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

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.

2020 ◽  
pp. 133-156
Author(s):  
Jim Baggott

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).


Author(s):  
Francesco De Martini

The nature of the scalar field responsible for the cosmological inflation is found to be rooted in the most fundamental concept of Weyl's differential geometry: the parallel displacement of vectors in curved space–time. Within this novel geometrical scenario, the standard electroweak theory of leptons based on the SU (2) L ⊗ U (1) Y as well as on the conformal groups of space–time Weyl's transformations is analysed within the framework of a general-relativistic, conformally covariant scalar-tensor theory that includes the electromagnetic and the Yang–Mills fields. A Higgs mechanism within a spontaneous symmetry breaking process is identified and this offers formal connections between some relevant properties of the elementary particles and the dark energy content of the Universe. An ‘effective cosmological potential’: V eff is expressed in terms of the dark energy potential: via the ‘mass reduction parameter’: , a general property of the Universe. The mass of the Higgs boson, which is considered a ‘free parameter’ by the standard electroweak theory, by our theory is found to be proportional to the mass which accounts for the measured cosmological constant, i.e. the measured content of vacuum-energy in the Universe. The non-integrable application of Weyl's geometry leads to a Proca equation accounting for the dynamics of a ϕ ρ -particle, a vector-meson proposed as an an optimum candidate for dark matter. On the basis of previous cosmic microwave background results our theory leads, in the condition of cosmological ‘critical density’, to the assessment of the average energy content of the ϕ ρ -excitation. The peculiar mathematical structure of V eff offers a clue towards a very general resolution of a most intriguing puzzle of modern quantum field theory, the ‘Cosmological Constant Paradox’ (here referred to as the ‘ Λ -Paradox’). Indeed, our ‘universal’ theory offers a resolution of the Λ -Paradox for all exponential inflationary potentials: V Λ ( T , ϕ )∝ e − nϕ , and for all linear superpositions of these potentials, where n belongs to the mathematical set of the ‘real numbers’. An explicit solution of the Λ -Paradox is reported for n =2. The resolution of the Λ -Paradox cannot be achieved in the context of Riemann's differential geometry. This article is part of the themed issue ‘Second quantum revolution: foundational questions’.


1999 ◽  
Vol 14 (05) ◽  
pp. 317-325 ◽  
Author(s):  
G. S. DJORDJEVIĆ ◽  
L. J. NEŠIĆ ◽  
B. DRAGOVICH

We consider spectral problem for a free relativistic particle in p-adic and adelic quantum mechanics. In particular, we found p-adic and adelic eigenfunctions. Within adelic approach there exist quantum states that exhibit discrete structure of space–time at the Planck scale.


2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Salvatore Mignemi ◽  
Rina Štrajn

We study the representations of the three-dimensional Euclidean Snyder-de Sitter algebra. This algebra generates the symmetries of a model admitting two fundamental scales (Planck mass and cosmological constant) and is invariant under the Born reciprocity for exchange of positions and momenta. Its representations can be obtained starting from those of the Snyder algebra and exploiting the geometrical properties of the phase space that can be identified with a Grassmannian manifold. Both the position and momentum operators turn out to have a discrete spectrum.


2019 ◽  
Author(s):  
kapil chandra

In this study we will show how quantum mechanics has failed to estimate the precise value of the cosmological constant because it uses the Planck mass/unit as the cut off. Since the expression for the Planck mass is numerically incorrect. This paper will show how a modification of the Planck unit gives a more accurate value and also fixes the long standing cosmological constant problem.


2006 ◽  
Vol 15 (12) ◽  
pp. 2153-2158 ◽  
Author(s):  
T. P. SINGH

We do not know the symmetries underlying string theory. Furthermore, there must exist an inherently quantum, and space–time independent, formulation of this theory. Independent of string theory, there should exist a description of quantum mechanics which does not refer to a classical space–time manifold. We propose such a formulation of quantum mechanics, based on noncommutative geometry. This description reduces to standard quantum mechanics, whenever an external classical space–time is available. However, near the Planck energy scale, self-gravity effects modify the Schrödinger equation to the non-linear Doebner–Goldin equation. Remarkably, this non-linear equation also arises in the quantum dynamics of D0-branes. This suggests that the noncommutative quantum dynamics proposed here is actually the quantum gravitational dynamics of D0-branes, and that automorphism invariance is a symmetry of string theory.


1994 ◽  
Vol 09 (04) ◽  
pp. 335-340 ◽  
Author(s):  
Y. JACK NG ◽  
H. VAN DAM

Applying simultaneously the principles of quantum mechanics and general relativity we find an intrinsic limitation to quantum measurements of space-time distances. The intrinsic uncertainty of a length is shown to be proportional to the one third power of the length itself. This uncertainty in space-time measurements implies an intrinsic uncertainty of the space-time metric and yields quantum decoherence for particles heavier than the Planck mass.


Author(s):  
William Lane Craig

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.


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