Linear optics quantum computing with single photons from an atom-cavity system
One of today’s challenges to realise computing based on quantum mechanics is to reliably and scalably encode information in quantum systems. Here, we present a photon source to on-demand deliver photonic quantum bits of information based on a strongly coupled atom-cavity system. The source operates...
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| Format: | Thesis |
| Language: | English |
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2015
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| _version_ | 1797110569126330368 |
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| author | Holleczek, A |
| author2 | Kuhn, A |
| author_facet | Kuhn, A Holleczek, A |
| author_sort | Holleczek, A |
| collection | OXFORD |
| description | One of today’s challenges to realise computing based on quantum mechanics is to reliably and scalably encode information in quantum systems. Here, we present a photon source to on-demand deliver photonic quantum bits of information based on a strongly coupled atom-cavity system. The source operates intermittently for periods of up to 100 <i>μ</i>s, with a single-photon repetition rate of 1 MHz, and an intra-cavity production efficiency of up to 85%. Our ability to arbitrarily control the photons’ wavepackets and phase profiles, together with long coherence times of 500 ns, allows to store time-bin encoded quantum information within a single photon. To do so, the spatio-temporal envelope of a single photon is sub-divided in d time bins which allows for the delivery of arbitrary qu-d-its. This is done with a fidelity of > 95% for qubits, and 94% for qutrits verified using a newly developed time-resolved quantum-homodyne measurement technique.<br/><br/> Additionally, we combine two separate fields of quantum physics by using our deterministic single-photon source to seed linear optics quantum computing (LOQC) circuits. As a step towards quantum networking, it is shown that this photon source can be combined with quantum gates, namely a chip-integrated beam splitter, a controlled-NOT (CNOT) gate as well as a CNOT4 gate. We use this CNOT4 gate to entangle photons deterministically emitted from our source and observe non-classical correlations between events separated by periods exceeding the travel time across the chip by three orders of magnitude. Additionally, we use time-bin encoded qubits to systematically study the de- and re-phasing of quantum states as well as the the effects of time-varying internal phases in photonic quantum circuits. |
| first_indexed | 2024-03-07T07:56:38Z |
| format | Thesis |
| id | oxford-uuid:d655fa1c-3405-413d-8af8-eecf6212ab74 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T07:56:38Z |
| publishDate | 2015 |
| record_format | dspace |
| spelling | oxford-uuid:d655fa1c-3405-413d-8af8-eecf6212ab742023-08-15T14:49:18ZLinear optics quantum computing with single photons from an atom-cavity systemThesishttp://purl.org/coar/resource_type/c_db06uuid:d655fa1c-3405-413d-8af8-eecf6212ab74Linear Optics Quantum ComputingSingle Photon ProductionQuantum physics and its applicationsEnglishORA Deposit2015Holleczek, AKuhn, AOne of today’s challenges to realise computing based on quantum mechanics is to reliably and scalably encode information in quantum systems. Here, we present a photon source to on-demand deliver photonic quantum bits of information based on a strongly coupled atom-cavity system. The source operates intermittently for periods of up to 100 <i>μ</i>s, with a single-photon repetition rate of 1 MHz, and an intra-cavity production efficiency of up to 85%. Our ability to arbitrarily control the photons’ wavepackets and phase profiles, together with long coherence times of 500 ns, allows to store time-bin encoded quantum information within a single photon. To do so, the spatio-temporal envelope of a single photon is sub-divided in d time bins which allows for the delivery of arbitrary qu-d-its. This is done with a fidelity of > 95% for qubits, and 94% for qutrits verified using a newly developed time-resolved quantum-homodyne measurement technique.<br/><br/> Additionally, we combine two separate fields of quantum physics by using our deterministic single-photon source to seed linear optics quantum computing (LOQC) circuits. As a step towards quantum networking, it is shown that this photon source can be combined with quantum gates, namely a chip-integrated beam splitter, a controlled-NOT (CNOT) gate as well as a CNOT4 gate. We use this CNOT4 gate to entangle photons deterministically emitted from our source and observe non-classical correlations between events separated by periods exceeding the travel time across the chip by three orders of magnitude. Additionally, we use time-bin encoded qubits to systematically study the de- and re-phasing of quantum states as well as the the effects of time-varying internal phases in photonic quantum circuits. |
| spellingShingle | Linear Optics Quantum Computing Single Photon Production Quantum physics and its applications Holleczek, A Linear optics quantum computing with single photons from an atom-cavity system |
| title | Linear optics quantum computing with single photons from an atom-cavity system |
| title_full | Linear optics quantum computing with single photons from an atom-cavity system |
| title_fullStr | Linear optics quantum computing with single photons from an atom-cavity system |
| title_full_unstemmed | Linear optics quantum computing with single photons from an atom-cavity system |
| title_short | Linear optics quantum computing with single photons from an atom-cavity system |
| title_sort | linear optics quantum computing with single photons from an atom cavity system |
| topic | Linear Optics Quantum Computing Single Photon Production Quantum physics and its applications |
| work_keys_str_mv | AT holleczeka linearopticsquantumcomputingwithsinglephotonsfromanatomcavitysystem |