Tuneable quantum interference in a 3D integrated circuit

Integrated photonics promises solutions to questions of stability, complexity, and size in quantum optics. Advances in tunable and non-planar integrated platforms, such laser-inscribed photonics, continue to bring the realisation of quantum advantages in computation and metrology ever closer, perhaps most easily seen in multi-path interferometry. Here we demonstrate control of two-photon interference in a chip-scale 3D multi-path interferometer, showing a reduced periodicity and enhanced visibility compared to single photon measurements. Observed non-classical visibilities are widely tunable, and explained well by theoretical predictions based on classical measurements. With these predictions we extract a Fisher information approaching a theoretical maximum, demonstrating the capability of the device for quantum enhanced phase measurements.Comment: 11 pages, 24 figure

On-chip generation of heralded photon-number states

Beyond the use of genuine monolithic integrated optical platforms, we report here a hybrid strategy enabling on-chip generation of configurable heralded two-photon states. More specifically, we combine two different fabrication techniques, \textit{i.e.}, non-linear waveguides on lithium niobate for efficient photon-pair generation and femtosecond-laser-direct-written waveguides on glass for photon manipulation. Through real-time device manipulation capabilities, a variety of path-coded heralded two-photon states can be produced, ranging from product to entangled states. Those states are engineered with high levels of purity, assessed by fidelities of 99.5$\pm$8\% and 95.0$\pm$8\%, respectively, obtained via quantum interferometric measurements. Our strategy therefore stands as a milestone for further exploiting entanglement-based protocols, relying on engineered quantum states, and enabled by scalable and compatible photonic circuits

Hybrid photonic circuit for multiplexed heralded single photons

A key resource for quantum optics experiments is an on-demand source of single and multiple photon states at telecommunication wavelengths. This letter presents a heralded single photon source based on a hybrid technology approach, combining high efficiency periodically poled lithium niobate waveguides, low-loss laser inscribed circuits, and fast (>1 MHz) fibre coupled electro-optic switches. Hybrid interfacing different platforms is a promising route to exploiting the advantages of existing technology and has permitted the demonstration of the multiplexing of four identical sources of single photons to one output. Since this is an integrated technology, it provides scalability and can immediately leverage any improvements in transmission, detection and photon production efficiencies.Comment: 5 pages, double column, 3 figure

Cavity-enhanced coherent light scattering from a quantum dot.

The generation of coherent and indistinguishable single photons is a critical step for photonic quantum technologies in information processing and metrology. A promising system is the resonant optical excitation of solid-state emitters embedded in wavelength-scale three-dimensional cavities. However, the challenge here is to reject the unwanted excitation to a level below the quantum signal. We demonstrate this using coherent photon scattering from a quantum dot in a micropillar. The cavity is shown to enhance the fraction of light that is resonantly scattered toward unity, generating antibunched indistinguishable photons that are 16 times narrower than the time-bandwidth limit, even when the transition is near saturation. Finally, deterministic excitation is used to create two-photon N00N states with which we make superresolving phase measurements in a photonic circuit.Engineering and Physical Sciences Research CouncilThis is the final version of the article. It first appeared from the American Association for the Advancement of Science via http://dx.doi.org/10.1126/sciadv.150125

APOLO-Bari, an internet-based program for longitudinal support of bariatric surgery patients: study protocol for a randomized controlled trial

Background: Despite evidence of successful weight loss for bariatric surgery patients, some patients experience considerable weight regain over the long term. Given the strong association between post-surgery health behaviors and outcomes, aftercare intervention to address key behaviors appears to be a reasonable relapse-prevention strategy. As the burden of obesity rates increases in healthcare centers, an internet-based program appears to be a reasonable strategy for supporting bariatric surgery patients in the long term. The primary purpose of the current project is to develop and test the efficacy and perceived utility of APOLO-Bari.Methods/design: This study is a randomized control trial, which will be conducted in two hospital centers in the North of Portugal; it includes a control group receiving treatment as usual and an intervention group receiving the APOLO-Bari program for one year in addition to treatment as usual. A total of 180 male and female participants who underwent bariatric surgery (gastric sleeve or gastric bypass surgery) for 12 to 20 months will be recruited. Both groups will complete a similar set of questionnaires at baseline, every 4 months until the end of the intervention, and at 6 and 12 months follow-up. Assessment includes anthropometric variables and psychological self-report measures. The primary outcome measure will be weight regain measured at the end of treatment, and at 6 and 12 months follow-up. The secondary aims are to test the cost-effectiveness of the intervention and to investigate psychological predictors and trajectories of weight regain. APOLO-Bari was developed to address the weight regain problem in the bariatric population by offering additional guidance to bariatric patients during the postoperative period. The program includes: (a) a psychoeducational cognitive-behavioral-based self-help manual, (b) a weekly feedback messaging system that sends a feedback statement related to information reported by the participant, and (c) interactive chat sessions scheduled witThis research was partially supported by the Fundacao para a Ciencia e a Tecnologia through a European Union COMPETE program grant to Eva Conceicao (IF/01219/2014 and PTDC/MHC-PCL/4974/2012), a doctoral scholarship to Ana Pinto-Bastos (SFRH/BD/104159/2014), a doctoral scholarship to Sofia Ramalho (SFRH/BD/104182/2014), and a postdoctoral scholarship to Ana Rita Vaz (SFRH/BPD/94490/2013), co-financed by FEDER under the PT2020 Partnership Agreement (UID/PSI/01662/2013).info:eu-repo/semantics/publishedVersio

Optical manufacturing : femtosecond-laser direct-written waveguides produce quantum circuits in glass

Integrated photonics can be written in glass through nonlinear absorption by focusing a short-pulse-duration laser into the glass; quantum-integrated- photonics (QIP) devices are being fabricated using this technique. The small size offered by integrated optics is of course also crucial to taking experiments out of laboratories and producing practical technologies. These on-chip optical circuits operate primarily by the process of total internal reflection. A fundamental theorem, called the 'no-cloning' theorem, precludes the amplification of quantum information; as a result, every photon in a quantum-information system is precious. An alternative technique to developing waveguides in glass is called the femtosecond laser direct-write (FLDW) technique. This exploits a nonlinear-absorption process that occurs at high laser intensities in a transparent material. Because of the potential to interface multiple different device platforms, it is likely that future small-scale quantum circuits will exploit the convenience of laser-written devices.4 page(s

Laser written integrated photonics for quantum information science

"A thesis submitted to Macquarie University for the degree of Doctor of Philosophy, Department of Physics and Astronomy""August 2014""Typeset in LaTeX2e"Bibliography: pages 137-165.1. Background to quantum information science -- 2. Background to integrated optics -- 3. Towards low loss waveguides -- 4. Multiport beamsplitters -- 5. Quantum circuits -- 6. Hybrid integration -- 7. Conclusion -- A. Appendix I: Waveguide theory -- B. Experimental methods.This thesis details the study of quantum information science (QIS) using integrated photonics. Integrated photonic devices are fabricated in glass using the femtosecond laser direct write (FLDW) technique. This method uses a focused high power laser to produce a localised refractive index change in a glass substrate which can be used to form waveguides. A rigorous parameter study of laser inscription and glass structure is performed to isolate regions where low loss waveguides can be formed. Unique, three dimensional,circuit designs are created which are then characterised to determine symmetry and to ascertain their performance for QIS.The circuit designs include 3D multiports which permit the unitary transformation of a set of optical modes. Single photons are injected into this device to determine its performance and compare it to bulk optic, fibre optic and lithographically fabricated examples. The 3D multiports show high fidelity operation and a comparable performance to other circuit design platforms. Building on this work which shows the high quality of laser inscribed devices, an inherently quantum circuit is designed. It has the function of operating as a basic two-qubit circuit element which applies a phase shift to a qubit in a target mode, conditional on the state of a control qubit. Thiscircuit is heralded, meaning that it operates in the presence of two additional ancilla modes which trigger the success of the probabilistic gate. The design of this circuit required detailed analysis of the reproducibility of laser written circuits in the presence of performance tolerance to fabrication imperfections.The devices described previously were characterised, non-classically, using a bulk source of photon pairs. This limits the application of the devices beyond demonstrations or prototypes, hence it is desirable to also integrate these devices with on-chip sources of single photons. Such a source of single photons is available in the form of a quasi phase-matched nonlinear crystal which emits heralded single photons. An experiment was undertaken to design a hybrid circuit, composed of both linear and nonlinear elements to produce heralded single photons, to produce multiple sources of heralded single photons. This was completed and experiments exploiting high speed switching to combine individual sources and an experiment to manipulate photon pair states is completed.This work builds on the knowledge of FLDW structures for on chip routing and manipulation of light. Demonstrations of integrated circuits and hybrid integrated devices shows the potential for high quality and compact monolithic on-chip quantum circuits.Mode of access: World wide web1 online resource (xvi, 165 pages) illustrations (many colour

Chat-bot Humour: A survey of Methodological Approaches for a Creative New Media Project

This paper surveys a range of methodological approaches to underpin a creative project that will develop a pair of online, computer-based conversational agents to interact as "comedian" and "straight man". The project will interrogate the scriptwriting process as it is applied to a pair of interacting chat-bots: a confluence of human and non-human agency. This survey is necessary due to the project's trans-disciplinary nature; it borrows from information science, drama and scriptwriting, creativity theory, humour theory, and interactive design. "Ontology and epistemology can be considered as the foundations upon which research is built. Methodology, methods and sources are closely connected to, and built upon, our ontological and epistemological assumptions" (Grix 2004, p. 58). These ontological and epistemological foundations are often viewed as tacit knowledge within the disciplines, however, there appears to be little agreement across disciplines. Positioned in this manner, the researcher is implicated inside larger research structures in much the same manner as the creative individual is implicated in the systemic view of creativity offered by Csikszentmihalyi (1999; 2003). This is not a privileged position. The researchers themselves operate within same "discourses and traditions" as the object of study, "consequently, knowledge is theoretically or discursively laden" (Marsh and Furlong 2002, p. 26). The purpose of this paper is to explore these issues from a variety of disciplinary perspectives to make the implicit explicit

Biodesign Here NOW 2019

Re:mains is a collection of art jewellery artefacts which form a multi-component output, having been developed broadly and disseminated at a series of national and international exhibitions since 2017. Through the practical application of making skills and techniques this research explored the extent to which art jewellery, created predominately using food waste, could effectively reference bodily forms and renew everyday acts of eating