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Main Author: Faruk, Mir Mehedi
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2603.07298
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author Faruk, Mir Mehedi
author_facet Faruk, Mir Mehedi
contents We study the Null Energy Condition (NEC) arising from the Virasoro constraint on the string worldsheet. We then analyze how the NEC in the external spacetime directions emerges under general time-dependent string compactifications. Finally, we exhibit compactifications in which the averaged Einstein-frame condition allows the lower-dimensional description of the external spacetime to violate the NEC, thereby realizing a bouncing cosmology, while the higher-dimensional NEC remains satisfied, as dictated by worldsheet symmetry. We comment on scale-separated solutions obtained through the averaged Einstein-frame condition
format Preprint
id arxiv_https___arxiv_org_abs_2603_07298
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Time Dependent String Compactification: Towards Bouncing Cosmology
Faruk, Mir Mehedi
High Energy Physics - Theory
General Relativity and Quantum Cosmology
We study the Null Energy Condition (NEC) arising from the Virasoro constraint on the string worldsheet. We then analyze how the NEC in the external spacetime directions emerges under general time-dependent string compactifications. Finally, we exhibit compactifications in which the averaged Einstein-frame condition allows the lower-dimensional description of the external spacetime to violate the NEC, thereby realizing a bouncing cosmology, while the higher-dimensional NEC remains satisfied, as dictated by worldsheet symmetry. We comment on scale-separated solutions obtained through the averaged Einstein-frame condition
title Time Dependent String Compactification: Towards Bouncing Cosmology
topic High Energy Physics - Theory
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2603.07298