Gravitons from a loop representation of linearised gravity
نویسنده
چکیده
Loop quantum gravity is based on a classical formulation of 3+1 gravity in terms of a real SU(2) connection. Linearization of this classical formulation about a flat background yields a description of linearised gravity in terms of a real U(1)× U(1)× U(1) connection. A ‘loop’ representation, in which holonomies of this connection are unitary operators, can be constructed. These holonomies are not well defined operators in the standard graviton Fock representation. We generalise our recent work on photons and U(1) holonomies to show that Fock space gravitons are associated with distributional states in the U(1)× U(1)× U(1) loop representation. Our results may illuminate certain aspects of the much deeper (and as yet unkown,) relation between gravitons and states in nonperturbative loop quantum gravity. This work leans heavily on earlier seminal work by Ashtekar, Rovelli and Smolin (ARS) on the loop representation of linearised gravity using complex connections. In the last part of this work, we show that the loop representation based on the real U(1)× U(1)× U(1) connection also provides a useful kinematic arena in which it is possible to express the ARS complex connectionbased results in the mathematically precise language currently used in the field.
منابع مشابه
Photons from quantized eletric flux representations
The quantum theory of U(1) connections admits a diffeomorphism invariant representation in which the electric flux through any surface is quantized. This representation is the analog of the representation of quantum SU(2) theory used in loop quantum gravity. We investigate the relation between this representation, in which the basic excitations are ‘polymer-like’, and the Fock representation, i...
متن کاملBasis states for gravitons in non-perturbative loop representation space
A relation between the non-perturbative loop representation space (for use of exact quantization of general relativity) and the semi-classical loop representation space (for use of approximate quantization of general relativity with a flat background spacetime) is studied. A sector of (approximate) states and a sector of operators in the non-perturbative loop representation space are made relat...
متن کاملGravitons and loops.
The recently proposed loop representation is used to quantize linearized general relativity. The Fock space of graviton states and its associated algebra of observables are represented in terms of functionals of loops. The “reality conditions” are realized by an inner product that is chiral asymmetric, resulting in a chiral asymmetric ordering for the Hamiltonian, and, in an asymmetric descript...
متن کاملGravity and Form Scattering and Renormalisation of Gravity in Six and Eight Dimensions
We calculate one-loop scattering amplitudes for gravitons and two-forms in dimensions greater than four. The string based Kawai-Lewellen-Tye relationships allow gravitons and two-forms to be treated in a unified manner. We use the results to determine the ultra-violet infinities present in these amplitudes and show how these determine the renormalised one-loop action in six and eight dimensions...
متن کاملFock representations from U(1) holonomy algebras
We revisit the quantization of U(1) holonomy algebras using the abelian C algebra based techniques which form the mathematical underpinnings of current efforts to construct loop quantum gravity. In particular, we clarify the role of “smeared loops” and of Poincare invariance in the construction of Fock representations of these algebras. This enables us to critically re-examine early pioneering ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2002