scholarly journals Effective field theory with dibaryon degrees of freedom

2008 ◽  
Vol 78 (2) ◽  
Author(s):  
Joan Soto ◽  
Jaume Tarrús
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Degrees Of Freedom ◽  
Effective Field

NUCLEAR FORCES AND FEW NUCLEON SYSTEMS IN CHIRAL EFFECTIVE FIELD THEORY

2009 ◽  
Vol 24 (11n13) ◽  
pp. 921-930
Author(s):  
HERMANN KREBS
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Degrees Of Freedom ◽  
Effective Field ◽  
Chiral Expansion ◽  
Light Nuclei ◽  
Nuclear Forces ◽  
Chiral Effective Field Theory ◽  
Promising Tool ◽  
Many Body Systems

Using chiral effective field theory (EFT) with explicit Δ degrees of freedom we calculated nuclear forces up to next-to-next-to-leading order (N2LO). We find a much improved convergence of the chiral expansion in all peripheral partial waves. We also present a novel lattice EFT method developed for systems with larger number of nucleons. Combining Monte Carlo lattice simulations with EFT allows one to calculate the properties of light nuclei, neutron and nuclear matter. Accurate description of two-nucleon phase-shifts and ground state energy ratio of dilute neutron matter up to corrections of higher orders show that lattice EFT is a promising tool for quantitative studies of low-energy few- and many-body systems.

scholarly journals Nonlocality in quantum gravity and the breakdown of effective field theory

2021 ◽  
Author(s):  
Nicolás Valdés-Meller
Keyword(s):  
Field Theory ◽  
Black Holes ◽  
Quantum Gravity ◽  
Effective Field Theory ◽  
Degrees Of Freedom ◽  
Effective Field ◽  
Length Scales ◽  
Effective Metric

We argue that quantum gravity is nonlocal, first by recalling well-known arguments that support this idea and then by focusing on a point not usually emphasized: that making a conventional effective field theory (EFT) for quantum gravity is particularly difficult, and perhaps impossible in principle. This inability to realize an EFT comes down to the fact that gravity itself sets length scales for a problem: when integrating out degrees of freedom above some cutoff, the effective metric one uses will be different, which will itself re-define the cutoff. We also point out that even if the previous problem is fixed, naïvely applying EFT in gravity can lead to problems — we give a particular example in the case of black holes.

scholarly journals How general relativity and Lorentz covariance arise from the spatially-covariant effective field theory of the transverse, traceless graviton

2014 ◽  
Vol 23 (12) ◽  
pp. 1442012 ◽  
Author(s):  
Justin Khoury ◽  
Godfrey E. J. Miller ◽  
Andrew J. Tolley
Keyword(s):  
Field Theory ◽  
General Relativity ◽  
Effective Field Theory ◽  
Degrees Of Freedom ◽  
Effective Field ◽  
Point Of View ◽  
Low Energy ◽  
Fundamental Physics ◽  
Lorentz Covariance

Traditional derivations of general relativity (GR) from the graviton degrees of freedom assume spacetime Lorentz covariance as an axiom. In this paper, we survey recent evidence that GR is the unique spatially-covariant effective field theory of the transverse, traceless graviton degrees of freedom. The Lorentz covariance of GR, having not been assumed in our analysis, is thus plausibly interpreted as an accidental or emergent symmetry of the gravitational sector. From this point of view, Lorentz covariance is a necessary feature of low-energy graviton dynamics, not a property of spacetime. This result has revolutionary implications for fundamental physics.

scholarly journals Holography as cutoff: A proposal for measure of inflationary universes

2014 ◽  
Vol 29 (18) ◽  
pp. 1450102
Author(s):  
Fábio Novaes ◽  
Bruno Carneiro da Cunha
Keyword(s):  
Field Theory ◽  
Quantum Theory ◽  
Scalar Field ◽  
Effective Field Theory ◽  
Degrees Of Freedom ◽  
Effective Field ◽  
Holographic Principle ◽  
Inflationary Model ◽  
Isotropic Space ◽  
Theory Of Gravity

We propose the holographic principle as a dynamical cutoff for any quantum theory of gravity, incorporating ideas of effective field theory. This is done by viewing the holographic bound as a limit on the number of degrees of freedom that can be turned on before the geometrical picture of gravity loses applicability. We illustrate the proposal by revisiting the problem of defining a measure for homogeneous and isotropic space–times coupled to a scalar field and conclude by discussing the implications to the single scalar field inflationary model.

scholarly journals Extending low energy effective field theory with a complete set of dimension-7 operators

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Yi Liao ◽  
Xiao-Dong Ma ◽  
Quan-Yu Wang
Keyword(s):  
Field Theory ◽  
Standard Model ◽  
Cross Sections ◽  
Effective Field Theory ◽  
Degrees Of Freedom ◽  
Independent Set ◽  
Effective Field ◽  
Low Energy ◽  
Tree Level ◽  
The Standard Model

Abstract We present a complete and independent set of dimension-7 operators in the low energy effective field theory (LEFT) where the dynamical degrees of freedom are the standard model five quarks and all of the neutral and charged leptons. All operators are non-Hermitian and are classified according to their baryon (∆B) and lepton (∆L) numbers violated. Including Hermitian-conjugated operators, there are in total 3168, 750, 588, 712 operators with (∆B, ∆L) = (0, 0), (0, ±2), (±1, ∓1), (±1, ±1) respectively. We perform the tree-level matching with the standard model effective field theory (SMEFT) up to dimension-7 (dim-7) operators in both LEFT and SMEFT. As a phenomenological application we study the effective neutrino-photon interactions due to dim-7 lepton number violating operators that are induced and much enhanced at one loop from dim-6 operators that in turn are matched from dim-7 SMEFT operators. We compare various neutrino-photon scattering cross sections with their counterparts in the standard model and highlight the new features. Finally, we illustrate how these effective interactions could arise from ultraviolet completion.

scholarly journals THE DELOCALIZED EFFECTIVE DEGREES OF FREEDOM OF A BLACK HOLE AT LOW FREQUENCIES

2008 ◽  
Vol 17 (13n14) ◽  
pp. 2617-2624 ◽  
Author(s):  
BARAK KOL
Keyword(s):  
Field Theory ◽  
Black Hole ◽  
Effective Field Theory ◽  
Degrees Of Freedom ◽  
World Line ◽  
Low Frequency ◽  
Effective Field ◽  
Theory Approach ◽  
Low Frequencies ◽  
Long Wavelength

Identifying the fundamental degrees of freedom of a black hole poses a long-standing puzzle. Recently Goldberger and Rothstein forwarded a theory of the low frequency degrees of freedom within the effective field theory approach, where they are relevancy-ordered but of unclear physical origin. Here these degrees of freedom are identified with near-horizon but non-compact gravitational perturbations which are decomposed into delocalized multipoles. Their world-line (kinetic) action is determined within the classical effective field theory (CLEFT) approach and their interactions are discussed. The case of the long-wavelength scattering of a scalar wave off a Schwarzschild black hole is treated in some detail, interpreting within the CLEFT approach the equality of the leading absorption cross section with the horizon area.

scholarly journals DsixTools 2.0: the effective field theory toolkit

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Javier Fuentes-Martín ◽  
Pedro Ruiz-Femenía ◽  
Avelino Vicente ◽  
Javier Virto
Keyword(s):  
Field Theory ◽  
Renormalization Group ◽  
Cross Sections ◽  
Effective Field Theory ◽  
Degrees Of Freedom ◽  
Effective Field ◽  
Low Energy ◽  
Weak Basis ◽  
The Standard Model ◽  
Group Evolution

Abstract is a package for the handling of the standard model effective field theory (SMEFT) and the low-energy effective field theory (LEFT) with operators up to dimension six, both at the algebraic and numerical level. contains a visually accessible and operationally convenient repository of all operators and parameters of the SMEFT and the LEFT. This repository also provides information concerning symmetry categories and number of degrees of freedom, and routines that allow to implement this information on global expressions (such as decay amplitudes and cross-sections). also performs weak basis transformations, and implements the full one-loop Renormalization Group Evolution in both EFTs (with SM beta functions up to five loops in QCD), and the full one-loop SMEFT-LEFT matching at the electroweak scale.

Sign in / Sign up

Export Citation Format

Share Document