Dynamically tunable transformation thermodynamics

Recently, the introduction of transformation thermodynamics has provided a way to design thermal media that alter the flow of heat according to any spatial deformation, enabling the construction of novel devices such as thermal cloaks or concentrators. However, in its current version, this technique only allows static deformations of space. Here, we develop a space-time theory of transformation thermodynamics that incorporates the possibility of performing time-varying deformations. This extra freedom greatly widens the range of achievable effects, providing an additional degree of control for heat management applications. As an example, we design a reconfigurable thermal cloak that can be opened and closed dynamically, therefore being able to gradually adjust the temperature distribution of a given region.C G-M acknowledges support from Generalitat Valenciana through the VALi+d postdoctoral program (exp APOSTD/2014/044).García Meca, C.; Barceló, C. (2016). Dynamically tunable transformation thermodynamics. Journal of Optics. 18(4):044026-1-044026-5. https://doi.org/10.1088/2040-8978/18/4/044026S044026-1044026-5184Guenneau, S., Amra, C., & Veynante, D. (2012). Transformation thermodynamics: cloaking and concentrating heat flux. Optics Express, 20(7), 8207. doi:10.1364/oe.20.008207Schittny, R., Kadic, M., Guenneau, S., & Wegener, M. (2013). Experiments on Transformation Thermodynamics: Molding the Flow of Heat. Physical Review Letters, 110(19). doi:10.1103/physrevlett.110.195901McCall, M. W., Favaro, A., Kinsler, P., & Boardman, A. (2011). A spacetime cloak, or a history editor. Journal of Optics, 13(2), 029501-029501. doi:10.1088/2040-8978/13/2/029501Cummer, S. A., & Thompson, R. T. (2010). Frequency conversion by exploiting time in transformation optics. Journal of Optics, 13(2), 024007. doi:10.1088/2040-8978/13/2/024007García-Meca, C., Carloni, S., Barceló, C., Jannes, G., Sánchez-Dehesa, J., & Martínez, A. (2013). Analogue Transformations in Physics and their Application to Acoustics. Scientific Reports, 3(1). doi:10.1038/srep02009García-Meca, C., Carloni, S., Barceló, C., Jannes, G., Sánchez-Dehesa, J., & Martínez, A. (2014). Space–time transformation acoustics. Wave Motion, 51(5), 785-797. doi:10.1016/j.wavemoti.2014.01.008Kinsler, P., & McCall, M. W. (2014). Transformation devices: Event carpets in space and space-time. Physical Review A, 89(6). doi:10.1103/physreva.89.063818Kinsler, P., & McCall, M. W. (2013). Cloaks, editors, and bubbles: applications of spacetime transformation theory. Annalen der Physik, 526(1-2), 51-62. doi:10.1002/andp.201300164Leonhardt, U., & Philbin, T. G. (2006). General relativity in electrical engineering. New Journal of Physics, 8(10), 247-247. doi:10.1088/1367-2630/8/10/247Guenneau, S., & Puvirajesinghe, T. M. (2013). Fick’s second law transformed: one path to cloaking in mass diffusion. Journal of The Royal Society Interface, 10(83), 20130106. doi:10.1098/rsif.2013.0106Guenneau, S., Petiteau, D., Zerrad, M., Amra, C., & Puvirajesinghe, T. (2015). Transformed Fourier and Fick equations for the control of heat and mass diffusion. AIP Advances, 5(5), 053404. doi:10.1063/1.4917492García-Meca, C., Carloni, S., Barceló, C., Jannes, G., Sánchez-Dehesa, J., & Martínez, A. (2014). Analogue transformation acoustics and the compression of spacetime. Photonics and Nanostructures - Fundamentals and Applications, 12(4), 312-318. doi:10.1016/j.photonics.2014.05.001Schittny, R., Kadic, M., Buckmann, T., & Wegener, M. (2014). Invisibility cloaking in a diffusive light scattering medium. Science, 345(6195), 427-429. doi:10.1126/science.1254524Chester, M. (1963). Second Sound in Solids. Physical Review, 131(5), 2013-2015. doi:10.1103/physrev.131.2013Ali, Y. M., & Zhang, L. C. (2005). Relativistic heat conduction. International Journal of Heat and Mass Transfer, 48(12), 2397-2406. doi:10.1016/j.ijheatmasstransfer.2005.02.003López Molina, J. A., Rivera, M. J., & Berjano, E. (2014). Fourier, hyperbolic and relativistic heat transfer equations: a comparative analytical study. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 470(2172), 20140547. doi:10.1098/rspa.2014.0547Christov, C. I., & Jordan, P. M. (2005). Heat Conduction Paradox Involving Second-Sound Propagation in Moving Media. Physical Review Letters, 94(15). doi:10.1103/physrevlett.94.154301Cho, J., Losego, M. D., Zhang, H. G., Kim, H., Zuo, J., Petrov, I., … Braun, P. V. (2014). Electrochemically tunable thermal conductivity of lithium cobalt oxide. Nature Communications, 5(1). doi:10.1038/ncomms5035Ihlefeld, J. F., Foley, B. M., Scrymgeour, D. A., Michael, J. R., McKenzie, B. B., Medlin, D. L., … Hopkins, P. E. (2015). Room-Temperature Voltage Tunable Phonon Thermal Conductivity via Reconfigurable Interfaces in Ferroelectric Thin Films. Nano Letters, 15(3), 1791-1795. doi:10.1021/nl504505

Detecting new physics contributions to the D0-D0bar mixing through their effects on B decays

New physics effects may yield a detectable mass difference in the D0-D0bar system, Delta m_D. Here we show that this has an important impact on some B --> D decays. The effect involves a new source of CP violation, which arises from the interference between the phases in the B --> D decays and those in the D0-D0bar system. This interference is naturally large. New physics may well manifest itself through Delta m_D contributions to these B decays.Comment: 10 pages, Revtex, no figures. To appear in PR

Exciting surface plasmons with transformation media

The final publication is available at Springer via http://dx.doi.org/10.1007/s11468-012-9361-5We present a way of exciting surface plasmon polaritons along non-patterned metallic surfaces by means of a flat squeezing slab designed with transformation optics. The slab changes the dispersion relation of incident light, enabling evanescent coupling to propagating surface plasmons. Unlike prism couplers, the proposed device does not introduce reflections at its input interface. Moreover, its compact geometry is suitable for integration. A feasible dielectric implementation of the coupler is suggested. Finally, we show that the angular response of the device can be engineered by using a non-uniform compression factor. As an example, we design a coupler with a half-power angular bandwidth 2. 5 times higher than that of a conventional dielectric coupler. © 2012 Springer Science+Business Media, LLC.Financial support by Spanish Ministerio de Ciencia e Innovacion (contracts CSD2008-00066 and TEC2008-06871-C02, and FPU grant) is gratefully acknowledged.García Meca, C.; Ortuño Molinero, R.; Martí Sendra, J.; Martínez Abietar, AJ. (2012). Exciting surface plasmons with transformation media. Plasmonics. 7(4):701-707. https://doi.org/10.1007/s11468-012-9361-5S70170774Raether H (1988) Surface plasmons on smooth and rough surfaces and on gratings. Springer-Verlag, BerlinBarnes WL, Dereux A, Ebbesen TW (2003) Surface plasmon subwavelength optics. Nature 424:824–830Maier SA (2007) Plasmonics: fundamentals and applications. Springer, New YorkSchuller JA, Barnard ES, Cai W, Jun YC, White JS, Brongersma ML (2010) Plasmonics for extreme light concentration and manipulation. Nat Mater 9:193–204Brongersma ML, Shalaev VM (2010) The case for plasmonics. Science 328:440–441Liu Y, Zentgraf T, Bartal G, Zhang X (2010) Transformational plasmon optics. Nano Lett 10:1991–1997Huidobro PA, Nesterov ML, Martín-Moreno L, García-Vidal FJ (2010) Transformation optics for plasmonics. Nano Lett 10:1985–1990Kadic M, Guenneau S, Enoch S (2010) Transformational plasmonics: cloak, concentrator and rotator for SPPs. Opt Express 18:12027–12032Zhang J, Xiao S, Wubs M, Mortensen NA (2011) Surface plasmon wave adapter designed with transformation optics. ACS Nano 5:4359–4364Pendry JB, Schurig D, Smith DR (2006) Controlling electromagnetic fields. Science 312:1780–1782Leonhardt U (2006) Optical conformal mapping. Science 312:1777–1780Leonhardt U, Philbin TG (2006) General relativity in electrical engineering. New J Phys 8:247Sambles JR, Bradbery GW, Yang F (1991) Optical excitation of surface plasmons: an introduction. Contemp Phys 32:173–183Rahm M, Roberts DA, Pendry JB, Smith DR (2008) Transformation-optical design of adaptive beam bends and beam expanders. Opt Express 16:11555–11567Vasic B, Isic G, Gajic R, Hingerl K (2009) Coordinate transformation based design of confined metamaterial structures. Phys Rev B 79:85103Tichit P, Burokur SN, Lustrac A (2009) Waveguide taper engineering using coordinate transformation technology. Opt Express 18:767–772Zang X, Jiang C (2010) Manipulating the field distribution via optical transformation. Opt Express 18:10168–10176García-Meca C, Tung MM, Galán JV, Ortuño R, Rodríguez-Fortuño FJ, Martí J, Martínez A (2011) Squeezing and expanding light without reflections via transformation optics. Opt Express 19:3562–3575Li J, Han S, Zhang S, Bartal G, Zhang X (2009) Designing the Fourier space with transformation optics. Opt Lett 34:3128–3130Li J, Pendry JB (2008) Hiding under the carpet: a new strategy for cloaking. Phys Rev Lett 101:20390

Magnetic hot spots in closely spaced thick gold nanorings

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Nano Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/page/policy/articlesonrequest/index.htmlLigh-matter interaction at optical frequencies is mostly mediated by the electric component of the electromagnetic field, with the magnetic component usually being considered negligible. Recently, it has been shown that properly engineered metallic nanostructures can provide a magnetic response at optical frequencies originated from real or virtual flows of electric current in the structure. In this work, we demonstrate a magnetic plasmonic mode which emerges in closely spaced thick gold nanorings. The plasmonic resonance obtains a magnetic dipole character by sufficiently increasing the height of the nanorings. Numerical simulations show that a virtual current loop appears at resonance for sufficiently thick nanorings, resulting in a strong concentration of the magnetic field in the gap region (magnetic hot spot). We find that there is an optimum thickness that provides the maximum magnetic intensity enhancement (over 200-fold enhancement) and give an explanation of this observation. This strong magnetic resonance, observed both experimentally and theoretically, can be used to build new metamaterials and resonant loop nanoantennas at optical frequencies.This work has been supported by Spanish Government and European Union (EU) funds under contracts CSD2008-00066 and TEC2011-28664-C02-02 and Universitat Politecnica de Valencia (program INNOVA 2011). The authors extend special thanks to Mr. J. Ross Aitken for his contribution to this work.Lorente Crespo, M.; Wang, L.; Ortuño Molinero, R.; García Meca, C.; Ekinci, Y.; Martínez Abietar, AJ. (2013). Magnetic hot spots in closely spaced thick gold nanorings. Nano Letters. 13(6):2654-2661. https://doi.org/10.1021/nl400798sS2654266113

A nationwide pilot study on breast cancer screening in Peru

"Introduction: A high prevalence of advanced breast cancer (BC) is a common scenario in Latin America. In Peru, the frequency of BC at Stages III/IV is ≈50% despite implementation of a programme for breast cancer screening (BCS) along the country. We carried out a study to assess the feasibility and develop an instrument to evaluate the knowledge, barriers and perception about BCS in a nationwide pilot study in Peru among candidates for BCS. Methods: We conducted a systematic review of 2,558 reports indexed in PubMed, Scopus, Web of Science, Medline-Ovid and EMBASE, regarding to our study theme. In total, 111 were selected and a 51-items survey was developed (eight items about sociodemographic characteristics). Patients were recruited in public hospitals or private clinics, in rural and urban areas of nine departments of Peru. Results: We surveyed 488 women from: Lima (150), Cajamarca (93), Ica (59), Arequipa (56), Loreto (48), Ancash (38), Junín (15), Puerto Maldonado (15) and Huancavelica (14); 27.9% of them were from rural areas. The mean of age was 53.3 years (standard deviation ± 9.1). Regarding education level, 29.8% had primary, 33.2% secondary and 37.0% higher education. In total, 28.7% of women did not know the term ‘mammogram’ and 47.1% reported never receiving a BCS (36.9% from urban and 73.5% from rural population). In women that underwent BCS, only 67% knew it is for healthy women. In total, 54.1% of patients had low levels of knowledge about risk factors for BC (i.e. 87.5% of women respond that injuries in the breast produce cancer). Cultural, economic and geographic barriers were significantly associated with having a mammogram where 56.9% of participants considered a cost ≤ 7 USD as appropriate. Mammogram was perceived as too painful for 54.9% of women. In addition, women with a self-perception of low-risk for BC and a fatalistic perception of cancer were less likely to have a BCS. Conclusion: We found that it is feasible to conduct a large-scale study in Peru. The results of this pilot study highlight an urgent need of extensive education and awareness about BCS in Peru.

Terahertz metamaterials on flexible polypropylene substrate

The final publication is available at Springer via http://dx.doi.org/10.1007/s11468-014-9724-1In this work, we present a metamaterial working at terahertz frequencies made over a flexible polypropylene sub-strate. The experimental measurements, in accordance with the numerical calculations, show the metamaterial reliance on the impinging electric field polarization. The structure s symmetry yields purely electrical resonant responses eliminating bianisotropy effects. The widely used bendable polypropylene polymer may promote the insertion of metamaterial-based structures with special electromagnetic response in a number of objects of our daily lives such as textiles, automotive components, and sensingThis work was supported by the Spanish MICINN under contracts CONSOLIDER EMET CSD2008-00066 and TEC2011-28664-C02-02 and by the Universitat Politecnica de Valencia under the program INNOVA 2011.Ortuño Molinero, R.; García Meca, C.; Martínez Abietar, AJ. (2014). 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