classical limit where quantum diffusion is small, we develop an expansion scheme that not only recovers the standard Gaussian PDF at leading order, but also allows us to calculate the first non-Gaussian corrections to the usual result. In the opposite limit where quantum diffusion is large, we find that the PDF is given by an elliptic theta function, which is fully characterised by the ratio between the squared width and height (in Planck mass units) of the region where stochastic effects dominate. We then apply these results to the calculation of the mass fraction of primordial black holes from inflation, and show that no more than ∼ 1 e -fold can be spent in regions of the potential dominated by quantum diffusion. We explain how this requirement constrains inflationary potentials with two examples.
Modeling animal-vehicle collisions using diagonal inflated bivariate Poisson regression.
Lao, Yunteng; Wu, Yao-Jan; Corey, Jonathan; Wang, Yinhai
2011-01-01
Two types of animal-vehicle collision (AVC) data are commonly adopted for AVC-related risk analysis research: reported AVC data and carcass removal data. One issue with these two data sets is that they were found to have significant discrepancies by previous studies. In order to model these two types of data together and provide a better understanding of highway AVCs, this study adopts a diagonal inflated bivariate Poisson regression method, an inflated version of bivariate Poisson regression model, to fit the reported AVC and carcass removal data sets collected in Washington State during 2002-2006. The diagonal inflated bivariate Poisson model not only can model paired data with correlation, but also handle under- or over-dispersed data sets as well. Compared with three other types of models, double Poisson, bivariate Poisson, and zero-inflated double Poisson, the diagonal inflated bivariate Poisson model demonstrates its capability of fitting two data sets with remarkable overlapping portions resulting from the same stochastic process. Therefore, the diagonal inflated bivariate Poisson model provides researchers a new approach to investigating AVCs from a different perspective involving the three distribution parameters (λ(1), λ(2) and λ(3)). The modeling results show the impacts of traffic elements, geometric design and geographic characteristics on the occurrences of both reported AVC and carcass removal data. It is found that the increase of some associated factors, such as speed limit, annual average daily traffic, and shoulder width, will increase the numbers of reported AVCs and carcass removals. Conversely, the presence of some geometric factors, such as rolling and mountainous terrain, will decrease the number of reported AVCs. Published by Elsevier Ltd.
Inflation with Fayet-Iliopoulos terms
International Nuclear Information System (INIS)
Wieck, Clemens; Winkler, Martin Wolfgang
2014-08-01
Two of the most attractive realizations of inflation in supergravity are based upon the presence of a constant Fayet-Iliopoulos (FI) term. In D-term hybrid inflation it is the FI term itself which sets the energy scale of inflation. Alternatively, the breaking of a U(1) symmetry induced by the FI term can dynamically generate the quadratic potential of chaotic inflation. The purpose of this note is to study the possible UV embedding of these schemes in terms of the 'field-dependent FI term' related to a string modulus field which is stabilized by a non-perturbative superpotential. We find that in settings where the FI term drives inflation, gauge invariance prevents a decoupling of the modulus from the inflationary dynamics. The resulting inflation models generically contain additional dynamical degrees of freedom compared to D-term hybrid inflation. However, the dynamical realization of chaotic inflation can be obtained in complete analogy to the case of a constant FI term. We present a simple string-inspired toy model of this type.
On the waterfall behavior in hybrid inflation
Kodama, Hideo; Kohri, Kazunori; Nakayama, Kazunori
2011-01-01
We revisit the hybrid inflation model focusing on the dynamics of the waterfall field in an analytical way. It is shown that inflation may last long enough during the waterfall regime for some parameter regions, confirming the claim of Clesse. In this case the scalar spectral index becomes red, and can fall into the best fit range of the WMAP observation.
Dynamical baryogenesis through complex hybrid inflation
International Nuclear Information System (INIS)
Delepine, D; MartInez, C; Urena-Lopez, L A
2008-01-01
We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U (1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry [1
Dynamical baryogenesis through complex hybrid inflation
Energy Technology Data Exchange (ETDEWEB)
Delepine, D; MartInez, C; Urena-Lopez, L A [Instituto de Fisica de la Universidad de Guanajuato, C.P. 37150, Leon, Guanajuato (Mexico)], E-mail: delepine@fisica.ugto.mx, E-mail: crmtz@fisica.ugto.mx, E-mail: lurena@fisica.ugto.mx
2008-06-01
We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U (1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry [1].
Targeting nominal income growth or inflation?
DEFF Research Database (Denmark)
Jensen, Henrik
2002-01-01
Within a simple New Keynesian model emphasizing forward-looking behavior of private agents, I evaluate optimal nominal income growth targeting versus optimal inflation targeting. When the economy is mainly subject to shocks that do not involve monetary policy trade-offs for society, inflation...
Inflation risk and international asset returns
G.A. Moerman (Gerard); M.A. van Dijk (Mathijs)
2010-01-01
textabstractWe show that inflation risk is priced in international asset returns. We analyze inflation risk in a framework that encompasses the International Capital Asset Pricing Model (ICAPM) of Adler and Dumas (1983). In contrast to the extant empirical literature on the ICAPM, we relax the
76 FR 56294 - Inflatable Personal Flotation Devices
2011-09-13
... direct final rule, UL 1191 was revised to return this value to 10%. Another commenter expressed concern... into effect, would facilitate teens using existing inflatable PFDs, and would enable the marketing of existing inflatable PFDs to youth. The commenter also expressed concern that this rulemaking is premature...
Robustness of inflation to inhomogeneous initial conditions
Energy Technology Data Exchange (ETDEWEB)
Clough, Katy; Lim, Eugene A. [Theoretical Particle Physics and Cosmology Group, Physics Department, Kings College London, Strand, London WC2R 2LS (United Kingdom); DiNunno, Brandon S.; Fischler, Willy; Flauger, Raphael; Paban, Sonia, E-mail: katy.clough@kcl.ac.uk, E-mail: eugene.a.lim@gmail.com, E-mail: bsd86@physics.utexas.edu, E-mail: fischler@physics.utexas.edu, E-mail: flauger@physics.utexas.edu, E-mail: paban@physics.utexas.edu [Department of Physics, The University of Texas at Austin, Austin, TX, 78712 (United States)
2017-09-01
We consider the effects of inhomogeneous initial conditions in both the scalar field profile and the extrinsic curvature on different inflationary models. In particular, we compare the robustness of small field inflation to that of large field inflation, using numerical simulations with Einstein gravity in 3+1 dimensions. We find that small field inflation can fail in the presence of subdominant gradient energies, suggesting that it is much less robust to inhomogeneities than large field inflation, which withstands dominant gradient energies. However, we also show that small field inflation can be successful even if some regions of spacetime start out in the region of the potential that does not support inflation. In the large field case, we confirm previous results that inflation is robust if the inflaton occupies the inflationary part of the potential. Furthermore, we show that increasing initial scalar gradients will not form sufficiently massive inflation-ending black holes if the initial hypersurface is approximately flat. Finally, we consider the large field case with a varying extrinsic curvature K , such that some regions are initially collapsing. We find that this may again lead to local black holes, but overall the spacetime remains inflationary if the spacetime is open, which confirms previous theoretical studies.
Fluctuations in models with primordial inflation
International Nuclear Information System (INIS)
Kahn, R.; Brandenberger, R.
1984-01-01
The recently proposed general framework for calculating the growth of primordial energy density fluctuations in cosmological models is applied to two models of phenomenological interest in which the cosmological evolution differs crucially from that in new inflationary universe models. Both in a model of primordial supersymmetric inflation and in Linde's proposal of chaotic inflation we verify the conjectured results. (orig.)
Inflation Metaphor in the TIME Magazine Corpus
Hu, Chunyu; Liu, Huijie
2016-01-01
A historical perspective on economy metaphor can shed new lights on economic thoughts. Based on the TIME Magazine Corpus (TMC), this paper investigates inflation metaphor over 83 years and compares findings against the economic data over the relatively corresponding period. The results show how inflation, an abstract concept and a normal economic…
Understanding Inflation and Revising National Price Data
International Development Research Centre (IDRC) Digital Library (Canada)
Pete
In parallel, official inflation statistics attribute inflation to other expenditure items. Whereas ..... Finally, instead of using a fixed-based index, other methods employ non-fixed bases for ...... Furniture and Household Maintenance. 7.9. 3.9. 8.18.
Inflation Targeting in Emerging Market Countries
Frederic S. Mishkin
2000-01-01
This paper outlines what inflation targeting involves for emerging market/transition countries and discusses the advantages and disadvantages of this monetary policy strategy. The discussion suggests that although inflation targeting is not a panacea and may not be appropriate for many emerging market countries, it can be a highly useful monetary policy strategy in a number of them.
THE PROSPECT OF INFLATION TARGETING IN KAZAKHSTAN
Directory of Open Access Journals (Sweden)
Zhandos Ybrayev
2017-02-01
Full Text Available Over the last two decades, there has been a significant increase in the number of countries that began to pursue an Inflation Targeting monetary policy framework. Since the collapse of the Soviet Union, each of the fifteen newly created independent countries started to develop and run their own autonomous monetary policies. Kazakhstan announced the implementation of an Inflation Targeting policy in August 2015. At the same time, a number of researches show that Inflation Targeting might not work as well for developing countries as it does for developed ones due to certain fundamental differences and preconditions that must be met before the implementation phase. Thus, this paper discusses the case of Kazakhstan as a typical emerging market economy example, examines its ability to respond to various external shocks and identifies the main transmission channels in order to contribute to the knowledge in this particular area. Identification assumptions generate contemporaneous monetary shocks on domestic inflation behavior, which also take into account various features of the small open economy as well as indicate different important transitory and persistent effects. The results show, based on the interpretation of impulse response functions, a positive interest rate shock has an uncertain inflationary impact, which raises questions about the effectiveness of interest rate manipulation in keeping inflation within the given band. In addition, a positive exchange rate shock leads to a stronger upward pressure in inflation rates. Finally, inflation inertia explains a substantial increase in future inflation rates.
The effect of inflation on nuclear energy
International Nuclear Information System (INIS)
Schofield, L.J.
A sophisticated analysis is given of the effects of inflation on the respective economics of CANDU power plants versus fossil fuel (especially coal-fired) power plants in Canada. Coal price escalation of 8% per annum or greater significantly favors CANDU plants. At 5%, especially with double digit inflation of capital costs, the competitive advantage of CANDU becomes small. (E.C.B.)
Demystify Learning Expectations to Address Grade Inflation
Hodges, Linda C.
2014-01-01
This article describes the subject of "grade inflation," a reference to educators giving higher grades to student work than their expectations for student achievement warrant. Of the many reasons why this practice happens, Hodges specifically discusses inflating grades as "a natural consequence" when the faculty really…
Grade Inflation: An Issue for Higher Education?
Caruth, Donald L.; Caruth, Gail D.
2013-01-01
Grade inflation impacts university credibility, student courses of study, choices of institution, and other areas. There has been an upward shift in grades without a corresponding upward shift in knowledge gained. Some of the most frequently mentioned causes of grade inflation are: (1) student evaluations of professors; (2) student teacher…
Inflation Metaphor in Contemporary American English
Hu, Chunyu; Chen, Zhi
2015-01-01
Inflation is often regarded as a dangerous phenomenon which poses a potential threat to economies in the world. It is thus an entity that demands the constant attention of economists, policymakers and the general public. In order to make this abstract entry more concrete and vivid, a number of metaphorical expressions are used to depict inflation.…
Inflation, large scale structure and particle physics
Indian Academy of Sciences (India)
Logo of the Indian Academy of Sciences ... Hybrid inflation; Higgs scalar field; structure formation; curvation. ... We then discuss a particle physics model of supersymmetric hybrid inflation at the intermediate scale in which ... May 2018. Home · Volumes & Issues · Special Issues · Forthcoming Articles · Search · Editorial Board ...
Inflatable antenna for earth observing systems
Wang, Hong-Jian; Guan, Fu-ling; Xu, Yan; Yi, Min
2010-09-01
This paper describe mechanical design, dynamic analysis, and deployment demonstration of the antenna , and the photogrammetry detecting RMS of inflatable antenna surface, the possible errors results form the measurement are also analysed. Ticra's Grasp software are used to predict the inflatable antenna pattern based on the coordinates of the 460 points on the parabolic surface, the final results verified the whole design process.
Inflation targeting and interest rate policy
Verhagen, W.H.
2001-01-01
The thesis contains a collection of papers on issues in inflation targeting and its implications for the way interest rates are set. In this respect, the first part deals with two largely positive issues: the effect of inflation forecast targeting on the term structure of interest rates and the
77 FR 19937 - Inflatable Personal Flotation Devices
2012-04-03
... Advancement Act OMB Office of Management and Budget PFD Personal flotation device STP Standards Technical... using existing inflatable PFDs, and would enable marketing of existing inflatable PFDs to youth. The... approved, and thus does not affect the availability, use, or marketing of existing PFDs to or by the youth...
Inflation targeting and economic performance: The case of Mexico
Directory of Open Access Journals (Sweden)
Carrasco Carlos A.
2011-01-01
Full Text Available In the paper we analyze the impact of Inflation Targeting (IT in Mexico. The objective is to evaluate the impact of the implementation of inflation targeting and full-fledged inflation targeting (FFIT on the level and the variability of the inflation and the output in the Mexican economy. We conclude that inflation rates had been reduced in Mexico before the introduction of IT and FFIT. In our opinion, the structural reforms, including the Banxico reforms, are the main determinants of the decrease in inflation and its variability. The main impact of IT would have been the lock-in of inflation expectations around a low rate of inflation.
Technology & Mechanics Overview of Air-Inflated Fabric Structures
National Research Council Canada - National Science Library
Cavallaro, Paul V
2006-01-01
.... Examples include air ships, weather balloons, inflatable radomes, shelters, pneumatic muscles, inflatable boats, bridging, and energy absorbers such as automotive air bags and landing cushions for space vehicles...
Towards matter inflation in heterotic string theory
International Nuclear Information System (INIS)
Antusch, Stefan; Erdmenger, Johanna; Halter, Sebastian; Dutta, Koushik
2011-02-01
Recently, a class of inflation models in supergravity with gauge non-singlet matter fields as the inflaton has been proposed. It is based on a 'tribrid' structure in the superpotential and on a 'Heisenberg symmetry' for solving the η-problem. We suggest that a generalization of this model class may be suitable for realising inflation in heterotic orbifold compactifications, where the Heisenberg symmetry is a property of the tree-level Kaehler potential of untwisted matter fields. We discuss moduli stabilization in this setup and propose a mechanism to stabilize the modulus associated to the inflaton, which respects the symmetry in the large radius limit. Inflation ends via a waterfall phase transition, as in hybrid inflation. We give conditions which have to be satisfied for realising inflation along these lines in the matter sector of heterotic orbifolds. (orig.)
Sneutrino hybrid inflation and nonthermal leptogenesis
International Nuclear Information System (INIS)
Antusch, Stefan; Baumann, Jochen P.; Domcke, Valerie F.; Kostka, Philipp M.
2010-01-01
In sneutrino hybrid inflation the superpartner of one of the right-handed neutrinos involved in the seesaw mechanism plays the role of the inflaton field. It obtains its large mass after the ''waterfall'' phase transition which ends hybrid inflation. After this phase transition the oscillations of the sneutrino inflaton field may dominate the universe and efficiently produce the baryon asymmetry of the universe via nonthermal leptogenesis. We investigate the conditions under which inflation, with primordial perturbations in accordance with the latest WMAP results, as well as successful nonthermal leptogenesis can be realized simultaneously within the sneutrino hybrid inflation scenario. We point out which requirements successful inflation and leptogenesis impose on the seesaw parameters, i.e. on the Yukawa couplings and the mass of the right-handed (s)neutrino, and derive the predictions for the CMB observables in terms of the right-handed (s)neutrino mass and the other relevant model parameters
Sneutrino hybrid inflation and nonthermal leptogenesis
Energy Technology Data Exchange (ETDEWEB)
Antusch, Stefan; Baumann, Jochen P.; Domcke, Valerie F.; Kostka, Philipp M., E-mail: antusch@mppmu.mpg.de, E-mail: jbaumann@mppmu.mpg.de, E-mail: domcke@mppmu.mpg.de, E-mail: kostka@mppmu.mpg.de [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, 80805 München (Germany)
2010-10-01
In sneutrino hybrid inflation the superpartner of one of the right-handed neutrinos involved in the seesaw mechanism plays the role of the inflaton field. It obtains its large mass after the ''waterfall'' phase transition which ends hybrid inflation. After this phase transition the oscillations of the sneutrino inflaton field may dominate the universe and efficiently produce the baryon asymmetry of the universe via nonthermal leptogenesis. We investigate the conditions under which inflation, with primordial perturbations in accordance with the latest WMAP results, as well as successful nonthermal leptogenesis can be realized simultaneously within the sneutrino hybrid inflation scenario. We point out which requirements successful inflation and leptogenesis impose on the seesaw parameters, i.e. on the Yukawa couplings and the mass of the right-handed (s)neutrino, and derive the predictions for the CMB observables in terms of the right-handed (s)neutrino mass and the other relevant model parameters.
Does string theory lead to extended inflation?
Campbell, Bruce A.; Linde, Andrei; Olive, Keith A.
1991-05-01
We consider the relationship between string theory and currently proposed models of extended inflation. In doing so, we discuss the conformal actions in string theory and in Jordan-Brans-Dicke gravity. We show explicitly the equivalence of pictures in which either gauge or gravitational couplings are changing with time. We demonstrate that the existence of the dilation in string theory does not naturally lead to extended inflation as currently discussed. We also discuss the resolution of the graceful exit problem of old inflation in Einstein gravity using either power-law inflation, or exponential inflation with a changing bubble formation rate. On leave of absence from School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA.
Towards matter inflation in heterotic string theory
Energy Technology Data Exchange (ETDEWEB)
Antusch, Stefan; Erdmenger, Johanna; Halter, Sebastian [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Muenchen (Germany); Dutta, Koushik [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2011-02-15
Recently, a class of inflation models in supergravity with gauge non-singlet matter fields as the inflaton has been proposed. It is based on a 'tribrid' structure in the superpotential and on a 'Heisenberg symmetry' for solving the {eta}-problem. We suggest that a generalization of this model class may be suitable for realising inflation in heterotic orbifold compactifications, where the Heisenberg symmetry is a property of the tree-level Kaehler potential of untwisted matter fields. We discuss moduli stabilization in this setup and propose a mechanism to stabilize the modulus associated to the inflaton, which respects the symmetry in the large radius limit. Inflation ends via a waterfall phase transition, as in hybrid inflation. We give conditions which have to be satisfied for realising inflation along these lines in the matter sector of heterotic orbifolds. (orig.)
Classical anisotropies in models of open inflation
International Nuclear Information System (INIS)
Garriga, J.; Mukhanov, V.F.
1997-01-01
In the simplest model of open inflation there are two inflaton fields decoupled from each other. One of them, the tunneling field, produces a first stage of inflation which prepares the ground for the nucleation of a highly symmetric bubble. The other, a free field, drives a second period of slow-roll inflation inside the bubble. However, the second field also evolves during the first stage of inflation, which to some extent breaks the needed symmetry. We show that this generates large supercurvature anisotropies which, together with the results of Tanaka and Sasaki, rule out this class of simple models (unless, of course, Ω 0 is sufficiently close to 1). The problem does not arise in modified models where the second field does not evolve in the first stage of inflation. copyright 1997 The American Physical Society
Affleck-Dine baryogenesis just after inflation
International Nuclear Information System (INIS)
Yamada, Masaki
2015-11-01
We propose a new scenario of Affleck-Dine baryogenesis where a at direction in the MSSM generates B-L asymmetry just after the end of inflation. The resulting amount of baryon asymmetry is independent of low-energy supersymmetric models but is dependent on inflation models. We consider the hybrid and chaotic inflation models and find that reheating temperature is required to be higher than that in the conventional scenario of Affleck-Dine baryogenesis. In particular, non-thermal gravitino-overproduction problem is naturally avoided in the hybrid inflation model. Our results imply that Affleck-Dine baryogenesis can be realized in a broader range of supersymmetry and inflation models than expected in the literature.
Higgs-Palatini inflation and unitarity
International Nuclear Information System (INIS)
Bauer, Florian; Demir, Durmus A.
2011-01-01
In the Higgs inflation scenario the Higgs field is strongly coupled to the Ricci scalar in order to drive primordial inflation. However, in its original form in pure metric formulation of gravity, the ultraviolet (UV) cutoff of the Higgs interactions and the Hubble rate are of the same magnitude, and this makes the whole inflationary evolution dependent of the unknown UV completion of the Higgs sector. This problem, the unitarity violation, plagues the Higgs inflation scenario. In this Letter we show that, in the Palatini formulation of gravitation, Higgs inflation does not suffer from unitarity violation since the UV cutoff lies parametrically much higher than the Hubble rate so that unknown UV physics does not disrupt the inflationary dynamics. Higgs-Palatini inflation, as we call it, is, therefore, UV-safe, minimal and endowed with predictive power.
B. HEITZ
2005-01-01
This paper seeks to apply the general framework of Markov-switching models to inflation in France and in the USA. We propose a model where inflation can, alternatively, follow two regimes: the first one, where inflation is stationary, is interpreted as a situation where there exists a credible inflation target, even if it is not explicit; the second one where inflation is integrated. Moreover, observing that the two oil shocks were followed by accelerating inflation periods, we allow dependen...
Energy Technology Data Exchange (ETDEWEB)
Freivogel, Ben; /Stanford U., Phys. Dept. /LBL, Berkeley; Hubeny, Veronika E.; /LBL, Berkeley /Durham U., Dept. of Math.; Maloney, Alexander; /Stanford U., Phys. Dept.; Myers, Rob; /Perimeter Inst. Theor. Phys. /Waterloo U.; Rangamani, Mukund; /LBL, Berkeley /Durham U., Dept. of Math.; Shenker, Stephen; /Stanford U., Phys. Dept.
2005-10-07
We study the realization of inflation within the AdS/CFT correspondence. We assume the existence of a string landscape containing at least one stable AdS vacuum and a (nearby) metastable de Sitter state. Standard arguments imply that the bulk physics in the vicinity of the AdS minimum is described by a boundary CFT. We argue that large enough bubbles of the dS phase, including those able to inflate, are described by mixed states in the CFT. Inflating degrees of freedom are traced over and do not appear explicitly in the boundary description. They nevertheless leave a distinct imprint on the mixed state. Analytic continuation allows us, in principle, to recover a large amount of nonperturbatively defined information about the inflating regime. Our work also shows that no scattering process can create an inflating region, even by quantum tunneling, since a pure state can never evolve into a mixed state under unitary evolution.We study the realization of inflation within the AdS/CFT correspondence. We assume the existence of a string landscape containing at least one stable AdS vacuum and a (nearby) metastable de Sitter state. Standard arguments imply that the bulk physics in the vicinity of the AdS minimum is described by a boundary CFT. We argue that large enough bubbles of the dS phase, including those able to inflate, are described by mixed states in the CFT. Inflating degrees of freedom are traced over and do not appear explicitly in the boundary description. They nevertheless leave a distinct imprint on the mixed state. Analytic continuation allows us, in principle, to recover a large amount of nonperturbatively defined information about the inflating regime. Our work also shows that no scattering process can create an inflating region, even by quantum tunneling, since a pure state can never evolve into a mixed state under unitary evolution.
Sequential stochastic optimization
Cairoli, Renzo
1996-01-01
Sequential Stochastic Optimization provides mathematicians and applied researchers with a well-developed framework in which stochastic optimization problems can be formulated and solved. Offering much material that is either new or has never before appeared in book form, it lucidly presents a unified theory of optimal stopping and optimal sequential control of stochastic processes. This book has been carefully organized so that little prior knowledge of the subject is assumed; its only prerequisites are a standard graduate course in probability theory and some familiarity with discrete-paramet
Remarks on stochastic acceleration
International Nuclear Information System (INIS)
Graeff, P.
1982-12-01
Stochastic acceleration and turbulent diffusion are strong turbulence problems since no expansion parameter exists. Hence the problem of finding rigorous results is of major interest both for checking approximations and for reference models. Since we have found a way of constructing such models in the turbulent diffusion case the question of the extension to stochastic acceleration now arises. The paper offers some possibilities illustrated by the case of 'stochastic free fall' which may be particularly interesting in the context of linear response theory. (orig.)
The Primordial Inflation Explorer (PIXIE)
Kogut, Alan; Chluba, Jens; Fixsen, Dale J.; Meyer, Stephan; Spergel, David
2016-07-01
The Primordial Inflation Explorer is an Explorer-class mission to open new windows on the early universe through measurements of the polarization and absolute frequency spectrum of the cosmic microwave background. PIXIE will measure the gravitational-wave signature of primordial inflation through its distinctive imprint in linear polarization, and characterize the thermal history of the universe through precision measurements of distortions in the blackbody spectrum. PIXIE uses an innovative optical design to achieve background-limited sensitivity in 400 spectral channels spanning over 7 octaves in frequency from 30 GHz to 6 THz (1 cm to 50 micron wavelength). Multi-moded non-imaging optics feed a polarizing Fourier Transform Spectrometer to produce a set of interference fringes, proportional to the difference spectrum between orthogonal linear polarizations from the two input beams. Multiple levels of symmetry and signal modulation combine to reduce systematic errors to negligible levels. PIXIE will map the full sky in Stokes I, Q, and U parameters with angular resolution 2.6° and sensitivity 70 nK per 1° square pixel. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r complements anticipated ground-based polarization measurements such as CMB- S4, providing a cosmic-variance-limited determination of the large-scale E-mode signal to measure the optical depth, constrain models of reionization, and provide a firm detection of the neutrino mass (the last unknown parameter in the Standard Model of particle physics). In addition, PIXIE will measure the absolute frequency spectrum to characterize deviations from a blackbody with sensitivity 3 orders of magnitude beyond the seminal COBE/FIRAS limits. The sky cannot be black at this level; the expected results will constrain physical processes ranging from inflation to the nature of the first stars and the
Leptogenesis in Complex Hybrid Inflation
International Nuclear Information System (INIS)
Martinez-Prieto, Carlos
2008-01-01
We study the transference of an initial leptonic charge contained in a complex scalar field (waterfall field) at the end of the inflation to the leptons of the standard model and then convert this leptonic charge in baryonic charge by sphaleron process. The proposal is that this is done trough the decay of the complex scalar field particles into the the right-handed neutrino which in turn decays into the left-handed lepton doublet and the Higgs field of the standard model. It must be analyzed in what environment the transference is done. We propose that the inflaton (the dominant energy density of the universe) decay into ultrarelativistic fermions before the waterfall field particles decay in the right handed-neutrino, leaving a thermalized bath where the transference of the leptonic asymmetry can be achieved.
Conformal frame dependence of inflation
International Nuclear Information System (INIS)
Domènech, Guillem; Sasaki, Misao
2015-01-01
Physical equivalence between different conformal frames in scalar-tensor theory of gravity is a known fact. However, assuming that matter minimally couples to the metric of a particular frame, which we call the matter Jordan frame, the matter point of view of the universe may vary from frame to frame. Thus, there is a clear distinction between gravitational sector (curvature and scalar field) and matter sector. In this paper, focusing on a simple power-law inflation model in the Einstein frame, two examples are considered; a super-inflationary and a bouncing universe Jordan frames. Then we consider a spectator curvaton minimally coupled to a Jordan frame, and compute its contribution to the curvature perturbation power spectrum. In these specific examples, we find a blue tilt at short scales for the super-inflationary case, and a blue tilt at large scales for the bouncing case
String moduli inflation. An overview
Energy Technology Data Exchange (ETDEWEB)
Cicoli, Michele [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Quevedo, Fernando [Cambridge Univ. (United Kingdom). DAMTP/CMS; Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)
2011-06-15
We present an overview of inflationary models derived from string theory focusing mostly on closed string moduli as inflatons. After a detailed discussion of the {eta}-problem and different approaches to address it, we describe possible ways to obtain a de Sitter vacuum with all closed string moduli stabilised. We then look for inflationary directions and present some of the most promising scenarios where the inflatons are either the real or the imaginary part of Kaehler moduli. We pay particular attention on extracting potential observable implications, showing how most of the scenarios predict negligible gravitational waves and could therefore be ruled out by the Planck satellite. We conclude by briefly mentioning some open challenges in string cosmology beyond deriving just inflation. (orig.)
Radiative inflation and dark energy
International Nuclear Information System (INIS)
Di Bari, Pasquale; King, Stephen F.; Luhn, Christoph; Merle, Alexander; Schmidt-May, Angnis
2011-01-01
We propose a model based on radiative symmetry breaking that combines inflation with dark energy and is consistent with the Wilkinson Microwave Anisotropy Probe 7-year regions. The radiative inflationary potential leads to the prediction of a spectral index 0.955 S < or approx. 0.967 and a tensor to scalar ratio 0.142 < or approx. r < or approx. 0.186, both consistent with current data but testable by the Planck experiment. The radiative symmetry breaking close to the Planck scale gives rise to a pseudo Nambu-Goldstone boson with a gravitationally suppressed mass which can naturally play the role of a quintessence field responsible for dark energy. Finally, we present a possible extra dimensional scenario in which our model could be realized.
Conformal frame dependence of inflation
Energy Technology Data Exchange (ETDEWEB)
Domènech, Guillem; Sasaki, Misao, E-mail: guillem.domenech@yukawa.kyoto-u.ac.jp, E-mail: misao@yukawa.kyoto-u.ac.jp [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)
2015-04-01
Physical equivalence between different conformal frames in scalar-tensor theory of gravity is a known fact. However, assuming that matter minimally couples to the metric of a particular frame, which we call the matter Jordan frame, the matter point of view of the universe may vary from frame to frame. Thus, there is a clear distinction between gravitational sector (curvature and scalar field) and matter sector. In this paper, focusing on a simple power-law inflation model in the Einstein frame, two examples are considered; a super-inflationary and a bouncing universe Jordan frames. Then we consider a spectator curvaton minimally coupled to a Jordan frame, and compute its contribution to the curvature perturbation power spectrum. In these specific examples, we find a blue tilt at short scales for the super-inflationary case, and a blue tilt at large scales for the bouncing case.
String moduli inflation. An overview
International Nuclear Information System (INIS)
Cicoli, Michele; Quevedo, Fernando
2011-06-01
We present an overview of inflationary models derived from string theory focusing mostly on closed string moduli as inflatons. After a detailed discussion of the η-problem and different approaches to address it, we describe possible ways to obtain a de Sitter vacuum with all closed string moduli stabilised. We then look for inflationary directions and present some of the most promising scenarios where the inflatons are either the real or the imaginary part of Kaehler moduli. We pay particular attention on extracting potential observable implications, showing how most of the scenarios predict negligible gravitational waves and could therefore be ruled out by the Planck satellite. We conclude by briefly mentioning some open challenges in string cosmology beyond deriving just inflation. (orig.)
Inflation in a superstring model
International Nuclear Information System (INIS)
Maeda, K.; Pollock, M.D.; Vayonakis, C.E.
1986-01-01
A new type of inflation is presented in the heterotic E 8 xE 8 superstring model. The inflaton is identified with the ''Polonyi'' field tau, which is related to the radius of the internal space. Radiative corrections to the gluino-condensation potential are supposed to give rise to a suitable potential which is adjusted to vanish at the minimum by addition of a constant ΔV, whose magnitude is fixed by the requirement that density perturbations are of the right order. Reheating is due to the decay of the ''Polonyi'' field tau and/or to the production of light particles through its oscillations. The resultant constraints upon the parameters of the potential can be satisfied without excessive fine tuning. (author)
Clustering fossils in solid inflation
Energy Technology Data Exchange (ETDEWEB)
Akhshik, Mohammad, E-mail: m.akhshik@ipm.ir [Department of Physics, Sharif University of Technology, Tehran (Iran, Islamic Republic of)
2015-05-01
In solid inflation the single field non-Gaussianity consistency condition is violated. As a result, the long tenor perturbation induces observable clustering fossils in the form of quadrupole anisotropy in large scale structure power spectrum. In this work we revisit the bispectrum analysis for the scalar-scalar-scalar and tensor-scalar-scalar bispectrum for the general parameter space of solid. We consider the parameter space of the model in which the level of non-Gaussianity generated is consistent with the Planck constraints. Specializing to this allowed range of model parameter we calculate the quadrupole anisotropy induced from the long tensor perturbations on the power spectrum of the scalar perturbations. We argue that the imprints of clustering fossil from primordial gravitational waves on large scale structures can be detected from the future galaxy surveys.
Systematics of constant roll inflation
Anguelova, Lilia; Suranyi, Peter; Wijewardhana, L. C. R.
2018-02-01
We study constant roll inflation systematically. This is a regime, in which the slow roll approximation can be violated. It has long been thought that this approximation is necessary for agreement with observations. However, recently it was understood that there can be inflationary models with a constant, and not necessarily small, rate of roll that are both stable and compatible with the observational constraint ns ≈ 1. We investigate systematically the condition for such a constant-roll regime. In the process, we find a whole new class of inflationary models, in addition to the known solutions. We show that the new models are stable under scalar perturbations. Finally, we find a part of their parameter space, in which they produce a nearly scale-invariant scalar power spectrum, as needed for observational viability.
Directory of Open Access Journals (Sweden)
Charles Nkeki
2013-11-01
Full Text Available This paper examines a mean-variance portfolio selection problem with stochastic salary and inflation protection strategy in the accumulation phase of a defined contribution (DC pension plan. The utility function is assumed to be quadratic. It was assumed that the flow of contributions made by the PPM are invested into a market that is characterized by a cash account, an inflation-linked bond and a stock. In this paper, inflationlinked bond is traded and used to hedge inflation risks associated with the investment. The aim of this paper is to maximize the expected final wealth and minimize its variance. Efficient frontier for the three classes of assets (under quadratic utility function that will enable pension plan members (PPMs to decide their own wealth and risk in their investment profile at retirement was obtained.
Stochastic processes inference theory
Rao, Malempati M
2014-01-01
This is the revised and enlarged 2nd edition of the authors’ original text, which was intended to be a modest complement to Grenander's fundamental memoir on stochastic processes and related inference theory. The present volume gives a substantial account of regression analysis, both for stochastic processes and measures, and includes recent material on Ridge regression with some unexpected applications, for example in econometrics. The first three chapters can be used for a quarter or semester graduate course on inference on stochastic processes. The remaining chapters provide more advanced material on stochastic analysis suitable for graduate seminars and discussions, leading to dissertation or research work. In general, the book will be of interest to researchers in probability theory, mathematical statistics and electrical and information theory.
Introduction to stochastic calculus
Karandikar, Rajeeva L
2018-01-01
This book sheds new light on stochastic calculus, the branch of mathematics that is most widely applied in financial engineering and mathematical finance. The first book to introduce pathwise formulae for the stochastic integral, it provides a simple but rigorous treatment of the subject, including a range of advanced topics. The book discusses in-depth topics such as quadratic variation, Ito formula, and Emery topology. The authors briefly address continuous semi-martingales to obtain growth estimates and study solution of a stochastic differential equation (SDE) by using the technique of random time change. Later, by using Metivier–Pellumail inequality, the solutions to SDEs driven by general semi-martingales are discussed. The connection of the theory with mathematical finance is briefly discussed and the book has extensive treatment on the representation of martingales as stochastic integrals and a second fundamental theorem of asset pricing. Intended for undergraduate- and beginning graduate-level stud...
Doberkat, Ernst-Erich
2009-01-01
Combining coalgebraic reasoning, stochastic systems and logic, this volume presents the principles of coalgebraic logic from a categorical perspective. Modal logics are also discussed, including probabilistic interpretations and an analysis of Kripke models.
Approximating Preemptive Stochastic Scheduling
Megow Nicole; Vredeveld Tjark
2009-01-01
We present constant approximative policies for preemptive stochastic scheduling. We derive policies with a guaranteed performance ratio of 2 for scheduling jobs with release dates on identical parallel machines subject to minimizing the sum of weighted completion times. Our policies as well as their analysis apply also to the recently introduced more general model of stochastic online scheduling. The performance guarantee we give matches the best result known for the corresponding determinist...
The stochastic goodwill problem
Marinelli, Carlo
2003-01-01
Stochastic control problems related to optimal advertising under uncertainty are considered. In particular, we determine the optimal strategies for the problem of maximizing the utility of goodwill at launch time and minimizing the disutility of a stream of advertising costs that extends until the launch time for some classes of stochastic perturbations of the classical Nerlove-Arrow dynamics. We also consider some generalizations such as problems with constrained budget and with discretionar...
International Nuclear Information System (INIS)
Hueffel, H.
1990-01-01
After a brief review of the BRST formalism and of the Parisi-Wu stochastic quantization method we introduce the BRST stochastic quantization scheme. It allows the second quantization of constrained Hamiltonian systems in a manifestly gauge symmetry preserving way. The examples of the relativistic particle, the spinning particle and the bosonic string are worked out in detail. The paper is closed by a discussion on the interacting field theory associated to the relativistic point particle system. 58 refs. (Author)
Primordial anisotropies in gauged hybrid inflation
Akbar Abolhasani, Ali; Emami, Razieh; Firouzjahi, Hassan
2014-05-01
We study primordial anisotropies generated in the model of gauged hybrid inflation in which the complex waterfall field is charged under a U(1)gauge field. Primordial anisotropies are generated either actively during inflation or from inhomogeneities modulating the surface of end of inflation during waterfall transition. We present a consistent δN mechanism to calculate the anisotropic power spectrum and bispectrum. We show that the primordial anisotropies generated at the surface of end of inflation do not depend on the number of e-folds and therefore do not produce dangerously large anisotropies associated with the IR modes. Furthermore, one can find the parameter space that the anisotropies generated from the surface of end of inflation cancel the anisotropies generated during inflation, therefore relaxing the constrains on model parameters imposed from IR anisotropies. We also show that the gauge field fluctuations induce a red-tilted power spectrum so the averaged power spectrum from the gauge field can change the total power spectrum from blue to red. Therefore, hybrid inflation, once gauged under a U(1) field, can be consistent with the cosmological observations.
Nonthermal gravitino production in tribrid inflation
Antusch, Stefan; Dutta, Koushik
2015-10-01
We investigate nonthermal gravitino production after tribrid inflation in supergravity, which is a variant of supersymmetric hybrid inflation where three fields are involved in the inflationary model and where the inflaton field resides in the matter sector of the theory. In contrast to conventional supersymmetric hybrid inflation, where nonthermal gravitino production imposes severe constraints on the inflationary model, we find that the "nonthermal gravitino problem" is generically absent in models of tribrid inflation, mainly due to two effects: (i) With the inflaton in tribrid inflation (after inflation) being lighter than the waterfall field, the latter has a second decay channel with a much larger rate than for the decay into gravitinos. This reduces the branching ratio for the decay of the waterfall field into gravitinos. (ii) The inflaton generically decays later than the waterfall field, and it does not produce gravitinos when it decays. This leads to a dilution of the gravitino population from the decays of the waterfall field. The combination of both effects generically leads to a strongly reduced gravitino production in tribrid inflation.
Primordial anisotropies in gauged hybrid inflation
International Nuclear Information System (INIS)
Abolhasani, Ali Akbar; Emami, Razieh; Firouzjahi, Hassan
2014-01-01
We study primordial anisotropies generated in the model of gauged hybrid inflation in which the complex waterfall field is charged under a U(1)gauge field. Primordial anisotropies are generated either actively during inflation or from inhomogeneities modulating the surface of end of inflation during waterfall transition. We present a consistent δN mechanism to calculate the anisotropic power spectrum and bispectrum. We show that the primordial anisotropies generated at the surface of end of inflation do not depend on the number of e-folds and therefore do not produce dangerously large anisotropies associated with the IR modes. Furthermore, one can find the parameter space that the anisotropies generated from the surface of end of inflation cancel the anisotropies generated during inflation, therefore relaxing the constrains on model parameters imposed from IR anisotropies. We also show that the gauge field fluctuations induce a red-tilted power spectrum so the averaged power spectrum from the gauge field can change the total power spectrum from blue to red. Therefore, hybrid inflation, once gauged under a U(1) field, can be consistent with the cosmological observations
Dual-chamber inflatable oil boom
International Nuclear Information System (INIS)
Blair, R.M.; Tedeschi, E.T.
1993-01-01
An elongated floating material containment boom section is described having a normally vertical ballasted skirt depending from flotation means, and convertible from a flattened collapsed condition to a deployable condition wherein buoyancy chamber means extending along the upper edge of said skirt are inflated to expanded buoyant configuration, including: a gas-impervious sleeve extending along the upper edge of said normally vertical skirt forming a first outer collapsible and inflatable flotation chamber, a first inflation valve connecting the interior of said sleeve with the ambient atmosphere, through which gas under pressure may be introduced into said sleeve to inflate said first buoyant outer flotation chamber, elongated gas-impervious tube means positioned inside said outer flotation chamber and forming second collapsible and inflatable internal flotation bladder chamber means, second inflation valve means connecting the interior of said bladder means through said outer flotation chamber to the ambient atmosphere through which gas under pressure may be introduced into said bladder means to inflate it forming said second flotation chamber means inside said outer flotation chamber
An evaluation of inflation expectations in Turkey
Directory of Open Access Journals (Sweden)
Barış Soybilgen
2017-03-01
Full Text Available Expectations of inflation play a critical role in the process of price setting in the market. Central banks closely follow developments in inflation expectations to implement a successful monetary policy. The Central Bank of the Republic of Turkey (CBRT conducts a survey of experts and decision makers in the financial and real sectors to reveal market expectations and predictions of current and future inflation. The survey is conducted every month. This paper examines the accuracy of these survey predictions using forecast evaluation techniques. We focus on both point and sign accuracy of the predictions. Although point predictions from CBRT surveys are compared with those of autoregressive models, sign predictions are evaluated on their value to a user. We also test the predictions for bias. Unlike the empirical evidence from other economies, our results show that autoregressive models outperform most of inflation expectations in forecasting inflation. This indicates that inflation expectations have poor point forecast accuracies. However, we show that sign predictions for all inflation expectations have value to a user.
Taxation, Fiscal Deficit and Inflation in Pakistan
Directory of Open Access Journals (Sweden)
Ghulam Rasool Madni
2014-09-01
Full Text Available Fiscal policy has more controversial debate regarding its effectiveness on different macroeconomic activities of an economy. Taxation and government expenditure are two main instruments of fiscal policy. This paper is aimed to analyze and update the effects of different instruments of fiscal policy on inflation in Pakistan economy. The data time span for this study is 1979-2013. The impact of fiscal policy on inflation is analyzed by utilizing the Bounds testing procedure and ARDL approach of co-integration which is a better estimation technique for small sample size. It is found that investment negatively and significantly affect the inflation rate. The outcomes of the study show that both types of taxes (direct and indirect are causing to increase the inflation level while fiscal deficit is also one of the reasons to increase the inflation in the country. The study proposed that government should decrease the level of expenditure to reduce the level of fiscal deficit and investment have to be promoted to decrease the inflation in the country. Furthermore, it is also suggested to decrease the level of taxation for controlling inflation.
Warm Inflation with Nonminimal Derivative Coupling
International Nuclear Information System (INIS)
Rashidi, N.; Nozari, Kourosh; Shoukrani, M.
2014-01-01
We study the effects of the nonminimal derivative coupling on the dissipative dynamics of the warm inflation where the scalar field is nonminimally coupled to gravity via its kinetic term. We present a detailed calculation of the cosmological perturbations in this setup. We use the recent observational data from the joint data set of WMAP9 + BAO + H 0 and also the Planck satellite data to constrain our model parameters for natural and chaotic inflation potentials. We study also the levels of non-Gaussianity in this warm inflation model and we confront the result with recent observational data from the Planck satellite
A general framework of automorphic inflation
International Nuclear Information System (INIS)
Schimmrigk, Rolf
2016-01-01
Automorphic inflation is an application of the framework of automorphic scalar field theory, based on the theory of automorphic forms and representations. In this paper the general framework of automorphic and modular inflation is described in some detail, with emphasis on the resulting stratification of the space of scalar field theories in terms of the group theoretic data associated to the shift symmetry, as well as the automorphic data that specifies the potential. The class of theories based on Eisenstein series provides a natural generalization of the model of j-inflation considered previously.
Inflation and Instability of a Polymeric Membrane
DEFF Research Database (Denmark)
Neergaard, Jesper; Hassager, Ole
1999-01-01
We consider an axisymmetric polymeric membrane inflated by a uniform pressure difference acting across the membrane. The polymeric materialis described by an arbitrary combination of a viscoelastic and a purely viscous component to the stress. Some viscoelastic materials described by a Mooney......-Rivlin model show a monotone increasingpressure during inflation of a spherical membrane. These materials develop a homogeneous membrane thickness in agreement with the Considere-Pearson condition. Molecularly based models such as the neo-Hookean, Doi-Edwards or Tom-Pom model show a pressure maximum when...... inflated. Membranesdescribed by these models develop a local thinning of the membrane which may lead to bursting in finite time....
Theories of inflation and conformal transformations
International Nuclear Information System (INIS)
Kalara, S.; Kaloper, N.; Olive, K.A.
1990-01-01
We show that several different theories of inflation including R 2 , Brans-Dicke, and induced-gravity inflation are all related to generalized or power-law inflation by means of conformal transformations. These theories all involve non-standard gravity, and the use of conformal transformations allows one to obtain standard inflationary predictions such as the expansion time-scale, reheating and density perturbations in each case very simply. We also discuss the possibilities of this method to be applied to string theory. (orig.)
Inflation in the Universe, circa 1986
International Nuclear Information System (INIS)
Turner, M.S.; Chicago Univ., IL
1988-01-01
The status of the 'Inflationary Paradigm', Circa 1986 is reviewed. At present essentially all inflationary models involve a very weakly-coupled scalar field which is displaced from the minimum of its potential. Regions of the Universe where the scalar field is initially displaced from its minimum undergo inflation as the scalar field relaxes, resulting in a Universe today which resembles ours in regions much larger than our present Hubble volume (≅ 10 28 cm), but which on very largescales (>> 10 28 cm) may be highly irregular. Some other unresolved issues facing inflation, including the confrontation between the predictions of inflation and observational data, are also reviewed. (author) 113 refs.; 4 figs
On the constant-roll inflation
Yi, Zhu; Gong, Yungui
2018-03-01
The primordial power spectra of scalar and tensor perturbations during slow-roll inflation are usually calculated with the method of Bessel function approximation. For constant-roll or ultra slow-roll inflation, the method of Bessel function approximation may be invalid. We compare the numerical results with the analytical results derived from the Bessel function approximation, and we find that they differ significantly on super-horizon scales if the constant slow-roll parameter ηH is not small. More accurate method is needed for calculating the primordial power spectrum for constant-roll inflation.
Spacetime Curvature and Higgs Stability after Inflation.
Herranen, M; Markkanen, T; Nurmi, S; Rajantie, A
2015-12-11
We investigate the dynamics of the Higgs field at the end of inflation in the minimal scenario consisting of an inflaton field coupled to the standard model only through the nonminimal gravitational coupling ξ of the Higgs field. Such a coupling is required by renormalization of the standard model in curved space, and in the current scenario also by vacuum stability during high-scale inflation. We find that for ξ≳1, rapidly changing spacetime curvature at the end of inflation leads to significant production of Higgs particles, potentially triggering a transition to a negative-energy Planck scale vacuum state and causing an immediate collapse of the Universe.
Macroeconomic susceptibility, inflation, and aggregate supply
Hawkins, Raymond J.
2017-03-01
We unify aggregate-supply dynamics as a time-dependent susceptibility-mediated relationship between inflation and aggregate economic output. In addition to representing well various observations of inflation-output dynamics this parsimonious formalism provides a straightforward derivation of popular representations of aggregate-supply dynamics and a natural basis for economic-agent expectations as an element of inflation formation. Our formalism also illuminates questions of causality and time-correlation that challenge central banks for whom aggregate-supply dynamics is a key constraint in their goal of achieving macroeconomic stability.
D-term uplifted racetrack inflation
Energy Technology Data Exchange (ETDEWEB)
Brax, P. [Unite de Recherche associee au CNRS, Gif sur Yvette (France). Service de Physique Theorique, CEA/DSM/SPhT; Davis, A.C. [Cambridge Univ. (United Kingdom). DAMTP, Centre for Mathematical Sciences; Davis, S.C. [Paris-11 Univ., 91 - Orsay (France). Lab. de Physique Theorique et Hautes Energies; Jeannerot, R. [Instituut-Lorentz for Theoretical Physics, Leiden (Netherlands); Postma, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)]|[Nationaal Inst. voor Kernfysica en Hoge-Energiefysica (NIKHEF), Amsterdam (Netherlands)
2007-10-15
It is shown that racetrack inflation can be implemented in a moduli stabilisation scenario with a supersymmetric uplifting D-term. The resulting model is completely described by an effective supergravity theory, in contrast to the original racetrack models. We study the inflationary dynamics and show that the gaugino condensates vary during inflation. The resulting spectral index is n{sub s} {approx}0.95 as in the original racetrack inflation model. Hence extra fields do not appear to alter the predictions of the model. An equivalent, simplified model with just a single field is presented. (orig.)
A general framework of automorphic inflation
Energy Technology Data Exchange (ETDEWEB)
Schimmrigk, Rolf [Department of Physics, Indiana University at South Bend,1700 Mishawaka Ave. South Bend, IN 46634 (United States)
2016-05-24
Automorphic inflation is an application of the framework of automorphic scalar field theory, based on the theory of automorphic forms and representations. In this paper the general framework of automorphic and modular inflation is described in some detail, with emphasis on the resulting stratification of the space of scalar field theories in terms of the group theoretic data associated to the shift symmetry, as well as the automorphic data that specifies the potential. The class of theories based on Eisenstein series provides a natural generalization of the model of j-inflation considered previously.
Accidental Kähler moduli inflation
International Nuclear Information System (INIS)
Maharana, Anshuman; Rummel, Markus; Sumitomo, Yoske
2015-01-01
We study a model of accidental inflation in type IIB string theory where inflation occurs near the inflection point of a small Kähler modulus. A racetrack structure helps to alleviate the known concern that string-loop corrections may spoil Kähler Moduli Inflation unless having a significant suppression via the string coupling or a special brane setup. Also, the hierarchy of gauge group ranks required for the separation between moduli stabilization and inflationary dynamics is relaxed. The relaxation becomes more significant when we use the recently proposed D-term generated racetrack model
78 FR 5722 - Civil Monetary Penalty Inflation Adjustment
2013-01-28
... Civil Monetary Penalty Inflation Adjustment AGENCY: U.S. Army Corps of Engineers, DoD. ACTION: Direct... for inflation. The adjustment of civil penalties to account for inflation is required by the Federal Civil Penalties Inflation Adjustment Act of 1990, as amended. Since we have not made any adjustments to...
12 CFR 263.65 - Civil penalty inflation adjustments.
2010-01-01
... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Civil penalty inflation adjustments. 263.65... Money Penalties § 263.65 Civil penalty inflation adjustments. (a) Inflation adjustments. In accordance with the Federal Civil Penalties Inflation Adjustment Act of 1990 (28 U.S.C. 2461 note), the Board has...
77 FR 65100 - Adjustment of Civil Monetary Penalties for Inflation
2012-10-25
... Penalties for Inflation AGENCY: Commodity Futures Trading Commission ACTION: Final rule. SUMMARY: The... civil monetary penalties, to adjust for inflation. This rule sets forth the maximum, inflation-adjusted... Federal Civil Penalties Inflation Adjustment Act of 1990, as amended by the Debt Collection Improvement...
46 CFR 506.3 - Civil monetary penalty inflation adjustment.
2010-10-01
... 46 Shipping 9 2010-10-01 2010-10-01 false Civil monetary penalty inflation adjustment. 506.3... PENALTY INFLATION ADJUSTMENT § 506.3 Civil monetary penalty inflation adjustment. The Commission shall... each civil monetary penalty provided by law within the jurisdiction of the Commission by the inflation...
78 FR 5760 - Civil Monetary Penalty Inflation Adjustment
2013-01-28
... Civil Monetary Penalty Inflation Adjustment AGENCY: U.S. Army Corps of Engineers, DoD. ACTION: Proposed... account for inflation. The adjustment of civil penalties to account for inflation is required by the Federal Civil Penalties Inflation Adjustment Act of 1990, as amended. Since we have not made any...
On the burst of branched polymer melts during inflation
DEFF Research Database (Denmark)
Rasmussen, Henrik K.; Yu, Kaijia
2008-01-01
Two molten low-density polyethylene melts, shaped as plates, have been inflated into a circular cylinder during isothermal conditions. Lowering the inflation rates allow the plates to be inflated into a larger volume of the cylinder before bursting. Numerical simulations of the inflations have been...
The mechanism of double-exponential growth in hyper-inflation
Mizuno, T.; Takayasu, M.; Takayasu, H.
2002-05-01
Analyzing historical data of price indices, we find an extraordinary growth phenomenon in several examples of hyper-inflation in which, price changes are approximated nicely by double-exponential functions of time. In order to explain such behavior we introduce the general coarse-graining technique in physics, the Monte Carlo renormalization group method, to the price dynamics. Starting from a microscopic stochastic equation describing dealers’ actions in open markets, we obtain a macroscopic noiseless equation of price consistent with the observation. The effect of auto-catalytic shortening of characteristic time caused by mob psychology is shown to be responsible for the double-exponential behavior.
Eternal extended inflation and graceful exit from old inflation without Jordan-Brans-Dicke
Linde, Andrei
1990-10-01
Recently a possible solution to the graceful exit problem of the old inflation was proposed in the context of the Jordan-Brans-Dicke theory (extended inflation). In this paper we will argue that inflation in this theory occurs in a most natural way if it starts near the Planck density, as in the standard version of chaotic inflation. With most natural initial conditions, the inflationary universe in the JBD theory enters the stage of permanent reproduction of new inflationary domains (eternal extended inflation). In order to realize the extended inflation scenario at least two classical scalar fields driving inflation are necessary, as distinct from the simplest versions of new and chaotic inflation. It is shown that in the theory of two scalar fields one can solve the graceful exit problem even without modifying the Einstein gravity theory, due to the possibility that the decay rate of the false rate vacuum in old inflation depends on the value of the second scalar field and hence on time. Address after 1 September 1990: Physics Department, Stanford University, Varian Building, Stanford, CA 94305, USA.
What Drives China's Food-Price Inflation and How does It Affect the Aggregate Inflation?
Wenlang Zhang; Daniel Law
2010-01-01
It is typically argued that China's food-price inflation has been mainly driven by supply-side shocks including natural disasters. Our research, however, shows that demand pressures have played a more important role from a medium-term perspective. This suggests surging food prices may call for policy reactions even if non-food-price inflation is tame. Meanwhile, we find food-price inflation has not generated significant second-round effects on non-food-price inflation. In particular, while fo...
IAS15 inflation adjustments and EVA: empirical evidence from a highly variable inflation regime
Directory of Open Access Journals (Sweden)
Pierre Erasmus
2011-08-01
Full Text Available Inflation can have a pronounced effect on the financial performance of a firm. This study makes inflation adjustments to a firm’s cost of sales, depreciation, level of gearing and assets in line with International Accounting Standard 15 (IAS15 in order to calculate an inflation-adjusted version of the economic value added (EVA measure. The study was conducted using data from South African industrial firms during a period characterised by highly variable inflation levels (1991-2005. The results indicate that during this period there were significant differences between the nominal and real values of the firms’ EVAs
Eternal extended inflation and graceful exit from old inflation without Jordan-Brans-Dicke
International Nuclear Information System (INIS)
Linde, A.
1990-01-01
Recently a possible solution to the graceful exit problem of the old inflation was proposed in the context of the Jordan-Brans-Dicke theory (extended inflation). In this paper we will argue that inflation in this theory occurs in a most natural way if it starts near the Planck density, as in the standard version of chaotic inflation. With most natural initial conditions, the inflationary universe in the JBD theory enters the stage of permanent reproduction of new inflationary domains (eternal extended inflation). In order to realize the extended inflation scenario at least two classical scalar fields driving inflation are necessary, as distinct from the simplest versions of new and chaotic inflation. It is shown that in the theory of two scalar fields one can solve the graceful exit problem even without modifying the Einstein gravity theory, due to the possibility that the decay rate of the false vacuum in old inflation depends on the value of the second scalar field and hence on time. (orig.)
Cosmological perturbations in transient phantom inflation scenarios
Energy Technology Data Exchange (ETDEWEB)
Richarte, Martin G. [Universidade Federal do Parana, Departamento de Fisica, Caixa Postal 19044, Curitiba (Brazil); Universidad de Buenos Aires, Ciudad Universitaria 1428, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Kremer, Gilberto M. [Universidade Federal do Parana, Departamento de Fisica, Caixa Postal 19044, Curitiba (Brazil)
2017-01-15
We present a model of inflation where the inflaton is accommodated as a phantom field which exhibits an initial transient pole behavior and then decays into a quintessence field which is responsible for a radiation era. We must stress that the present unified model only deals with a single field and that the transition between the two eras is achieved in a smooth way, so the model does not suffer from the eternal inflation issue. We explore the conditions for the crossing of the phantom divide line within the inflationary era along with the structural stability of several critical points. We study the behavior of the phantom field within the slow-climb approximation along with the necessary conditions to have sufficient inflation. We also examine the model at the level of classical perturbations within the Newtonian gauge and determine the behavior of the gravitational potential, contrast density and perturbed field near the inflation stage and the subsequent radiation era. (orig.)
Vapor pressure measured with inflatable plastic bag
1965-01-01
Deflated plastic bag in a vacuum chamber measures initial low vapor pressures of materials. The bag captures the test sample vapors and visual observation of the vapor-inflated bag under increasing external pressures yields pertinent data.
National Research Council Canada - National Science Library
Goldberg, Matthew
1997-01-01
.... A variety of inflation indices are used in updating the DHP budget requirement. This paper evaluates the appropriateness of those indices, and identifies alternative indices that are theoretically superior to those currently in use...
Fibre inflation and α-attractors
Energy Technology Data Exchange (ETDEWEB)
Kallosh, Renata; Linde, Andrei [Stanford Univ., Stanford, CA (United States). Stanford Inst. for Theoretical Physics and Dept. of Physics; Leiden Univ. (Netherlands). Lorentz Inst. for Theoretical Physics; Roest, Diederik [Groningen Univ. (Netherlands). Van Swinderen Inst. for Particle Physics and Gravity; Westphal, Alexander [DESY, Hamburg (Germany). Theory Group; Yamada, Yusuke [Stanford Univ., Stanford, CA (United States). Stanford Inst. for Theoretical Physics and Dept. of Physics
2017-07-15
Fibre inflation is a specific string theory construction based on the Large Volume Scenario that produces an inflationary plateau. We outline its relation to α-attractor models for inflation, with the cosmological sector originating from certain string theory corrections leading to α=2 and α=1/2. Above a certain field range, the steepening effect of higher-order corrections leads first to the breakdown of single-field slow-roll and after that to the onset of 2-field dynamics: the overall volume of the extra dimensions starts to participate in the effective dynamics. Finally, we propose effective supergravity models of fibre inflation based on an D3 uplift term with a nilpotent superfield. Specific moduli dependent D3 induced geometries lead to cosmological fibre models but have in addition a de Sitter minimum exit. These supergravity models motivated by fibre inflation are relatively simple, stabilize the axions and disentangle the Hubble parameter from supersymmetry breaking.
Solid State Inflation Balloon Active Deorbiter
National Aeronautics and Space Administration — The Solid State Inflation Balloon (SSIB) is a simple, reliable, low-cost, non-propulsive system for deliberate deorbit and control of downrange point-of-impact that...
Higher Curvature Supergravity, Supersymmetry Breaking and Inflation
Ferrara, Sergio
2017-01-01
In these lectures, after a short introduction to cosmology, we discuss the supergravity embedding of higher curvature models of inflation. The supergravity description of such models is presented for the two different formulations of minimal supergravity.
Metric fluctuations and their evolution during inflation
International Nuclear Information System (INIS)
Anabitarte, M.; Bellini, M.
2004-01-01
We discuss the evolution of the fluctuations in a symmetric φ c -exponential potential which provides a power-law expansion during inflation using both the gauge-invariant field Φ and the Sasaki-Mukhanov field. (orig.)
Inflatable Air Beam Standard Interface Connector
National Aeronautics and Space Administration — The project will develop a system of 3D-printed connectors that can be used as a kit of parts to connect inflatable air beams to form a variety of spacecraft...
Lightweight Materials and Structures (LMS): Inflatable Structures
National Aeronautics and Space Administration — Current inflatable structures are designed on the restraint layer’s short term properties with a Factor of Safety of 4 due to lack of long-term data on structural...
Private Sector Credit and Inflation Volatility
Directory of Open Access Journals (Sweden)
Lorna Katusiime
2018-04-01
Full Text Available This paper investigates the effect of inflation volatility on private sector credit growth. The results indicate that private sector credit growth is positively linked to the one period lagged inflation volatility. Given that past monetary policy actions continue to affect the targeted variables due to the substantial lags in the transmission mechanism, the positive response of private sector credit growth to past inflation volatility suggests a credible monetary policy regime in Uganda, which has led to a reduction in the level of macroeconomic uncertainty and the restoration of favorable economic conditions and prospects, thus increasing the demand for credit. Further, the study finds that the lagged private sector credit growth, nominal exchange rate, and inflation have a statistically significant effect on private sector credit growth while financial innovation, interest rates, and GDP growth appear not to be important determinants of private sector credit growth. The robustness of our findings is confirmed by sensitivity checks.
Inflation's Impact on Faculty Retirement Annuities
Dorfman, Nancy S.
1975-01-01
The discussion is confined to the Teachers Insurance and Annuity Association (TIAA) and College Retirement Equities Fund (CREF) and how they have remained effective with the rise of inflation. (Author/BP)
Inflation gifts and endogenous growth through learning-by-doing
Andrea Vaona
2013-01-01
We investigate the link between inflation, growth and unemployment nesting a model of fair wages into one of endogenous growth of learning by doing and assuming that firms protect wages' purchasing power against inflation in exchange of worker's effort. Unemployment decreases with higher inflation and real growth rates. These effects tends to vanish as inflation and growth increase. Depending on the assumptions on learning-by-doing mechanisms, the effect of inflation on growth can be either n...
Determinant and impacts of dynamic inflation in Ethiopia
Biresaw, Temesgen Tezera
2014-01-01
This thesis uses quarterly data for the period 1998-2010 to investigate the determinant and impacts of dynamic inflation in Ethiopia. By using Granger causality model approach four testable hypotheses are investigated: (1) does the money supply growth Granger-cause inflation? (2) Does currency devaluation Granger cause inflation? (3) Does inflation affect economic growth? And (4) Does oil price Granger cause of inflation? The empirical results suggest that there existed a bi-directional ...
Thermal history of the universe after inflation
Energy Technology Data Exchange (ETDEWEB)
Watson, Scott, E-mail: gswatson@syr.edu [Department of Physics, Syracuse University, Syracuse, NY 13244 (United States)
2016-06-21
When did the universe thermalize? In this talk I review the status of this issue and its importance in establishing the expected properties of dark matter, the growth of large-scale structure, and the viability of inflation models when confronted with CMB observations. I also present a novel approach to tackling the theoretical challenges surrounding inflationary (p)reheating, which seeks to extend past work on the Effective Field Theory of Inflation to the time of reheating.
Finite temperature effects in primordial inflation
Gelmini, G. B.; Nanopoulos, D. V.; Olive, K. A.
1983-11-01
We present a detailed study of a recently proposed model for primordial inflation based on an N=1 locally supersymmetric potential. For a large class of parameters with which all cosmological constraints are satisfied, the temperature corrections can be neglected during the inflation period. At higher temperatures, the minimum is not at the origin, but very close to it. Address after July 1, 1983: Theory Group, Fermilab, PO Box 500, Batavia, IL 60510, USA.
Gravitino problem in minimal supergravity inflation
Directory of Open Access Journals (Sweden)
Fuminori Hasegawa
2017-04-01
Full Text Available We study non-thermal gravitino production in the minimal supergravity inflation. In this minimal model utilizing orthogonal nilpotent superfields, the particle spectrum includes only graviton, gravitino, inflaton, and goldstino. We find that a substantial fraction of the cosmic energy density can be transferred to the longitudinal gravitino due to non-trivial change of its sound speed. This implies either a breakdown of the effective theory after inflation or a serious gravitino problem.
Gravitino problem in minimal supergravity inflation
Energy Technology Data Exchange (ETDEWEB)
Hasegawa, Fuminori [Institute for Cosmic Ray Research, The University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Mukaida, Kyohei [Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Nakayama, Kazunori [Department of Physics, Faculty of Science, The University of Tokyo, Bunkyo-ku, Tokyo 133-0033 (Japan); Terada, Takahiro, E-mail: terada@kias.re.kr [School of Physics, Korea Institute for Advanced Study (KIAS), Seoul 02455 (Korea, Republic of); Yamada, Yusuke [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University, Stanford, CA 94305 (United States)
2017-04-10
We study non-thermal gravitino production in the minimal supergravity inflation. In this minimal model utilizing orthogonal nilpotent superfields, the particle spectrum includes only graviton, gravitino, inflaton, and goldstino. We find that a substantial fraction of the cosmic energy density can be transferred to the longitudinal gravitino due to non-trivial change of its sound speed. This implies either a breakdown of the effective theory after inflation or a serious gravitino problem.
Dynamical Baryogenesis in Complex Hybrid Inflation
International Nuclear Information System (INIS)
Delepine, David; Martinez, Carlos; Urena-Lopez, L. Arturo
2008-01-01
We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U (1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vev of the waterfall field, which is well constrained by diverse cosmological observations
Texture and inflation in a closed universe
International Nuclear Information System (INIS)
Hacyan, S.; Sarmiento, A.
1993-01-01
We present a cosmological model with a global homogeneous texture and inflation, but without an initial singularity. The Universe starts from an equilibrium configuration in a symmetric vacuum; the dynamic stability of this configuration is studied. We obtain numerical solutions which show that the Universe expands exponentially and the texture field decays in a finite time; this corresponds to a period of inflation followed naturally by a Friedmann expansion
Taxation, Fiscal Deficit and Inflation in Pakistan
Ghulam Rasool Madni
2014-01-01
Fiscal policy has more controversial debate regarding its effectiveness on different macroeconomic activities of an economy. Taxation and government expenditure are two main instruments of fiscal policy. This paper is aimed to analyze and update the effects of different instruments of fiscal policy on inflation in Pakistan economy. The data time span for this study is 1979-2013. The impact of fiscal policy on inflation is analyzed by utilizing the Bounds testing procedure and ARDL approach of...
Inflation Hedging for Long-Term Investors
Shaun K. Roache; Alexander P. Attie
2009-01-01
Long-term investors face a common problem-how to maintain the purchasing power of their assets over time and achieve a level of real returns consistent with their investment objectives. While inflation-linked bonds and derivatives have been developed to hedge the effects of inflation, their limited supply and liquidity lead many investors to continue to rely on the indirect hedging properties of traditional asset classes. In this paper, we assess these properties over different time horizons,...