155 citations · 459 across the 5 of their papers we have counts for
5 papers
Density matrix embedding theory for interacting electron-phonon systems
Barbara Sandhoefer, Garnet Kin-Lic Chan
We describe the extension of the density matrix embedding theory (DMET) framework to coupled interacting fermion-boson systems. This provides a frequency-independent, entanglement…
On the quantum fate of singularities in a dark-energy dominated universe
Mariam Bouhmadi-Lopez, Claus Kiefer, Barbara Sandhoefer +1
Classical models for dark energy can exhibit a variety of singularities, many of which occur for scale factors much bigger than the Planck length. We address here the issue whether…
Effective Constraints for Quantum Systems
Martin Bojowald, Barbara Sandhoefer, Aureliano Skirzewski +1
An effective formalism for quantum constrained systems is presented which allows manageable derivations of solutions and observables, including a treatment of physical reality cond…
Quantum cosmology with big-brake singularity
Alexander Kamenshchik, Claus Kiefer, Barbara Sandhoefer
We investigate a cosmological model with a big-brake singularity in the future: while the first time derivative of the scale factor goes to zero, its second time derivative tends t…
Quantum phantom cosmology
Mariusz P. Dabrowski, Claus Kiefer, Barbara Sandhoefer
We apply the formalism of quantum cosmology to models containing a phantom field. Three models are discussed explicitly: a toy model, a model with an exponential phantom potential,…