James Garrison with Tanmay Vachaspati

An Investigation of Classically-Forbidden Quantum Detection and its Application to Island Cosmology

Island cosmology is a cosmological model that is an alternative to the inflationary paradigm. In island cosmology, the universe is initially void of matter but filled with cosmological constant. Quantum fluctuations of an existing field then have some probability of violating the null energy condition, suddenly making the Hubble length scale very small with an island of matter. This island then evolves according to the Friedman-Robertson-Walker model, which is generally thought to describe the universe in which we live. The mechanism behind the null energy condition is analogous to the observation of a quantum particle in a classically forbidden region, such as under a potential energy barrier during quantum tunneling. The present study will explore the nature of detection and measurement in quantum mechanics. Then, we will attempt to determine restraints on other internal degrees of freedom when a particle is detected under the barrier. In other words, if quantum tunneling occurs in the x direction, can conclusions be made about the nature of the wavefunction in the y and z directions? We will then attempt to extend these conclusions to the infinite number of modes present in a quantum field and relate our findings to island cosmology.