Advances in Applied Clifford Algebras 

About: Advances in Applied Clifford Algebras is an academic journal published by Birkhäuser. The journal publishes majorly in the area(s): Clifford algebra & Clifford analysis. It has an ISSN identifier of 0188-7009. Over the lifetime, 1419 publications have been published receiving 12188 citations. The journal is also known as: AACA.

Quaternion Fourier Transform on Quaternion Fields and Generalizations

Abstract: We treat the quaternionic Fourier transform (QFT) applied to quaternion fields and investigate QFT properties useful for applications. Different forms of the QFT lead us to different Plancherel theorems. We relate the QFT computation for quaternion fields to the QFT of real signals. We research the general linear (GL) transformation behavior of the QFT with matrices, Clifford geometric algebra and with examples. We finally arrive at wide-ranging non-commutative multivector FT generalizations of the QFT. Examples given are new volume-time and spacetime algebra Fourier transformations.

On Fibonacci Quaternions

Abstract: In this paper, we investigate the Fibonacci and Lucas quaternions. We give the generating functions and Binet formulas for these quaternions. Moreover, we derive some sums formulas for them.

ELKO, flagpole and flag-dipole spinor fields, and the instanton Hopf fibration

Abstract: In a previous paper we explicitly constructed a mapping that leads Dirac spinor fields to the dual-helicity eigenspinors of the charge conjugation operator (ELKO spinor fields). ELKO spinor fields are prime candidates for describing dark matter, and belong to a wider class of spinor fields, the so-called flagpole spinor fields, corresponding to the class-(5), according to Lounesto spinor field classification, based on the relations and values taken by their associated bilinear covariants. Such a mapping between Dirac and ELKO spinor fields was obtained in an attempt to extend the Standard Model in order to encompass dark matter. Now we prove that such a mapping, analogous to the instanton Hopf fibration map S3...S7 → S4, indicates that ELKO is not suitable to describe the instanton. We review ELKO spinor fields as type-(5) spinor fields under the Lounesto spinor field classification, explicitly computing the associated bilinear covariants. This paper is also devoted to investigate some formal aspects of the flag-dipole spinor fields, which correspond to the class-(4) under the Lounesto spinor field classification and, in addition, we prove that type-(4) spinor fields — corresponding to flag-dipoles — and ELKO spinor fields — corresponding to flagpoles — can also be entirely described in terms of the Majorana and Weyl spinor fields. After all, by choosing a projection endomorphism of the spacetime algebra \({\mathcal C}\ell_{1,3}\) it is shown how to obtain ELKO, flagpole, Majorana and Weyl spinor fields, respectively corresponding to type-(5) and -(6) spinor fields, uniquely from limiting cases of a type-(4) — flag-dipole — spinor field, in a similar result obtained by Lounesto.

Clifford Fourier Transform on Multivector Fields and Uncertainty Principles for Dimensions n = 2 (mod 4) and n = 3 (mod 4)

Abstract: First, the basic concepts of the multivector functions, vector differential and vector derivative in geometric algebra are introduced. Second, we define a generalized real Fourier transform on Clifford multivector-valued functions (\(f : {{\mathbb{R}}}^n \rightarrow Cl_{n,0}, n = 2, 3\) (mod 4)). Third, we show a set of important properties of the Clifford Fourier transform on Cln,0, n = 2, 3 (mod 4) such as differentiation properties, and the Plancherel theorem, independent of special commutation properties. Fourth, we develop and utilize commutation properties for giving explicit formulas for fxm, f ∇m and for the Clifford convolution. Finally, we apply Clifford Fourier transform properties for proving an uncertainty principle for Cln,0, n = 2, 3 (mod 4) multivector functions.

The theory of local mass dimension one fermions of spin one half

Abstract: About a decade ago the present author in collaboration with Daniel Grumiller presented an ‘unexpected theoretical discovery’ of spin one-half fermions with mass dimension one (Ahluwalia-Khalilova and Grumiller in Phys Rev D 72:067701 arXiv:hep-th/0410192 , 2005, JCAP 0507:012, arXiv:hep-th/0412080 , 2005). In the decade that followed a significant number of groups explored intriguing mathematical and physical properties of the new construct. However, the formalism suffered from two troubling features, that of non-locality and a subtle violation of Lorentz symmetry. Here, we trace the origin of both of these issues to a hidden freedom in the definition of duals of spinors and the associated field adjoints. In the process, for the first time, we provide a quantum theory of spin one-half fermions that is free from all the mentioned issues. The interactions of the new fermions are restricted to dimension-four quartic self interaction, and also to a dimension-four coupling with the Higgs. A generalised Yukawa coupling of the new fermions with neutrinos provides an hitherto unsuspected source of lepton-number violation. The new fermions thus present a first-principle dark matter partner to Dirac fermions of the standard model of high energy physics with contrasting mass dimensions—that of three halves for the latter versus one of the former without mutating the statistics from fermionic to bosonic.