The discussion revolves around Sabine Hossenfelder's proposal for resolving the tensions between quantum gravity (QG) and quantum field theory (QFT). Participants explore the implications of her idea, which suggests a mechanism where gravity can be treated classically at high energies while remaining perturbatively quantized at low energies. The conversation includes theoretical implications, comparisons to historical ideas, and critiques of the proposal.
Participants express a mix of enthusiasm and skepticism regarding Hossenfelder's proposal. While some find it original and potentially groundbreaking, others raise significant concerns about its foundations and implications. No consensus is reached on the validity or appeal of the idea.
Participants note limitations regarding the clarity of the relationship between the c-number field and the operator in Hossenfelder's framework, particularly at high energies. The discussion reflects a range of interpretations and uncertainties about the proposal's implications.
This suggests another argument against the hossi's proposal. If at high energies quantum fluctuations vanish, then the early inflationary phase of the Universe expansion cannot explain the primordial density fluctuations, which are needed to explain the observed inhomogenities in the spectrum of cosmic microwave background.Berlin said:If at high energies h --> 0 it would also mean that the big bang would consist of a near classical bose gas of spin-0 particles without Pauli exclusion.
Fermi-Dirac statistics in the limit h->0 is still a Fermi-Dirac statistics. This limit does not turn the anti-commutator into a commutator.Berlin said:But what would happen with the fermi statistics kicking in? Could we calculate the pressure of a developing fermi gas, maybe mimicking inflation?