Fluctuation energies in quantum cosmology

Understand

Quantum fluctuations or other moments of a state contribute to energy expectation values and can imply interesting physical effects.

• In quantum cosmology, they turn out to be important for a discussion of density bounds and instabilities of initial-value problems in the presence of signature change in loop-quantized models.
• This article provides an effective description of these issues, accompanied by a comparison with existing numerical results and an extension to squeezed states.
• The comparison confirms that canonical effective methods are well-suited for computations of properties of physical states.