scholarly journals Why the Length of a Quantum String Cannot Be Lorentz Contracted

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Antonio Aurilia ◽  
Euro Spallucci
Keyword(s):  
Quantum Gravity ◽  
Particle Phase ◽  
Extended Form ◽  
Compton Wavelength ◽  
String Length ◽  
Length Contraction ◽  
Physical Limit ◽  
Hoop Conjecture ◽  
Ordinary Particle ◽  
Schwarzschild Radius

We propose a quantum gravity-extended form of the classical length contraction law obtained in special relativity. More specifically, the framework of our discussion is the UV self-complete theory of quantum gravity. We show how our results are consistent with (i) the generalized form of the uncertainty principle (GUP), (ii) the so-called hoop-conjecture, and (iii) the intriguing notion of “classicalization” of trans-Planckian physics. We argue that there is a physical limit to the Lorentz contraction rule in the form of some minimal universal length determined by quantum gravity, say the Planck Length, or any of its current embodiments such as the string length, or the TeV quantum gravity length scale. In the latter case, we determine the critical boost that separates the ordinary “particle phase,” characterized by the Compton wavelength, from the “black hole phase,” characterized by the effective Schwarzschild radius of the colliding system.

scholarly journals Quantum gravity effects around Sagittarius A*

2016 ◽  
Vol 25 (12) ◽  
pp. 1644021 ◽  
Author(s):  
Hal M. Haggard ◽  
Carlo Rovelli
Keyword(s):  
Black Hole ◽  
Quantum Gravity ◽  
Event Horizon ◽  
Sagittarius A ◽  
Vlbi Observations ◽  
Gravity Effects ◽  
Sgr A ◽  
Schwarzschild Radius ◽  
Number Of Authors

Recent VLBI observations have resolved Sagittarius A* at horizon scales. The event horizon telescope is expected to provide increasingly good images of the region around the Schwarzschild radius [Formula: see text] of Sgr A* soon. A number of authors have recently pointed out the possibility that nonperturbative quantum gravitational phenomena could affect the space surrounding a black hole. Here, we point out that the existence of a region around [Formula: see text], where these effects should be maximal.

A new length scale for quantum gravity: A resolution of the black hole information loss paradox

2017 ◽  
Vol 26 (12) ◽  
pp. 1743015 ◽  
Author(s):  
Tejinder P. Singh
Keyword(s):  
Black Hole ◽  
Information Loss ◽  
Einstein Equations ◽  
Dirac Field ◽  
Length Scale ◽  
Compton Wavelength ◽  
Information Loss Paradox ◽  
Torsion Field ◽  
Black Hole Information ◽  
Schwarzschild Radius

We show why and how Compton wavelength and Schwarzschild radius should be combined into one single new length scale, which we call the Compton–Schwarzschild length. Doing so offers a resolution of the black hole information loss paradox, and suggests Planck mass remnant black holes as candidates for dark matter. It also compels us to introduce torsion, and identify the Dirac field with a complex torsion field. Dirac equation and Einstein equations, are shown to be mutually dual limiting cases of an underlying gravitation theory which involves the Compton–Schwarzschild length scale, and includes a complex torsion field.

scholarly journals Does Compton–Schwarzschild duality in higher dimensions exclude TeV quantum gravity?

2018 ◽  
Vol 27 (16) ◽  
pp. 1930001 ◽  
Author(s):  
Matthew J. Lake ◽  
Bernard Carr
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Wave Function ◽  
Quantum Gravity ◽  
Extra Dimensions ◽  
Planck Length ◽  
Compton Wavelength ◽  
Planck Mass ◽  
Higher Dimensional ◽  
Spatial Dimensions

In three spatial dimensions, the Compton wavelength [Formula: see text]) and Schwarzschild radius [Formula: see text]) are dual under the transformation [Formula: see text], where [Formula: see text] is the Planck mass. This suggests that there could be a fundamental link — termed the Black Hole Uncertainty Principle or Compton–Schwarzschild correspondence — between elementary particles with [Formula: see text] and black holes in the [Formula: see text] regime. In the presence of [Formula: see text] extra dimensions, compactified on some scale [Formula: see text] exceeding the Planck length [Formula: see text], one expects [Formula: see text] for [Formula: see text], which breaks this duality. However, it may be restored in some circumstances because the effective Compton wavelength of a particle depends on the form of the [Formula: see text]-dimensional wave function. If this is spherically symmetric, then one still has [Formula: see text], as in the [Formula: see text]-dimensional case. The effective Planck length is then increased and the Planck mass reduced, allowing the possibility of TeV quantum gravity and black hole production at the LHC. However, if the wave function of a particle is asymmetric and has a scale [Formula: see text] in the extra dimensions, then [Formula: see text], so that the duality between [Formula: see text] and [Formula: see text] is preserved. In this case, the effective Planck length is increased even more but the Planck mass is unchanged, so that TeV quantum gravity is precluded and black holes cannot be generated in collider experiments. Nevertheless, the extra dimensions could still have consequences for the detectability of black hole evaporations and the enhancement of pair-production at accelerators on scales below [Formula: see text]. Though phenomenologically general for higher-dimensional theories, our results are shown to be consistent with string theory via the minimum positional uncertainty derived from [Formula: see text]-particle scattering amplitudes.

scholarly journals ARE MASSIVE ELEMENTARY PARTICLES BLACK HOLES?

2004 ◽  
Vol 19 (02) ◽  
pp. 143-149 ◽  
Author(s):  
B. F. L. WARD
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Standard Model ◽  
Quantum Gravity ◽  
Point Particle ◽  
Exact Results ◽  
New Approach ◽  
Massive Point ◽  
The Standard Model ◽  
Schwarzschild Radius

We use exact results in a new approach to quantum gravity to study the effect of quantum loop corrections on the behavior of the metric of spacetime near the Schwarzschild radius of a massive point particle in the standard model. We show that the classical conclusion that such a system is a black hole is obviated. Phenomenological implications are discussed.

scholarly journals Planck Mass Measured Totally Independent of Big G Utilizing McCulloch-HeisenbergNewtonian Equivalent Gravity

2018 ◽  
Author(s):  
Espen Gaarder Haug
Keyword(s):  
Quantum Gravity ◽  
Gravitational Constant ◽  
Fundamental Constant ◽  
Universal Constant ◽  
Planck Length ◽  
Speed Of Light ◽  
Planck Constant ◽  
Planck Mass ◽  
Heisenberg's Uncertainty Principle ◽  
Schwarzschild Radius

In 2014, McCulloch showed, in a new and interesting way, how to derive a gravity theoryfrom Heisenberg's uncertainty principle that is equivalent to Newtonian gravity. McCulloch utilizesthe Planck mass in his derivation and obtains a gravitational constant of hbar*c/m_p^2. This is a composite constant, which is equivalent in value to Newton's gravitational constant. However, McCulloch has pointed out that his approach requires an assumption on the value of G, and that this involves some circular reasoning. This is in line with the view that the Planck mass is a derived constantfrom Newton's gravitational constant, while big G is a universal fundamental constant. Here we willshow that we can go straight from the McCulloch derivation to measuring the Planck mass withoutany knowledge of the gravitational constant. From this perspective, there are no circular problemswith his method. This means that we can measure the Planck mass without Newton's gravitationalconstant, and shows that the McCulloch derivation is a theory of quantum gravity that stands onits own. Even more importantly, we show that we can easily measure the Schwarzschild radius ofa mass without knowing its mass, or Newton's gravitational constant, or the Planck constant. Thevery essence of gravity is linked to the Planck length and the speed of light, but here we will claimthat we do not need to know the Planck length itself. Our conclusion is that Newton's gravitationalconstant is a universal constant, but it is a composite constant of the form G=l_p^2*c^3/hbar where thePlanck length and the speed of light are the keys to gravity. This could be an important step towards the development of a full theory of quantum gravity.

scholarly journals On the inverse hoop conjecture of Hod

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
K. K. Nandi ◽  
R. N. Izmailov ◽  
A. A. Potapov ◽  
N. G. Migranov
Keyword(s):  
Black Holes ◽  
Vector Field ◽  
String Theory ◽  
Quantum Gravity ◽  
Lorentz Symmetry ◽  
Dilaton Field ◽  
Hoop Conjecture

AbstractRecently, Hod has shown that Thorne’s hoop conjecture ($$\frac{C(R)}{4\pi M(r\le R)} \le 1\Rightarrow $$ C ( R ) 4 π M ( r ≤ R ) ≤ 1 ⇒ horizon) is violated by stationary black holes and so he proposed a new inverse hoop conjecture characterizing such black holes (that is, horizon $$\Rightarrow \mathcal {H =} \frac{\pi \mathcal {A} }{\mathcal {C}_{{eq} }^{2}} \le 1$$ ⇒ H = π A C eq 2 ≤ 1 ). In this paper, it is exemplified that stationary hairy black holes, endowed with Lorentz symmetry violating Bumblebee vector field related to quantum gravity and dilaton field of string theory, also respect the inverse conjecture. It is shown that stationary hairy singularity, recently derived by Bogush and Galt’sov, does not respect the conjecture thereby protecting it. However, curiously, there are two horizonless stationary wormholes that can also respect the conjecture. Thus one may also state that throat $$\Rightarrow \mathcal {H \le }1$$ ⇒ H ≤ 1 , suggesting that the inverse conjecture may be a necessary but not sufficient proposition.

scholarly journals Fate of the Hoop Conjecture in Quantum Gravity

2017 ◽  
Vol 119 (23) ◽  
Author(s):  
Fabio Anzà ◽  
Goffredo Chirco
Keyword(s):  
Quantum Gravity ◽  
Hoop Conjecture

scholarly journals Low energy consequences of loop quantum gravity

2020 ◽  
pp. 2150035
Author(s):  
Salman Sajad Wani ◽  
Behnam Pourhassan ◽  
Mir faizal ◽  
Ahmed Jellal
Keyword(s):  
Quantum Gravity ◽  
Short Distance ◽  
Loop Quantum Gravity ◽  
Low Energy ◽  
Fermi Gases ◽  
Planck Length ◽  
String Length ◽  
Heisenberg Algebras ◽  
Degenerate Fermi Gases ◽  
Theoretical Considerations

Using the loop quantum gravity, based on polymer quantization, we will argue that the polymer length (like string length) can be several orders larger than the Planck length, and this can have low energy consequences. We will demonstrate that a short distance modification of a quantum system by polymer quantization and by string theoretical considerations can produce similar behavior. Moreover, it will be demonstrated that a family of different deformed Heisenberg algebras can produce similar low energy effects. We will analyze such polymer correction to a degenerate Fermi gases in a harmonic trap, and its polymer corrected thermodynamics.

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