<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="static/style.xsl"?><OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd"><responseDate>2026-09-22T15:13:47Z</responseDate><request verb="GetRecord" identifier="oai:www.repository.cam.ac.uk:1810/332645" metadataPrefix="uketd_dc">https://api.repository.cam.ac.uk/server/oai/request</request><GetRecord><record><header><identifier>oai:www.repository.cam.ac.uk:1810/332645</identifier><datestamp>2025-03-29T01:37:34Z</datestamp><setSpec>com_1810_205871</setSpec><setSpec>com_1810_256064</setSpec><setSpec>col_1810_206446</setSpec></header><metadata><uketd_dc:uketddc xmlns:uketd_dc="http://naca.central.cranfield.ac.uk/ethos-oai/2.0/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:uketdterms="http://naca.central.cranfield.ac.uk/ethos-oai/terms/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:doc="http://www.lyncode.com/xoai" xsi:schemaLocation="http://naca.central.cranfield.ac.uk/ethos-oai/2.0/ http://naca.central.cranfield.ac.uk/ethos-oai/2.0/uketd_dc.xsd">
   <dc:title>Integrability from Chern-Simons theories</dc:title>
   <dc:identifier xsi:type="dcterms:DOI">10.17863/CAM.80090</dc:identifier>
   <dc:creator>Bittleston, Roland</dc:creator>
   <uketdterms:advisor>Skinner, David</uketdterms:advisor>
   <uketdterms:authoridentifier xsi:type="uketdterms:ORCID">0000000230149127</uketdterms:authoridentifier>
   <dcterms:abstract>This thesis details my work exploring connections between integrable systems and Chern-Simons theories. It is divided into two parts. The first concerns the application of 4d Chern-Simons theory to describe integrable models with boundary, while the second concerns relations between holomorphic Chern-Simons theory on twistor space, 4d Chern-Simons theory and the anti-self-dual Yang-Mills equations.

Part one opens with a review of 4d Chern-Simons theory, including a discussion of its connections to both quantum and classical integrable systems. It then turns to the results of this thesis concerning the application of 4d Chern-Simons theory to generate solutions of the boundary Yang-Baxter equation. They include: defining the boundary analogue of a quasi-classical $R$-matrix and classical $r$-matrix; realising $K$-matrices as the vacuum expectation values of Wilson lines in 4d Chern-Simons theory on a $\bbZ_2$ orbifold; deriving the order $\hbar$ contribution to a $K$-matrix in the rational case and verifying that it obeys the boundary Yang-Baxter equation to second order in $\hbar$; determining the OPE of bulk and boundary Wilson lines; demonstrating that boundary line operators are labelled by representations of twisted Yangians; giving the gauge theory realisation of boundary unitarity and the Sklyanin determinant; proving the uniqueness of the rational $K$-matrix; obtaining explicit formulae for the order $\hbar$ contributions to trigonometric and elliptic $K$-matrices and matching them to examples in the literature.

Part two begins with a review of twistor theory. This is followed by the results of this thesis concerning the connections between holomorphic Chern-Simons theory on twistor space, 4d Chern-Simons theory and the anti-self-dual Yang-Mills equations. They include: showing that holomorphic Chern-Simons theory on twistor space for a meromorphic measure descends to an integrable theory on 4d spacetime; extending these results to indefinite signatures; identifying 4d Chern-Simons theory as the quotient of a 6d Chern-Simons theory on twistor correspondence space by an appropriate lift of the 2d translation group on spacetime; quotienting holomorphic Chern-Simons theory on twistor space by a 1 dimensional group of translations to obtain a 5d Chern-Simons theory on minitwistor correspondence space describing the Bogomolny equations.</dcterms:abstract>
   <uketdterms:institution>University of Cambridge</uketdterms:institution>
   <dcterms:issued>2022-08-02</dcterms:issued>
   <dc:type>Thesis</dc:type>
   <uketdterms:qualificationlevel>Doctoral</uketdterms:qualificationlevel>
   <uketdterms:qualificationname>Doctor of Philosophy (PhD)</uketdterms:qualificationname>
   <dc:language>eng</dc:language>
   <dcterms:isReferencedBy xsi:type="dcterms:URI">https://www.repository.cam.ac.uk/handle/1810/332645</dcterms:isReferencedBy>
   <dc:identifier xsi:type="dcterms:URI">https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/00f3b31b-be82-4953-8aab-ae8bb6bd1d1a/download</dc:identifier>
   <uketdterms:checksum xsi:type="uketdterms:MD5">e0856e1ff3c1a2568f30cc4bce77ce9a</uketdterms:checksum>
   <dc:rights>http://purl.org/NET/rdflicense/allrightsreserved</dc:rights>
   <dc:subject>Chern-Simons</dc:subject>
   <dc:subject>Integrability</dc:subject>
   <dc:subject>Twistor</dc:subject>
   <dc:subject>Integrable</dc:subject>
</uketd_dc:uketddc>
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