Consistent histories of systems and measurements in spacetime

Traditional interpretations of quantum theory in terms of wave function collapse are particularly unappealing when considering the universe as a whole, where there is no clean separation between classical observer and quantum system and where the description is inherently relativistic. As an alternative, the consistent histories approach provides an attractive "no collapse" interpretation of quantum physics. Consistent histories can also be linked to path-integral formulations that may be readily generalized to the relativistic case. A previous paper described how, in such a relativistic spacetime path formalism, the quantum history of the universe could be considered to be an eignestate of the measurements made within it. However, two important topics were not addressed in detail there: a model of measurement processes in the context of quantum histories in spacetime and a justification for why the probabilities for each possible cosmological eigenstate should follow Born's rule. The present paper addresses these topics by showing how Zurek's concepts of einselection and envariance can be applied in the context of relativistic spacetime and quantum histories. The result is a model of systems and subsystems within the universe and their interaction with each other and their environment.Comment: RevTeX 4; 37 pages; v2 is a revision in response to reviewer comments, connecting the discussion in the paper more closely to consistent history concepts; v3 has minor editorial corrections; accepted for publication in Foundations of Physics; v4 has a couple minor typographical correction

Quantum field theory and Hopf algebra cohomology

We exhibit a Hopf superalgebra structure of the algebra of field operators of quantum field theory (QFT) with the normal product. Based on this we construct the operator product and the time-ordered product as a twist deformation in the sense of Drinfeld. Our approach yields formulas for (perturbative) products and expectation values that allow for a significant enhancement in computational efficiency as compared to traditional methods. Employing Hopf algebra cohomology sheds new light on the structure of QFT and allows the extension to interacting (not necessarily perturbative) QFT. We give a reconstruction theorem for time-ordered products in the spirit of Streater and Wightman and recover the distinction between free and interacting theory from a property of the underlying cocycle. We also demonstrate how non-trivial vacua are described in our approach solving a problem in quantum chemistry.Comment: 39 pages, no figures, LaTeX + AMS macros; title changed, minor corrections, references update

Shaping the future of rare diseases after a global health emergency: Organisational points to consider

The unexpected outbreak of the COVID-19 disease had significant and enormous repercussions on the healthcare systems, such as the need to reorganise healthcare organisations in order to concentrate resources needed to the care of COVID-19 patients and to respond in general to this health emergency. Due to these challenges, the care of several chronic conditions was in many cases discontinued and patients and healthcare professionals treating these conditions had to cope with this new scenario. This was the case of the world rare diseases (RDs) that had to face this global emergency despite the vulnerability of people with RDs and the well-known need for high expertise required to treat and manage them. The numerous lessons learned so far regarding health emergencies and RDs should represent the basis for the establishment of new healthcare policies and plans aimed at ensuring the preparedness of our health systems in providing appropriate care to people living with RDs in the case of eventual new emergencies. This paper aims at providing pragmatic considerations that might be useful in designing future actions to create or optimise existing organisational models for the care of RDs in case of future emergencies or any other situation that might threaten the provision of routine care. These policies and plans should benefit from the multi-stakeholder RDs networks (such as the European Reference Networks), that should join forces at European, national, and local levels to minimise the economic, organisational, and health-related impact and the negative effects of potential emergencies on the RDs community. In order to design and develop these policies and plans, a decalogue of points to consider were developed to ensure appropriate care for people living with RDs in the case of eventual future health emergencies

Exploring disease perception in Behçet's syndrome: combining a quantitative and a qualitative study based on a narrative medicine approach

Background: Behçet Syndrome (BS) has a significant psychological and social impact on patients, caregivers and families. The present study aims at exploring disease perception in BS patients, using both a co-designed survey and the narrative medicine (NM) approach. Methods: An ad-hoc questionnaire was co-designed by clinicians expert in BS, BS patients and caregivers and BS adult patients were invited to answer the online questionnaires. Cluster analysis was used to analyse data from the survey and to identify groups of patients with diverse disease perception. To further explore real-life perspectives, the stories of illness of a smaller group of adult BS patients were anonymously collected online and analysed by means of text, sentiment and qualitative analysis. Results: Two hundred and seven patients answered the survey and forty-three stories were collected. The cluster analysis highlighted that accepting or not the disease has a strong impact on the daily life, on how BS patients perceive themselves and in terms of hope for the future. The stories revealed that patients often address common issues, such as the long and complex journey faced from the disease onset until the BS diagnosis, which was strongly connected to the concept of time and perceived as an exhausting period of their lives. Conclusion: To our knowledge, this is the first study that addressed disease perception also applying the NM principles in BS. The current perception that BS patients have of their disease should encourage the BS scientific and patient community in joining forces in order to improve the journey of BS patients

Being a caregiver of a Behçet’s syndrome patient: challenges and perspectives during a complex journey

Background: As often seen in many chronic diseases, the disease impact on patients also induces a significant impact on the quality of life (QoL) of caregivers. Caregivers are the ones who are really willing to offer care in the general approach of many aspects of the disease, including the awareness of the diseases itself, the daily management of therapy, and all the potential challenges that living with a chronic disease can include. The main objectives of the study were to explore the perspectives and views of caregivers of Behçet’s syndrome (BS) patients, to study their level of awareness on the disease and the impact that BS may have on their lives by means of a survey co-designed with caregivers and patients with this purpose. A survey was entirely co-designed with a panel of caregivers of patients living with BS patients. Results: Results show that BS caregivers organise their life according to the needs of the patient, that they (79%) considered themselves as helpful for the patient and 53% of them replied that they can freely express their emotions. Notably, 70% and 68% of the respondents reported they renounced with a variable frequency to sexual relationships due to concerns regarding the health of the partner or to the partner’s illness, respectively. The majority (79%) of respondents indicated that they are familiar with the treatment taken by the patients and that 68% deal with the administration of some medicines. In terms of awareness, a good percentage (64%) of respondents reported to understand the illness and, in terms of education, 68% of participants are willing to take part in training programmes dedicated to BS. Conclusions: The results of this survey contribute to provide new information on BS caregivers and on their important role, and to identify areas in which new initiatives could provide BS caregivers (and therefore patients) with tools and knowledge that can empower them in reducing the burden of the disease on their lives, on families, and on the patient