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AI for Particle Physics
Published in Volker Knecht, AI for Physics, 2023
Mario Campanelli, Volker Knecht
In string theory, the point-like particles of the SM are superseded by one-dimensional objects called strings.8 Bosonic string theory contained only bosons. In contrast, supersymmetric string theory – or superstring theory for short – accounts for both fermions and bosons and integrates supersymmetry to model gravity. This theory may also explain the observed forces and particles of the SM, justify their masses, and shed light on the nature of dark matter plus dark energy. In that sense, it provides a theory of everything (check out Chapter 8).
Some Aspects of Superstring Theory
Published in Harish Parthasarathy, Advanced Probability and Statistics: Applications to Physics and Engineering, 2023
operators. Thus the quantum superstring acts in a tensor product of Boson and Fermion Fock space. The Hamiltonian of the superstring can be expressed as H=∑n≥1c(n)α(−n)α(n)+∑n≥1d(n)β(−n)β(n) where α(−n)=α(n)*,β(−n)=β(n)* and the α' s satisfy the CCR while the β's satisfy the CAR: [α(n),α(m)]=δ(n+m){β(n),β(m)}=δ(n+m)
Some Aspects of Superstring Theory
Published in Harish Parthasarathy, Supersymmetry and Superstring Theory with Engineering Applications, 2023
[1] The superstring Lagrangian density is a quadratic form in the Bosonic and Fermionic component string fields. The corresponding string-field equations give the basic equations for the Bosonic and Fermionic strings in decoupled from. The Bosonic part is simply the wave equation with one time variable and one spatial variable. The Fermionic part is simply the Dirac equation with zero mass in one time and one spatial dimension. The solutions to these equations yield the Bosonic string field as a linear combination of a countably infinite number of Bosonic creation and annihilation operators and the Fermionic string field as a linear combination of a countably infinite of Fermionic creation and annihilation operators. Thus the quantum superstring acts in a tensor product of Boson and Fermion Fock space. The Hamiltonian of the superstring can be expressed as H=∑n≥1c(n)α(−n)α(n)+∑n≥1d(n)β(−n)β(n) where α(−n)=α(n)*,β(−n)=β(n)* and the α′s satisfy the CCR while the β′s satisfy the CAR: [α(n),α(m)]=δ(n+m){β(n),β(m)}=δ(n+m)
Geometric theory of topological defects: methodological developments and new trends
Published in Liquid Crystals Reviews, 2021
Sébastien Fumeron, Bertrand Berche, Fernando Moraes
A major contemporary challenge in physics is to find an extension of General Relativity able to describe gravity at all energy scales, in particular at the very beginning of the universe. This is the mission devoted to quantum gravity theories, which have the daunting task of reconciling Einstein's general relativity and quantum field theory. Despite promising attempts, including superstring theories, M-theory or quantum loop gravity, no proposal is entirely satisfactory up to now, and even so, the energy scales required to test these theories are far beyond our current scientific capabilities. A way out of this gridlock is to rely on simpler models that capture the essential features of quantum gravity but remain connected to low-energy-physics systems, i.e. analog gravity. The rare pearl was first introduced in a seminal paper by Deser, Jackiw and 't Hooft [141]: 2 + 1 gravity with point-particle sources.