arXiv subjects

Drew Backhouse

Publications and source records attributed to Drew Backhouse.

5 recordsLinked to original sources

arXiv2024

Tunnelling and the Casimir effect on a $D$-dimensional sphere

Two fundamental signatures of Quantum Mechanics are tunnelling and the Casimir effect. We examine the ground state energetic properties of a scalar field confined on a $D$-dimensional sphere, and subjected to these two effects. We focus on $D=2$ and $D=3$, with a non-minimal coupling of a massless scalar field to curvature, which provides a radius-dependent effective mass. This scenario allows tunnelling to be more important than the Casimir effect, in a certain regime of parameters, and potential implications in Early Cosmology are discussed for the case $D=3$, which could avoid a cosmological singularity.

hep-th↗

arXiv2024

Mapping 1+1-dimensional black hole thermodynamics to finite volume effects

Both black hole thermodynamics and finite volume effects in quantum field theory violate the null energy condition. Motivated by this, we compare thermodynamic features between two $1+1$-dimensional systems: (i) a scalar field confined to a periodic spatial interval of length $a$ and tunneling between two degenerate vacua; (ii) a dilatonic black hole at temperature $T$ in the presence of matter fields. If we identify $a\propto T^{-1}$, we find similar thermodynamic behaviour, which suggests some deeper connection arising from the presence of non-trivial boundary conditions in both systems. We then extend our results to $2+1$ and $3+1$-dimensions and, although a more complete study is necessary, the connection found in $1+1$-dimensions seems to be valid in higher dimensions too.

hep-th↗

arXiv2023

Null energy condition violation: Tunnelling versus the Casimir effect

We show that tunnelling between two degenerate minima, as allowed in a finite volume, leads to a non-extensive symmetric ground state. This results in Null Energy Condition violation for sufficiently low temperatures, when a continuous set of momenta in the box containing the field is assumed. Taking into account discrete momenta can modify this picture and is achieved via the addition of the Casimir energy to the tunnelling-induced ground state energy. Focusing on zero-temperature, these non-trivial effects are found to compete, depending on the typical length scales involved.

hep-th↗

arXiv2022

One-loop tunnelling-induced energetics

Tunnelling between degenerate vacuua is allowed in finite-volume Quantum Field Theory, and features remarkable energetic properties, which result from the competition of different dominant configurations in the partition function. We derive the one-loop effective potential based on two homogeneous vacuua of the bare theory, and we discuss the resulting Null Energy Condition violation in O(4)-symmetric Euclidean spacetime, as a result of a non-extensive effective action.

hep-th↗

arXiv2021

The Phenomenological Motivation of Axions: A Review

Setting aside anthropic arguments, there is no reason for CP symmetry to be obeyed within the theory of quantum chromodynamics. However, no such violation of CP symmetry has ever been observed in a strongly interacting experiment. This is known as the strong CP problem which, in its simplest manifestations, can be quantitatively formulated via a calculation of the pion masses and the neutron electric dipole moment. The former yields a larger mass for the neutral pion than its charged counterparts, the latter yields a far larger result than is experimentally measured, where in both cases the discrepancies are parameterised by the physical quantity $\barθ$. The strong CP problem can be solved via the inclusion of a new particle, the axion, which dynamically sets $\barθ$ to zero, eliminating these two manifestations. Thus, experimental searches for such a particle are an active field of research. This dissertation acts as a review of the aforementioned concepts.

hep-ph↗