Physics and Astronomyhttp://hdl.handle.net/10012/99492020-10-28T17:04:35Z2020-10-28T17:04:35ZTowards simulating 2D effects in lattice gauge theories on a quantum computerPaulson, Danielhttp://hdl.handle.net/10012/164642020-10-27T02:31:33Z2020-10-26T00:00:00ZTowards simulating 2D effects in lattice gauge theories on a quantum computer
Paulson, Daniel
Quantum Field Theories (QFTs) are the most successful theories for describing nature at its most fundamental level. Despite the fact that QFTs are capable of predicting a wide range of phenomena, obtaining solutions to QFTs in parameter regimes where perturbation theory cannot be applied remains a challenge. We propose an experimental scheme to perform quantum simulations of two-dimensional Abelian lattice gauge theories using contemporary quantum devices, paving the way to reach beyond the capabilities of classical simulations. We consider quantum electrodynamics and examine the basic building block of the two-dimensional lattice to study non-trivial magnetic field effects, which are absent in one-dimensional systems. By imposing periodic boundary conditions, we extend the scope of our work to include an infinite 2D structure. Our protocol uses a variational quantum-classical approach to relax the hardware requirements for capturing the intricate many-body interactions that naturally arise in the formulation of gauge-invariant effective field theories. Although we remain platform-independent, we also provide a detailed example of implementation on state-of-the-art trapped ion quantum devices, which can be generalized to other platforms. The techniques for simulating QFTs presented here, combined with advancements in quantum hardware, pose the potential to address longstanding questions in high energy physics.
2020-10-26T00:00:00ZExperimental and theoretical investigations of radio-frequency and optical trapping potentials for atomic ionsSajjan, Manashttp://hdl.handle.net/10012/164332020-10-09T02:31:39Z2020-10-08T00:00:00ZExperimental and theoretical investigations of radio-frequency and optical trapping potentials for atomic ions
Sajjan, Manas
Over the years, trapped ion have emerged as one of the premier candidates for universal
quantum simulation due to its long coherence time, low initialization and detection errors,
robust high-fidelity gate sets and fully connected yet tunable spin-graph. In this thesis
we exclusively focus on the generation of the trapping potential in a four-rod trap, one of
the most commonly studied ion-trapping architecture. We elaborate the fabrication of the
trapping electrodes using electro-etching techniques and explore the underlying mechanism
in details. We discuss how these electrodes are powered by DC and RF field to generate
the confining potential responsible for trapping the ions of interest in 3D. We conclude by
studying how this trapping potential can be modified by external means like using an optical
tweezer. Employing such an optical tweezer we propose a new quantum-thermodynamic
protocol which shall allow us to experimentally access the thermal properties of a mixed specie
ion chain using a single-specie ion chain. The scheme is based on Jarynski's equality
and obviates the need to trap dual-ionic species as far as illustrating the mechanical properties
of the chain are concerned. We present results ratifying the utility of the proposal.
The scheme is useful to obtain mode-specific thermal properties hitherto unexplored experimentally.
2020-10-08T00:00:00ZThe S-Matrix of Gauge and Gravity Theories and The Two-Black Hole ProblemGuevara, Alfredohttp://hdl.handle.net/10012/164212020-10-02T02:31:46Z2020-10-01T00:00:00ZThe S-Matrix of Gauge and Gravity Theories and The Two-Black Hole Problem
Guevara, Alfredo
This thesis is devoted to diverse aspects of scattering amplitudes in gauge theory and gravity including interactions with matter particles. In Part I we focus on the applications of massive scattering amplitudes in gravity to the Black Hole two-body problem. For this we construct a classical limit putting especial emphasis on the multipole expansion of certain massive amplitudes, which we will use to model spinning black holes in a large distance effective regime or particle approximation. In Part II we study scattering amplitudes in six dimensions, and construct a compact formula analogous to the four-dimensional Witten-RSV/rational maps formulation. This provides a supersymmetric extension of moduli space localization formulae such as the CHY integral. We explore the cases of Super Yang-Mills and Maximal Supergravity theories, among others.
2020-10-01T00:00:00ZQuantum Black Holes in the SkyWang, Qingwenhttp://hdl.handle.net/10012/164132020-10-01T02:32:47Z2020-09-30T00:00:00ZQuantum Black Holes in the Sky
Wang, Qingwen
Black Holes are possibly the most enigmatic objects in our Universe. From their detection in gravitational waves upon their mergers, to their snapshot eating at the centres of galaxies, black hole astrophysics has undergone an observational renaissance in the past 4 years. Nevertheless, they remain active playgrounds for strong gravity and quantum effects, where novel aspects of the elusive theory of quantum gravity may be hard at work. In this thesis, we provide an overview of the strong motivations for why ''Quantum Black Holes'' may be radically different from their classical counterparts in Einsteinâ€™s General Relativity. We then discuss the observational signatures of quantum black holes, focusing on gravitational wave echoes as smoking guns for quantum horizons (or exotic compact objects), which have led to significant recent excitement and activity. We review the theoretical underpinning of gravitational wave echoes and build up realistic templates for further data analysis. Finally, we discuss the future theoretical and observational landscape for unraveling the ''Quantum Black Holes in the Sky''.
2020-09-30T00:00:00Z