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String field from Loop SpinfoamQG:how to build SM matter on discrete quantum geometry
note: EPRL is the current standard spinfoam formulation of Loop Quantum Gravity.
http://arxiv.org/abs/1201.0525
String Field Theory from Quantum Gravity
Louis Crane
(Submitted on 2 Jan 2012)
Recent work on neutrino oscillations suggests that the three generations of fermions in the standard model are related by representations of the finite group A(4), the group of symmetries of the tetrahedron. Motivated by this, we explore models which extend the EPRL model for quantum gravity by coupling it to a bosonic quantum field of representations of A(4). This coupling is possible because the representation category of A(4) is a module category over the representation categories used to construct the EPRL model. The vertex operators which interchange vacua in the resulting quantum field theory reproduce the bosons and fermions of the standard model, up to issues of symmetry breaking which we do not resolve. We are led to the hypothesis that physical particles in nature represent vacuum changing operators on a sea of invisible excitations which are only observable in the A(4) representation labels which govern the horizontal symmetry revealed in neutrino oscillations. The quantum field theory of the A(4) representations is just the dual model on the extended lattice of the Lie group E6, as explained by the quantum Mckay correspondence of Frenkel Jing and Wang. The coupled model can be thought of as string field theory, but propagating on a discretized quantum spacetime rather than a classical manifold.
15 pages
Excerpt from introduction:"In the last few years, a new development [1] [2] [3] [4] has largely resolved the problems of the old BC model [5] for quantum gravity. It is now a natural task to study extensions of the EPRL model which would include realistic matter fields. It would be extremely desirable to find an algebraic extension of the EPRL model which was essentially unique or at least had a small number of possibilities and which gave us the standard model..."
Excerpt from conclusions: "It was quite a surprise to have the string appear in this theory, which started from a completely different program. Rather than ending up with an almost infinite landscape as in Kaluza-Klein theories, we get an essentially unique theory, which relates fairly directly to the standard model.
Embedding the string field in a discrete model for spacetime removes the difficulties that beset string field theories in a continuum.
There is no longer the integration over worldsheet metrics which leads to bad behavior on moduli space in the Polyakov string; rather the dual models couple to the quantum geometry of the EPRL model itself."
note: EPRL is the current standard spinfoam formulation of Loop Quantum Gravity.
http://arxiv.org/abs/1201.0525
String Field Theory from Quantum Gravity
Louis Crane
(Submitted on 2 Jan 2012)
Recent work on neutrino oscillations suggests that the three generations of fermions in the standard model are related by representations of the finite group A(4), the group of symmetries of the tetrahedron. Motivated by this, we explore models which extend the EPRL model for quantum gravity by coupling it to a bosonic quantum field of representations of A(4). This coupling is possible because the representation category of A(4) is a module category over the representation categories used to construct the EPRL model. The vertex operators which interchange vacua in the resulting quantum field theory reproduce the bosons and fermions of the standard model, up to issues of symmetry breaking which we do not resolve. We are led to the hypothesis that physical particles in nature represent vacuum changing operators on a sea of invisible excitations which are only observable in the A(4) representation labels which govern the horizontal symmetry revealed in neutrino oscillations. The quantum field theory of the A(4) representations is just the dual model on the extended lattice of the Lie group E6, as explained by the quantum Mckay correspondence of Frenkel Jing and Wang. The coupled model can be thought of as string field theory, but propagating on a discretized quantum spacetime rather than a classical manifold.
15 pages
Excerpt from introduction:"In the last few years, a new development [1] [2] [3] [4] has largely resolved the problems of the old BC model [5] for quantum gravity. It is now a natural task to study extensions of the EPRL model which would include realistic matter fields. It would be extremely desirable to find an algebraic extension of the EPRL model which was essentially unique or at least had a small number of possibilities and which gave us the standard model..."
Excerpt from conclusions: "It was quite a surprise to have the string appear in this theory, which started from a completely different program. Rather than ending up with an almost infinite landscape as in Kaluza-Klein theories, we get an essentially unique theory, which relates fairly directly to the standard model.
Embedding the string field in a discrete model for spacetime removes the difficulties that beset string field theories in a continuum.
There is no longer the integration over worldsheet metrics which leads to bad behavior on moduli space in the Polyakov string; rather the dual models couple to the quantum geometry of the EPRL model itself."
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