Quantum simulations are an invaluable tool in condensed matter physics, enabling the precise generation and control of physical phenomena abstracted from the complexity of the underlying many-body system. At the heart of such complexity lies entanglement, the intrinsically quantum correlations that have attracted renewed interest as a fundamental resource in quantum computation and information. In this thesis, we explore the use of one- and two-dimensional lattice models to simulate and harness such correlations for next-generation quantum technologies.
We begin in one dimension with a spin-chain model that allows complete control over bipartite correlation structures. Specifically, we introduce a model of nearest-neighbour couplings and transverse field terms, whose exact solution yields a q-deformed rainbow ground state formed from a tensor product of q-deformed singlets, each with directly tunable entanglement. This framework acts as a universal simulator of free-fermion entanglement spectra, with numerical studies confirming high-fidelity realisations across a range of examples.
We then turn to strong correlations in two dimensions, where topologically ordered systems host exotic quasiparticles known as anyons. Braiding non-Abelian anyons enacts unitary transformations on a logically encoded fusion space, offering a natural pathway to fault-tolerant quantum computation. Using Kitaev’s quantum double model D(G), we focus on the smallest non-Abelian instance, D(S3), realised on a lattice of d=6 qudits. We develop a minimal protocol in which braiding and fusion are simulated solely through operators that create and measure anyons, demonstrating that D(S3) anyons generate magic states, a vital resource for universal quantum computation. Finally, a dense encoding scheme is presented, rendering the minimal realisation of this protocol accessible with current quantum technologies and a circuit model for realisation within the framework of linear optics is presented. Notably, error analysis of this encoding scheme reveals an inherent passive protection provided by the topological encoding, extending beyond conventional notions of topological fault tolerance.
