Cosmic Strings from the SV0 Quantum Bounce: Formation, Tension, and Gravitational Wave Signatures

Abstract:Cosmic strings are one-dimensional topological defects that may have formed during phase transitions in the early universe. They are a natural prediction of Grand Unified Theories and String Theory, and are a leading source candidate for the stochastic gravitational wave background (SGWB) recently detected by Pulsar Timing Arrays (PTAs). In this paper (Paper LVI of the SV0 series), we demonstrate that cosmic strings emerge naturally from the SV0 quantum bounce. We show that during the bounce, the discrete Spacetime Quanta lattice (Paper XLVI) undergoes a topological phase transition in which the two-sector constraint |V_A| + |V_B| = V_0 creates stable line defects. We identify these defects with fundamental strings of the String Theory embedding (Paper VIII). We calculate the string tension and find Gμ ~ 10⁻⁷, consistent with the NANOGrav 15-year signal. Finally, we show that the SV0 cosmic string network produces a characteristic SGWB with spectral shape and amplitude that are falsifiable by current and future PTAs. Keywords:Cosmic Strings; Topological Defects; Gravitational Waves; NANOGrav; Pulsar Timing Arrays; SV0 Theory; String Theory; Early Universe.