Zeno dynamics in wave-packet diffraction spreading

We analyze a simple and feasible practical scheme displaying Zeno, anti-Zeno, and inverse-Zeno effects in the observation of wave-packet spreading caused by free evolution. The scheme is valid both in spatial diffraction of classical optical waves and in time diffraction of a quantum wave packet. In the optical realization, diffraction spreading is observed by placing slits between a light source and a light-power detector. We show that the occurrence of Zeno or anti-Zeno effects depends just on the frequency of observations between the source and detector. These effects are seen to be related to the diffraction mode theory in Fabry-Perot resonators.Comment: 7 pages, 8 figure

Form-factors and current correlators: chiral couplings L_10(mu) and C_87(mu) at NLO in 1/N(C)

Using the resonance chiral theory Lagrangian, we perform a calculation of the vector and axial-vector two-point functions at the next-to-leading order (NLO) in the 1/N(C) expansion. We have analyzed these correlators within the single-resonance approximation and have also investigated the corrections induced by a second multiplet of vector and axial-vector resonance states. Imposing the correct QCD short-distance constraints, one determines the difference of the two correlators Pi(t) = Pi_VV(t)- Pi_AA(t) in terms of the pion decay constant and resonance masses. Its low momentum expansion fixes then the low-energy chiral couplings L_10 and C_87 at NLO, keeping full control of their renormalization scale dependence. At mu_0=0.77 GeV, we obtain L_10(mu_0) = (-4.4 \pm 0.9)10^{-3} and C_87^r(mu_0)=(3.1 \pm 1.1)10^{-5}

Setting up tunneling conditions by means of Bohmian mechanics

Usually tunneling is established after imposing some matching conditions on the (time-independent) wave function and its first derivative at the boundaries of a barrier. Here an alternative scheme is proposed to determine tunneling and estimate transmission probabilities in time-dependent problems, which takes advantage of the trajectory picture provided by Bohmian mechanics. From this theory a general functional expression for the transmission probability in terms of the system initial state can be reached. This expression is used here to analyze tunneling properties and estimate transmissions in the case of initial Gaussian wave packets colliding with ramp-like barriers.Comment: 18 pages, 4 figure

Quantum Simulator for Transport Phenomena in Fluid Flows

Transport phenomena still stand as one of the most challenging problems in computational physics. By exploiting the analogies between Dirac and lattice Boltzmann equations, we develop a quantum simulator based on pseudospin-boson quantum systems, which is suitable for encoding fluid dynamics transport phenomena within a lattice kinetic formalism. It is shown that both the streaming and collision processes of lattice Boltzmann dynamics can be implemented with controlled quantum operations, using a heralded quantum protocol to encode non-unitary scattering processes. The proposed simulator is amenable to realization in controlled quantum platforms, such as ion-trap quantum computers or circuit quantum electrodynamics processors.Comment: 8 pages, 3 figure

Sustainability and creativity through mail art: A case study with young artists in universities

Universities around the world are making considerable efforts to contribute to sustainable development through their institutional frameworks, education, research or community awareness. This article discusses how young artists connect with sustainability problems through an analysis of individual artistic creativity (visions, sources of inspiration, messages and communicative strategies) by means of a novel interpretive arts-based research methodology: mail art. A collection of mail art individually created by 29 young artists who also provide self-reports on the meaning of their work, the creation process and its intent are analyzed using a qualitative content analysis methodology complemented by an aesthetic inquiry into the artistic qualities and creative techniques of the collection. The research concludes that the collection reproduces but also produces messages promoting a sustainability culture. It promotes individual actions for sustainability with everyday creativity using expert knowledge and describes visions and attitudes expressed by young people to detect gaps and to develop a more informed education for sustainable development in universities. Although there are individual differences, the participants generally show appropriate values -such as universalism-, and a desire for ethical action within an ecocentric worldview, displaying constructive hope. However, the collection stands out for a collective, global and future-oriented, versus individual, local and present-oriented framing, running the risk of becoming visions that can delay transformative actions. Some of the most conclusive recommendations of the study are the need to work on the issues of equity and equality in universities today, to enhance the critical perspective of students and to change their current role from that of merely observers to agents for change. © 2021 The Author

Control of the geometric phase and pseudo-spin dynamics on coupled Bose-Einstein condensates

We describe the behavior of two coupled Bose-Einstein condensates in time-dependent (TD) trap potentials and TD Rabi (or tunneling) frequency, using the two-mode approach. Starting from Bloch states, we succeed to get analytical solutions for the TD Schroedinger equation and present a detailed analysis of the relative and geometric phases acquired by the wave function of the condensates, as well as their population imbalance. We also establish a connection between the geometric phases and constants of motion which characterize the dynamic of the system. Besides analyzing the affects of temporality on condensates that differs by hyperfine degrees of freedom (internal Josephson effect), we also do present a brief discussion of a one specie condensate in a double-well potential (external Josephson effect).Comment: 1 tex file and 11 figures in pdf forma

Pion and Kaon Decay Constants: Lattice vs. Resonance Chiral Theory

The Lattice results for the pion and kaon decay constants are analysed within the Resonance Chiral Theory framework in the large NC limit. The approximately linear behaviour of the observable at large light-quark mass is explained through the interaction with the lightest multiplet of scalar resonances. The analysis of the Lattice results allows to obtain the resonance mass MS=1049 +- 25 MeV and the Chiral Perturbation Theory parameters at leading order in 1/NC.Comment: 10 pages, 2 figure

Time resolved pattern evolution in a large aperture laser

We have measured quasi-instantaneous transverse patterns in a broad aperture laser. Non-ordered patterns yielding to boundary determined regular structures in progressive time-integrated recording are observed. The linear analysis and numerical integration of the full Maxwell-Bloch equations allow us to interpret the features of the experiment. We show that this system being far from threshold cannot be fully understood with a perturbative model.Comment: 7 pages, 5 GIF figures . To be published in Phys. Rev. Let