Towards Laser Driven Hadron Cancer Radiotherapy: A Review of Progress

It has been known for about sixty years that proton and heavy ion therapy is a very powerful radiation procedure for treating tumours. It has an innate ability to irradiate tumours with greater doses and spatial selectivity compared with electron and photon therapy and hence is a tissue sparing procedure. For more than twenty years powerful lasers have generated high energy beams of protons and heavy ions and hence it has been frequently speculated that lasers could be used as an alternative to RF accelerators to produce the particle beams necessary for cancer therapy. The present paper reviews the progress made towards laser driven hadron cancer therapy and what has still to be accomplished to realise its inherent enormous potential.Comment: 40 pages, 24 figure

Photon echo quantum memories in inhomogeneously broadened two level atoms

Here we propose a solid-state quantum memory that does not require spectral holeburning, instead using strong rephasing pulses like traditional photon echo techniques. The memory uses external broadening fields to reduce the optical depth and so switch off the collective atom-light interaction when desired. The proposed memory should allow operation with reasonable efficiency in a much broader range of material systems, for instance Er3+ doped crystals which have a transition at 1.5 um. We present analytic theory supported by numerical calculations and initial experiments.Comment: 7 pages, 8 figure

A Single-Photon-compatible Telecom-C-Band Quantum Memory in a Hot Atomic Gas

The efficient storage and on-demand retrieval of quantum optical states that are compatible with the telecommunications C-band is a requirement for future terrestrial-based quantum optical networking. Spectrum in the C-band minimises optical fiber-propagation losses, and broad optical bandwidth facilitates high-speed networking protocols. Here we report on a telecommunication wavelength and bandwidth compatible quantum memory. Using the Off-Resonant Cascaded Absorption protocol in hot $^{87}$Rb vapour, we demonstrate a total memory efficiency of $20.90(1)\,\%$ with a Doppler-limited storage time of $1.10(2)\,$ns. We characterise the memory performance with weak coherent states, demonstrating signal-to-noise ratios greater than unity for mean photon number inputs above $4.5(6)\times10^{-6}$ per pulse

Theory of noise suppression in {\Lambda}-type quantum memories by means of a cavity

Quantum memories, capable of storing single photons or other quantum states of light, to be retrieved on-demand, offer a route to large-scale quantum information processing with light. A promising class of memories is based on far-off-resonant Raman absorption in ensembles of $\Lambda$-type atoms. However at room temperature these systems exhibit unwanted four-wave mixing, which is prohibitive for applications at the single-photon level. Here we show how this noise can be suppressed by placing the storage medium inside a moderate-finesse optical cavity, thereby removing the main roadblock hindering this approach to quantum memory.Comment: 10 pages, 3 figures. This paper provides the theoretical background to our recent experimental demonstration of noise suppression in a cavity-enhanced Raman-type memory ( arXiv:1510.04625 ). See also the related paper arXiv:1511.05448, which describes numerical modelling of an atom-filled cavity. Comments welcom

High-speed noise-free optical quantum memory

Quantum networks promise to revolutionise computing, simulation, and communication. Light is the ideal information carrier for quantum networks, as its properties are not degraded by noise in ambient conditions, and it can support large bandwidths enabling fast operations and a large information capacity. Quantum memories, devices that store, manipulate, and release on demand quantum light, have been identified as critical components of photonic quantum networks, because they facilitate scalability. However, any noise introduced by the memory can render the device classical by destroying the quantum character of the light. Here we introduce an intrinsically noise-free memory protocol based on two-photon off-resonant cascaded absorption (ORCA). We consequently demonstrate for the first time successful storage of GHz-bandwidth heralded single photons in a warm atomic vapour with no added noise; confirmed by the unaltered photon statistics upon recall. Our ORCA memory platform meets the stringent noise-requirements for quantum memories whilst offering technical simplicity and high-speed operation, and therefore is immediately applicable to low-latency quantum networks

A concise patient reported outcome measure for people with aphasia: the aphasia impact questionnaire 21

Background: There are many validated and widely used assessments within aphasiology. Few, however, describe language and life with aphasia from the perspective of the person with aphasia. Across healthcare, patient experience and user involvement are increasingly acknowledged as fundamental to person-centred care. As part of this movement, Patient Reported Outcome Measures (PROMs) are being used in service evaluation and planning. Aims: This paper reports the quantitative aspects of a mixed methods study that developed and validated a concise PROM, the Aphasia Impact Questionnaire (AIQ), co-produced with People with Aphasia (PWA). Methods & Procedures: The AIQ was developed within the social model of disability and all stages of the development of the AIQ were performed in partnership with PWA. It was adapted from a pre-existing and lengthier PROM for PWA, the Communication Disability Profile. The first iterations of the AIQ focused on domains of communication, participation and well-being/emotional state. Subsequently the AIQ was extended to include additional items relating to reading and writing (AIQ-21). The research design was iterative. Initially, concurrent validity, internal consistency, and sensitivity of the AIQ-prototype were obtained. The AIQ-prototype was modified to become the AIQ-21. Statistical testing with a new group of PWA was performed, investigating internal consistency and concurrent validity of the AIQ-21. Outcomes & Results: Results for both the AIQ-prototype and AIQ-21 showed statistically significant concurrent validity and good internal consistency. Repeated measurement using the AIQ-prototype demonstrated statistically significant change after PWA accessed a community intervention. Conclusions: The AIQ-21 is a PROM that has great potential to be one of the core set of aphasia tests for clinical and research use. Results can be used alongside language assessment to enable person-centred goal setting and partnership working for people with aphasia