Quantum fluctuations near the classical space-time singularity

1979 ◽  
Vol 10 (11) ◽  
pp. 883-896 ◽  
Author(s):  
J. V. Narlikar
Keyword(s):  
Quantum Fluctuations ◽  
Space Time ◽  
Time Singularity ◽  
Classical Space

Quantum fluctuations near a space–time singularity

1989 ◽  
Vol 67 (10) ◽  
pp. 935-938
Author(s):  
K. D. Krori ◽  
P. Borgohain ◽  
Dipali Das Kar
Keyword(s):  
Wave Function ◽  
Quantum Mechanics ◽  
Bianchi Type ◽  
Quantum Fluctuations ◽  
Space Time ◽  
Operator Technique ◽  
Time Singularity ◽  
Quantum Uncertainty ◽  
Initial Epoch ◽  
The Universe

The well-known operator technique in quantum mechanics is used to study quantum fluctuations near the space–time singularity using Kantowski–Sachs and Bianchi type VIo metrics. In both cases the wave function of the universe is found to diverge near the space–time singularity, indicating the divergence of the quantum uncertainty near the initial epoch.

Quantum conformal fluctuations near the classical space-time singularity

1981 ◽  
Vol 11 (5-6) ◽  
pp. 473-492 ◽  
Author(s):  
J. V. Narlikar
Keyword(s):  
Space Time ◽  
Time Singularity ◽  
Classical Space

The Kalam Cosmological Argument

2018 ◽  
Author(s):  
William Lane Craig
Keyword(s):  
Space Time ◽  
Cosmological Argument ◽  
Philosophical Literature ◽  
The Past ◽  
Classical Space ◽  
Kalam Cosmological Argument ◽  
Kalām Cosmological Argument ◽  
The Universe

A survey of recent philosophical literature on the kalam cosmological argument reveals that arguments for the finitude of the past and, hence, the beginning of the universe remain robust. Plantinga’s brief criticisms of Kant’s argument in his First Antinomy concerning time are shown not to be problematic for the kalam argument. This chapter addresses, one by one, the two premises of the kalam, focusing on their philosophical aspects. The notion of infinity, both actual and potential, is discussed in relation to the coming into being of the universe. In addition, the scientific aspects of the two premises are also, briefly, addressed. Among these are the Borde-Guth-Vilenkin theorem, which proves that classical space-time cannot be extended to past infinity but must reach a boundary at some time in the finite past. This, among other factors, lends credence to the kalam argument’s second premise.

Induced Quantum Fluctuations in the Spherically Symmetric Space–Time

1997 ◽  
Vol 12 (18) ◽  
pp. 3171-3180 ◽  
Author(s):  
Kamal K. Nandi ◽  
Anwarul Islam ◽  
James Evans
Keyword(s):  
Symmetric Space ◽  
Light Cone ◽  
Quantum Fluctuation ◽  
Quantum Fluctuations ◽  
Dynamical Variable ◽  
Nonrelativistic Limit ◽  
Space Time ◽  
Spherically Symmetric ◽  
Speed Of Light

In the Schwarzschild field due to a mass moving with velocity v → c0, where c0 is the speed of light in vacuum, the source-induced quantum fluctuation in the light cone exhibits consistency with the Aichelburg–Sexl solution while that in the metric dynamical variable does not. At the horizon, none of the fluctuations is proportional to anything finite. However, in the nonrelativistic limit (v → 0), known expressions follow.

The Future of Fundamental Physics

Daedalus ◽  
2012 ◽  
Vol 141 (3) ◽  
pp. 53-66
Author(s):  
Nima Arkani-Hamed
Keyword(s):  
Twentieth Century ◽  
Quantum Mechanics ◽  
Short Distance ◽  
Quantum Fluctuations ◽  
Building Blocks ◽  
Space Time ◽  
First Century ◽  
Fundamental Physics ◽  
Theoretical Structure ◽  
Radical Ideas

Fundamental physics began the twentieth century with the twin revolutions of relativity and quantum mechanics, and much of the second half of the century was devoted to the construction of a theoretical structure unifying these radical ideas. But this foundation has also led us to a number of paradoxes in our understanding of nature. Attempts to make sense of quantum mechanics and gravity at the smallest distance scales lead inexorably to the conclusion that space-time is an approximate notion that must emerge from more primitive building blocks. Furthermore, violent short-distance quantum fluctuations in the vacuum seem to make the existence of a macroscopic world wildly implausible, and yet we live comfortably in a huge universe. What, if anything, tames these fluctuations? Why is there a macroscopic universe? These are two of the central theoretical challenges of fundamental physics in the twenty-first century. In this essay, I describe the circle of ideas surrounding these questions, as well as some of the theoretical and experimental fronts on which they are being attacked.

scholarly journals SPECTRAL GEOMETRY AND CAUSALITY

1998 ◽  
Vol 13 (15) ◽  
pp. 2693-2708 ◽  
Author(s):  
TOMÁŠ KOPF
Keyword(s):  
Field Theory ◽  
Quantum Gravity ◽  
Spectral Data ◽  
Physical Interpretation ◽  
Lorentzian Manifold ◽  
Space Time ◽  
Effective Field ◽  
Spectral Geometry ◽  
Causal Relationships ◽  
Classical Space

For a physical interpretation of a theory of quantum gravity, it is necessary to recover classical space–time, at least approximately. However, quantum gravity may eventually provide classical space–times by giving spectral data similar to those appearing in noncommutative geometry, rather than by giving directly a space–time manifold. It is shown that a globally hyperbolic Lorentzian manifold can be given by spectral data. A new phenomenon in the context of spectral geometry is observed: causal relationships. The employment of the causal relationships of spectral data is shown to lead to a highly efficient description of Lorentzian manifolds, indicating the possible usefulness of this approach. Connections to free quantum field theory are discussed for both motivation and physical interpretation. It is conjectured that the necessary spectral data can be generically obtained from an effective field theory having the fundamental structures of generalized quantum mechanics: a decoherence functional and a choice of histories.

On the collision of impulsive gravitational waves when coupled with fluid motions

1985 ◽  
Vol 402 (1822) ◽  
pp. 37-65 ◽  
Keyword(s):  
Exact Solution ◽  
Gravitational Waves ◽  
Massive Particle ◽  
Natural Generalization ◽  
Space Time ◽  
Direct Result ◽  
Sound Waves ◽  
Time Singularity ◽  
Consistent Extension ◽  
Ultimate Result

An exact solution of Einstein’s equations, with a source derived from a perfect fluid in which the energy density, ε , is equal to the pressure, p , is obtained. The solution describes the space–time following the collision of plane impulsive gravitational waves and is the natural generalization of the Nutku─Halil solution of the vacuum equations, in the region of interaction under similar basic conditions. A consistent extension of the solution, prior to the instant of collision, requires that the fluid in the region of interaction is the direct result of a transformation of incident null-dust (i. e. of massless particles describing null trajectories). The ultimate result of the collision is the development of a space─time singularity, the nature of which is strongly dependent on the amplitude and the character of the sound waves that are present. The distribution of ε that follows the collision has many intriguing features. The solution obtained in this paper provides the first example of an induced transformation of a massless into a massive particle.

A NOTE ON THE ANALOGY BETWEEN KOLMOGOROV TURBULENCE AND QUANTUM GRAVITY

2010 ◽  
Vol 21 (11) ◽  
pp. 1329-1340 ◽  
Author(s):  
SAURO SUCCI
Keyword(s):  
Quantum Gravity ◽  
Quantum Fluctuations ◽  
Space Time ◽  
Scaling Properties ◽  
Fluid Turbulence ◽  
New Class ◽  
Kolmogorov Turbulence ◽  
Time Quantum ◽  
Dynamic Growth ◽  
The Universe

Based on a formal analogy between space-time quantum fluctuations and classical Kolmogorov fluid turbulence, we suggest that the dynamic growth of the Universe from Planckian to macroscopic scales should be characterized by the presence of a fluctuating volume-flux (FVF) invariant. The existence of such an invariant could be tested in numerical simulations of quantum gravity, and may also stimulate the development of a new class of hierarchical models of quantum foam, similar to those currently employed in modern phenomenological research on fluid turbulence. The use of such models shows that the simple analogy with Kolmogorov turbulence is not compatible with a fine-scale fractal structure of quantum space-time. Hence, should such theories prove correct, they would imply that the scaling properties of quantum fluctuations of space-time are subtler than those described by the simple Kolmogorov analogy.

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