The Experts below are selected from a list of 18051 Experts worldwide ranked by ideXlab platform
Quentin G Bailey - One of the best experts on this subject based on the ideXlab platform.
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construction of higher order metric fluctuation terms in Spacetime Symmetry breaking effective field theory
Symmetry, 2021Co-Authors: Quentin G BaileyAbstract:We examined the basic conservation laws for diffeomorphism Symmetry in the context of spontaneous diffeomorphism and local Lorentz-Symmetry breaking. The conservation laws were used as constraints on a generic series of terms in an expansion around a flat background. We found all such terms for a two-tensor coupling to cubic order in the metric and tensor field fluctuations. The results are presented in a form that can be used for phenomenological calculations. One key result is that if we preserve the underlying diffeomorphism Symmetry in a spontaneous-Symmetry breaking scenario, one cannot decouple the two-tensor fluctuations from the metric fluctuations at the level of the action, except in special cases of the quadratic actions.
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construction of higher order metric fluctuation terms in Spacetime Symmetry breaking effective field theory
arXiv: General Relativity and Quantum Cosmology, 2021Co-Authors: Quentin G BaileyAbstract:We examine the basic conservation laws for diffeomorphism Symmetry in the context of spontaneous diffeomorphism and local Lorentz-Symmetry breaking. The conservation laws are used as constraints on a generic series of terms in an expansion around a flat background. We find all such terms for a two-tensor coupling to cubic order in the metric and tensor field fluctuations. The results are presented in a form that can be used for phenomenological calculations. One key result is that if we preserve the underlying diffeomorphism Symmetry in a spontaneous-Symmetry breaking scenario, one cannot decouple the two-tensor fluctuations from the metric fluctuations at the level of the action, except in special cases of the quadratic actions.
Eugen Radu - One of the best experts on this subject based on the ideXlab platform.
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asymptotically flat black holes with scalar hair a review
International Journal of Modern Physics, 2015Co-Authors: Carlos A R Herdeiro, Eugen RaduAbstract:We consider the status of black hole (BH) solutions with nontrivial scalar fields but no gauge fields, in four-dimensional asymptotically flat Spacetimes, reviewing both classical results and recent developments. We start by providing a simple illustration on the physical difference between BHs in electro-vacuum and scalar-vacuum. Next, we review no-scalar-hair theorems. In particular, we detail an influential theorem by Bekenstein and stress three key assumptions: (1) The type of scalar field equation; (2) the Spacetime Symmetry inheritance by the scalar field and (3) an energy condition. Then, we list regular (on and outside the horizon), asymptotically flat BH solutions with scalar hair, organizing them by the assumption which is violated in each case and distinguishing primary from secondary hair. We provide a table summary of the state-of-the-art.
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asymptotically flat black holes with scalar hair a review
arXiv: General Relativity and Quantum Cosmology, 2015Co-Authors: Carlos A R Herdeiro, Eugen RaduAbstract:We consider the status of black hole solutions with non-trivial scalar fields but no gauge fields, in four dimensional asymptotically flat space-times, reviewing both classical results and recent developments. We start by providing a simple illustration on the physical difference between black holes in electro-vacuum and scalar-vacuum. Next, we review no-scalar-hair theorems. In particular, we detail an influential theorem by Bekenstein and stress three key assumptions: 1) the type of scalar field equation; 2) the Spacetime Symmetry inheritance by the scalar field; 3) an energy condition. Then, we list regular (on and outside the horizon), asymptotically flat BH solutions with scalar hair, organizing them by the assumption which is violated in each case and distinguishing primary from secondary hair. We provide a table summary of the state of the art.
Shakeel Ur Rahaman - One of the best experts on this subject based on the ideXlab platform.
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Characters and Group Invariant Polynomials of (Super)fields: Road to "Lagrangian"
2020Co-Authors: Banerjee Upalaparna, Chakrabortty Joydeep, Prakash Suraj, Shakeel Ur RahamanAbstract:The dynamics of the subatomic fundamental particles, represented by quantum fields, and their interactions are determined uniquely by the assigned transformation properties, i.e., the quantum numbers associated with the underlying Symmetry of the model. These fields constitute a finite number of group invariant operators which are assembled to build a polynomial, known as the Lagrangian. The order of the polynomial is determined by the mass dimension. In this paper, we have introduced a Mathematica package, GrIP, that computes the complete set of operators that form a basis at each such order for a model containing any number of fields transforming under connected compact groups. The Spacetime Symmetry is restricted to the Lorentz group. The first part of the paper is dedicated to formulating the algorithm of GrIP. In this context, the detailed and explicit construction of the characters of different representations corresponding to connected compact groups and respective Haar measures have been discussed in terms of the coordinates of their respective maximal torus. In the second part, we have documented the user manual of GrIP that captures the generic features and guides to prepare the input file. This program works very efficiently to find out the higher mass (non-supersymmetric) and canonical (supersymmetric) dimensional operators relevant to the Effective Field Theory. We have demonstrated the working principles with two examples:- the SM and the MSSM. We have further highlighted important features of GrIP, e.g., identification of effective operators leading to specific rare processes linked with the violation of baryon and lepton numbers, using several BSM scenarios. We have also tabulated a complete set of dimension-6 operators for each such model. Some of the operators possess rich flavour structures which are discussed in detail. This work paves the way towards BSM-EFT.Comment: 103 pages, 11 figure
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Characters and group invariant polynomials of (super)fields: road to “Lagrangian”
'Springer Science and Business Media LLC', 2020Co-Authors: Upalaparna Banerjee, Joydeep Chakrabortty, Suraj Prakash, Shakeel Ur RahamanAbstract:The dynamics of the subatomic fundamental particles, represented by quantum fields, and their interactions are determined uniquely by the assigned transformation properties, i.e., the quantum numbers associated with the underlying Symmetry of the model under consideration. These fields constitute a finite number of group invariant operators which are assembled to build a polynomial, known as the Lagrangian of that particular model. The order of the polynomial is determined by the mass dimension. In this paper, we have introduced an automated $${\texttt {Mathematica}}^{\tiny \textregistered }$$ package, GrIP, that computes the complete set of operators that form a basis at each such order for a model containing any number of fields transforming under connected compact groups. The Spacetime Symmetry is restricted to the Lorentz group. The first part of the paper is dedicated to formulating the algorithm of GrIP. In this context, the detailed and explicit construction of the characters of different representations corresponding to connected compact groups and respective Haar measures have been discussed in terms of the coordinates of their respective maximal torus. In the second part, we have documented the user manual of GrIP that captures the generic features of the main program and guides to prepare the input file. We have attached a sub-program CHaar to compute characters and Haar measures for $$SU(N), SO(2N), SO(2N+1), Sp(2N)$$. This program works very efficiently to find out the higher mass (non-supersymmetric) and canonical (supersymmetric) dimensional operators relevant to the effective field theory (EFT). We have demonstrated the working principles with two examples: the standard model (SM) and the minimal supersymmetric standard model (MSSM). We have further highlighted important features of GrIP, e.g., identification of effective operators leading to specific rare processes linked with the violation of baryon and lepton numbers, using several beyond standard model (BSM) scenarios. We have also tabulated a complete set of dimension-6 operators for each such model. Some of the operators possess rich flavour structures which are discussed in detail. This work paves the way towards BSM-EFT
Carlos A R Herdeiro - One of the best experts on this subject based on the ideXlab platform.
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asymptotically flat black holes with scalar hair a review
International Journal of Modern Physics, 2015Co-Authors: Carlos A R Herdeiro, Eugen RaduAbstract:We consider the status of black hole (BH) solutions with nontrivial scalar fields but no gauge fields, in four-dimensional asymptotically flat Spacetimes, reviewing both classical results and recent developments. We start by providing a simple illustration on the physical difference between BHs in electro-vacuum and scalar-vacuum. Next, we review no-scalar-hair theorems. In particular, we detail an influential theorem by Bekenstein and stress three key assumptions: (1) The type of scalar field equation; (2) the Spacetime Symmetry inheritance by the scalar field and (3) an energy condition. Then, we list regular (on and outside the horizon), asymptotically flat BH solutions with scalar hair, organizing them by the assumption which is violated in each case and distinguishing primary from secondary hair. We provide a table summary of the state-of-the-art.
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asymptotically flat black holes with scalar hair a review
arXiv: General Relativity and Quantum Cosmology, 2015Co-Authors: Carlos A R Herdeiro, Eugen RaduAbstract:We consider the status of black hole solutions with non-trivial scalar fields but no gauge fields, in four dimensional asymptotically flat space-times, reviewing both classical results and recent developments. We start by providing a simple illustration on the physical difference between black holes in electro-vacuum and scalar-vacuum. Next, we review no-scalar-hair theorems. In particular, we detail an influential theorem by Bekenstein and stress three key assumptions: 1) the type of scalar field equation; 2) the Spacetime Symmetry inheritance by the scalar field; 3) an energy condition. Then, we list regular (on and outside the horizon), asymptotically flat BH solutions with scalar hair, organizing them by the assumption which is violated in each case and distinguishing primary from secondary hair. We provide a table summary of the state of the art.
Spenta R Wadia - One of the best experts on this subject based on the ideXlab platform.
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asymptotically free four fermi theory in 4 dimensions at the z 3 lifshitz like fixed point
Physical Review D, 2009Co-Authors: Avinash Dhar, Gautam Mandal, Spenta R WadiaAbstract:We show that a Nambu-Jona-Lasinio type four-fermion coupling at the z=3 Lifshitz-like fixed point in 3+1 dimensions is asymptotically free and generates a mass scale dynamically. This result is nonperturbative in the limit of a large number of fermion species. The theory is ultraviolet complete and at low energies exhibits Lorentz invariance as an emergent Spacetime Symmetry. Many of our results generalize to z=d in odd d spatial dimensions; z=d=1 corresponds to the Gross-Neveu model. The above mechanism of mass generation has potential applications to the fermion mass problem and to dynamical electroweak Symmetry breaking. We present a scenario in which a composite Higgs field arises from a condensate of these fermions, which then couples to quarks and leptons of the standard model. Such a scenario could eliminate the need for the Higgs potential and the associated hierarchy problem. We also show that the axial anomaly formula at z=3 coincides with the usual one in the relativistic domain.