A New Inflationary Universe Scenario with Inhomogeneous Quantum Vacuum

We investigate the quantum vacuum and find that the fluctuations can lead to the inhomogeneous quantum vacuum. We find that the vacuum fluctuations can significantly influence the cosmological inhomogeneity, which is different from what was previously expected. By introducing the modified Green’s function, we reach a new inflationary scenario which can explain why the Universe is still expanding without slowing down. We also calculate the tunneling amplitude of the Universe based on the inhomogeneous vacuum. We find that the inhomogeneity can lead to the penetration of the Universe over the potential barrier faster than previously thought.

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FROM VACUUM IN AN INFLATIONARY UNIVERSE TO FLUCTUATIONS IN THE MICROWAVE BACKGROUND: THE THREAD OF THE ARGUMENT

International Journal of Modern Physics D ◽

10.1142/s0218271894000046 ◽

1994 ◽

Vol 03 (01) ◽

pp. 23-30

Author(s):

NATHALIE DERUELLE ◽

DAVID LANGLOIS ◽

DAVID POLARSKI

Keyword(s):

Background Radiation ◽

Temperature Fluctuations ◽

Inflationary Universe ◽

Quantum Vacuum ◽

Vacuum Fluctuations ◽

Microwave Background ◽

Evolution Of The Universe ◽

Inflationary Phase ◽

Microwave Background Radiation ◽

The Universe

We sketch the logics of the argument which claims that the temperature fluctuations in the microwave background radiation, observed by the COBE satellite, have originated from quantum vacuum fluctuations in an early, inflationary phase of the evolution of the universe.

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Gravitational waves and the (quantum) nature of the primordial seed

International Journal of Modern Physics D ◽

10.1142/s0218271814410053 ◽

2014 ◽

Vol 23 (12) ◽

pp. 1441005 ◽

Cited By ~ 2

Author(s):

Rafael A. Porto

Keyword(s):

Gravitational Waves ◽

Large Scale ◽

Direct Detection ◽

Indirect Measurement ◽

Effective Field ◽

Quantum Vacuum ◽

Vacuum Fluctuations ◽

Early Universe Cosmology ◽

New Generation ◽

The Universe

At first glance, the (indirect) measurement of primordial tensor modes by the BICEP2 Collaboration supports an inflationary paradigm for early universe cosmology together with quantum vacuum fluctuations (aka gravitons) as the origin of the spectrum. In this paper, we argue the observed signal may instead be a signature of semiclassical sources of perturbations during inflation. In this scenario, despite a large tensor-to-scalar ratio r ≃ 0.2, it may be possible to write an effective field theory (EFT) of a rolling scalar field without super-Planckian excursions. If the results from BICEP2 withstand further scrutiny, measurements of primordial non-Gaussianity with large scale structure surveys, and direct detection of gravitational waves (GWs) with the new generation of observatories, will be of paramount importance to elucidate the (quantum) origin of structure in the universe.

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ALFVEN MODES DRIVEN NONLINEARLY BY METRIC PERTURBATIONS IN ANISOTROPIC MAGNETIZED COSMOLOGIES

International Journal of Modern Physics A ◽

10.1142/s0217751x07036415 ◽

2007 ◽

Vol 22 (12) ◽

pp. 2197-2209 ◽

Cited By ~ 1

Author(s):

APOSTOLOS KUIROUKIDIS ◽

KOSTAS KLEIDIS ◽

DEMETRIOS B. PAPADOPOULOS

Keyword(s):

Magnetic Field ◽

Electric Field ◽

High Frequency ◽

Nonlinear Coupling ◽

Quantum Vacuum ◽

Pump Field ◽

Vacuum Fluctuations ◽

First Order ◽

Density Perturbations ◽

The Universe

We consider anisotropic magnetized cosmologies filled with conductive plasma fluid and study the implications of metric perturbations that propagate parallel to the ambient magnetic field. It is known that in the first-order (linear) approximation with respect to the amplitude of the perturbations no electric field and density perturbations arise. However when we consider the nonlinear coupling of the metric perturbations with their temporal derivatives, certain classes of solutions can induce steeply increasing in time, electric field perturbations. This is verified both numerically and analytically. The source of these perturbations can be either high-frequency quantum vacuum fluctuations, driven by the cosmological pump field, in the early stages of the evolution of the Universe, or astrophysical processes, or a nonlinear isotropization process, of an initially anisotropic cosmological space–time.

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Calculation of neutron slowing down spectrum in water using green's function

Journal of Nuclear Energy ◽

10.1016/0022-3107(73)90060-9 ◽

1973 ◽

Vol 27 (4) ◽

pp. 247-262

Author(s):

R.A. Bhatti

Keyword(s):

Green’S Function ◽

Green's Function ◽

Slowing Down

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Non-Gaussianity of inflationary gravitational waves from the field equation

International Journal of Modern Physics D ◽

10.1142/s0218271819500366 ◽

2019 ◽

Vol 28 (02) ◽

pp. 1950036 ◽

Cited By ~ 2

Author(s):

Aniket Agrawal

Keyword(s):

Field Equation ◽

Green’S Function ◽

Gravitational Waves ◽

Green's Function ◽

Tree Level ◽

Gauge Fields ◽

Vacuum Fluctuations ◽

Scale Invariant ◽

Left Handed ◽

Primordial Gravitational Waves

We demonstrate equivalence of the in–in formalism and Green’s function method for calculating the bispectrum of primordial gravitational waves generated by vacuum fluctuations of the metric. The tree-level bispectrum from the field equation, [Formula: see text], agrees with the results obtained previously using the in–in formalism exactly. Characterizing non-Gaussianity of the fluctuations using the ratio [Formula: see text] in the equilateral configuration, where [Formula: see text] is the power spectrum of scale-invariant gravitational waves, we show that it is much weaker than in models with spectator gauge fields. We also calculate the tree-level bispectrum of two right-handed and one left-handed gravitational wave using Green’s function, reproducing the results from in–in formalism, and show that it can be as large as the bispectrum of three right-handed gravitational waves.

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