Computational Quantum Physics

Burcin Temel

Timothy Schmitz

Author(s): Schmitz, Timothy | Advisor(s): Barrett, Jeffrey A | Abstract: Our epistemic limits depend on the nature of the physical world we inhabit and the ways in which we can observe and manipulate it. This dissertation examines these limits in the realm of physical computation. It focuses on quantum computing and particularly computing in GRW quantum mechanics, although it has implications for both quantum computing in particular and physical computation more broadly. By rigorously investigating the conceptual issues that arise when looking at computation in GRW, we see how the conceptual issues in the foundations of quantum mechanics and our solutions to these issues determine what models of quantum computation can be realized and what quantum computing can achieve. More broadly, we see how grounding our discussions of physical computation in precise physical theories informs our understanding of computational and epistemic limits and illustrates the challenges and nuances involved in the work of developing a rigorous understanding of what is physically computable.

Burigede Liu, M. Ortíz, Fehmi Cirak

Hans A. De Raedt, Kristel F. L. Michielsen, Anthony Hams +2 more

We study effects of the physical realization of quantum computers on their logical operation. Through simulation of physical models of quantum computer hardware, we analyze the difficulties that are encountered in programming physical realizations of quantum computers. Examples of logically identical implementations of the controlled-NOT operation and Grover's database search algorithm are used to demonstrate that the results of a quantum computation are unstable with respect to the physical realization of the quantum computer. We discuss the origin of these instabilities and discuss possibilities to overcome this, for practical purposes, fundamental limitation of quantum computers.

Hans A. De Raedt, Kristel F. L. Michielsen, Seiji Miyashita +1 more

We discuss the impact of the physical implementation of a quantum computer on its computational efficiency, using computer simulations of physical models of quantum computer hardware. We address the computational efficiency of practical procedures to extract the results of a quantum computation from the wave function respresenting the final state of the quantum computer.

Bart D’Hooghe, Jarosław Pykacz