scholarly journals Celestial amplitudes from UV to IR

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
N. Arkani-Hamed ◽  
M. Pate ◽  
A.-M. Raclariu ◽  
A. Strominger
Keyword(s):  
Quantum Gravity ◽  
Real Axis ◽  
Scattering Amplitude ◽  
Flat Space ◽  
Analytic Structure ◽  
Positive Real ◽  
Soft Factor ◽  
Hard Particles ◽  
Positive Axis ◽  
Asymptotic Symmetries

Abstract Celestial amplitudes represent 4D scattering of particles in boost, rather than the usual energy-momentum, eigenstates and hence are sensitive to both UV and IR physics. We show that known UV and IR properties of quantum gravity translate into powerful constraints on the analytic structure of celestial amplitudes. For example the soft UV behavior of quantum gravity is shown to imply that the exact four-particle scattering amplitude is meromorphic in the complex boost weight plane with poles confined to even integers on the negative real axis. Would-be poles on the positive real axis from UV asymptotics are shown to be erased by a flat space analog of the AdS resolution of the bulk point singularity. The residues of the poles on the negative axis are identified with operator coefficients in the IR effective action. Far along the real positive axis, the scattering is argued to grow exponentially according to the black hole area law. Exclusive amplitudes are shown to simply factorize into conformally hard and conformally soft factors. The soft factor contains all IR divergences and is given by a celestial current algebra correlator of Goldstone bosons from spontaneously broken asymptotic symmetries. The hard factor describes the scattering of hard particles together with the boost-eigenstate clouds of soft photons or gravitons required by asymptotic symmetries. These provide an IR safe $$ \mathcal{S} $$ S -matrix for the scattering of hard particles.

scholarly journals The Complexity of Approximating the Matching Polynomial in the Complex Plane

2021 ◽  
Vol 13 (2) ◽  
pp. 1-37
Author(s):  
Ivona Bezáková ◽  
Andreas Galanis ◽  
Leslie Ann Goldberg ◽  
Daniel Štefankovič
Keyword(s):  
Real Axis ◽  
Complex Plane ◽  
Maximum Degree ◽  
Negative Real Axis ◽  
Positive Real ◽  
Bounded Degree ◽  
Matching Polynomial ◽  
Correlation Decay ◽  
Connective Constant ◽  
General Complex

We study the problem of approximating the value of the matching polynomial on graphs with edge parameter γ, where γ takes arbitrary values in the complex plane. When γ is a positive real, Jerrum and Sinclair showed that the problem admits an FPRAS on general graphs. For general complex values of γ, Patel and Regts, building on methods developed by Barvinok, showed that the problem admits an FPTAS on graphs of maximum degree Δ as long as γ is not a negative real number less than or equal to −1/(4(Δ −1)). Our first main result completes the picture for the approximability of the matching polynomial on bounded degree graphs. We show that for all Δ ≥ 3 and all real γ less than −1/(4(Δ −1)), the problem of approximating the value of the matching polynomial on graphs of maximum degree Δ with edge parameter γ is #P-hard. We then explore whether the maximum degree parameter can be replaced by the connective constant. Sinclair et al. showed that for positive real γ, it is possible to approximate the value of the matching polynomial using a correlation decay algorithm on graphs with bounded connective constant (and potentially unbounded maximum degree). We first show that this result does not extend in general in the complex plane; in particular, the problem is #P-hard on graphs with bounded connective constant for a dense set of γ values on the negative real axis. Nevertheless, we show that the result does extend for any complex value γ that does not lie on the negative real axis. Our analysis accounts for complex values of γ using geodesic distances in the complex plane in the metric defined by an appropriate density function.

scholarly journals An Extension of the Almost Isolated Singularity of Finite Exponential Order

1964 ◽  
Vol 14 (2) ◽  
pp. 137-141
Author(s):  
R. Wilson
Keyword(s):  
Real Axis ◽  
Taylor Series ◽  
Positive Real Axis ◽  
Isolated Singularity ◽  
Positive Real ◽  
Small Disk ◽  
Exponential Order ◽  
Disk Centre ◽  
Image Position

Let f(z) be represented on its circle of convergence |z| = 1 by the Taylor seriesand suppose that its sole singularity on |z| = 1 is an almost isolated singularity at z = 1. In the neighbourhood of such a singularity f(z) is regular on a sufficiently small disk, centre z = 1, with the outward drawn radius along the positive real axis excised. If also in this neighbourhood |f(z)| e−(1/δ)ρ remains bounded for some finite ρ, where δ is the distance from the excised radius, then the singularity is said to be of finite exponential order.

THE DEVELOPMENT OF THE GRAVITATIONAL AND YANG–MILLS FIELDS, AND THE TREATMENT OF ACCELERATED FRAMES

2005 ◽  
Vol 20 (32) ◽  
pp. 7485-7504 ◽  
Author(s):  
JONG-PING HSU ◽  
DANA FINE
Keyword(s):  
Quantum Gravity ◽  
Flat Space ◽  
Physical World ◽  
Space Time ◽  
Yang Mills ◽  
Inertial Frames ◽  
Theory Of Gravity ◽  
Mills Field ◽  
Time Transformations ◽  
Accelerated Frames

We discuss ideas and problems regarding classical and quantum gravity, gauge theory of gravity, and space–time transformations between accelerated frames. Both Einstein's theory of gravity and Yang–Mills theory are gauge invariant. The invariance principles are at the very heart of our understanding of the physical world. This paper attempts to survey the development and to reveal problems and limitations of various formulations to gravitational and Yang–Mills fields, and to space–time transformations of accelerated frames. Gravitational force and accelerated frames are two ingredients in Einstein's thought in the period around 1907. Accelerated frames are difficult to define and are not well developed. However, one cannot claim to have a complete understanding of the physical world, if one understands flat space–time physics only from the viewpoint of the special class of inertial frames and ignores the vast class of noninertial frames. The paper highlights three aspects: (1) ideas of gravity as a Yang–Mills field, first discussed by Utiyama; (2) problems of quantum gravity, discussed by Feynman, Dyson and others; (3) space–time properties and the physics of fields and particles in accelerated frames of reference. These unfulfilled aspects of Einstein and Yang–Mills' profound thoughts present a challenge to physicists and mathematicians in the 21st century.

scholarly journals Conformal bootstrap in dS/CFT and topological quantum gravity

2019 ◽  
Vol 17 (01) ◽  
pp. 2050007
Author(s):  
Andrea Addazi ◽  
Antonino Marcianò
Keyword(s):  
Black Hole ◽  
Quantum Gravity ◽  
Scattering Amplitude ◽  
Black Hole Entropy ◽  
Gravitational Instantons ◽  
Conformal Bootstrap ◽  
Topological Quantum ◽  
Black Hole Information ◽  
Kitaev Model ◽  
Spin Representations

We show that the correspondence among [Formula: see text], the 1D Schwarzian Model, Sachdev–Ye–Kitaev model and [Formula: see text] Topological Quantum Gravity can be extended to the case of [Formula: see text]. The [Formula: see text]-matrix, related to the gravitational scattering amplitude near the horizon of [Formula: see text] black hole, corresponds (on the side of the holographic projection) to a crossing kernel in the Schwarzian Model. The [Formula: see text]-matrix is related to the 6j-symbol of SU[Formula: see text]. We also find that in the Euclidean [Formula: see text] a new Kac–Moody symmetry of instantons emerges out. We dub these new solutions Kac–Moodions. A one-to-one correspondence of Kac–Moodion levels and SU[Formula: see text] spin representations is established. Every instanton then corresponds to spin representations deployed in Topological Quantum Gravity. The instantons are directly connected to the Black Hole entropy as punctures on its horizon. This strongly supports the recent proposal, in arXiv:1707.00347, that a Kac–Moody symmetry of gravitational instantons is related to the black hole information processing. We also comment on a further correspondence that can be established between the Schwarzian Model and noncommutative spacetimes in [Formula: see text]D, passing through the equivalence with Topological Quantum Gravity with cosmological constant, in the limit when the latter vanishes.

scholarly journals Integral representations of Mittag-Leffler function on the positive real axis

2019 ◽  
Vol 20 (2) ◽  
pp. 217
Author(s):  
Eliana Contharteze Grigoletto ◽  
Edmundo Capelas Oliveira ◽  
Rubens Figueiredo Camargo
Keyword(s):  
Fractional Calculus ◽  
Laplace Transform ◽  
Real Axis ◽  
Integral Representations ◽  
Positive Real Axis ◽  
Inverse Laplace Transform ◽  
Positive Real

The Mittag-Leffler functions appear in many problems associated with fractional calculus. In this paper, we use the methodology for evaluation of the inverse Laplace transform, proposed by M. N. Berberan-Santos, to show that the three-parameter Mittag-Leffler function has similar integral representations on the positive real axis. Some of the integrals are also presented.

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