Electromagnetic Decays of Heavy Baryons

The electromagnetic decays of the ground state baryon multiplets with one heavy quark are calculated using Heavy Hadron Chiral Perturbation Theory. The M1 and E2 amplitudes for S^{*}--> S gamma, S^{*} --> T gamma and S --> T gamma are separately computed. All M1 transitions are calculated up to O(1/Lambda_chi^2). The E2 amplitudes contribute at the same order for S^{*}--> S gamma, while for S^{*} --> T gamma they first appear at O(1/(m_Q \Lambda_\chi^2)) and for S --> T gamma are completely negligible. The renormalization of the chiral loops is discussed and relations among different decay amplitudes are derived. We find that chiral loops involving electromagnetic interactions of the light pseudoscalar mesons provide a sizable enhancement of these decay widths. Furthermore, we obtain an absolute prediction for the widths of Xi^{0'(*)}_c--> Xi^{0}_c gamma and Xi^{-'(*)}_b--> Xi^{-}_b gamma. Our results are compared to other estimates existing in the literature.Comment: 17 pages, 3 figures, submitted to Phys. Rev.

Quantum walks: a comprehensive review

Quantum walks, the quantum mechanical counterpart of classical random walks, is an advanced tool for building quantum algorithms that has been recently shown to constitute a universal model of quantum computation. Quantum walks is now a solid field of research of quantum computation full of exciting open problems for physicists, computer scientists, mathematicians and engineers. In this paper we review theoretical advances on the foundations of both discrete- and continuous-time quantum walks, together with the role that randomness plays in quantum walks, the connections between the mathematical models of coined discrete quantum walks and continuous quantum walks, the quantumness of quantum walks, a summary of papers published on discrete quantum walks and entanglement as well as a succinct review of experimental proposals and realizations of discrete-time quantum walks. Furthermore, we have reviewed several algorithms based on both discrete- and continuous-time quantum walks as well as a most important result: the computational universality of both continuous- and discrete- time quantum walks.Comment: Paper accepted for publication in Quantum Information Processing Journa

Cost-effective SU-8 micro-structures by DUV excimer laser lithography for label-free biosensing

Cost-effective SU-8 micro-structures on a silicon substrate were developed using 248 nm excimer laser KrF projection, studying the influence of the different variables on the final pattern geometry, finding out that the most critical are exposure dose and post-bake condition. Also a novel and cost effective type of photomask based on commercial polyimide Kapton produced by 355 nm DPSS laser microprocessing was developed, studying the influence of the cutting conditions on the photomask. Finally, as a likely application the biosensing capability with a standard BSA/antiBSA immunoassay over a 10 × 10 micro-plates square lattice of around 10 ¿m in diameter, 15 ¿m of spacing and 400 nm in height was demonstrated, finding a limit of detection (LOD) of 33.4 ng/ml which is in the order of magnitude of bioapplications such as detection of cortisol hormone or insulin-like growth factor. Low cost fabrication and vertical interrogation characterization techniques lead to a promising future in the biosensing technology field. © 2010 Elsevier B.V. All rights reserved.Funding for the study was provided by the Spanish Ministry of Science and Innovation under BIOPSIA project no. TEC2008-06574-C03.Sanza, FJ.; Laguna, MF.; Casquel Del Campo, R.; Holgado, M.; Angulo Barrios, C.; Ortega Higueruelo, FJ.; López-Romero, D.... (2011). Cost-effective SU-8 micro-structures by DUV excimer laser lithography for label-free biosensing. Applied Surface Science. 257(12):5403-5407. https://doi.org/10.1016/j.apsusc.2010.10.010S540354072571

Bio-Photonic Sensing Cells over transparent substrates for anti-gestrinone antibodies biosensing

[EN] In a previous work we introduced the term Bio-Photonic Sensing Cells (BICELLs), referred to periodic networks of nano-pillar suitable for biosensing when are vertically interrogated. In this article, we demonstrate the biosensing capabilities of a type of micrometric size BICELLs made of SU-8 nano-pillars fabricated over transparent substrates. We verify the biochips functionality comparing the theoretical simulations with the experimental results when are optically interrogated in transmission. We also demonstrate a sensitivity enhancement by reducing the pitch among nano-pillars from 800 to 700. nm. Thus, the Limit of Detection achievable in these types of BICELLs is in the order of 64. pg/mL for 700. nm in pitch among nano-pillars in comparison with 292. pg/mL for 800. nm in pitch when are interrogated by Fourier Transform Visible and Infrared Spectrometry. The experiments exhibited a good reproducibility with a relative standard deviation of 0.29% measured within 8 days for a specific concentration. Finally, BICELLs functionality was tested in real conditions with unpurified rabbit serum for detecting anti-gestrinone antibodies, demonstrating the high performance of this type of BICELLs to detect specific antibodies having immobilized the suitable bioreceptors onto the sensing surface. © 2011 Elsevier B.V.This work is done within the support of the Spanish Ministry of Science and Innovation under project BIOPSIA (REF: TEC2008-06574). The authors thanks the Comunidad de Madrid and Universidad Politecncia de Madrid (Project BIO-VERSATIL, Ref CCG10-UPM/SEM-5096), Generalitat Valenciana (project ACOMP/2010/009 and PROMETEO 2010/008) and Dr Eva Brun for providing the rabbit serum containing polyclonal antibodies for gestrinone studies. F.J.O. is grateful to the Generalitat Valenciana for the postdoctoral grant included in the VALi + d 2010 Programme for Postdoctoral Researchers.Sanza, F.; Holgado, M.; Ortega Higueruelo, FJ.; Casquel Del Campo, R.; López-Romero, D.; Bañuls Polo, MJ.; Laguna, MF.... (2011). Bio-Photonic Sensing Cells over transparent substrates for anti-gestrinone antibodies biosensing. Biosensors and Bioelectronics. 26:4842-4847. https://doi.org/10.1016/j.bios.2011.06.010S484248472