When: Wednesday, November 13, 2024, 3:30 PM - 4:30 PMWhere: G.O. Jones 610
Are there observable signatures of quantum effects during inflation? Quantum contributions to cosmological correlators from loop corrections are usually required to be much smaller than semiclassical tree-level terms by perturbativity: loops are typically unobservably small. Motivated by recent interest in parity violation in four-point correlations of galaxies, I will describe a scenario in which the leading contribution to a parity-odd signal arises at one-loop order in perturbation theory. Parity is violated in the Standard Model of particle physics, so it may not be a symmetry of the early universe, but parity violation cannot be observed in lower-point scalar correlators. Therefore, in this scenario, a quantum effect provides the leading signature of parity violation. This is possible thanks to a no-go theorem for four-point scalar correlators at tree level. After explaining the calculation of this signal in dimensional regularisation, I will discuss observational prospects. Its signal-to-noise ratio is generally much less than that of an associated parity-even correlation.