515 citations · 4.3k across the 76 of their papers we have counts for
18 papers · 1 filter
Entanglement masquerading in the CMB
Arsalan Adil, Andreas Albrecht, Rose Baunach +3
The simplest single-field inflation models capture all the relevant contributions to the patterns in the Cosmic Microwave Background (CMB) observed today. A key assumption in these…
Einselection, Equilibrium and Cosmology
Andreas Albrecht, Rose Baunach, Andrew Arrasmith
Our observed Universe has a very strong arrow of time rooted in its low entropy starting point. This low entropy start can be related to various "tuning puzzles" about the early st…
Non-Gaussianity from Entanglement During Inflation
Nadia Bolis, Andreas Albrecht, R. Holman
We compute the bi-spectrum of CMB temperature fluctuations for a state where the metric perturbation is entangled with a spectator scalar field . Novel terms in the cubic $ζ…
Cosmic Inflation: The Most Powerful Microscope in the Universe
Andreas Albrecht, Nadia Bolis, R. Holman
How well can we constrain the initial quantum state of metric perturbations sourced during inflation? We exhibit an interesting new class of quantum states that entangle the scalar…
Quantum entanglement in de Sitter space with a wall, and the decoherence of bubble universes
Andreas Albrecht, Sugumi Kanno, Misao Sasaki
We study the effect of a bubble wall on the entanglement entropy of a free massive scalar field between two causally disconnected open charts in de Sitter space. We assume there is…
Modifications to Cosmological Power Spectra from Scalar-Tensor Entanglement and their Observational Consequences
Nadia Bolis, Andreas Albrecht, R. Holman
We consider the effects of entanglement in the initial quantum state of scalar and tensor fluctuations during inflation. We allow the gauge-invariant scalar and tensor fluctuations…
Spinodal Instabilities and Super-Planckian Excursions in Natural Inflation
Andreas Albrecht, R. Holman, Benoit J. Richard
Models such as Natural Inflation that use Pseudo-Nambu-Goldstone bosons (PNGB's) as the inflaton are attractive for many reasons. However, they typically require trans-Planckian fi…
Cosmological Consequences of Initial State Entanglement
Andreas Albrecht, Nadia Bolis, R. Holman
We explore the cosmological consequences of having the fluctuations of the inflaton field entangled with those of another scalar, within the context of a toy model consisting of no…
Tuning, Ergodicity, Equilibrium and Cosmology
Andreas Albrecht
I explore the possibility that the cosmos is fundamentally an equilibrium system, and review the attractive features of such theories. Equilibrium cosmologies are commonly thought…
Lorentz symmetry from a random Hamiltonian
Andreas Albrecht, Alberto Iglesias
We match the density of energy eigenstates of a local field theory with that of a random Hamiltonian order by order in a Taylor expansion. In our previous work we assumed Lorentz s…
The clock ambiguity: Implications and new developments
Andreas Albrecht, Alberto Iglesias
We consider the ambiguity associated with the choice of clock in time reparameterization invariant theories. This arbitrariness undermines the goal of prescribing a fixed set of ph…
The clock ambiguity and the emergence of physical laws
Andreas Albrecht, Alberto Iglesias
The process of identifying a time variable in time reparameterization invariant theories results in great ambiguities about the actual laws of physics described by a given theory.…
On Open Inflation, the string theory landscape and the low CMB quadrupole
Michael Barnard, Andreas Albrecht
Cosmologists have embraced a particular ad hoc formula for the primordial power spectrum from inflation for universes with . However, the so-called ``Open Inflation'' mode…
Can the universe afford inflation?
Andreas Albrecht, Lorenzo Sorbo
Cosmic inflation is envisioned as the ``most likely'' start for the observed universe. To give substance to this claim, a framework is needed in which inflation can compete with ot…
Holographic Limitations of the Effective Field Theory of Inflation
Andreas Albrecht, Nemanja Kaloper, Yong-Seon Song
Holographic considerations may provide a glimpse of quantum gravity beyond what is currently accessible by other means. Here we apply holography to inflationary cosmology. We argue…
Exponentially Large Extra Dimensions
A. Albrecht, C. P. Burgess, F. Ravndal +1
We show how the presence of a very light scalar with a cubic self-interaction in six dimensions can stabilize the extra dimensions at radii which are naturally exponentially large,…
Some Remarks on Quantum Coherence
Andreas Albrecht
There are many striking phenomena which are attributed to ``quantum coherence''. It is natural to wonder if there are new quantum coherence effects waiting to be discovered which c…
Following a "Collapsing" Wavefunction
Andreas Albrecht
I study the quantum mechanics of a spin interacting with an ``apparatus''. Although the evolution of the whole system is unitary, the spin evolution is not. The system is chosen so…