ORCID Profile
0000-0002-3576-8285
Current Organisation
University of Bristol
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Publisher: IOP Publishing
Date: 18-07-2008
Publisher: Springer Science and Business Media LLC
Date: 17-09-2014
DOI: 10.1038/NCOMMS5856
Abstract: The ability to rapidly switch between orbital angular momentum modes of light has important implications for future classical and quantum systems. In general, orbital angular momentum beams are generated using free-space bulk optical components where the fastest reconfiguration of such systems is around a millisecond using spatial light modulators. In this work, an extremely compact optical vortex emitter is demonstrated with the ability to actively tune between different orbital angular momentum modes. The emitter is tuned using a single electrically contacted thermo-optical control, maintaining device simplicity and micron scale footprint. On-off keying and orbital angular momentum mode switching are achieved at rates of 10 μs and 20 μs respectively.
Publisher: Springer Science and Business Media LLC
Date: 15-12-2013
Publisher: Springer Science and Business Media LLC
Date: 27-03-2013
DOI: 10.1038/SREP01539
Publisher: American Physical Society (APS)
Date: 17-02-2015
Publisher: American Physical Society (APS)
Date: 20-11-2013
Publisher: IEEE
Date: 06-2007
Publisher: IEEE
Date: 06-2009
Publisher: The Optical Society
Date: 03-05-2012
Publisher: Springer Science and Business Media LLC
Date: 23-07-2014
DOI: 10.1038/NCOMMS5213
Publisher: Wiley
Date: 04-09-2017
DOI: 10.1111/PHP.12807
Abstract: Sun exposure is the main cause of squamous (SCC) and basal cell carcinoma (BCC) although pattern and amount differ by cancer type, and sun sensitivity is the major host risk factor. Our study investigated risk factors and residential ambient UV in a population-based s le of Australian 45 and Up Study participants: 916 BCC cases, 433 SCC cases, 1224 controls. Unconditional logistic regression models adjusting for key covariates demonstrated 60% increased BCC risk and two-fold increased SCC risk with sun sensitivity, and three- and four-fold increased risk, respectively, with solar keratoses. BCC but not SCC risk increased with higher early-life residential UV in all participants (odds ratio (OR) = 1.54 95% CI 1.22-1.96 for intermediate OR = 1.31 95% CI 1.03-1.68 for high UV at birthplace) and similarly in Australian-born participants (P-values < 0.05). Risk of SCC but not BCC increased with long-term cumulative sun exposure assessed by self-reported outdoor work (OR 1.74, 95% CI 1.21-2.49). In conclusion, sun sensitivity is important for both cancers, early-life UV but not cumulative UV appears to increase BCC risk, the former an apparently novel finding, and SCC risk appears only to be related to long-term cumulative sun exposure.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2012
Publisher: American Physical Society (APS)
Date: 05-05-2009
Publisher: IOP Publishing
Date: 21-02-2011
Publisher: Springer Science and Business Media LLC
Date: 2011
DOI: 10.1038/469043A
Publisher: SPIE
Date: 19-11-2001
DOI: 10.1117/12.454617
Publisher: IOP Publishing
Date: 12-03-2013
Publisher: IOP Publishing
Date: 26-05-2011
Publisher: American Physical Society (APS)
Date: 09-06-2005
Publisher: American Physical Society (APS)
Date: 09-08-2007
Publisher: American Physical Society (APS)
Date: 10-06-2005
Publisher: American Physical Society (APS)
Date: 18-07-2005
Publisher: American Association for the Advancement of Science (AAAS)
Date: 19-10-2012
Abstract: The angular momentum of photons can be used to encode and transmit information. Cai et al. (p. 363 ) developed a method for generating and emitting controllable orbital angular momentum states of light from a reconfigurable and scalable silicon photonic chip. Using micro-ring resonators embedded with angular gratings allowed the imprinting of optical angular momentum on the light propagating in the whispering gallery modes of the resonator. The method may enable large-scale integration of optical vortex emitters on complementary metal-oxide–semiconductor-compatible silicon chips.
Publisher: American Physical Society (APS)
Date: 02-03-2006
Publisher: Springer Science and Business Media LLC
Date: 11-12-2011
Publisher: Springer Science and Business Media LLC
Date: 05-2011
Publisher: American Physical Society (APS)
Date: 14-02-2008
Publisher: IEEE
Date: 06-2009
Publisher: IOP Publishing
Date: 02-07-2013
Publisher: American Physical Society (APS)
Date: 02-04-2014
Publisher: IEEE
Date: 09-2011
Publisher: American Physical Society (APS)
Date: 30-11-2009
Publisher: IEEE
Date: 2008
Publisher: IOP Publishing
Date: 07-01-2009
Publisher: American Association for the Advancement of Science (AAAS)
Date: 23-01-2009
Abstract: The ability to filter quantum states is a key capability in quantum information science and technology, in which one-qubit filters, or polarizers, have found wide application. Filtering on the basis of entanglement requires extension to multi-qubit filters with qubit-qubit interactions. We demonstrated an optical entanglement filter that passes a pair of photons if they have the desired correlations of their polarization. Such devices have many important applications to quantum technologies.
Publisher: Optica Publishing Group
Date: 09-07-2009
DOI: 10.1364/OE.17.012546
Abstract: We report photonic quantum circuits created using an ultrafast laser processing technique that is rapid, requires no lithographic mask and can be used to create three-dimensional networks of waveguide devices. We have characterized directional couplers--the key functional elements of photonic quantum circuits--and found that they perform as well as lithographically produced waveguide devices. We further demonstrate high-performance interferometers and an important multi-photon quantum interference phenomenon for the first time in integrated optics. This direct-write approach will enable the rapid development of sophisticated quantum optical circuits and their scaling into three-dimensions.
Publisher: IEEE
Date: 05-2011
Publisher: Springer Science and Business Media LLC
Date: 12-2009
Publisher: IOP Publishing
Date: 28-04-2015
Publisher: IEEE
Date: 11-2010
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-05-2007
Abstract: Precision measurements are important across all fields of science. In particular, optical phase measurements can be used to measure distance, position, displacement, acceleration, and optical path length. Quantum entanglement enables higher precision than would otherwise be possible. We demonstrated an optical phase measurement with an entangled four-photon interference visibility greater than the threshold to beat the standard quantum limit—the limit attainable without entanglement. These results open the way for new high-precision measurement applications.
Publisher: AIP Publishing
Date: 31-01-2011
DOI: 10.1063/1.3549744
Abstract: We demonstrate a 1550 nm correlated photon-pair source in an integrated glass platform—a chalcogenide As2S3 waveguide. A measured pair coincidence rate of 80s−1 was achieved using 57 mW of continuous-wave pump. The coincidence to accidental ratio was shown to be limited by spontaneous Raman scattering effects that are expected to be mitigated by using a pulsed pump source.
Publisher: Springer Science and Business Media LLC
Date: 02-08-2011
DOI: 10.1038/NCOMMS1392
Publisher: AIP Publishing
Date: 04-06-2012
DOI: 10.1063/1.4724105
Abstract: Optical interferometry is amongst the most sensitive techniques for precision measurement. By increasing the light intensity, a more precise measurement can usually be made. However, if the s le is light sensitive entangled states can achieve the same precision with less exposure. This concept has been demonstrated in measurements of known optical components. Here, we use two-photon entangled states to measure the concentration of a blood protein in an aqueous buffer solution. We use an opto-fluidic device that couples a waveguide interferometer with a microfluidic channel. These results point the way to practical applications of quantum metrology to light-sensitive s les.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 02-11-2012
Abstract: Photons can display wavelike or particle-like behavior, depending on the experimental technique used to measure them. Understanding this duality lies at the heart of quantum mechanics. In two reports, Peruzzo et al. (p. 634 ) and Kaiser et al. (p. 637 see the Perspective on both papers by Lloyd ) perform an entangled version of John Wheeler's delayed-choice gedanken experiment, in which the choice of detection can be changed after a photon passes through a double-slit to avoid the measurement process affecting the state of the photon. The original proposal allowed the wave and particle nature of light to be interchanged after the light had entered the interferometer. By contrast in this study, entanglement allowed the wave and particle nature to be interchanged after the light was detected and revealed the quantum nature of the photon, for ex le, it displays wave- and particle-like behavior simultaneously.
Publisher: AIP Publishing
Date: 13-08-2012
DOI: 10.1063/1.3519847
Abstract: The efficiency of photon collection from optically active defect centers in bulk diamond is greatly reduced by refraction at the diamond-air interface. We report on the fabrication and measurement of a geometrical solution to the problem integrated solid immersion lenses (SILs) etched directly into the surface of diamond. An increase of a factor of 10 was observed in the saturated count-rate from a single negatively charged nitrogen-vacancy (NV−) within a 5 μm diameter SIL compared with NV−’s under a planar surface in the same crystal. Such a system is potentially scalable and easily adaptable to other defect centers in bulk diamond.
Publisher: American Association for Cancer Research (AACR)
Date: 2020
DOI: 10.1158/1055-9965.EPI-19-0400
Abstract: Human papillomavirus (HPV) infection is highly prevalent worldwide and may have a role, with sun exposure, in causing cutaneous squamous cell carcinoma. Little is known about the relationship of UV exposure and seroprevalence of cutaneous HPVs in the general population. Using multiplex serology, we estimated the seroprevalence of 23 beta and 7 gamma HPVs and 7 other antigens (mu HPV1, HPV63, nu HPV41, alpha HPV16 polyomaviruses HPyV7 and MCV p53) in a population-based s le of 1,161 Australian 45 and Up Study participants with valid data from blood specimens collected from 2010 to 2012. We calculated prevalence ratios (PR) for the association of each antigen with residential ambient solar UV and other UV-related variables. Seropositivity for at least one beta or gamma HPV was high at 88% (beta HPVs 74%, gamma HPVs 70%), and less in women than men [e.g., PR beta-2 HPV38 = 0.70 95% confidence interval (CI), 0.56–0.87 any gamma = 0.90 95% CI, 0.84–0.97]. A high ambient UV level in the 10 years before study enrollment was associated with elevated seroprevalence for genus beta (PRtertile3vs1 any beta = 1.17 95% CI, 1.07–1.28), and beta-1 to beta-3 species, but not for gamma HPVs. Other UV-related measures had less or no evidence of an association. Seroprevalence of cutaneous beta HPVs is higher with higher ambient UV exposure in the past 10 years. The observed association between ambient UV in the past 10 years and cutaneous HPVs supports further study of the possible joint role of solar UV and HPV in causing skin cancer.
Publisher: American Physical Society (APS)
Date: 26-09-2008
Publisher: IEEE
Date: 05-2013
Publisher: AIP Publishing
Date: 14-03-2011
DOI: 10.1063/1.3567413
Publisher: Springer Science and Business Media LLC
Date: 24-05-2009
Publisher: American Physical Society (APS)
Date: 11-09-2008
Publisher: American Association for Cancer Research (AACR)
Date: 03-2022
DOI: 10.1158/1055-9965.EPI-21-1000
Abstract: Sun exposure causes cutaneous squamous (SCC) and basal cell (BCC) carcinomas. Human papillomavirus (HPV) infection might cause SCC. We examined associations of β and γ HPV infection in skin-swab DNA and serum antibodies with skin cancer risk, and modification of the carcinogenic effects of sun exposure by them, in case–control studies of 385 SCC cases, 832 BCC cases, and 1,100 controls nested in an Australian prospective cohort study (enrolled 2006–2009). Presence of β-1 and β-3 HPV DNA appeared to increase risks for SCC and BCC by 30% to 40% (P adjusted & .01). BCC was also associated with genus β DNA, OR = 1.48 95% confidence interval (CI), 1.10 to 2.00 (P adjusted & .01). Associations were strengthened with each additional positive β HPV DNA type: SCC (OR = 1.07 95% CI, 1.02–1.12) and BCC (OR = 1.06 95% CI, 1.03–1.10), Ptrend& .01. Positivity to genus β or γ in serology, and genus γ in DNA, was not associated with either cancer. There was little evidence that any β HPV type was more strongly associated than others with either cancer. A weaker association of sun exposure with SCC and BCC in the presence of β-3 HPVs than in their absence suggests that β-3 HPVs modify sun exposure's effect. Our substantive findings are at the level of genus β HPV. Like SCC, BCC risk may increase with increasing numbers of β HPV types on skin. The consistency in our findings that HPV infection may moderate the effects of sun exposure, the main environmental cause of SCC and BCC, merits further investigation.
Publisher: American Physical Society (APS)
Date: 17-09-2008
Publisher: IOP Publishing
Date: 11-01-2010
Publisher: IEEE
Date: 09-2010
Publisher: IEEE
Date: 2005
Publisher: American Association for the Advancement of Science (AAAS)
Date: 17-09-2010
Abstract: Random walks are powerful tools for modeling statistical events. The analogous quantum walk involves particles tunneling between available sites. Peruzzo et al. (p. 1500 see the Perspective by Hillery ) now report on the quantum walk of a correlated pair of photons propagating through a coupled waveguide array. The output pattern resulting from the injection of two correlated photons possess quantum features, indicating that the photons retain their correlations as they walk randomly through the waveguide array, allowing scale-up and parallel searches over many possible paths.
Publisher: SPIE
Date: 18-08-2005
DOI: 10.1117/12.616166
Publisher: Springer Science and Business Media LLC
Date: 24-02-2013
Publisher: American Physical Society (APS)
Date: 31-01-2012
Publisher: American Physical Society (APS)
Date: 12-05-2004
Publisher: Optica Publishing Group
Date: 26-01-2007
Publisher: American Physical Society (APS)
Date: 26-02-2010
Publisher: Elsevier BV
Date: 06-1999
Publisher: IEEE
Date: 09-2011
Publisher: Wiley
Date: 12-09-2012
Publisher: American Physical Society (APS)
Date: 26-03-2009
Publisher: AIP Publishing
Date: 22-11-2010
DOI: 10.1063/1.3497087
Abstract: We demonstrate photonic quantum circuits that operate at the stringent levels that will be required for future quantum information science and technology. These circuits are fabricated from silica-on-silicon waveguides forming directional couplers and interferometers. While our focus is on the operation of quantum circuits, to test this operation required construction of a photon source that produced near-identical pairs of photons. We show nonclassical interference with two photons and a two-photon entangling logic gate that operate with near-unit fidelity. These results are a significant step toward large-scale operation of photonic quantum circuits.
Publisher: IEEE
Date: 09-2011
Publisher: IEEE
Date: 05-2007
Publisher: American Physical Society (APS)
Date: 17-09-2007
Publisher: AIP Publishing
Date: 28-03-2011
DOI: 10.1063/1.3573870
Abstract: We describe a technique for fabricating micro- and nanostructures incorporating fluorescent defects in diamond with a positional accuracy better than hundreds of nanometers. Using confocal fluorescence microscopy and focused ion beam etching, we initially locate a suitable defect with respect to registration marks on the diamond surface then etch a structure using these coordinates. We demonstrate the technique by etching an 8 μm diameter hemisphere positioned with single negatively charged nitrogen-vacancy defect lies at its origin. Direct comparison of the fluorescence photon count rate before and after fabrication shows an eightfold increase due to the presence of the hemisphere.
Publisher: The Optical Society
Date: 25-09-2013
DOI: 10.1364/OE.21.023401
Publisher: American Association for the Advancement of Science (AAAS)
Date: 30-11-2007
Publisher: IEEE
Date: 06-2013
Publisher: Springer Science and Business Media LLC
Date: 07-12-2009
DOI: 10.1038/NPHYS1150
Publisher: MDPI AG
Date: 22-09-2022
DOI: 10.3390/ELECTRONICS11193011
Abstract: Breaking up prolonged sitting with short bouts of light physical activity including standing and walking has been shown to be beneficial for people with type 2 diabetes (T2D). This paper presents the development of an android mobile app to deliver a just-in-time adaptive intervention (JITAI) to reduce sedentary time in people with T2D. A total of six design workshops were conducted with seven experts to identify design requirements, a behavioural framework, and required contextual adaptations for the development of a bespoke mobile app (iMOVE). Moreover, a focus group was conducted among people with T2D as potential end-users (N = 10) to ascertain their perceptions of the app. Feedback from the focus group was used in subsequent iterations of the iMOVE app. Data were analysed using an inductive qualitative thematic analysis. Based on workshops, key features of iMOVE were developed, including simplicity (e.g., navigation, login), colours and font sizes, push notifications, messaging algorithms, and a triggering system for breaking up sitting time and moving more. Based on the user testing results, a goal-setting tab was added, font sizes were made larger, the brightness of colours was reduced, and a colour indicator was used to indicate device connectivity with an activity tracker. A user-centric app was developed to support people with T2D to transition from sedentary to active lifestyles.
Publisher: American Physical Society (APS)
Date: 31-01-2006
Publisher: IOP Publishing
Date: 14-06-2013
Publisher: IOP Publishing
Date: 02-02-2017
Publisher: Journal of Mobile Technology in Medicine
Date: 10-2018
DOI: 10.7309/JMTM.7.2.2
Publisher: American Association for the Advancement of Science (AAAS)
Date: 07-12-2007
Abstract: In 2001, all-optical quantum computing became feasible with the discovery that scalable quantum computing is possible using only single-photon sources, linear optical elements, and single-photon detectors. Although it was in principle scalable, the massive resource overhead made the scheme practically daunting. However, several simplifications were followed by proof-of-principle demonstrations, and recent approaches based on cluster states or error encoding have dramatically reduced this worrying resource overhead, making an all-optical architecture a serious contender for the ultimate goal of a large-scale quantum computer. Key challenges will be the realization of high-efficiency sources of indistinguishable single photons, low-loss, scalable optical circuits, high-efficiency single-photon detectors, and low-loss interfacing of these components.
Publisher: American Physical Society (APS)
Date: 13-05-2004
Publisher: American Physical Society (APS)
Date: 07-07-2010
Publisher: American Physical Society (APS)
Date: 10-07-2013
Publisher: IEEE
Date: 05-2011
Publisher: OSA
Date: 2015
Publisher: Springer Science and Business Media LLC
Date: 11-2003
DOI: 10.1038/NATURE02054
Publisher: IOP Publishing
Date: 04-04-2012
Publisher: American Association for the Advancement of Science (AAAS)
Date: 02-05-2008
Abstract: Quantum technologies based on photons will likely require an integrated optics architecture for improved performance, miniaturization, and scalability. We demonstrate high-fidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits, including two-photon quantum interference with a visibility of 94.8 ± 0.5% a controlled-NOT gate with an average logical basis fidelity of 94.3 ± 0.2% and a path-entangled state of two photons with fidelity of %. These results show that it is possible to directly “write” sophisticated photonic quantum circuits onto a silicon chip, which will be of benefit to future quantum technologies based on photons, including information processing, communication, metrology, and lithography, as well as the fundamental science of quantum optics.
Publisher: American Physical Society (APS)
Date: 10-04-2014
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.JNEB.2017.02.002
Abstract: To assess the efficacy of an educational workshop for child care center staff to improve menus. Staff from 18 centers attended a nutrition educational workshop that included an activity that compared center menus to MyPlate standards. Four weeks of menus collected before and after the workshop were imported into SuperTracker the Food Details report produced menu data clustered by day and center. Changes in pre-post menus were assessed using Healthy Eating Index scores and the SAS software macro, MIXCORR. After the workshop, there was a lower probability that fruit juice (P = .03) and starchy vegetables (P = .004) and a higher probability that non-starchy vegetables (P < .001) and whole grains (P = .004) were on menus amounts of refined grains (P = .004), savory snacks (P < .001), and cheese (P = .004) were significantly lower. Total Healthy Eating Index scores improved after the workshop (P = .009). Comparing 4 weeks of menus revealed menu changes. Workshop interventions show promise for improving children's health.
Publisher: Elsevier BV
Date: 09-2014
Publisher: AIP Publishing
Date: 22-08-2011
DOI: 10.1063/1.3628328
Abstract: We demonstrate photon-pair generation in a reverse proton exchanged waveguide fabricated on a periodically poled magnesium doped stoichiometric lithium tantalate substrate. Detected pairs are generated via a cascaded second order nonlinear process where a pump laser at wavelength of 1.55 μm is first doubled in frequency by second harmonic generation and subsequently downconverted around the same spectral region. Pairs are detected at a rate of 42/s with a coincidence to accidental ratio of 0.7. This cascaded pair generation process is similar to four-wave-mixing where two pump photons annihilate and create a correlated photon pair.
Publisher: IEEE
Date: 05-2013
Publisher: IEEE
Date: 09-2010
Publisher: American Physical Society (APS)
Date: 18-11-2005
Publisher: Springer Science and Business Media LLC
Date: 02-05-2020
DOI: 10.1007/S10995-020-02935-1
Abstract: To compare diet quality of convenience s les of children 2-3 and 4-5 years attending 11 of 75 childcare centers in Hays County, Texas to a nationally representative s le, as part of a needs assessment to inform a childcare center-based intervention. Parents completed 24-h recalls of their child's diet in 2014. Usual dietary intake of the regional and age-matched s le from the National Health and Nutrition Examination Survey (2011-2014) was estimated using the National Cancer Institute method. Diet quality was assessed using the Healthy Eating Index. Quantile regression and t-tests compared nutrient intake and Healthy Eating Index scores between the two s les. Children ages 2-3 and 4-5 years in the regional s le (n = 124) consumed a higher percent of calories from protein (19%) than children in the national s le (n = 1613 14%, P < .0.0001). In the regional s le, 21% of children 2-3 years consumed protein in excess of the AMDR compared to fewer than 1% of children in the national s le. Assessing regional diet while planning health outreach is important. Among children in childcare in this community, high protein intake may contribute to weight disparity. Workshops with childcare center staff to address center policies, environments, and parent outreach could address replacing some high-protein foods with other nutrient-rich foods.
Publisher: Elsevier BV
Date: 06-2003
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-09-2009
Abstract: A quantum algorithm to factor numbers is implemented on an optical chip.
Publisher: American Physical Society (APS)
Date: 11-10-2011
Publisher: American Physical Society (APS)
Date: 20-08-2004
Publisher: IOP Publishing
Date: 23-11-2011
Publisher: Springer Science and Business Media LLC
Date: 06-08-2015
DOI: 10.1038/NCOMMS8948
Abstract: Entanglement—one of the most delicate phenomena in nature—is an essential resource for quantum information applications. Scalable photonic quantum devices must generate and control qubit entanglement on-chip, where quantum information is naturally encoded in photon path. Here we report a silicon photonic chip that uses resonant-enhanced photon-pair sources, spectral demultiplexers and reconfigurable optics to generate a path-entangled two-qubit state and analyse its entanglement. We show that ring-resonator-based spontaneous four-wave mixing photon-pair sources can be made highly indistinguishable and that their spectral correlations are small. We use on-chip frequency demultiplexers and reconfigurable optics to perform both quantum state tomography and the strict Bell-CHSH test, both of which confirm a high level of on-chip entanglement. This work demonstrates the integration of high-performance components that will be essential for building quantum devices and systems to harness photonic entanglement on the large scale.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2009
Publisher: The Optical Society
Date: 06-11-2013
DOI: 10.1364/OE.21.027826
Publisher: American Physical Society (APS)
Date: 26-07-2004
Publisher: American Physical Society (APS)
Date: 06-09-2005
Publisher: Springer Science and Business Media LLC
Date: 18-04-2013
DOI: 10.1038/SREP01719
Publisher: American Physical Society (APS)
Date: 16-11-2007
Publisher: IEEE
Date: 06-2009
Publisher: IOP Publishing
Date: 20-09-2002
Publisher: American Physical Society (APS)
Date: 31-05-2007
Publisher: American Physical Society (APS)
Date: 16-05-2007
Publisher: IEEE
Date: 2014
Publisher: AIP Publishing
Date: 02-05-2011
DOI: 10.1063/1.3587628
Publisher: The Royal Society
Date: 15-07-2003
Abstract: We review progress at the Australian Centre for Quantum Computer Technology towards the fabrication and demonstration of spin qubits and charge qubits based on phosphorus donor atoms embedded in intrinsic silicon. Fabrication is being pursued via two complementary pathways: a 'top-down' approach for near-term production of few-qubit demonstration devices and a 'bottom-up' approach for large-scale qubit arrays with sub-nanometre precision. The 'top-down' approach employs a low-energy (keV) ion beam to implant the phosphorus atoms. Single-atom control during implantation is achieved by monitoring on-chip detector electrodes, integrated within the device structure. In contrast, the 'bottom-up' approach uses scanning tunnelling microscope lithography and epitaxial silicon overgrowth to construct devices at an atomic scale. In both cases, surface electrodes control the qubit using voltage pulses, and dual single-electron transistors operating near the quantum limit provide fast read-out with spurious-signal rejection.
Publisher: American Physical Society (APS)
Date: 09-06-2005
Publisher: AIP Publishing
Date: 24-05-2010
DOI: 10.1063/1.3413948
Abstract: Advanced quantum information science and technology (QIST) applications place exacting demands on optical components. Quantum waveguide circuits offer a route to scalable QIST on a chip. Superconducting single-photon detectors (SSPDs) provide infrared single-photon sensitivity combined with low dark counts and picosecond timing resolution. In this study, we bring these two technologies together. Using SSPDs we observe a two-photon interference visibility of 92.3±1.0% in a silica-on-silicon waveguide directional coupler at λ=804 nm—higher than that measured with silicon detectors (89.9±0.3%). We further operated controlled-NOT gate and quantum metrology circuits with SSPDs. These demonstrations present a clear path to telecom-wavelength quantum waveguide circuits.
Publisher: Springer Science and Business Media LLC
Date: 04-2014
DOI: 10.1038/NPHYS2931
Publisher: Optica Publishing Group
Date: 24-05-2010
Publisher: IOP Publishing
Date: 20-02-2019
Publisher: Springer Science and Business Media LLC
Date: 03-2010
DOI: 10.1038/NATURE08812
Abstract: Over the past several decades, quantum information science has emerged to seek answers to the question: can we gain some advantage by storing, transmitting and processing information encoded in systems that exhibit unique quantum properties? Today it is understood that the answer is yes, and many research groups around the world are working towards the highly ambitious technological goal of building a quantum computer, which would dramatically improve computational power for particular tasks. A number of physical systems, spanning much of modern physics, are being developed for quantum computation. However, it remains unclear which technology, if any, will ultimately prove successful. Here we describe the latest developments for each of the leading approaches and explain the major challenges for the future.
Publisher: American Physical Society (APS)
Date: 21-09-2005
Publisher: Proceedings of the National Academy of Sciences
Date: 06-06-2011
Abstract: Quantum information science addresses how uniquely quantum mechanical phenomena such as superposition and entanglement can enhance communication, information processing, and precision measurement. Photons are appealing for their low-noise, light-speed transmission and ease of manipulation using conventional optical components. However, the lack of highly efficient optical Kerr nonlinearities at the single photon level was a major obstacle. In a breakthrough, Knill, Laflamme, and Milburn (KLM) showed that such an efficient nonlinearity can be achieved using only linear optical elements, auxiliary photons, and measurement [Knill E, Laflamme R, Milburn GJ (2001) Nature 409:46–52]. KLM proposed a heralded controlled-NOT (CNOT) gate for scalable quantum computation using a photonic quantum circuit to combine two such nonlinear elements. Here we experimentally demonstrate a KLM CNOT gate. We developed a stable architecture to realize the required four-photon network of nested multiple interferometers based on a displaced-Sagnac interferometer and several partially polarizing beamsplitters. This result confirms the first step in the original KLM “recipe” for all-optical quantum computation, and should be useful for on-demand entanglement generation and purification. Optical quantum circuits combining giant optical nonlinearities may find wide applications in quantum information processing, communication, and sensing.
Publisher: Proceedings of the National Academy of Sciences
Date: 10-01-2011
Abstract: By weakly measuring the polarization of a photon between two strong polarization measurements, we experimentally investigate the correlation between the appearance of anomalous values in quantum weak measurements and the violation of realism and nonintrusiveness of measurements. A quantitative formulation of the latter concept is expressed in terms of a Leggett–Garg inequality for the outcomes of subsequent measurements of an in idual quantum system. We experimentally violate the Leggett–Garg inequality for several measurement strengths. Furthermore, we experimentally demonstrate that there is a one-to-one correlation between achieving strange weak values and violating the Leggett–Garg inequality.
Publisher: OSA
Date: 2015
Publisher: Springer Science and Business Media LLC
Date: 25-06-2012
DOI: 10.1038/SREP00470
Publisher: Springer Science and Business Media LLC
Date: 30-03-2015
Publisher: American Physical Society (APS)
Date: 13-08-2008
Publisher: American Physical Society (APS)
Date: 28-06-2012
Publisher: American Physical Society (APS)
Date: 06-2005
Location: Australia
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Jeremy O'Brien.