Bounce Cosmology in a Locally Scale Invariant Physics with a U(1) Symmetry
An asymmetric non-singular bouncing cosmological model is proposed in the framework of a locally scale-invariant scalar-tensor version of the standard model of particle physics and gravitation. The scalar field <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" displ...
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2025-03-01
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| author | Meir Shimon |
| author_facet | Meir Shimon |
| author_sort | Meir Shimon |
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| description | An asymmetric non-singular bouncing cosmological model is proposed in the framework of a locally scale-invariant scalar-tensor version of the standard model of particle physics and gravitation. The scalar field <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ϕ</mi></semantics></math></inline-formula> is complex. In addition to local scale invariance, the theory is U(1)-symmetric and has a conserved global charge associated with time variations of the phase of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ϕ</mi></semantics></math></inline-formula>. An interplay between the positive energy density contributions of relativistic and non-relativistic matter and that of the negative kinetic energy associated with the phase of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ϕ</mi></semantics></math></inline-formula> results in a classical non-singular stable bouncing dynamics deep in the radiation-dominated era. This encompasses the observed redshifting era, which is preceded by a blueshifting era. The proposed model potentially avoids the flatness and horizon problems, as well as allowing for the generation of a scale-invariant spectrum of metric perturbations of the scalar type during a matter-dominated-like pre-bounce phase, with no recourse to an inflationary era. |
| format | Article |
| id | doaj-art-8e2fac5a19204bb5b1fd6443e30b36ca |
| institution | OA Journals |
| issn | 2218-1997 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | MDPI AG |
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| series | Universe |
| spelling | doaj-art-8e2fac5a19204bb5b1fd6443e30b36ca2025-08-20T01:48:50ZengMDPI AGUniverse2218-19972025-03-011139310.3390/universe11030093Bounce Cosmology in a Locally Scale Invariant Physics with a U(1) SymmetryMeir Shimon0School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, IsraelAn asymmetric non-singular bouncing cosmological model is proposed in the framework of a locally scale-invariant scalar-tensor version of the standard model of particle physics and gravitation. The scalar field <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ϕ</mi></semantics></math></inline-formula> is complex. In addition to local scale invariance, the theory is U(1)-symmetric and has a conserved global charge associated with time variations of the phase of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ϕ</mi></semantics></math></inline-formula>. An interplay between the positive energy density contributions of relativistic and non-relativistic matter and that of the negative kinetic energy associated with the phase of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>ϕ</mi></semantics></math></inline-formula> results in a classical non-singular stable bouncing dynamics deep in the radiation-dominated era. This encompasses the observed redshifting era, which is preceded by a blueshifting era. The proposed model potentially avoids the flatness and horizon problems, as well as allowing for the generation of a scale-invariant spectrum of metric perturbations of the scalar type during a matter-dominated-like pre-bounce phase, with no recourse to an inflationary era.https://www.mdpi.com/2218-1997/11/3/93cosmologynonsingular bouncescalar-tensor gravity |
| spellingShingle | Meir Shimon Bounce Cosmology in a Locally Scale Invariant Physics with a U(1) Symmetry Universe cosmology nonsingular bounce scalar-tensor gravity |
| title | Bounce Cosmology in a Locally Scale Invariant Physics with a U(1) Symmetry |
| title_full | Bounce Cosmology in a Locally Scale Invariant Physics with a U(1) Symmetry |
| title_fullStr | Bounce Cosmology in a Locally Scale Invariant Physics with a U(1) Symmetry |
| title_full_unstemmed | Bounce Cosmology in a Locally Scale Invariant Physics with a U(1) Symmetry |
| title_short | Bounce Cosmology in a Locally Scale Invariant Physics with a U(1) Symmetry |
| title_sort | bounce cosmology in a locally scale invariant physics with a u 1 symmetry |
| topic | cosmology nonsingular bounce scalar-tensor gravity |
| url | https://www.mdpi.com/2218-1997/11/3/93 |
| work_keys_str_mv | AT meirshimon bouncecosmologyinalocallyscaleinvariantphysicswithau1symmetry |