Classical and quantum aspects of bosonic production and detection

Thesis

This thesis presents methods for producing and detecting gravitational waves (GWs) and particles within or beyond the Standard Model. Chapter 2 and chapter 3 describe axion production from an accelerated electron within the WKB approximation. In Chapter 2, we consider an electron accelerated by a time dependent external potential and consider two trajectories: uniform acceleration and oscillating motion in a standing wave created by two counter-propagating linearly polarized laser beams. We calculate the spectrum and total energy of the emitted particles. Chapter 3 generalizes the results of chapter 2 for an arbitrary electromagnetic field. We find that the rotation of the electron spin follows the Thomas-BMT equation. We propose an experimental setup for producing axions using laser beams and converting them into photons to impose bounds on the axion-electron coupling constant. We find that the addition of magnetic fields significantly increases particle production. The projected bounds are similar to other laboratory-based experiments for axion masses $m_a \lesssim 10$ keV. Chapter 4 discusses the Unruh effect, which is essential to describe radiation from an accelerating charge in its rest frame. We couple a classical source to a scalar field and derive the emission rate and power. The latter agrees with the classical Larmor result for scalar particles. In chapter 5, we generalize the results of chapter 4 and discuss emission of photons in the context of the Unruh effect. Finally, chapter 6 is dedicated to the production and detection of GWs using high-energy pulsed lasers through the Gertsenshtein effect. Whereas the strain of produced GWs is too weak to be detected, we find that with today’s laser performances, one could detect GWs of astrophysical origin with strains $h \gtrsim 10^{−20}$ and in the future, sensitivities of $h \gtrsim 10^{−26}$ could be reached. Overall, the thesis examines the plausibility to use high-energy lasers to produce and detect particles of spin 0, 1 and 2 (where for the spin 2 case, we consider classical GWs instead of gravitons).

Authors: Vacalis, G

• DOI: 10.5287/ora-yq6z2vb2x
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: lasers; particle production; axion; Unruh effect; gravitational waves; Larmor radiation
• Subjects: Bosons; Gravitational waves; Quantum theory; Laser beams