We use the excited coherent states built over the initial non-de Sitter modes,to study the modification of spectra of primordial scalar fluctuation.Non-de Sitter modes are actually the asymptotic solution of the infla...We use the excited coherent states built over the initial non-de Sitter modes,to study the modification of spectra of primordial scalar fluctuation.Non-de Sitter modes are actually the asymptotic solution of the inflaton field equation[J.High Energy Phys.09（2014） 020].We build excited coherent states over the non-de Sitter modes and despite the Jack of interactions in the Lagrangian,we find a non-zero one-point function.It is shown that the primordial non-Gaussianity resulting from excited-de Sitter modes depend both of time and background space-time.It is very tiny of order（≤10^-24）,at the Planck initial fixed time that confirmed by resent observations for single field inflation but it grows in the present epoch.Moreover,our results at the leading order are similar to what obtained with general initial states and in the dS limit leads to standard results[J.Cosmol.Astropart.Phys.1202（2012） 005].We will show that the non-dS modes and its resulting spectrum are more usable for far past time limit.展开更多
On several levels of theoretical physics, especially particle physics and early universe cosmology, de Sitter space-time has become an attractive possibility. The principle of local gauge invariance governs all known ...On several levels of theoretical physics, especially particle physics and early universe cosmology, de Sitter space-time has become an attractive possibility. The principle of local gauge invariance governs all known fundamental interactions of elementary particles, from electromagnetism and weak interactions to strong interactions and gravity. This paper presents a procedure for defining the gauge-covariant derivative and gauge invariant Lagrangian densityin de Sitter ambient space-time formalism. The gauge invariant field equation is then explicitly calculated in detailfor a massless spit 3/2gauge field.展开更多
Since trans-Planckian considerations can be associated with the re-definition of the initial vacuum, we investigate further the influence of trans-Planckian physics on the spectra produced by the initial quasi-de Sit...Since trans-Planckian considerations can be associated with the re-definition of the initial vacuum, we investigate further the influence of trans-Planckian physics on the spectra produced by the initial quasi-de Sitter（d S） state during inflation. We use the asymptotic-d S mode to study the trans-Planckian correction of the power spectrum to the quasi-d S inflation. The obtained spectra consist of higher order corrections associated with the type of geometry and harmonic terms sensitive to the fluctuations of space-time（or gravitational waves） during inflation.As an important result, the amplitude of the power spectrum is dependent on the choice of c, i.e. the type of spacetime in the period of inflation. Also, the results are always valid for any asymptotic d S space-time and particularly coincide with the conventional results for d S and flat space-time.展开更多
According to inflationary cosmology, the CMB anisotropy gives an opportunity to test predictions of new physics hypotheses. The initial state of quantum fluctuations is one of the important options at high energy scal...According to inflationary cosmology, the CMB anisotropy gives an opportunity to test predictions of new physics hypotheses. The initial state of quantum fluctuations is one of the important options at high energy scale, as it can affect observables such as the CMB power spectrum. In this study a quasi-de Sitter inflationary background with approximate de Sitter mode function built over the Bunch-Davies mode is applied to investigate the scale-dependency of the CMB anisotropy. The recent Planck constraint on spectral index motivated us to examine the effect of a new excited mode function （instead of pure de Sitter mode） on the CMB anisotropy at large angular scales. In so doing, it is found that the angular scale-invariance in the CMB temperature fluctuations is broken and in the limit l 〈 200 a tiny deviation appears. Also, it is shown that the power spectrum of CMB anisotropy is dependent on a free parameter with mass dimension H 〈〈 M＊ 〈 Mp and on the slow-roll parameter ε.展开更多
基金supported by the Islamic Azad University,Ayatollah Amoli Branch, Amol,Mazandaran,Iran
文摘We use the excited coherent states built over the initial non-de Sitter modes,to study the modification of spectra of primordial scalar fluctuation.Non-de Sitter modes are actually the asymptotic solution of the inflaton field equation[J.High Energy Phys.09（2014） 020].We build excited coherent states over the non-de Sitter modes and despite the Jack of interactions in the Lagrangian,we find a non-zero one-point function.It is shown that the primordial non-Gaussianity resulting from excited-de Sitter modes depend both of time and background space-time.It is very tiny of order（≤10^-24）,at the Planck initial fixed time that confirmed by resent observations for single field inflation but it grows in the present epoch.Moreover,our results at the leading order are similar to what obtained with general initial states and in the dS limit leads to standard results[J.Cosmol.Astropart.Phys.1202（2012） 005].We will show that the non-dS modes and its resulting spectrum are more usable for far past time limit.
基金supported by the Islamic Azad University,Science and Research Branch,Tehran,Iran
文摘On several levels of theoretical physics, especially particle physics and early universe cosmology, de Sitter space-time has become an attractive possibility. The principle of local gauge invariance governs all known fundamental interactions of elementary particles, from electromagnetism and weak interactions to strong interactions and gravity. This paper presents a procedure for defining the gauge-covariant derivative and gauge invariant Lagrangian densityin de Sitter ambient space-time formalism. The gauge invariant field equation is then explicitly calculated in detailfor a massless spit 3/2gauge field.
基金supported by the Islamic Azad University,Qom Branch,Qom,Iran
文摘Since trans-Planckian considerations can be associated with the re-definition of the initial vacuum, we investigate further the influence of trans-Planckian physics on the spectra produced by the initial quasi-de Sitter（d S） state during inflation. We use the asymptotic-d S mode to study the trans-Planckian correction of the power spectrum to the quasi-d S inflation. The obtained spectra consist of higher order corrections associated with the type of geometry and harmonic terms sensitive to the fluctuations of space-time（or gravitational waves） during inflation.As an important result, the amplitude of the power spectrum is dependent on the choice of c, i.e. the type of spacetime in the period of inflation. Also, the results are always valid for any asymptotic d S space-time and particularly coincide with the conventional results for d S and flat space-time.
基金Supported by the Islamic Azad University,Rasht Branch,Rasht,Iran
文摘According to inflationary cosmology, the CMB anisotropy gives an opportunity to test predictions of new physics hypotheses. The initial state of quantum fluctuations is one of the important options at high energy scale, as it can affect observables such as the CMB power spectrum. In this study a quasi-de Sitter inflationary background with approximate de Sitter mode function built over the Bunch-Davies mode is applied to investigate the scale-dependency of the CMB anisotropy. The recent Planck constraint on spectral index motivated us to examine the effect of a new excited mode function （instead of pure de Sitter mode） on the CMB anisotropy at large angular scales. In so doing, it is found that the angular scale-invariance in the CMB temperature fluctuations is broken and in the limit l 〈 200 a tiny deviation appears. Also, it is shown that the power spectrum of CMB anisotropy is dependent on a free parameter with mass dimension H 〈〈 M＊ 〈 Mp and on the slow-roll parameter ε.
