123 research outputs found
On the transverse symbol of vectorial distributions and some applications to harmonic analysis
AbstractThe transverse symbol of a vector-valued distribution supported on a submanifold is introduced and a micro-local vanishing theorem for spaces of such distributions invariant under a Lie group is proved. We give transparent proofs of results of Bruhat and Harish-Chandra on the irreducibility of parabolically or normally induced representations, and of Harish-Chandra in Whittaker theory
Structure, classifcation, and conformal symmetry, of elementary particles over non-archimedean space-time
It is known that no length or time measurements are possible in sub-Planckian
regions of spacetime. The Volovich hypothesis postulates that the
micro-geometry of spacetime may therefore be assumed to be non-archimedean. In
this letter, the consequences of this hypothesis for the structure,
classification, and conformal symmetry of elementary particles, when spacetime
is a flat space over a non-archimedean field such as the -adic numbers, is
explored. Both the Poincar\'e and Galilean groups are treated. The results are
based on a new variant of the Mackey machine for projective unitary
representations of semidirect product groups which are locally compact and
second countable. Conformal spacetime is constructed over -adic fields and
the impossibility of conformal symmetry of massive and eventually massive
particles is proved
Airy functions over local fields
Airy integrals are very classical but in recent years they have been
generalized to higher dimensions and these generalizations have proved to be
very useful in studying the topology of the moduli spaces of curves. We study a
natural generalization of these integrals when the ground field is a
non-archimedean local field such as the field of p-adic numbers. We prove that
the p-adic Airy integrals are locally constant functions of moderate growth and
present evidence that the Airy integrals associated to compact p-adic Lie
groups also have these properties.Comment: Minor change
Fomenko-Mischenko Theory, Hessenberg Varieties, and Polarizations
The symmetric algebra g (denoted S(\g)) over a Lie algebra \g (frak g) has
the structure of a Poisson algebra. Assume \g is complex semi-simple. Then
results of Fomenko- Mischenko (translation of invariants) and A.Tarasev
construct a polynomial subalgebra \cal H = \bf C[q_1,...,q_b] of S(\g) which is
maximally Poisson commutative. Here b is the dimension of a Borel subalgebra of
\g. Let G be the adjoint group of \g and let \ell = rank \g. Identify \g with
its dual so that any G-orbit O in \g has the structure (KKS) of a symplectic
manifold and S(\g) can be identified with the affine algebra of \g. An element
x \in \g is strongly regular if \{(dq_i)_x\}, i=1,...,b, are linearly
independent. Then the set \g^{sreg} of all strongly regular elements is Zariski
open and dense in \g, and also \g^{sreg \subset \g^{reg} where \g^{reg} is the
set of all regular elements in \g. A Hessenberg variety is the b-dimensional
affine plane in \g, obtained by translating a Borel subalgebra by a suitable
principal nilpotent element. This variety was introduced in [K2]. Defining Hess
to be a particular Hessenberg variety, Tarasev has shown that Hess \subset
\g^sreg. Let R be the set of all regular G-orbits in \g. Thus if O \in R, then
O is a symplectic manifold of dim 2n where n= b-\ell. For any O\in R let
O^{sreg} = \g^{sreg}\cap O. We show that O^{sreg} is Zariski open and dense in
O so that O^{sreg} is again a symplectic manifold of dim 2n. For any O \in R
let Hess (O) = Hess \cap O. We prove that Hess(O) is a Lagrangian submanifold
of O^{sreg} and Hess =\sqcup_{O \in R} Hess(O). The main result here shows that
there exists, simultaneously over all O \in R, an explicit polarization (i.e.,
a "fibration" by Lagrangian submanifolds) of O^{sreg} which makes O^{sreg}
simulate, in some sense, the cotangent bundle of Hess(O).Comment: 36 pages, plain te
The Spin-Statistics Theorem for Anyons and Plektons in d=2+1
We prove the spin-statistics theorem for massive particles obeying braid
group statistics in three-dimensional Minkowski space. We start from first
principles of local relativistic quantum theory. The only assumption is a gap
in the mass spectrum of the corresponding charged sector, and a restriction on
the degeneracy of the corresponding mass.Comment: 21 pages, 2 figures. Citation added; Minor modifications of Appendix
Testing axioms for Quantum Mechanics on Probabilistic toy-theories
In Ref. [1] one of the authors proposed postulates for axiomatizing Quantum
Mechanics as a "fair operational framework", namely regarding the theory as a
set of rules that allow the experimenter to predict future events on the basis
of suitable tests, having local control and low experimental complexity. In
addition to causality, the following postulates have been considered: PFAITH
(existence of a pure preparationally faithful state), and FAITHE (existence of
a faithful effect). These postulates have exhibited an unexpected theoretical
power, excluding all known nonquantum probabilistic theories. Later in Ref. [2]
in addition to causality and PFAITH, postulate LDISCR (local discriminability)
and PURIFY (purifiability of all states) have been considered, narrowing the
probabilistic theory to something very close to Quantum Mechanics. In the
present paper we test the above postulates on some nonquantum probabilistic
models. The first model, "the two-box world" is an extension of the
Popescu-Rohrlich model, which achieves the greatest violation of the CHSH
inequality compatible with the no-signaling principle. The second model "the
two-clock world" is actually a full class of models, all having a disk as
convex set of states for the local system. One of them corresponds to the "the
two-rebit world", namely qubits with real Hilbert space. The third model--"the
spin-factor"--is a sort of n-dimensional generalization of the clock. Finally
the last model is "the classical probabilistic theory". We see how each model
violates some of the proposed postulates, when and how teleportation can be
achieved, and we analyze other interesting connections between these postulate
violations, along with deep relations between the local and the non-local
structures of the probabilistic theory.Comment: Submitted to QIP Special Issue on Foundations of Quantum Informatio
On the realization of Symmetries in Quantum Mechanics
The aim of this paper is to give a simple, geometric proof of Wigner's
theorem on the realization of symmetries in quantum mechanics that clarifies
its relation to projective geometry. Although several proofs exist already, it
seems that the relevance of Wigner's theorem is not fully appreciated in
general. It is Wigner's theorem which allows the use of linear realizations of
symmetries and therefore guarantees that, in the end, quantum theory stays a
linear theory. In the present paper, we take a strictly geometrical point of
view in order to prove this theorem. It becomes apparent that Wigner's theorem
is nothing else but a corollary of the fundamental theorem of projective
geometry. In this sense, the proof presented here is simple, transparent and
therefore accessible even to elementary treatments in quantum mechanics.Comment: 8 page
Spinor Algebras
We consider supersymmetry algebras in space-times with arbitrary signature
and minimal number of spinor generators. The interrelation between super
Poincar\'e and super conformal algebras is elucidated. Minimal super conformal
algebras are seen to have as bosonic part a classical semimisimple algebra
naturally associated to the spin group. This algebra, the Spin-algebra,
depends both on the dimension and on the signature of space time. We also
consider maximal super conformal algebras, which are classified by the
orthosymplectic algebras.Comment: References added, misprints corrected. Version to appear in the
Journal of Geometry and Physic
Rotational symmetries of crystals with defects
I use the theory of Lie groups/algebras to discuss the symmetries of crystals with uniform distributions of defects
Reproducing subgroups of . Part I: algebraic classification
We classify the connected Lie subgroups of the symplectic group
whose elements are matrices in block lower triangular form.
The classification is up to conjugation within . Their study
is motivated by the need of a unified approach to continuous 2D signal
analyses, as those provided by wavelets and shearlets.Comment: 26 page
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