Quantum Computation has attracted massive interest because of the recent technological advancement in both hardware and software suggesting the potential of quantum advantage.
On the software side, hybrid classical-quantum algorithms are extensively studied as they can be implemented on the current noisy intermediate-scale quantum devices.
On the hardware side, researchers are striving for faster and more noise-robustness quantum operations to achieve higher quantum processing power.
The dissertation presents two topics in the above-mentioned aspects.
The first one is constructing adaptive ans"atze for variational quantum eigensolver, one of the most promising hybrid algorithms.
We present how to compress different required quantum resources by designing different ans"atze.
The second topic is about designing fast entangling gates with a geometric approach.
We show that the geometric approach can improve the existing numerical methods by locating the good initial guesses. / Doctor of Philosophy / Scientists believe that the era of quantum computing will bring revolutionary changes to our lives as it provides novel solutions to currently hard or unsolvable problems, such as breaking the most advanced cryptographic scheme and simulating complex molecular dynamics.
Since quantum computation was first proposed decades ago, numerous efforts have been spent to realize advantages over the classical computer.
While the novel characteristics of quantum physics against the classical world provide potential for computational speed up and advantage, they induce obstacles for experimental implementation.
For instance, the quantum counter of a classical bit, qubit, cannot be cloned generally, and any errors that occur on the qubits have to be detected and corrected carefully with error-correcting schemes distinct from its classical counterpart.
This dissertation presents works on two different topics.
The first one is about constructing adaptive quantum circuits for a hybrid quantum simulation algorithm.
The adaptive property provides flexibility in simulating different problems while maintaining good accuracy.
The work presented here extends previous results, testing different kinds of building blocks for constructing adaptive quantum circuits to reduce the required quantum resources for the same accuracy.
The second topic discussed in this dissertation is designing fast control pulses for entangling pairs of qubits with a framework of space curves.
By expressing the dynamics of qubits as space curves, we develop methods to design space curves representing the desired entangling process.
We show that this space curve approach improves the existing numerical methods by locating the good initial guesses.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/119509 |
| Date | 25 June 2024 |
| Creators | Tang, Ho Lun |
| Contributors | Physics, Economou, Sophia Eleftherios, Mayhall, Nicholas, Barnes, Edwin Fleming, Cheng, Shengfeng |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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