Scheme for the implementation of a universal quantum cloning machine via cavity-assisted atomic collisions in cavity QED

We propose a scheme to implement the $1\to2$ universal quantum cloning machine of Buzek et.al [Phys. Rev.A 54, 1844(1996)] in the context of cavity QED. The scheme requires cavity-assisted collision processes between atoms, which cross through nonresonant cavity fields in the vacuum states. The cavity fields are only virtually excited to face the decoherence problem. That's why the requirements on the cavity quality factor can be loosened.Comment: to appear in PR

Theory of Coexistence of Superconductivity and Ferroelectricity : A Dynamical Symmetry Model

We propose and investigate a model for the coexistence of Superconductivity (SC) and Ferroelectricity (FE) based on the dynamical symmetries $su(2)$ for the pseudo-spin SC sector, $h(4)$ for the displaced oscillator FE sector, and $su(2) \otimes h(4)$ for the composite system. We assume a minimal symmetry-allowed coupling, and simplify the hamiltonian using a double mean field approximation (DMFA). A variational coherent state (VCS) trial wave-function is used for the ground state: the energy, and the relevant order parameters for SC and FE are obtained. For positive sign of the SC-FE coupling coefficient, a non-zero value of either order parameter can suppress the other (FE polarization suppresses SC and vice versa). This gives some support to "Matthias' Conjecture" [1964], that SC and FE tend to be mutually exclusive. For such a Ferroelectric Superconductor we predict: a) the SC gap $\Delta$ (and $T_c$) will increase with increasing applied pressure when pressure quenches FE as in many ferroelectrics, and b) the FE polarization will increase with increaesing magnetic field up to $H_c$. The last result is equivalent to the prediction of a new type of Magneto-Electric Effect in a coexistent SC-FE material. Some discussion will be given of the relation of these results to the cuprate superconductors.Comment: 46 page

Nucleosynthesis Constraints on a Massive Gravitino in Neutralino Dark Matter Scenarios

The decays of massive gravitinos into neutralino dark matter particles and Standard Model secondaries during or after Big-Bang nucleosynthesis (BBN) may alter the primordial light-element abundances. We present here details of a new suite of codes for evaluating such effects, including a new treatment based on PYTHIA of the evolution of showers induced by hadronic decays of massive, unstable particles such as a gravitino. We also develop an analytical treatment of non-thermal hadron propagation in the early universe, and use this to derive analytical estimates for light-element production and in turn on decaying particle lifetimes and abundances. We then consider specifically the case of an unstable massive gravitino within the constrained minimal supersymmetric extension of the Standard Model (CMSSM). We present upper limits on its possible primordial abundance before decay for different possible gravitino masses, with CMSSM parameters along strips where the lightest neutralino provides all the astrophysical cold dark matter density. We do not find any CMSSM solution to the cosmological Li7 problem for small m_{3/2}. Discounting this, for m_{1/2} ~ 500 GeV and tan beta = 10 the other light-element abundances impose an upper limit m_{3/2} n_{3/2}/n_\gamma < 3 \times 10^{-12} GeV to < 2 \times 10^{-13} GeV for m_{3/2} = 250 GeV to 1 TeV, which is similar in both the coannihilation and focus-point strips and somewhat weaker for tan beta = 50, particularly for larger m_{1/2}. The constraints also weaken in general for larger m_{3/2}, and for m_{3/2} > 3 TeV we find a narrow range of m_{3/2} n_{3/2}/n_\gamma, at values which increase with m_{3/2}, where the Li7 abundance is marginally compatible with the other light-element abundances.Comment: 74 pages, 40 Figure

Milk for a girl and bananas for a boy:recipes and reasons for sex-preference practices in a British Internet forum

Using postings from an internet forum, this paper explores the ways in which some women try to influence the sex of a future child. The extensive reproductive work involved give an indication of the women’s commitment to being able to choose a particular sex; in this case a preference for girls rather than boys. The findings revealed stereotypical views of masculinity and femininity at the heart of the preference. The presumption of fixed gendered identities helped to frame this desire as ‘natural,’ lessen the threat to maternal identities, and reinforce the logic of ‘choice,’ and support their reproductive work practices

Legal, medical and lay understanding of embryos in Portugal: alignment with biology?

Pretende-se contribuir para o debate em torno dos processos de circulação de conhecimentos e sentidos entre especialistas e “leigos” no que concerne ao estatuto dos embriões humanos em Portugal. Reflete-se sobre as expectativas e preocupações manifestadas quanto à confiança, qualidade, segurança e eficácia das tecnologias médicas de reprodução assistida. O estudo assenta na realização de entrevistas individuais, com vistas a explorar as complexidades, similitudes e diferenças entre as visões e os valores de juristas, médicos e casais envolvidos em tratamentos de fertilização in vitro. Trata-se de uma análise qualitativa em um estudo de caso. Se os juristas e os médicos enquadram o estatuto dos embriões em categorias de índole biológica, técnica e/ou jurídico-legal, já os casais estabelecem com os mesmos diversas relações ontológicas de índole moral, afetiva e social, pelo que estes podem ser representados como seres éticos face à biologização médico-legal dos embriões.Our aim is to contribute towards the debate about the processes through which knowledge and meanings regarding the status of human embryos circulate among experts and laymen in Portugal. Expectations and concerns expressed regarding the reliability, quality, safety and efficacy of medical technologies for assisted reproduction were assessed. This study is based on data from individual interviews that sought to explore the complexities, similarities and differences among the views and values of jurists, doctors and couples involved in in vitro fertilization treatments. It consists of a qualitative analysis on a case study. If jurists and doctors frame the status of embryos as categories of a biological, technical and/or legal nature, couples establish between themselves a variety of ontological relationships of a moral, affective and social nature. Through these, they can be represented as ethical beings, thus contrasting with the medical-legal biologization of the embryos.To the jurists, doctors and women and men who we interviewed and who shared with us their views and experiences, our sincere thanks. We also thank Helena Lima and Filomena Louro (Scientific Editing Programme, University of Minho) for the translation of the Portuguese text into English; and the revision of David George Elliff. The authors thank the Foundation for Science and Technology (Portuguese Ministry of Science, Technology and Higher Education) for the financial support for this research, through a PhD fellowship (SFRH/BD/10396/2002) and a post-doctoral fellowship (SFRH/BPD/47020/2008).info:eu-repo/semantics/publishedVersio

Physics with the KLOE-2 experiment at the upgraded DAϕ\phiNE

Investigation at a $\phi$--factory can shed light on several debated issues in particle physics. We discuss: i) recent theoretical development and experimental progress in kaon physics relevant for the Standard Model tests in the flavor sector, ii) the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled kaon states, iii) the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and eta/eta$^\prime$ mesons, iv) the contribution to understand the nature of light scalar mesons, and v) the opportunity to search for narrow di-lepton resonances suggested by recent models proposing a hidden dark-matter sector. We also report on the $e^+ e^-$ physics in the continuum with the measurements of (multi)hadronic cross sections and the study of gamma gamma processes.Comment: 60 pages, 41 figures; added affiliation for one of the authors; added reference to section

Chance, choice and control: Lay debate on prenatal social sex selection

Assisted reproductive technologies are typically positioned as increasing the range of choices open to the healthcare consumer, thereby enhancing ‘reproductive freedom’. In this paper, we question the equivalence of reproductive choice and personal freedom in ethical theory, using results from a project investigating how lay people make ethical evaluations about the new genetic and reproductive technologies. We took the topic of social sex selection by preimplantation genetic diagnosis (PGD), and used group discussions and interviews in the north-east of England to trace how lay people develop and express their ethical evaluations, and to identify the implicit or explicit normative framework that gave rise to their opinions on prenatal sex selection. There was a striking level of ambivalence towards choice in general and reproductive choice in particular. Participants offered few positive statements and numerous reasons why reproductive choice might be problematic. Our participants’ argumentation shares with mainstream bioethical analysis the weighing of the possible harms of prenatal sex selection for social reasons against the harm of restricting reproductive freedom. However, unlike most secular–liberal bioethicists, many of our participants concluded that prenatal sex selection is undesirable because it is an expression of parental preference instead of a response to the future child's need. Our interpretation of their reasoning is that they work from an ideal of “good parents”, one of the features of which is the relinquishing of control over their children, except to protect them from harm. This voluntary self-limitation does not indicate reduced autonomy, because parental autonomy can only operate within the limits set by this relational framework. We suggest that a model of relational autonomy captures our lay participants’ framing of the problem better than a more traditional understanding of autonomy. Our study also shows that in appropriately structured discussion of bioethical issues, lay people can articulate reasons for their opinions that are grounded in sophisticated and morally relevant concepts