Instant Folded Strings, Dark Energy and a Cyclic Bouncing Universe

Journal Article · Wed Jan 01 00:00:00 EST 2025 · ArXiv

DOI:https://doi.org/10.48550/arXiv.2508.09745· OSTI ID:3010801

Itzhaki, Nissan; Peleg, Uri; Steinhardt, Paul J.

We present a wholly self-consistent, complete cyclic bouncing cosmology based on components drawn from string theory and constructed in a way that is under perturbative control throughout (e.g., with temperature much less than the string scale and string coupling $$g_s \ll 1$$ at all times). The cyclic evolution is governed by standard dilaton-gravity in $(3+1)$-dimensions with a perturbatively generated potential and a coupling between the dilaton and a second field that becomes massless at $$ϕ= ϕ_{ESP}$$, resulting in an enhanced symmetry point (ESP) that prevents the dilaton from running all the way to zero coupling. A central role is played by instant folded strings (IFSs) - fundamental strings with the unusual property of being much lighter than the string mass while extending far beyond the string length, and violating the Null Energy Condition (NEC). IFSs are produced classically when the string coupling grows with time, which occurs at two critical points in each cycle. In turn, they fulfill a dual function: enabling cosmological bounces and initiating transient epochs of dark-energy domination that naturally transition into slow contraction. The resulting cosmology eliminates the cosmic singularity and multiverse problems of big bang inflationary models and robustly predicts time-varying IFS-induced dark energy and the absence of primordial B-mode polarization in the cosmic microwave background.

• Research Organization: The Trustees of Princeton University
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: SC0007968
• OSTI ID: 3010801
• Alternate ID(s): OSTI ID: 3011143
• Journal Information: ArXiv, Journal Name: ArXiv
• Country of Publication: United States
• Language: English

Related Subjects

Cosmology and Nongalactic Astrophysics (astro-ph.CO)
FOS: Physical sciences
General Relativity and Quantum Cosmology (gr-qc)
High Energy Physics - Theory (hep-th)