An Algebraic Approach to Linear-Optical Schemes for Deterministic Quantum Computing

Linear-Optical Passive (LOP) devices and photon counters are sufficient to implement universal quantum computation with single photons, and particular schemes have already been proposed. In this paper we discuss the link between the algebraic structure of LOP transformations and quantum computing. We first show how to decompose the Fock space of N optical modes in finite-dimensional subspaces that are suitable for encoding strings of qubits and invariant under LOP transformations (these subspaces are related to the spaces of irreducible unitary representations of U(N)). Next we show how to design in algorithmic fashion LOP circuits which implement any quantum circuit deterministically. We also present some simple examples, such as the circuits implementing a CNOT gate and a Bell-State Generator/Analyzer.Comment: new version with minor modification

The quantum state vector in phase space and Gabor's windowed Fourier transform

Representations of quantum state vectors by complex phase space amplitudes, complementing the description of the density operator by the Wigner function, have been defined by applying the Weyl-Wigner transform to dyadic operators, linear in the state vector and anti-linear in a fixed `window state vector'. Here aspects of this construction are explored, with emphasis on the connection with Gabor's `windowed Fourier transform'. The amplitudes that arise for simple quantum states from various choices of window are presented as illustrations. Generalized Bargmann representations of the state vector appear as special cases, associated with Gaussian windows. For every choice of window, amplitudes lie in a corresponding linear subspace of square-integrable functions on phase space. A generalized Born interpretation of amplitudes is described, with both the Wigner function and a generalized Husimi function appearing as quantities linear in an amplitude and anti-linear in its complex conjugate. Schr\"odinger's time-dependent and time-independent equations are represented on phase space amplitudes, and their solutions described in simple cases.Comment: 36 pages, 6 figures. Revised in light of referees' comments, and further references adde

Comunicación estratégica con perspectiva de género para organizaciones de la sociedad civil y grupos minoritarios

Durante el curso de Primavera 2023, el trabajo estuvo orientado a la creación de materiales gráficos e informativos sobre diversas problemáticas sociales como discriminación por género, violencia sexual y migración. Así mismo, se realizó un taller para la reconstrucción del tejido social. Esto tuvo lugar en cinco escenarios: Comisión de Atención a Violencia de Género ITESO, Caminantas, FM4 Paso Libre, Colmena Miramar y Centro Comunitario Teresiano A.C. Las actividades propuestas fueron diseñadas en conjunto con las y los encargados de cada una de las organizaciones mencionadas anteriormente, partiendo de las necesidades planteadas en las entrevistas de diagnóstico y a las cuales se les dio seguimiento para su validación y realización durante el semestre.ITESO, A.C

What is Donald Trump?:Forms of 'Celebrity' in Celebrity Politics

It is widely assumed that Donald Trump is a ‘celebrity politician’, and that he has cashed in his success on the reality show The Apprentice to secure political credibility and attention. In this respect he fits what Matthew Wood et al (2016) have labelled the ‘superstar celebrity politician’. This characterisation is the latest in a number of refinements to the definition and understanding of the celebrity politician. While this is a helpful move, I want to suggest that it might overlook one key dimension of the phenomenon. Definitions of the celebrity politician tend to focus on the source of their ‘celebrity’ – how they became famous, rather than on how they act out their celebrity role. This latter dimension features in media coverage, where journalists and commentators borrow from showbusiness to describe politics, but is less often analysed in the political science literature. It matters because, I want to suggest, celebrity politicians like Trump act as stars, whether of reality television, rock music or film. They do not just resemble stars; they are them. This is evident in how they are represented, how they perform and how their ‘fans’ respond to them. It is also symptomatic of wider changes in the conduct and form of the contemporary, mediatised political realm

Data from: Benefit of transferred mutations is better predicted by the fitness of recipients than by their ecological or genetic relatedness

The effect of a mutation depends on its interaction with the genetic background in which it is assessed. Studies in experimental systems have demonstrated that such interactions are common among beneficial mutations and often follow a pattern consistent with declining evolvability of more fit genotypes. However, these studies generally examine the consequences of interactions between a small number of focal mutations. It is not clear, therefore, that findings can be extrapolated to natural populations, where new mutations may be transferred between genetically divergent backgrounds. We build on work that examined interactions between four beneficial mutations selected in a laboratory-evolved population of Escherichia coli to test how they interact with the genomes of diverse natural isolates of the same species. We find that the fitness effect of transferred mutations depends weakly on the genetic and ecological similarity of recipient strains relative to the donor strain in which the mutations were selected. By contrast, mutation effects were strongly inversely correlated to the initial fitness of the recipient strain. That is, there was a pattern of diminishing returns whereby fit strains benefited proportionally less from an added mutation. Our results strengthen the view that the fitness of a strain can be a major determinant of its ability to adapt. They also support a role for barriers of transmission, rather than differential selection of transferred DNA, as an explanation of observed phylogenetically determined patterns of restricted recombination among E. coli strains