Broken Symmetries

Author(s):  
Laurent Baulieu ◽  
John Iliopoulos ◽  
Roland Sénéor

Exlicitly and spontaneously broken symmetries in classical and quantum physics. The linear and non-linear σ‎-model. The Goldstone theorem and the appearance of massless particles. The extension to Abelian and non-Abelian gauge symmetries and the Brout–Englert–Higgs mechanism.

2021 ◽  
pp. 287-303
Author(s):  
J. Iliopoulos ◽  
T.N. Tomaras

The phenomenon of spontaneous symmetry breaking is a common feature of phase transitions in both classical and quantum physics. In a first part we study this phenomenon for the case of a global internal symmetry and give a simple proof of Goldstone’s theorem. We show that a massless excitation appears, corresponding to every generator of a spontaneously broken symmetry. In a second part we extend these ideas to the case of gauge symmetries and derive the Brout–Englert–Higgs mechanism. We show that the gauge boson associated with the spontaneously broken generator acquires a mass and the corresponding field, which would have been the Goldstone boson, decouples and disappears. Its degree of freedom is used to allow the transition from a massless to a massive vector field.


2009 ◽  
Vol 24 (35n37) ◽  
pp. 2802-2802 ◽  
Author(s):  
DMITRY V. SHIRKOV

A retrospective historical overview of the phenomenon of spontaneous symmetry breaking (SSB) in quantum theory, the issue that has been implemented in particle physics in the form of the Higgs mechanism. The main items are: – The Bogoliubov's microscopical theory of superfluidity (1946); – The BCS-Bogoliubov theory of superconductivity (1957); – Superconductivity as a superfluidity of Cooper pairs (Bogoliubov - 1958); – Transfer of the SSB into the QFT models (early 60s); – The Higgs model triumph in the electro-weak theory (early 80s). The role of the Higgs mechanism and its status in the current Standard Model is also touched upon. Note from Publisher: This article contains the abstract only.


2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Upalaparna Banerjee ◽  
Joydeep Chakrabortty ◽  
Suraj Prakash ◽  
Shakeel Ur Rahaman ◽  
Michael Spannowsky

Abstract It is not only conceivable but likely that the spectrum of physics beyond the Standard Model (SM) is non-degenerate. The lightest non-SM particle may reside close enough to the electroweak scale that it can be kinematically probed at high-energy experiments and on account of this, it must be included as an infrared (IR) degree of freedom (DOF) along with the SM ones. The rest of the non-SM particles are heavy enough to be directly experimentally inaccessible and can be integrated out. Now, to capture the effects of the complete theory, one must take into account the higher dimensional operators constituted of the SM DOFs and the minimal extension. This construction, BSMEFT, is in the same spirit as SMEFT but now with extra IR DOFs. Constructing a BSMEFT is in general the first step after establishing experimental evidence for a new particle. We have investigated three different scenarios where the SM is extended by additional (i) uncolored, (ii) colored particles, and (iii) abelian gauge symmetries. For each such scenario, we have included the most-anticipated and phenomenologically motivated models to demonstrate the concept of BSMEFT. In this paper, we have provided the full EFT Lagrangian for each such model up to mass dimension 6. We have also identified the CP, baryon (B), and lepton (L) number violating effective operators.


Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 143
Author(s):  
Jose Beltrán Jiménez ◽  
Tomi S. Koivisto

In this paper, we provide a general framework for the construction of the Einstein frame within non-linear extensions of the teleparallel equivalents of General Relativity. These include the metric teleparallel and the symmetric teleparallel, but also the general teleparallel theories. We write the actions in a form where we separate the Einstein–Hilbert term, the conformal mode due to the non-linear nature of the theories (which is analogous to the extra degree of freedom in f(R) theories), and the sector that manifestly shows the dynamics arising from the breaking of local symmetries. This frame is then used to study the theories around the Minkowski background, and we show how all the non-linear extensions share the same quadratic action around Minkowski. As a matter of fact, we find that the gauge symmetries that are lost by going to the non-linear generalisations of the teleparallel General Relativity equivalents arise as accidental symmetries in the linear theory around Minkowski. Remarkably, we also find that the conformal mode can be absorbed into a Weyl rescaling of the metric at this order and, consequently, it disappears from the linear spectrum so only the usual massless spin 2 perturbation propagates. These findings unify in a common framework the known fact that no additional modes propagate on Minkowski backgrounds, and we can trace it back to the existence of accidental gauge symmetries of such a background.


1989 ◽  
Vol 326 (2) ◽  
pp. 307-332 ◽  
Author(s):  
Stefano Bellucci ◽  
Maarten F.L. Golterman ◽  
Donald N. Petcher

1998 ◽  
Vol 57 (5) ◽  
pp. 3017-3030 ◽  
Author(s):  
K. Farakos ◽  
N. E. Mavromatos

2015 ◽  
Vol 1 (2) ◽  
Author(s):  
Marc Henry

The claim that chemistry has been explained in terms of quantum theory is received wisdom. Yet quantum physics is unable to explain the strong association of water molecules in liquid or ice. Marc Henry suggests the hydrogen bond is an emergent property of matter resulting from a non-linear coupling between quantified energy levels of water molecules and a quantified internal electromagnetic field.


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