992 research outputs found

    Quantizing non-Lagrangian gauge theories: an augmentation method

    Get PDF
    We discuss a recently proposed method of quantizing general non-Lagrangian gauge theories. The method can be implemented in many different ways, in particular, it can employ a conversion procedure that turns an original non-Lagrangian field theory in dd dimensions into an equivalent Lagrangian topological field theory in d+1d+1 dimensions. The method involves, besides the classical equations of motion, one more geometric ingredient called the Lagrange anchor. Different Lagrange anchors result in different quantizations of one and the same classical theory. Given the classical equations of motion and Lagrange anchor as input data, a new procedure, called the augmentation, is proposed to quantize non-Lagrangian dynamics. Within the augmentation procedure, the originally non-Lagrangian theory is absorbed by a wider Lagrangian theory on the same space-time manifold. The augmented theory is not generally equivalent to the original one as it has more physical degrees of freedom than the original theory. However, the extra degrees of freedom are factorized out in a certain regular way both at classical and quantum levels. The general techniques are exemplified by quantizing two non-Lagrangian models of physical interest.Comment: 46 pages, minor correction

    Sexual minority women and parenthood: Perceptions of friendship among childfree and new parents

    Get PDF
    Many individuals experience shifts in their friendship networks after becoming parents. The current study investigated the narratives of how a sample of sixty-six sexual minority women, most of whom do not yet have children but who expect to be parents in the future, perceive the changes in friendship networks following becoming parents. A thematic analysis uncovered three themes: (1) general expectations surrounding future parenthood and friendships; (2) changes in lifestyle and priorities; and (3) LGBTQ + community attachment. Further, the theme of general expectations surrounding future parenthood and friendships was largely represented among lesbian and queer women, while the theme of changes in lifestyle and priorities was predominately represented among lesbian women, and finally, the theme of LGBTQ + community attachment was shared among all sexual minority women in our sample across different sexual identities. We discuss the diversity of shared and non-shared narratives among sexual minority women, the intentionality in how friendship during parenthood is perceived, as well as why some themes were particularly prevalent among women with specific sexual identities

    Envisioning future parenthood among bisexual, lesbian, and heterosexual women

    Get PDF
    For many individuals, becoming a parent is an important milestone. The current study examined attitudes and beliefs about parenting among a sample of 196 self-identified bisexual, lesbian, and heterosexual women. Results showed no differences by sexual orientation for women’s desires and intentions to have children, their idealization of parenthood, and perceptions of their parental self-efficacy (i.e., their ability to care for a child). In contrast, differences did emerge by sexual orientation in aspects such as partner expectations as well as professional intentions (i.e., wanting a permanent position before becoming a parent). Bisexual women tended to anticipate lower partner support compared to heterosexual women. Lesbian women, however, had a greater preference to work full-time during parenthood and wanted a permanent position before becoming a parent compared to both bisexual and heterosexual women. Implications are discussed of how bisexual women’s perceptions of parenthood are both similar to and distinct from lesbian and heterosexual women

    Spatial Natural Language Generation for Location Description in Photo Captions

    Get PDF
    We present a spatial natural language generation system to create captions that describe the geographical context of geo-referenced photos. An analysis of existing photo captions was used to design templates representing typical caption language patterns, while the results of human subject experiments were used to create field-based spatial models of the applicability of some commonly used spatial prepositions. The language templates are instantiated with geo-data retrieved from the vicinity of the photo locations. A human subject evaluation was used to validate and to improve the spatial language generation procedure, examples of the results of which are presented in the paper

    Faddeev-Merkuriev equations for resonances in three-body Coulombic systems

    Full text link
    We reconsider the homogeneous Faddeev-Merkuriev integral equations for three-body Coulombic systems with attractive Coulomb interactions and point out that the resonant solutions are contaminated with spurious resonances. The spurious solutions are related to the splitting of the attractive Coulomb potential into short- and long-range parts, which is inherent in the approach, but arbitrary to some extent. By varying the parameters of the splitting the spurious solutions can easily be ruled out. We solve the integral equations by using the Coulomb-Sturmian separable expansion approach. This solution method provides an exact description of the threshold phenomena. We have found several new S-wave resonances in the e- e+ e- system in the vicinity of thresholds.Comment: LaTeX with elsart.sty 13 pages, 5 figure

    Asymmetric quantum channel for quantum teleportation

    Get PDF
    There are a few obstacles, which bring about imperfect quantum teleportation of a continuous variable state, such as unavailability of maximally entangled two-mode squeezed states, inefficient detection and imperfect unitary transformation at the receiving station. We show that all those obstacles can be understood by a combination of an {\it asymmetrically-decohered} quantum channel and perfect apparatuses for other operations. For the asymmetrically-decohered quantum channel, we find some counter-intuitive results; one is that teleportation does not necessarily get better as the channel is initially squeezed more and another is when one branch of the quantum channel is unavoidably subject to some imperfect operations, blindly making the other branch as clean as possible may not result in the best teleportation result. We find the optimum strategy to teleport an unknown field for a given environment or for a given initial squeezing of the channel.Comment: 4pages, 1figur

    Quantum teardrops

    Full text link
    Algebras of functions on quantum weighted projective spaces are introduced, and the structure of quantum weighted projective lines or quantum teardrops are described in detail. In particular the presentation of the coordinate algebra of the quantum teardrop in terms of generators and relations and classification of irreducible *-representations are derived. The algebras are then analysed from the point of view of Hopf-Galois theory or the theory of quantum principal bundles. Fredholm modules and associated traces are constructed. C*-algebras of continuous functions on quantum weighted projective lines are described and their K-groups computed.Comment: 18 page

    Schwinger-Dyson equation for non-Lagrangian field theory

    Full text link
    A method is proposed of constructing quantum correlators for a general gauge system whose classical equations of motion do not necessarily follow from the least action principle. The idea of the method is in assigning a certain BRST operator Ω^\hat\Omega to any classical equations of motion, Lagrangian or not. The generating functional of Green's functions is defined by the equation Ω^Z(J)=0\hat\Omega Z (J) = 0 that is reduced to the standard Schwinger-Dyson equation whenever the classical field equations are Lagrangian. The corresponding probability amplitude Ψ\Psi of a field ϕ\phi is defined by the same equation Ω^Ψ(ϕ)=0\hat\Omega \Psi (\phi) = 0 although in another representation. When the classical dynamics are Lagrangian, the solution for Ψ(ϕ)\Psi (\phi) is reduced to the Feynman amplitude eiℏSe^{\frac{i}{\hbar}S}, while in the non-Lagrangian case this amplitude can be a more general distribution.Comment: 33 page
    • …
    corecore