Braid Topologies for Quantum Computation

In topological quantum computation, quantum information is stored in states which are intrinsically protected from decoherence, and quantum gates are carried out by dragging particle-like excitations (quasiparticles) around one another in two space dimensions. The resulting quasiparticle trajectories define world-lines in three dimensional space-time, and the corresponding quantum gates depend only on the topology of the braids formed by these world-lines. We show how to find braids that yield a universal set of quantum gates for qubits encoded using a specific kind of quasiparticle which is particularly promising for experimental realization.Comment: 4 pages, 4 figures, minor revision

Topological Quantum Compiling

A method for compiling quantum algorithms into specific braiding patterns for non-Abelian quasiparticles described by the so-called Fibonacci anyon model is developed. The method is based on the observation that a universal set of quantum gates acting on qubits encoded using triplets of these quasiparticles can be built entirely out of three-stranded braids (three-braids). These three-braids can then be efficiently compiled and improved to any required accuracy using the Solovay-Kitaev algorithm.Comment: 20 pages, 20 figures, published versio

The Added Value of Analyzing Pooled Health-Related Quality of Life Data: A Review of the EORTC PROBE Initiative

BACKGROUND: The European Organisation for Research and Treatment of Cancer (EORTC) Patient-Reported Outcomes and Behavioural Evidence (PROBE) initiative was established to investigate critical topics to better understand health-related quality of life (HRQOL) of cancer patients and to educate clinicians, policy makers, and healthcare providers. METHODS: The aim of this paper is to review the major research outcomes of the pooled analysis of HRQOL data along with the clinical data. We identified 30 pooled EORTC randomized controlled trials (RCTs), 18 NCIC-Clinical Trials Group RCTs, and two German Ovarian Cancer Study Group RCTs, all using the EORTC QLQ-C30. All statistical tests were two-sided. RESULTS: Evidence was found that HRQOL data can offer prognostic information beyond clinical measures and improve prognostic accuracy in cancer RCTs (by 5.9%-8.3%). Moreover, models that considered both patient- and clinician-reported scores gained more prognostic overall survival accuracy for fatigue (P < .001), vomiting (P = .01), nausea (P < .001), and constipation (P = .01). Greater understanding of the association between symptom and/or functioning scales was developed by identifying physical, psychological, and gastrointestinal clusters. Additionally, minimally important differences in interpreting HRQOL changes for improvement and deterioration were found to vary across different patient populations and disease stages. Finally, HRQOL scores are statistically significantly affected by deviations from the intended time point at which the questionnaire is completed. CONCLUSIONS: The use of existing pooled data shows that it is possible to learn about general aspects of cancer HRQOL and methodology. Our work shows that setting up international pooled datasets holds great promise for understanding patients' unmet psychosocial needs and calls for additional empirical investigation to improve clinical care and understand cancer through retrospective HRQOL analyses

Does change in health-related quality of life score predict survival? Analysis of EORTC 08975 lung cancer trial

Background:Little is known about whether changes in health-related quality of life (HRQoL) scores from baseline during treatment also predict survival, which we aim to investigate in this study.Methods:We analysed data from 391 advanced non-small-cell lung cancer (NSCLC) patients enrolled in the EORTC 08975 study, which compared palliative chemotherapy regimens. HRQoL was assessed at baseline and after each chemotherapy cycle using the EORTC QLQ-C30 and QLQ-LC13. The prognostic significance of HRQoL scores at baseline and their changes over time was assessed with Cox regression, after adjusting for clinical and socio-demographic variables.Results:After controlling for covariates, every 10-point increase in baseline pain and dysphagia was associated with 11% and 12% increased risk of death with hazard ratios (HRs) of 1.11 and 1.12, respectively. Every 10-point improvement of physical function at baseline (HR=0.93) was associated with 7% lower risk of death. Every 10-point increase in pain (HR=1.08) was associated with 8% increased risk of death at cycle 1. Every 10-point increase in social function (HR=0.91) at cycle 2 was associated with 9% lower risk of death.Conclusions:Our findings suggest that changes in HRQoL scores from baseline during treatment, as measured on subscales of the EORTC QLQ-C30 and QLQ-LC13, are significant prognostic factors for survival

The effects of age on health-related quality of life in cancer populations: A pooled analysis of randomized controlled trials using the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 involving 6024 cancer patients.

Cancer incidence increases exponentially with advancing age, cancer patients live longer than in the past, and many new treatments focus on stabilizing disease and HRQOL. The objective of this study is to examine how cancer affects patients' HRQOL and whether their HRQOL is age-dependent.Data from 25 EORTC randomized controlled trials was pooled. EORTC QLQ-C30 mean scores for the cancer cohort and five general population cohorts were compared to assess the impact of cancer on patients' HRQOL. Within the cancer cohort, multiple linear regressions (two-sided level P-value = 0.05 adjusted for multiple testing.) were used to investigate the association between age and HRQOL, adjusted for gender, WHO performance status (PS), distant metastasis and stratified by cancer site. A difference of 10 points on the 0-100 scale was considered clinically important.Cancer patients generally have worse HRQOL compared to the general population, but the specific HRQOL domains impaired vary with age. When comparing the cancer versus the general population, young cancer patients had worse financial problems, social and role functioning, while the older cancer groups had more appetite loss. Within the cancer cohort, HRQOL was worse with increasing age for physical functioning and constipation, and better with increasing age for social functioning, insomnia and financial problems (all p < 0.05).HRQOL is impaired in cancer patients compared to the general population, but the impact on specific HRQOL domains varies by age. Within the cancer population, some HRQOL components improve with age while others deteriorate. Optimal care for older cancer patients should target HRQOL domains most relevant to this population