2,074 research outputs found
Continuous spin and tensionless strings
A classical action is proposed which upon quantisation yields massless
particles belonging to the continuous spin representation of the Poincar\'e
group. The string generalisation of the action is identical to the tensionless
extrinsic curvature action proposed by Savvidy. We show that the BRST
quantisation of the string action gives a critical dimension of 28. The
constraints result in a number of degrees of freedom which is the same as the
bosonic string.Comment: 13 pages; v2 added references; v3 discussion adde
Continuous spin particles from a string theory
It has been shown that the massless irreducible representations of the
Poincar\'e group with continuous spin can be obtained from a classical point
particle action which admits a generalization to a conformally invariant string
action. The continuous spin string action is quantized in the BRST formalism.
We show that the vacuum carries a continuous spin representation of the
Poincar\'e group and that the spectrum is ghost-free.Comment: 13 pages, LaTe
Quantum Space-time and Classical Gravity
A method has been recently proposed for defining an arbitrary number of
differential calculi over a given noncommutative associative algebra. As an
example a version of quantized space-time is considered here. It is found that
there is a natural differential calculus using which the space-time is
necessarily flat Minkowski space-time. Perturbations of this calculus are shown
to give rise to non-trivial gravitational fields.Comment: 21 pages LaTe
Deformations of Differential Calculi
It has been suggested that quantum fluctuations of the gravitational field
could give rise in the lowest approximation to an effective noncommutative
version of Kaluza-Klein theory which has as extra hidden structure a
noncommutative geometry. It would seem however from the Standard Model, at
least as far as the weak interactions are concerned, that a double-sheeted
structure is the phenomenologically appropriate one at present accelerator
energies. We examine here to what extent this latter structure can be
considered as a singular limit of the former.Comment: 11 pages of Late
Open Supermembranes Coupled to M-Theory Five-Branes
We consider open supermembranes in eleven dimensions in the presence of
closed M-Theory five-branes. It has been shown that, in a flat space-time, the
world-volume action is kappa invariant and preserves a fraction of the eleven
dimensional supersymmetries if the boundaries of the membranes lie on the
five-branes. We calculate the reparametrisation anomalies due to the chiral
fermions on the boundaries of the membrane and examine their cancellation
mechanism. We show that these anomalies cancel with the aid of a classical term
in the world-volume action, provided that the tensions of the five-brane and
the membrane are related to the eleven dimensional gravitational constant in a
way already noticed in M-Theory.Comment: Latex, 14 page
The continuous spin limit of higher spin field equations
We show that the Wigner equations describing the continuous spin
representations can be obtained as a limit of massive higher-spin field
equations. The limit involves a suitable scaling of the wave function, the mass
going to zero and the spin to infinity with their product being fixed. The
result allows to transform the Wigner equations to a gauge invariant
Fronsdal-like form. We also give the generalisation of the Wigner equations to
higher dimensions with fields belonging to arbitrary representations of the
massless little group.Comment: 18 pages, JHEP style. Typos corrected, references adde
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