scholarly journals The cosmological phonon: symmetries and amplitudes on sub-horizon scales

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Tanguy Grall ◽  
Sadra Jazayeri ◽  
David Stefanyszyn
Keyword(s):  
Perturbation Theory ◽  
Scattering Amplitudes ◽  
Total Energy ◽  
Classification Scheme ◽  
Detailed Account ◽  
Additional Symmetry ◽  
Gauge Symmetries ◽  
Coset Construction ◽  
The Common ◽  
Lorentz Boosts

Abstract In contrast to massless spinning particles, scalars are not heavily constrained by unitarity and locality. Off-shell, no gauge symmetries are required to write down manifestly local theories, while on-shell consistent factorisation is trivial. Instead a useful classification scheme for scalars is based on the symmetries they can non-linearly realise. Motivated by the breaking of Lorentz boosts in cosmology, in this paper we classify the possible symmetries of a shift-symmetric scalar that is assumed to non-linearly realise Lorentz boosts as, for example, in the EFT of inflation. Our classification method is algebraic; guided by the coset construction and inverse Higgs constraints. We rediscover some known phonon theories within the superfluid and galileid classes, and discover a new galileid theory which we call the extended galileid. Generic galileids correspond to the broken phase of galileon scalar EFTs and our extended galileids correspond to special subsets where each galileon coupling is fixed by an additional symmetry. We discuss the broken phase of theories that also admit a perturbation theory around Poincaré invariant vacua and we show that the so-called exceptional EFTs, the DBI scalar and special galileon, do not admit such a broken phase. Concentrating on DBI we provide a detailed account of this showing that the scattering amplitudes are secretly Poincaré invariant when the theory is expanded around the superfluid background used in the EFT of inflation. We point out that DBI is an exception to the common lore that the residue of the total energy pole of cosmological correlators is proportional to the amplitude. We also discuss the inevitability of poles in 2 → 2 scattering amplitudes when boost are spontaneously broken meaning that such theories do not admit Adler zeros and generalisations even in the presence of a shift symmetry.

A Perturbation Theory for the Population of Atomic Energy Levels in Non-Lte Plasmas

1988 ◽  
Vol 102 ◽  
pp. 343-347
Author(s):  
M. Klapisch
Keyword(s):  
Perturbation Theory ◽  
Small Parameter ◽  
Classification Scheme ◽  
Sum Rules ◽  
Energy Levels ◽  
Natural Classification ◽  
Quantum Numbers ◽  
Formal Expansion ◽  
Atomic Energy Levels ◽  
As Effects

AbstractA formal expansion of the CRM in powers of a small parameter is presented. The terms of the expansion are products of matrices. Inverses are interpreted as effects of cascades.It will be shown that this allows for the separation of the different contributions to the populations, thus providing a natural classification scheme for processes involving atoms in plasmas. Sum rules can be formulated, allowing the population of the levels, in some simple cases, to be related in a transparent way to the quantum numbers.

scholarly journals Spurious poles in the scattering of electric and magnetic charges

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
John Terning ◽  
Christopher B. Verhaaren
Keyword(s):  
Perturbation Theory ◽  
Scattering Amplitudes ◽  
Pair Production ◽  
Magnetic Particles ◽  
Single Photon ◽  
Low Energy ◽  
Magnetic Interactions ◽  
Parity Conservation ◽  
Non Local ◽  
The Way

Abstract Theories with both electric and magnetic charges (“mutually non-local” theories) have several major obstacles to calculating scattering amplitudes. Even when the interaction arises through the kinetic mixing of two, otherwise independent, U(1)’s, so that all low-energy interactions are perturbative, difficulties remain: using a self-dual, local formalism leads to spurious poles at any finite order in perturbation theory. Correct calculations must show how the spurious poles cancel in observable scattering amplitudes. Consistency requires that one type of charge is confined as a result of one of the U(1)’s being broken. Here we show how the constraints of confinement and parity conservation on observable processes manages to cancel the spurious poles in scattering and pair production amplitudes, paving the way for systematic studies of the experimental signatures of “dark” electric-magnetic processes. Along the way we demonstrate some novel effects in electric-magnetic interactions, including that the amplitude for single photon production of magnetic particles by electric particles vanishes.

Aristotle

2020 ◽  
pp. 34-50
Author(s):  
Terence Irwin
Keyword(s):  
Common Good ◽  
Detailed Account ◽  
Virtuous Person ◽  
The Common Good ◽  
Rational Part ◽  
Human Good ◽  
The Common ◽  
The Right

Aristotle agrees with Plato that virtue requires the cooperation of the rational and the non-rational parts of the soul, and that the virtuous person is always better off than the non-virtuous, even though virtue alone is not sufficient for happiness. To strengthen Plato’s argument for this claim, he offers a more detailed account of the nature of happiness, and of the relation between virtue and happiness. Since happiness is the supreme human good, it should be identified with rational activity in accordance with virtue in a complete life, in which external circumstances are favourable. A virtue of character is the appropriate agreement between the rational and the non-rational parts of the soul, aiming at fine action (i.e., action that promotes the common good). This requirement of appropriate agreement distinguishes virtue from continence (mere control of the rational over the non-rational part). To show that a life of virtue, so defined, promotes the agent’s happiness, Aristotle argues that one’s own happiness requires the right kind of friendship with others, in which one aims at the good of others for their own sake.

Iteration-Perturbation Theory of Covalent Bonding in Crystals

1981 ◽  
Vol 36 (11) ◽  
pp. 1146-1154
Author(s):  
Genrich L. Krasko
Keyword(s):  
Perturbation Theory ◽  
Total Energy ◽  
Electron Density ◽  
Covalent Bonding ◽  
Atomic Volume ◽  
Electronic Density ◽  
Density Distributions ◽  
Energy Gaps ◽  
Volume Energy ◽  
Effective Charges

Using the theory developed in Part I of this work, the calculations of the total energy, equilib­rium volume, energy gaps and electronic density distributions are performed for magnesium hydride. The predicted equilibrium atomic volume and energy gaps are close to those observed experimentally. The calculations reveal a strong non-homogeneity in the electron density distri­bution. The estimated effective charges of the ions of Mg and H are respectively +1.90 and -0.65 which confirms that the bonding in this compound cannot be considered as a purely ionic one.

ALTERNATIVE LOW ENERGY SUPERSYMMETRY

1990 ◽  
Vol 05 (07) ◽  
pp. 467-472 ◽  
Author(s):  
LAWRENCE J. HALL
Keyword(s):  
Baryon Number ◽  
Lepton Number ◽  
Low Energy ◽  
Additional Symmetry ◽  
Alternative Models ◽  
Gauge Symmetries

Models of low energy supersymmetry require some additional symmetry beyond the known gauge symmetries. The usual preference for R parity, which leads to the standard low energy supersymmetry model, has no clear theoretical motivation. The alternative models with minimal field content are reviewed. In one case R parity is spontaneously broken by a large sneutrino vev. In three other cases R parity is replaced by an alternative symmetry; baryon number, lepton number or ZN.

Perturbation Theory of Scattering Amplitudes at High Energies

1963 ◽  
Vol 130 (6) ◽  
pp. 2566-2572 ◽  
Author(s):  
James D. Bjorken ◽  
Tai Tsun Wu
Keyword(s):  
Perturbation Theory ◽  
Scattering Amplitudes ◽  
High Energies

Common Ground

2018 ◽  
Author(s):  
Andreas Stokke
Keyword(s):  
Common Ground ◽  
Detailed Account ◽  
The Common ◽  
Definition Of

This chapter provides a detailed account of the notion of the common ground of conversations, which plays a central role in the Stalnakerian account of assertion that the book relies on for its characterization of lying. The chapter specifies that common ground information is defined in terms of acceptance, rather than belief, and shows how this feature allows that bald-faced lies are assertions. Moreover, the chapter demonstrates how the Stalnakerian conception of communication makes room for bald-faced implicatures. A number of objections to this picture of assertion and the common ground definition of lying are rebutted, including issues concerning the notion of proposing information for common ground uptake, as well as problems involving metaphor and malapropism.

Exploring Novel Strategies for Lipid-Based Drug Delivery

2018 ◽  
Vol 3 (1) ◽  
pp. 1-22
Author(s):  
Sabna Kotta ◽  
Navneet Sharma ◽  
Prateek Raturi ◽  
Mohd Aleem ◽  
Rakesh Kumar Sharma
Keyword(s):  
Drug Delivery ◽  
Drug Delivery System ◽  
Delivery System ◽  
Drug Delivery Systems ◽  
Classification Scheme ◽  
Delivery Systems ◽  
Primary Objective ◽  
Formulation Development ◽  
The Common ◽  
Do So

Currently, the concept of lipid-based drug delivery systems has gained much interest because of their capability to deliver drugs which dissolve sparingly in water or insoluble in nature. Several methods of lipid-based drug delivery exist, and each method has its own advantages as well as limitations. The primary objective of the formulation development is to improve the bioavailability of the drug. The nano-sized lipid-based drug delivery systems have enough potential to do so. This article addresses the various barriers to the transportation of drugs through certain routes and also the common excipients which used to develop the lipid-based drug delivery systems. It provides a thorough overview of the lipid formulation classification scheme (LFCS) and also deals with several formulation & evaluation aspects of lipid-based drug delivery system. Further, it focuses on the formulations which are already available in the market and their regulatory concerns, respectively.

scholarly journals Hidden non-locality and self-superrenormalization of quantum gravity

2020 ◽  
Vol 35 (35) ◽  
pp. 2050288
Author(s):  
Andrea Addazi
Keyword(s):  
Black Holes ◽  
Perturbation Theory ◽  
Scattering Amplitudes ◽  
Quantum Gravity ◽  
Uncertainty Principle ◽  
Quantum Effects ◽  
Perturbative Quantum ◽  
Heisenberg's Uncertainty Principle ◽  
Non Locality

We show that the formation/evaporation of Black Holes (BH) unitarizes quantum gravity at all the orders of the perturbation theory. Non-perturbative quantum effects save the scattering amplitudes from any polynomial divergences. Such a phenomena is intimately related to the dynamical emergence of an effective non-locality as well as emergent modifications of the Heisenberg’s uncertainty principle. The BH production delocalizes quantum gravity vertices and propagators as a consequence of its holographically stored entropy. In this sense, quantum gravity is a superrenormalizable theory, although non-locality is hidden in its action.

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