MAXIMAL ACCELERATION TUNNELING FROM “NOTHING”

1994 ◽  
Vol 03 (02) ◽  
pp. 485-492 ◽  
Author(s):  
E.R. CAIANIELLO ◽  
A. FEOLI ◽  
G. SCARPETTA ◽  
S. CAPOZZIELLO ◽  
R. DE RITIS
Keyword(s):  
Wave Function ◽  
Scalar Field ◽  
Degrees Of Freedom ◽  
Nonminimal Coupling ◽  
Maximal Acceleration ◽  
Walker Metric ◽  
The Universe

We find the Wheeler-DeWitt equation for a Friedman-Robertson-Walker metric modified according to a model with maximal acceleration and discuss the new conditions in which the wave function of the universe tunnels from the Euclidean regime to the Lorentzian one. We argue that the acceleration induces a nonminimal coupling of the scalar field with the gravitational degrees of freedom and provides a new dynamical possibility of tunneling through the quantum boundary when [Formula: see text].

INTERPRETATION AND PREDICTABILITY OF QUANTUM MECHANICS AND QUANTUM COSMOLOGY

1988 ◽  
Vol 03 (07) ◽  
pp. 645-651 ◽  
Author(s):  
SUMIO WADA
Keyword(s):  
Wave Function ◽  
Quantum Mechanics ◽  
Quantum Theory ◽  
Physical Meaning ◽  
Quantum Cosmology ◽  
Degrees Of Freedom ◽  
Interpretation Of Quantum Mechanics ◽  
Probabilistic Interpretation ◽  
The Universe ◽  
Classical Picture

A non-probabilistic interpretation of quantum mechanics asserts that we get a prediction only when a wave function has a peak. Taking this interpretation seriously, we discuss how to find a peak in the wave function of the universe, by using some minisuperspace models with homogeneous degrees of freedom and also a model with cosmological perturbations. Then we show how to recover our classical picture of the universe from the quantum theory, and comment on the physical meaning of the backreaction equation.

scholarly journals Quantum Cosmology of Quadratic f(R) Theories with a FRW Metric

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
V. Vázquez-Báez ◽  
C. Ramírez
Keyword(s):  
Wave Function ◽  
Scalar Field ◽  
Boundary Conditions ◽  
Numerical Solution ◽  
Quantum Cosmology ◽  
Free Parameter ◽  
Equations Of Motion ◽  
Frw Metric ◽  
The Universe

We study the quantum cosmology of a quadratic fR theory with a FRW metric, via one of its equivalent Horndeski type actions, where the dynamic of the scalar field is induced. The classical equations of motion and the Wheeler-DeWitt equation, in their exact versions, are solved numerically. There is a free parameter in the action from which two cases follow: inflation + exit and inflation alone. The numerical solution of the Wheeler-DeWitt equation depends strongly on the boundary conditions, which can be chosen so that the resulting wave function of the universe is normalizable and consistent with Hermitian operators.

NÖTHER’S SYMMETRIES IN QUANTUM COSMOLOGY

1994 ◽  
Vol 03 (03) ◽  
pp. 609-621 ◽  
Author(s):  
SALVATORE CAPOZZIELLO ◽  
RUGGIERO DE RITIS ◽  
PAOLO SCUDELLARO
Keyword(s):  
Wave Function ◽  
Scalar Field ◽  
Quantum Cosmology ◽  
Selection Rule ◽  
Theories Of Gravity ◽  
The Universe ◽  
Semiclassical Regime

We construct minisuperspace models for a class of theories of gravity nonminimally coupled with a scalar field. We show that when a Nöther symmetry exists, it is always possible to integrate the Wheeler-DeWitt equation and recover the semiclassical regime for the wave function of the universe. In this sense, we can interpret the Nöther symmetries as a selection rule in the philosophy of the so called Hartle criterion: when they exist, it is possible to select classical universes.

QUANTUM COSMOLOGY WITH A NONLINEAR BORN–INFELD TYPE SCALAR FIELD

1999 ◽  
Vol 08 (05) ◽  
pp. 625-634 ◽  
Author(s):  
H. Q. LU ◽  
T. HARKO ◽  
K. S. CHENG
Keyword(s):  
Wave Function ◽  
Scalar Field ◽  
Quantum Cosmology ◽  
Vacuum Energy ◽  
Quantum Model ◽  
Inflationary Universe ◽  
Cosmological Scale ◽  
Scale Factors ◽  
Nonlinear Scalar Field ◽  
The Universe

A quantum model of gravitation interacting with a Born–Infeld type nonlinear scalar field φ is considered. The corresponding Wheeler–DeWitt equation can be solved analytically for both large and small [Formula: see text]. In the extreme limits of small and large cosmological scale factors the wave function of the Universe can also be obtained by applying the methods developed by Vilenkin and Hartle and Hawking. An inflationary Universe is predicted with the largest possible vacuum energy and the largest interaction between the particles of the nonlinear scalar field.

scholarly journals A SCHRÖDINGER EQUATION FOR MINIUNIVERSES

1995 ◽  
Vol 10 (05) ◽  
pp. 611-633 ◽  
Author(s):  
MARCO CAVAGLIÀ ◽  
VITTORIO DE ALFARQ ◽  
ALEXANDRE T. FILIPPOV
Keyword(s):  
Wave Function ◽  
Schrödinger Equation ◽  
Finite Number ◽  
Schrodinger Equation ◽  
Degrees Of Freedom ◽  
Effective Hamiltonian ◽  
Zero Modes ◽  
Walker Metric ◽  
Time Reparametrization Invariance ◽  
Reparametrization Invariance

We discuss how to fix the gauge in the canonical treatment of Lagrangians, with a finite number of degrees of freedom, endowed with time reparametrization invariance. The motion can be described by an effective Hamiltonian acting on the gauge shell canonical space. The system is then suited for quantization. We apply this treatment to the case of a Robertson–Walker metric interacting with zero modes of bosonic fields and write a Schrödinger equation for the on-shell wave function.

scholarly journals QUANTIZATION OF THE BIANCHI TYPE IX MODEL IN N=1 SUPERGRAVITY IN THE PRESENCE OF SUPERMATTER

1996 ◽  
Vol 11 (10) ◽  
pp. 1763-1795 ◽  
Author(s):  
P.V. MONIZ
Keyword(s):  
Wave Function ◽  
Scalar Field ◽  
General Theory ◽  
Bianchi Type ◽  
Two Dimensional ◽  
Kahler Geometry ◽  
Complex Scalar ◽  
Analytical Potential ◽  
Complex Scalar Field ◽  
The Universe

The general theory of N=1 supergravity with supermatter is applied to a Bianchi type IX diagonal model. The supermatter is constituted by a complex scalar field and its [Formula: see text] fermionic partners. The Kähler geometry is chosen to be a two-dimensional flat one. The Lorentz-invariant ansatz for the wave function of the universe is taken to be as simple as possible in order to obtain new solutions. The set of differential equations derived from the quantum constraints are analyzed in two different cases: if the supermatter terms include an analytical potential or not. In the latter the wave function is found to have a simple form.

THE STABILITY OF THE MINISUPERSPACE

1993 ◽  
Vol 08 (36) ◽  
pp. 3413-3427 ◽  
Author(s):  
ATUSHI ISHIKAWA ◽  
TOSHIKI ISSE
Keyword(s):  
Scalar Field ◽  
Early Universe ◽  
Degrees Of Freedom ◽  
Einstein Gravity ◽  
Scale Factor ◽  
Planck Length ◽  
Inhomogeneous Wave ◽  
The Stability ◽  
The Universe ◽  
Wave Modes

The stability of the minisuperspace model of the early universe is studied by solving the Wheeler-DeWitt equation numerically. We consider a system of Einstein gravity with a scalar field. When we solve the Wheeler-DeWitt equation, we pick up some inhomogeneous wave modes from infinite wave modes adequately: degrees of freedom of the superspace are restricted to finite. We show that the minisuperspace is stable when a scale factor (a) of the universe is a few times larger than the Planck length, while it becomes unstable when a is comparable to the Planck length.

CLASSICAL CHANGE OF SIGNATURE INDUCED BY ACCELERATION

1993 ◽  
Vol 02 (01) ◽  
pp. 79-83
Author(s):  
S. CAPOZZIELLO ◽  
A. FEOLI
Keyword(s):  
Wave Function ◽  
Quantum Cosmology ◽  
Maximal Acceleration ◽  
Rindler Space ◽  
The Universe

We discuss the classical change of signature in Rindler space modified according to a model with maximal acceleration. This fact acquires great interest in quantum cosmology, when one considers the wave function of the universe tunneling from the Euclidean regime to the Lorentzian one.

Quantum Bohmian description of a primordial universe with Fermionic and Bosonic sources

2021 ◽  
pp. 2150103
Author(s):  
Marlos O. Ribas ◽  
Fernando P. Devecchi ◽  
Gilberto M. Kremer
Keyword(s):  
Scalar Field ◽  
Degrees Of Freedom ◽  
Hamiltonian Formalism ◽  
Bohmian Mechanics ◽  
Smooth Transition ◽  
Conformal Time ◽  
Classical Analysis ◽  
Fermionic Field ◽  
Relativistic Fluid ◽  
The Universe

We present a model of an early universe where the sources of gravitational effects are a scalar field, a relativistic fluid based on Schutz’s model and a self-interacting fermionic field. From the classical analysis based on the Hamiltonian formalism we show that the scale factor of the universe can be expressed in terms of a conformal time that emerges from the fluid’s degrees of freedom. From the Wheeler–DeWitt equation, a wave packet solution as function of the conformal time is determined. It is shown that the combination of the scalar and the fermionic field furnishes a consistent quantum regime and a smooth transition to the classical description, working with the aid of the Bohmian mechanics and in particular with the concept of quantum potential. The influence of the presence of the scalar field is also discussed.

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