scholarly journals Quantum Gravity at the Corner

Universe ◽  
2018 ◽  
Vol 4 (10) ◽  
pp. 107 ◽  
Author(s):  
Laurent Freidel ◽  
Alejandro Perez
Keyword(s):  
Quantum Gravity ◽  
Symplectic Form ◽  
Direct Application ◽  
Quantum Geometry ◽  
Quantum Level ◽  
Gravitational System ◽  
Gauge Transformations ◽  
First Order ◽  
Conformal Field ◽  
First Time

We investigate the quantum geometry of a 2d surface S bounding the Cauchy slices of a 4d gravitational system. We investigate in detail for the first time the boundary symplectic current that naturally arises in the first-order formulation of general relativity in terms of the Ashtekar–Barbero connection. This current is proportional to the simplest quadratic form constructed out of the pull back to S of the triad field. We show that the would-be-gauge degrees of freedo arising from S U ( 2 ) gauge transformations plus diffeomorphisms tangent to the boundary are entirely described by the boundary 2-dimensional symplectic form, and give rise to a representation at each point of S of S L ( 2 , R ) × S U ( 2 ) . Independently of the connection with gravity, this system is very simple and rich at the quantum level, with possible connections with conformal field theory in 2d. A direct application of the quantum theory is modelling of the black horizons in quantum gravity.

scholarly journals Non-Linear First-Order Differential Boundary Problems with Multipoint and Integral Conditions

2021 ◽  
Vol 5 (1) ◽  
pp. 15
Author(s):  
Misir J. Mardanov ◽  
Yagub A. Sharifov ◽  
Yusif S. Gasimov ◽  
Carlo Cattani
Keyword(s):  
Integral Equation ◽  
Integral Boundary Conditions ◽  
Contraction Mapping Principle ◽  
Boundary Problems ◽  
Integral Boundary ◽  
Multipoint Problem ◽  
First Order ◽  
Banach Contraction ◽  
First Time ◽  
Banach Contraction Mapping Principle

This paper considers boundary value problem (BVP) for nonlinear first-order differential problems with multipoint and integral boundary conditions. A suitable Green function was constructed for the first time in order to reduce this problem into a corresponding integral equation. So that by using the Banach contraction mapping principle (BCMP) and Schaefer’s fixed point theorem (SFPT) on the integral equation, we can show that the solution of the multipoint problem exists and it is unique.

The kinetics of the decarboxylation of β-resorcylic acid in catechol

1976 ◽  
Vol 29 (2) ◽  
pp. 443 ◽  
Author(s):  
MA Haleem ◽  
MA Hakeem
Keyword(s):  
Rate Equation ◽  
Kinetic Data ◽  
Reaction Rate ◽  
Complex Mechanism ◽  
First Order ◽  
Absolute Reaction Rate ◽  
First Time ◽  
Kinetics Of ◽  
Absolute Reaction ◽  
Reaction Rate Equation

Kinetic data are reported for the decarboxylation of β-resorcylic acid in resorcinol and catechol for the first time. The reaction is first order. The observation supports the view that the decomposition proceeds through an intermediate complex mechanism. The parameters of the absolute reaction rate equation are calculated.

scholarly journals CONSTRAINTS IN QUANTUM GEOMETRODYNAMICS

2004 ◽  
Vol 19 (10) ◽  
pp. 1609-1638 ◽  
Author(s):  
ADRIAN P. GENTLE ◽  
NATHAN D. GEORGE ◽  
ARKADY KHEYFETS ◽  
WARNER A. MILLER
Keyword(s):  
Quantum Gravity ◽  
General Setting ◽  
Square Root ◽  
Dynamical Equations ◽  
Dynamic Content ◽  
Quantization Formalism ◽  
Canonical Quantum Gravity ◽  
First Time ◽  
Quantum Geometrodynamics ◽  
Canonical Quantum

We compare different treatments of the constraints in canonical quantum gravity. The standard approach on the superspace of 3-geometries treats the constraints as the sole carriers of the dynamic content of the theory, thus rendering the traditional dynamical equations obsolete. Quantization of the constraints in both the Dirac and ADM square root Hamiltonian approaches leads to the well known problems of time evolution. These problems of time are of both an interpretational and technical nature. In contrast, the geometrodynamic quantization procedure on the superspace of the true dynamical variables separates the issues of quantization from the enforcement of the constraints. The resulting theory takes into account states that are off-shell with respect to the constraints, and thus avoids the problems of time. We develop, for the first time, the geometrodynamic quantization formalism in a general setting and show that it retains all essential features previously illustrated in the context of homogeneous cosmologies.

Production and Technical Characteristics of a New Class of Amorphous Metals

1995 ◽  
Vol 400 ◽  
Author(s):  
R.T. Malkhassian
Keyword(s):  
Amorphous Phase ◽  
Quantum Chemical ◽  
New Technology ◽  
Chemical Technology ◽  
Quantum Level ◽  
Vibrationally Excited ◽  
New Class ◽  
The Third ◽  
Hydrogen Molecules ◽  
First Time

AbstractA new technology for obtainment of amorphous single-component metals is presented.For the first time the reduction of molybdenum oxide with formation of its amorphous phase is realized in conditions of a given quantum-chemical technology by means of vibrationally excited to the third quantum level hydrogen molecules with 1.5 ± 0.2 eV energy. The evidences of formation of this nonequilibrium amorphous phase are presented along with certain physicochemical properties of the obtained amorphous molybdenum.A model is proposed for the origin of amorphous phase under the influence of nonequilibrium quantum-chemical technology.

scholarly journals Measurements of hydrogen cyanide (HCN) and acetylene (C<sub>2</sub>H<sub>2</sub>) from the Infrared Atmospheric Sounding Interferometer (IASI)

2013 ◽  
Vol 6 (4) ◽  
pp. 917-925 ◽  
Author(s):  
V. Duflot ◽  
D. Hurtmans ◽  
L. Clarisse ◽  
Y. R'honi ◽  
C. Vigouroux ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Hydrogen Cyanide ◽  
Atmospheric Transport ◽  
Trace Gases ◽  
First Order ◽  
Line Mixing ◽  
Atmospheric Sounding ◽  
First Time ◽  
Order Comparison ◽  
Emission Ratios

Abstract. Hydrogen cyanide (HCN) and acetylene (C2H2) are ubiquitous atmospheric trace gases with medium lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. Because of their weak infrared absorption, overlapped by the CO2 Q branch near 720 cm−1, nadir sounders have up to now failed to measure these gases routinely. Taking into account CO2 line mixing, we provide for the first time extensive measurements of HCN and C2H2 total columns at Reunion Island (21° S, 55° E) and Jungfraujoch (46° N, 8° E) in 2009–2010 using observations from the Infrared Atmospheric Sounding Interferometer (IASI). A first order comparison with local ground-based Fourier transform infraRed (FTIR) measurements has been carried out allowing tests of seasonal consistency which is reasonably captured, except for HCN at Jungfraujoch. The IASI data shows a greater tendency to high C2H2 values. We also examine a nonspecific biomass burning plume over austral Africa and show that the emission ratios with respect to CO agree with previously reported values.

scholarly journals A CRITICAL ANALYSIS OF THE COSMOLOGICAL IMPLEMENTATION OF LOOP QUANTUM GRAVITY

2012 ◽  
Vol 27 (07) ◽  
pp. 1250032 ◽  
Author(s):  
FRANCESCO CIANFRANI ◽  
GIOVANNI MONTANI
Keyword(s):  
Quantum Gravity ◽  
Quantum Cosmology ◽  
Loop Quantum Gravity ◽  
Critical Discussion ◽  
Point Of View ◽  
Graph Structure ◽  
Quantum Geometry ◽  
Cosmological Problem ◽  
New Perspective ◽  
Made In

This papers offers a critical discussion on the procedure by which Loop Quantum Cosmology (LQC) is constructed from the full Loop Quantum Gravity (LQG) theory. Revising recent issues in preserving SU(2) symmetry when quantizing the isotropic Universe, we trace a new perspective in approaching the cosmological problem within quantum geometry. The cosmological sector of LQG is reviewed and a critical point of view on LQC is presented. It is outlined how a polymer-like scale for quantum cosmology can be predicted from a proper fundamental graph underlying the homogeneous and isotropic continuous picture. However, such a minimum scale does not coincide with the choice made in LQC. Finally, the perspectives towards a consistent cosmological LQG model based on such a graph structure are discussed.

scholarly journals First-order action and Euclidean quantum gravity

2009 ◽  
Vol 26 (14) ◽  
pp. 145004 ◽  
Author(s):  
Tomáš Liko ◽  
David Sloan
Keyword(s):  
Quantum Gravity ◽  
First Order

scholarly journals A First Approach to Loop Quantum Gravity in the Momentum Representation

2019 ◽  
pp. 1-8
Author(s):  
W. F. Chagas-Filho
Keyword(s):  
General Relativity ◽  
Quantum Gravity ◽  
Loop Quantum Gravity ◽  
Classical System ◽  
Momentum Representation ◽  
First Order

We present a generalization of the first-order formalism used to describe the dynamics of a classical system. The generalization is then applied to the first-order action that describes General Relativity. As a result we obtain equations that can be interpreted as describing quantum gravity in the momentum representation.

scholarly journals Generation of over 1000 Diffraction Spots from 2D Graded Photonic Super-Crystals

Photonics ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 27
Author(s):  
Safaa Hassan ◽  
Yan Jiang ◽  
Khadijah Alnasser ◽  
Noah Hurley ◽  
Hualiang Zhang ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
Cell Size ◽  
Lattice Constant ◽  
Field Intensity ◽  
Lattice Model ◽  
Dual Lattice ◽  
First Order ◽  
Super Cell ◽  
First Time ◽  
Fractional Orders

For the first time, we are able to generate over 1000 diffraction spots from a graded photonic super-crystal with a unit super-cell size of 12a × 12a where a is the lattice constant and hole radii are gradually changed in dual directions. The diffraction pattern from the graded photonic super-crystal reveals unique diffraction properties. The first order diffractions of (±1,0) or (0,±1) disappear. Fractional diffraction orders are observed in the diffraction pattern inside a square with vertices of (1,1), (1,−1), (−1,−1) and (−1,−1). The fractional diffraction can be understood from lattices with a period of a. However, a dual-lattice model is considered in order to explain higher-order diffractions. E-field intensity simulations show a coupling and re-distribution among fractional orders of Bloch waves. There are a total of 12 × 12 spots in E-field intensity in the unit supercell corresponding to 12 × 12 fractional diffraction orders in the diffraction pattern and 12 × 12 fractional orders of momentum in the first Brillouin zone in k-space.

Manifest non-locality in quantum mechanics, quantum field theory and quantum gravity

2019 ◽  
Vol 34 (28) ◽  
pp. 1941004
Author(s):  
Laurent Freidel ◽  
Robert G. Leigh ◽  
Djordje Minic
Keyword(s):  
Quantum Theory ◽  
String Theory ◽  
Quantum Gravity ◽  
Closed String ◽  
Covariant Formulation ◽  
Quantum Field ◽  
Quantum Geometry ◽  
Local Quantum ◽  
Generic Representation ◽  
Non Locality

We summarize our recent work on the foundational aspects of string theory as a quantum theory of gravity. We emphasize the hidden quantum geometry (modular spacetime) behind the generic representation of quantum theory and then stress that the same geometric structure underlies a manifestly T-duality covariant formulation of string theory, that we call metastring theory. We also discuss an effective non-commutative description of closed strings implied by intrinsic non-commutativity of closed string theory. This fundamental non-commutativity is explicit in the metastring formulation of quantum gravity. Finally we comment on the new concept of metaparticles inherent to such an effective non-commutative description in terms of bi-local quantum fields.

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