Clocks Beyond Classical Space-Time

2017 ◽  
pp. 99-114
Author(s):  
Magdalena Zych
Keyword(s):  
Space Time ◽  
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.

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.

Heisenberg, Bohr, Robertson, and the Uncertainty Principle

2020 ◽  
pp. 133-156
Author(s):  
Jim Baggott
Keyword(s):  
Quantum Mechanics ◽  
Uncertainty Principle ◽  
Laboratory Experiments ◽  
Space Time ◽  
Spectral Lines ◽  
Planck’S Constant ◽  
Classical Space ◽  
Planck's Constant

From the outset, Heisenberg had resolved to eliminate classical space-time pictures involving particles and waves from the quantum mechanics of the atom. He had wanted to focus instead on the properties actually observed and recorded in laboratory experiments, such as the positions and intensities of spectral lines. Alone in Copenhagen in February 1927, he now pondered on the significance and meaning of such experimental observables. Feeling the need to introduce at least some form of ‘visualizability’, he asked himself some fundamental questions, such as: What do we actually mean when we talk about the position of an electron? He went on to discover the uncertainty principle: the product of the ‘uncertainties’ in certain pairs of variables—called complementary variables—such as position and momentum cannot be smaller than Planck’s constant h (now h / 4π‎).

scholarly journals Detection of non-classical space-time correlations with a novel type of single-photon camera

2014 ◽  
Vol 22 (14) ◽  
pp. 17561 ◽  
Author(s):  
Felix Just ◽  
Mykhaylo Filipenko ◽  
Andrea Cavanna ◽  
Thilo Michel ◽  
Thomas Gleixner ◽  
...  
Keyword(s):  
Single Photon ◽  
Space Time ◽  
Classical Space ◽  
Time Correlations

scholarly journals NONCOMMUTATIVE GRAVITY, A "NO STRINGS ATTACHED" QUANTUM–CLASSICAL DUALITY, AND THE COSMOLOGICAL CONSTANT PUZZLE

2008 ◽  
Vol 17 (13n14) ◽  
pp. 2593-2598
Author(s):  
T. P. SINGH
Keyword(s):  
Differential Geometry ◽  
Quantum Mechanics ◽  
Cosmological Constant ◽  
Relativistic Particle ◽  
Space Time ◽  
Planck Mass ◽  
Classical Space ◽  
Classical Duality ◽  
Noncommutative Gravity ◽  
The Masses

There ought to exist a reformulation of quantum mechanics which does not refer to an external classical space–time manifold. Such a reformulation can be achieved using the language of noncommutative differential geometry. A consequence which follows is that the "weakly quantum, strongly gravitational" dynamics of a relativistic particle whose mass is much greater than the Planck mass is dual to the "strongly quantum, weakly gravitational" dynamics of another particle whose mass is much less than the Planck mass. The masses of the two particles are inversely related to each other, and the product of their masses is equal to the square of the Planck mass. This duality explains the observed value of the cosmological constant, and also why this value is nonzero but extremely small in Planck units.

Emergence of classical space-time from the Planck era

1999 ◽  
Vol 448 (1-2) ◽  
pp. 13-19 ◽  
Author(s):  
M.D. Pollock
Keyword(s):  
Space Time ◽  
Classical Space

A discrete classical space–time could require 6 extra-dimensions

2018 ◽  
Vol 388 ◽  
pp. 428-442 ◽  
Author(s):  
Philippe Guillemant ◽  
Marc Medale ◽  
Cherifa Abid
Keyword(s):  
Extra Dimensions ◽  
Space Time ◽  
Classical Space

CLASSICAL p-ADIC SPACE-TIME

1990 ◽  
Vol 05 (19) ◽  
pp. 1521-1528 ◽  
Author(s):  
BRANKO G. DRAGOVIC ◽  
PAUL H. FRAMPTON ◽  
BRANKO V. UROSEVIC
Keyword(s):  
Variational Principle ◽  
Particle Motion ◽  
Lorentz Invariance ◽  
Free Particle ◽  
Space Time ◽  
Product Formula ◽  
Special Care ◽  
Classical Space

A classical space-time manifold with p-adic valued coordinates is introduced and it is shown that special care is needed to distinguish space-like and time-like directions. Lorentz invariance and isometries of the manifold are derived. From a variational principle, it is shown how free particle motion satisfies a product formula.

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